Author name cluster

Tatsuo Arai

Possible papers associated with this exact author name in Arrow. This page groups case-insensitive exact name matches and is not a full identity disambiguation profile.

130 papers

1 author row

IROS Conference 2025 Conference Paper

Compact R-X-Y Stage and Dual-Finger Micromanipulator under Inverted Optical Microscope for Microassembly

Jichao Pang
Zhuo Chen 0006
Yan Chen
Yuke Li
Yunsheng Li
Qiang Huang 0002
Tatsuo Arai
Xiaoming Liu 0007

Microassembly plays an important role in fabricating complex structures with small basic components in industrial and biomedical fields. Inverted optical microscope could provide high-quality image feedback for microassembly with its continuously improving resolution. However, a compact stage capable of positioning and reorienting micro-objects while fitting within the limited space under an inverted optical microscope remains unavailable. This paper proposes a compact R-X-Y stage that can transport micro-objects over long distances in the X and Y directions, and reorient the objects by the 360-degree continuous rotation. Additionally, different from commonly putting the rotational stage on the X-Y stage, we mount the thin X-Y stage on a rotational stage. Thus, after aligning the centers of the visual field and rotational stage at the beginning, all the visiable micro-objects will not move out of the visual field during the rotation. We further integrate the R-X-Y stage and the dual-finger micromanipulator, and then use them to assemble 2-D patterns and complex 3-D micromachine. The obtained results and preliminary demonstration indicate that the proposed compact R-X-Y has great potential in assembling complex micromachines.

IROS Conference 2025 Conference Paper

Contactless and Economical Chemical Reaction Platform Based on Ultrasonic Field

Yunsheng Li
Qiao Wang
Yuyan Liu
Bo Yuan
Zhuo Chen
Qiang Huang 0002
Tatsuo Arai
Xiaoming Liu 0007

Chemical reactions constitute a cornerstone of fundamental scientific inquiry, yet traditional methodologies and platforms are encumbered by excessive reagent and consumable demands. Emerging alternatives, such as microfluidic systems, while innovative, suffer from intricate fabrication processes and elevated costs associated with operator training. Other contemporary approaches face limitations including reagent compatibility constraints and prohibitively expensive instrumentation. To address these challenges, this study introduces a contactless chemical reaction platform leveraging an ultrasonic vortex field to achieve stable capture, microscale droplet transport, and sequential multi-droplet mixing without direct contact. This platform substantially reduces contamination risks, minimizes reagent and consumable usage, accommodates a broad spectrum of reagent types, and imposes minimal demands on operator expertise. Demonstrating robust performance in microdose reaction control, the system offers significant potential for advancing chemical research and its applications.

IROS Conference 2025 Conference Paper

Design of DNA Origami-Engineered Tetrahedral Nanorobots

Haowen Chen
Fengyu Liu
Qiang Huang 0002
Tatsuo Arai
Xiaoming Liu 0007

During the past decade, DNA origami has emerged as a promising technology to construct DNA nanorobots with programmable configurations and excellent biocompatibility. However, existing DNA origami-based nanorobots exhibit weak stability in complex biological environments and lack efficient delivery capabilities when serving as drug carriers. This study introduces a reconfigurable tetrahedral DNA nanorobot, whose conformational transition pathways are validated by multi-resolution molecular dynamics simulations. Building on this, we systematically analyzed the structural stability of the tetrahedral nanorobot using multiple simulation methods. We then fabricated the specific molecule-triggered tetrahedral DNA nanorobot with high structural stability and efficient drug delivery capacity. The proposed nanorobot was further employed for the recognition and inhibition of circulating tumor cells. These results highlight the application potential of the proposed DNA origami-engineered nanorobot in biomedicine and nanosensing.

IROS Conference 2025 Conference Paper

DMPBot: A high-speed, high-precision, omnidirectional, insect-scale piezoelectric robot

Yan Chen
Shu Chen
Zheyu Yang
Pengyu Liu
Sicheng Chen
Ziru Deng
Junqi An
Qiang Huang 0002

Microrobots have garnered significant attention due to their vast potential applications across various fields. Among various types of microrobots, piezoelectric robots stand out due to their exceptional motion accuracy, low power consumption, and simple structural design. This work introduces a novel piezoelectric microrobot, the Dual-Modal Piezoelectric Robot (DMPBot), which is fabricated with an innovative carbon fiber substrate through a heat-pressing process with a compact size of 6 mm × 9 mm × 1. 1 mm and a weight of only 0. 05 g. DMPBot can achieve both high-speed and high-precision motion in non-resonant mode, as well as omnidirectional movement by integrating non-resonant and resonant modes. In non-resonant mode, the robot can reach a speed of 33 mm/s (3. 67 body lengths per second) and a sub-micron resolution of 0. 4 μm by adjusting the applied signal. This work presents an analysis of the design, fabrication, and performance of DMPBot, focusing on its dynamic response, motion mechanisms, high-speed and high-precision motion, and omnidirectional movement capabilities. Experimental results validate the ability of DMPBot to perform high-speed, high-precision, and omnidirectional motion, demonstrating its promising potential in the field of micromanipulation.

IROS Conference 2025 Conference Paper

Dual-Bubble Coordinated Acoustic Micromanipulator for Multidirectional Object Rotation *

Yuyang Li 0003
Zhongqiang Zhang
Chenglin Miao
Xu Du
Qiang Huang 0002
Tatsuo Arai
Xiaoming Liu 0007

Micromanipulation techniques struggle to achieve three-dimensional rotational control at the microscale without compromising biocompatibility or spatial flexibility. Conventional methods based on mechanical contact, optical forces, or confined microfluidics constrain dynamic reconfiguration and surgical accessibility. Here, we introduce a dual-bubble acoustic micromanipulator that enables multidirectional rotation through controlled hydrodynamic fields. By placing oscillating microbubbles at the tips of micropipettes, this system creates adjustable vortex patterns: a single microbubble generates toroidal flows for out-of-plane rotation, while two microbubbles produce shear forces for in-plane spinning. This approach uses simple mechanical adjustments to control rotational axes in open fluid environments, without needing frequency modulation or phase synchronization. Flow-field simulations and experiments with polystyrene microspheres confirm deterministic orientation control, and tests with shrimp embryos demonstrate rotation at clinically relevant speeds. The open architecture integrates seamlessly with standard microscopy and robotic injection systems, offering a non-contact, precise tool for applications such as polar body alignment, intracellular surgery, and 3-D imaging.

IROS Conference 2025 Conference Paper

Enhanced Rolling Motion of Magnetic Microparticles by Turning Interface Lubrication

Yuke Li
Xiyue Liang
Zhuo Chen 0053
Hongzhe Liao
Yue Zhao 0025
Masaru Kojima
Qiang Huang 0002
Tatsuo Arai

Micro-nano robots must break the symmetry of the flow field to generate net displacement in the low Reynolds number environment. The spherical micro-robots utilize the frictional forces generated through interaction with the surface. We designed a magnetic microroller robot powered by the rotating AC magnetic field. Here, we employed dual measurements of laser ranging and computer vision to demonstrate that a single 100 μm microroller maintains a lubrication film of 1 to 15 μm with the surface during normal motion. We found that the translational velocity of the microroller is correlated with the lubrication film thickness. Based on the robot's gravity, we controlled an additional downward gradient magnetic field to effectively increase the load of robot and reduce the lubrication film thickness, thereby controllably increasing the translational velocity of the robot. For example, the gradient magnetic field generated by superimposing a 30mA direct current input can reduce the lubrication film thickness from 8 μm to 4 μm in a 10 Hz rotating magnetic field, and increase the translational velocity from 230 μm/s to 460 μm/s. The enhancement of the robot's motion performance enables it to better control its movement in fluids. Finally, we validated the strategy for controllable acceleration of micro-scale particles rolling on surfaces, applied to control fluid motion in multiple arteries within blood vessels. These results offer deeper insights into the physical motion mechanism of surface robots and hold significant implications for future applications in biomedical engineering.

IROS Conference 2025 Conference Paper

Magnetically Actuated Steerable Catheter with Redundant DoF for Cardiovascular Interventions

Hongzhe Liao
Han Jin
Jialong Du
Xiyue Liang
Yuke Li
Qiang Huang 0002
Tatsuo Arai
Xiaoming Liu 0007

A magnetically controlled catheter system is proposed to enhance the precision and safety of vascular interventions by reducing procedure time and radiation exposure. The system can also function as a support channel for guidewire deployment. A novel navigation approach is introduced, employing an external permanent magnet capable of controlled rotation to actuate a catheter with an embedded magnetic tip. Leveraging magnetic coupling and a redundant rotational DoF, the system achieves fine angular tip control with minimal spatial displacement, significantly enhancing maneuverability in constrained vascular environments. The magnetic field distribution and its influence on catheter response are characterized, and a kinematic model of the actuation mechanism is established. Experimental validation is conducted under varying magnetic field strengths and orientations, demonstrating reliable steering performance. Application-based experiments in simulated clinical environments further confirm precise navigation capability. The results highlight the advantages of rotational magnetic control in enhancing flexibility and accuracy. The proposed system presents a promising solution for automating catheter-based interventions, offering improved efficiency and power in minimally invasive procedures.

IROS Conference 2025 Conference Paper

On-Chip Dynamic Mechanical Characterization: from Cells to Nucleus

Jingjin Ge
Zhuo Chen 0053
Chenhao Bai
Fengyu Liu
Yuke Li
Masaru Kojima
Qiang Huang 0002
Tatsuo Arai

Traditional single-cell mechanical characterization techniques (e. g. , atomic force microscopy) often face limitations in throughput, require invasive labeling, or fail to replicate physiological microenvironments, impeding their clinical utility for rapid cancer cell analysis. To address these limitations for automated characterization of cellular mechanical properties, this study proposes a novel method using microchannels with narrow geometric structures to measure cellular mechanical characteristics. A dynamic mechanical characterization technique with serially connected microchannels simulates malignant tumor cell deformation and migration in vivo, enabling precise identification of three malignant tumor cell lines and three normal cell lines through consecutive compressions. High-speed imaging combined with computer vision and image processing techniques facilitates rapid and accurate automated analysis for tumor cells. Furthermore, this study reveals that the mechanical properties of the cell nucleus determine the overall cellular mechanics, with the differences between tumor and normal cells attributed to variations in nucleus mechanics. This approach shows promise for early cancer diagnosis.

ICRA Conference 2024 Conference Paper

Acoustically Driven Micropipette for Hydrodynamic Manipulation of Mouse Oocytes

Zhaofeng Zuo
Xiaoming Liu 0007
Zhuo Chen 0053
Yuyang Li 0003
Xiaoqing Tang
Dan Liu 0009
Qiang Huang 0002
Tatsuo Arai

Micromanipulation techniques that can achieve controlled fine operations at the micro scale play an important role in biomedical fields including embryo engineering, gene engineering, drug screening, and cell analysis. However, micromanipulation of biological micro-objects, such as cells and micro tissues, suffers from mechanical damage and low efficiency. Several techniques have been introduced to manipulate cells more easily, but most of them are restricted by expensive devices, limited work area, and potential damage to cellular structure. Here we develop a hydrodynamic manipulation method to rotate and transport mouse oocytes, which utilizes acoustic waves and micropipette to generate acoustic radiation force and excite microstreaming. This method can accomplish rotational and translational operations precisely and controllably. We tested the process of trapping, rotation, and transportation of the mouse oocytes, and measured rotational and translational speed with a range of applied voltage. The method was able to shorten the cost time of delivery and posture adjustment before oocyte injection. Our study provides an easy-to-use technique for oocyte manipulation without contact, and it has the potential to be universally applied in many cellular studies.

ICRA Conference 2024 Conference Paper

Automated Assembly by Two-Fingered Microhand for Fabrication of Soft Magnetic Microrobots

Yue Zhao 0025
Xiaoming Liu 0007
Ruixi Wang
Dan Liu 0009
Masaru Kojima
Qiang Huang 0002
Tatsuo Arai

Micro-assembly is an emerging method to fabricate microrobots with multiple modules or particles. However, there is always a lack of a flexible and efficient method to freely create the desired magnetic soft microrobots. In this paper, an automated assembly system based on a two-fingered microhand is presented for fabricating magnetic soft microrobots. Our proposed system can automatically pick and place components to assemble microrobots with a two-fingered micromanipulator, and orient these components through an external magnetic field. The automated assembly has the advantages of high accuracy, high speed, and high success rate. It can endow magnetic microrobots with flexible material selection, arbitrary geometry design, and programable magnetization profile. We can make full use of this system to fabricate multiple magnetic soft microrobots. The experiment results demonstrate that this system can efficiently fabricate microrobots with excellent mechanical properties, which have application potential in robotics, biomedical engineering, and environmental governance.

ICRA Conference 2024 Conference Paper

Development of a 3-RRS Micromanipulator Based on Origami-Inspired Spherical Joint

Haoqi Han
Xiaoming Liu 0007
Yan Chen
Hao Pang
Xiaoqing Tang
Dan Liu 0009
Qiang Huang 0002
Tatsuo Arai

In recent years, micromanipulation technology has achieved extensive applications in industry and life science. Improving the precision and bandwidth of the micromanipulator and simultaneously reducing size, weight, and cost pose significant challenges to the existing micromanipulator design and fabrication methods. Here, we propose a 3-RRS micromanipulator with an origami-inspired spherical joint based on the PC-MEMS process, aiming for miniaturization and cost-effectiveness. The spherical joint allows rotations of 140° around the x-axis approximately, 140° around the y-axis approximately, and 20° around the z-axis approximately. The micromanipulator has weights of 0. 8 g, dimensions of 16 mm × 16 mm × 22 mm, and workspace of 0. 7 mm 3. The end platform of the micromanipulator can be equipped with various effectors to accomplish different kinds of tasks. Experimental results validated its high precision and bandwidth, exhibiting its potential to perform intricate micromanipulation tasks.

IROS Conference 2023 Conference Paper

Programable On-Chip Fabrication of Magnetic Soft Micro-Robot

Yuke Li
Xiaoqing Tang
Xiaoming Liu 0007
Dan Liu 0009
Zhuo Chen 0053
Masaru Kojima
Qiang Huang 0002
Tatsuo Arai

In the last decade, researchers have been trying to develop many microrobots that mimic the extraordinary abilities of bionts in complex environments. How to fabricate the biomimetic microrobot with satisfying deformability and complex shapes to realize desired precise motion is the key issue. In this paper, we proposed an efficient programable fabrication method of the magnetic soft micro-robot through an on-chip photopolymerization system. The superparamagnetic nanoparticles were compiled according to the magnetic anisotropy and assembled in the micro-robot. Then these nanoparticles were immobilized by photopolymerization of the hydrogel polymer. With this fabrication method, a joint rotation mechanism was first fabricated to characterize the deformation performance under the magnetic field control. Besides, the snake-like micro-robot were also fabricated, and the desired motions were achieved. The experimental results show that the proposed programable on-chip fabrication of magnetic soft micro-robot has the potential to facilitate the development of magnetic microrobots and their applications in the biomedical field.

IROS Conference 2022 Conference Paper

Controlled Fabrication of Micro-Chain Robot Using Magnetically Guided Arraying Microfluidic Devices

Xiaoqing Tang
Xiaoming Liu 0007
Yuyang Li 0003
Dan Liu 0009
Yuke Li
Masaru Kojima
Qiang Huang 0002
Tatsuo Arai

The magnetic microrobot has become a promising approach in many biomedical applications due to its small volume, flexible motion, and untethered micromachines. The micro-chain robot is one of the most popular magnetic microrobots. However, the uncontrollable magnetic moment direction and quantity of the magnetic beads consisted in the existing self-assembled micro-chain robot limit their locomotion and applications. This paper proposed an on-chip micro-chain robot fabrication method to assemble the magnetic beads with controllable magnetic moment direction and quantity. The bead quantity can be controlled by the structure limits of the microchannel, and the direction of the magnetic moment can be adj usted by the integrated external magnetic field. The assembled magnetic beads are then glued by the hydrogel under UV exposure. The micro-chain robots with different quantities and magnetic moment directions of the magnetic beads were successfully fabricated and tested in experiments. Due to the array structure of the microfluidic device, batch manufacturing of low-cost magnetic robots was achieved in our method. The movement of dual-bead microrobots with two orthogonal magnetic moment directions was analyzed and compared. One of the dual-bead microrobots was applied in the transportation of the hydrogel module using pushing and pulling modes. It indicated that the proposed controllable on-chip fabrication of the magnetic micro-chain robots has the potential to enhance the microrobot ability in biomedical applications.

ICRA Conference 2020 Conference Paper

Automated Tracking System with Head and Tail Recognition for Time-Lapse Observation of Free-Moving C. elegans

Shengnan Dong
Xiaoming Liu 0007
Pengyun Li
Xiaoqing Tang
Dan Liu 0009
Masaru Kojima
Qiang Huang 0002
Tatsuo Arai

In this paper, an automated tracking system with head and tail recognition for time-lapse observation of free-moving C. elegans is presented. In microscale field, active C. elegans can move out of the view easily without an automated tracking system because of the narrow field of view and rapid speed of C. elegans. In our previous works, we constructed an automated platform with 3D freedom to track centroid region of the nematode successfully. However, tracking time was not long enough to support a full time-lapse observation. Our proposed system in this study integrate the detection method in horizontal plane with depth evaluation more tightly. Tracking time and response speed have been greatly improved. Besides, we make full use of curvature calculation to make the system recognize the head and tail of C. elegans and the recognition rate can be up to 95%. The results demonstrate that the system can fully achieve automated long-term tracking of a free-living nematode and will be a nice tool for C. elegans behavioral analysis.

IROS Conference 2019 Conference Paper

Automatic Cell Assembly by Two-fingered Microhand

Junnan Chen
Xiaoming Liu 0007
Shengnan Dong
Pengyun Li
Xiaoqing Tang
Dan Liu 0009
Masaru Kojima
Qiang Huang 0002

We have successfully achieved manipulation and assembly of microbeads having the size of 100μm diameter by hemispherical end-effectors with high stability and accuracy. The motivation of achieving assembly of actual cells lies in the great significance of it in tissue regeneration and cell analysis. Firstly, the most difficult problem we need to solve is the releasing problem caused by adhesion force. The viscosity on cell surface is much larger than the microbeads which makes cell releasing challenging. Secondly, the cell can generate its deformation, then contact area with end-effector will change during grasping process. This may influence the adhesion force and also bring problem to releasing. Thirdly, cell is much smaller, around 15μm in diameter, so we need to fabricate smaller end-effector to achieve successful manipulation and ensure the stability in the meantime. In this paper, we realize the manipulation by decreasing the adhesion forces and apply vibration to release a cell stably. We found the appropriate scale size for the end-effector is around 10μm diameter. It can not only grasp a 15μm cell but also bring little interference to the environment. As a demonstration of the proposed manipulation method, the repeated experiments were conducted to explore the dependence of adhesion force on the grasping distance, which can be helpful in the improvement of successful rate. Finally, we achieved automatic cell assembly using Hela cells.

ICRA Conference 2019 Conference Paper

Capillary Ionic Transistor and Precise Transport Control for Nano Manipulation

Yuqing Lin 0003
Xiaoming Liu 0007
Tatsuo Arai

Capillary Ionic Transistor (CIT) is introduced as a nanodevice which provides control of ionic transport through nanochannel by gate voltage. CIT is Ionic transistor which employs pulled capillary as nanochannel with tip diameter smaller than 100 nm. We observed that gate voltage applied to gate electrode, deposited on the outer wall of capillary, affect a conductance of nanochannel, due to change of surface charge at the solution/capillary interface. Negative gate voltage corresponds to lower conductivity and positive gate increase conductance of the channel. This effect strongly depends on the size of the channel. In general, at least one dimension of the channel has to be small enough for electrical double layer to overlap. As a demonstration of the gate control ability, we performed Si nanoparticle delivery via CIT and recorded the deliverance through resistive pulse method. Size and velocity measurement are also conducted, to showcase the versatility of CIT device.

IROS Conference 2018 Conference Paper

Friendly Motion Learning towards Sustainable Human Robot Interaction

Shuhei Sato
Hiroko Kamide
Yasushi Mae
Masaru Kojima
Tatsuo Arai

For generating interactive behavior of robot to build a long-term relationship between humans and robots, we focus on the difference in familiarity of the human behaviors during conversation. It is difficult to extract interaction motion features correlated to such familiarity as a model in manual. Therefore, we use a machine learning technique: convolution neural network to learn and generate interaction behavior with different familiarity. In the evaluation experiment, we generated interaction behavior using a convolution neural network, which learned from the behaviors of friendship and unknown relationship, who have high and low familiarity respectively. We evaluated how much such interaction behavior affect the human impression by questionnaire survey.

IROS Conference 2018 Conference Paper

Resistive Pulse Study of Liposome Stability: Towards Precision and Efficient Drug Delivery

Yuqing Lin 0003
Xiaoming Liu 0007
Tatsuo Arai

In this work, the authors report the investigation of liposomes' stability as a drug delivery vehicle, using the method of resistive pulse method. The main objects of interest are the 50nm diameter liposomes, while the 100nm diameter liposomes are widely used for its stability. However, certain drug delivery scenarios arise, like tighter cancerous tissue arrangement and different circulation time requirement, which dictates the necessity of sub-100nm diameter vesicles. The size measurements upon freshly fabricated liposomes are performed frequently on increasing time interval. The results exhibit a trend of size increasing, suggesting the existence of liposome fusion. The possible models of fusion are proposed and discussed. This work demonstrates the localized organic nanoparticle measurement with fine dual 3D manipulator positioning, which paves the way for the possible cellular in-vivo measurement within an environmental SEM chamber.

ICRA Conference 2017 Conference Paper

Non-contact transportation and rotation of micro objects by vibrating glass needle circularly under water

Xiaoming Liu 0007
Masaru Kojima
Qing Shi
Huaping Wang
Tao Sun 0001
Yasushi Mae
Qiang Huang 0002
Tatsuo Arai

In micromanipulation, lots of methods have been developed to manipulate objects in microscale. However, few of them can be applied in both the transportation and the rotation of the micro objects. In this paper, we present a novel method to realize the non-contact transportation and rotation of the micro objects based on the vibration-induced swirl flow. A piezo actuator is set between the glass needle and a metal rod. The sine wave with controlled frequency and amplitude is input into the piezo actuator to drive the glass needle to move circularly, which is caused by resonance of the actuator and the metal rod. We place the glass needle under water and keep a limited distance to the bottom. The circular vibration of the glass needle can generate a swirl flow and low pressure around it. The low pressure can trap and transport the micro objects vertically to the glass needle, and the swirl flow can rotate the objects continuously. Finally, we realize the trap and rotation of micro object with only one piezo actuator. Experiments of transportation and rotation of microbeads are carried out, and the results demonstrate it is a simple, low-cost, effective micromanipulation method.

IROS Conference 2016 Conference Paper

Accurate releasing of biological cells using two release methods generated by high speed motion of an end effector

Eunhye Kim 0003
Masaru Kojima
Kazuto Kamiyama
Mitsuhiro Horade
Yasushi Mae
Tatsuo Arai

The reliable manipulation of micro-objects has been a still difficult work in scientific and technical field due to scale effects. This paper presents two types of release methods, using local stream and inertia force generated by 3D high speed motion of an end effector, for releasing and accurate positioning of biological cells. Two-fingered microhand driven by DC motors for both end effectors and PZT actuators for right end effector is employed. A parallel mechanism controlled by three PZT actuators generates 3D high speed motions to release cells adhered to one of the end effector. The local stream and inertia force created by high speed motion of the right end effector detach the cells adhered to the left end effector and right end effector, respectively. To generate the necessary external forces for separation of the attached cells, the vibration having high frequency and suitable amplitude is applied. For accurate positioning of the object, circular motions are proposed. To verify the advantage of the proposed motion, we compare five motions, three 1D motions and two circular motions. Experiments were conducted employing 16μm NIH3T3 cells. From these analyses of experiments, we conclude that the proposed motions can detach micro objects (100%) with high position accuracy (3±0. 7μm) on desired position after release.

IROS Conference 2016 Conference Paper

Fault-tolerant adaptive gait generation for multi-limbed robot

Takeyuki Kawata
Kazuto Kamiyama
Masaru Kojima
Mitsuhiro Horade
Yasushi Mae
Tatsuo Arai

The paper describes a method of fault-tolerant adaptive gait generation based on CPG controller with interlimb coordination for multi-limbed working robot. Multi-limbed robot is expected to work in dangerous, complicated narrow spaces, where human workers cannot reach. However, if one of the limbs is broken in the dangerous/narrow working space, human operators cannot go to the space to repair it. Even in these situations, the proposed method generates a new gait adaptively using the remaining usable limbs depending on the current situation of the multi-limbed robot. This fault-tolerant ability is effective for multi-limbed robots working in dangerous/narrow space. The method is implemented to a model of a multi-limbed robot “ASTERISK” in a dynamical simulator (ODE). Experimental results show effectiveness of the proposed method.

ICRA Conference 2016 Conference Paper

Micro-hand positioning in consideration of the obstacle avoidance and the grasping part by using the automatic stage

Kotaro Yamamoto
Masaru Kojima
Mitsuhiro Horade
Kazuto Kamiyama
Yasushi Mae
Tatsuo Arai

Recently, manipulation and observation of the cells are actively conducted in order to analyze the biological phenomena. Since the micro hand is usually fixed to the work environment, grasping target point of the cell on the opposite side of the micro hand by using a micro hand is limited by narrow workspace. If we move the micro hand in vertical direction to grasp the target point of the cell on the opposite side of the micro hand, we cannot focus the micro hand and the object in the microscopic field of view at the same time. In order to overcome the limitations of the limited workspace of micro hand, we assist the target point of the cell grasped by translation and rotation of the automatic stage. In this paper, we propose an automatic stage system for support the operation of the micro hand. Our automatic stage system can detect the object in the microscopic field of view by the template matching using Hu moment invariant and determine the grasping convex part of the object. by convex hull. Additionally this system can do 2d path planning considering convex part of the object to want to grasp and obstacles, and lead the micro hand to the object.

ICRA Conference 2015 Conference Paper

Development of a real-time local environment stimulation system with visual feedback control

Takahiro Motoyoshi
Masaru Kojima
Kenichi Ohara
Mitsuhiro Horade
Kazuto Kamiyama
Yasushi Mae
Tatsuo Arai

Single cell analysis has attracted much attention for revealing detailed and localized biological information. A local environmental control technique is desired when analyzing the detailed and localized properties of single cells. In this paper, we propose a local environmental stimulation system with micro dual-pipettes to stimulate the local reagent concentration dynamically, freely and automatically. When the local environment is controlled with chemical stimuli, the chemical solution is diffused and affects other objects. The local environment stimulation system with micro dual-pipettes can solve this problem by using spout pipette and suction pipette. As a cell analysis system, system quantification is necessary, so we try to realize it using a fluorescent substance. First step, we try to measure and control the light intensity. As an application of the system, the system can construct two-dimensional cell-organization by peeling off certain area of cell-sheet. Therefore, we try to control the area of peeling off cells using the system.

IROS Conference 2015 Conference Paper

Development of thermos responsive gel coated end effector for micro manipulation

Hideaki Saijo
Masaru Kojima
Mitsuhiro Horade
Kazuto Kamiyama
Yasushi Mae
Tatsuo Arai

In the field of medicine and biology, many studies to be related to regenerative medicine are accomplished. In particular, the purpose of helping the operation of the cells under a microscope, many research related to micro manipulation techniques with robotic technology has been proposed. In such background, we studied two finger micro hand that realized control of the sub-micro order size object. The accurate operation of the end effector against the object by the micro hand is demanded to users. To reduce the burden, we focus on making the manipulation easy. User can perform micro manipulation with rough operation by using the actuator that varies in size. Since the actuator fills space between the end effectors and the object. Then we focus on the gel that varies in size. In this paper, we evaluate the gel that varies in size. Then we propose the manipulation that take advantage of the gel.

IROS Conference 2015 Conference Paper

Generation of swirl flow by needle vibration for micro manipulation

Takayuki Hattori
Kazuto Kamiyama
Masaru Kojima
Mitsuhiro Horade
Yasushi Mae
Tatsuo Arai

Recently micro manipulation techniques for cell or microorganism has attracted attention in life sciences. In this paper, non-contact manipulation method using water stream is proposed. Water stream is generated by a glass needle vibration that is actuated by a piezoelectric actuator. The stream is controlled by changing input voltage or frequency to the actuator. An accuracy of the motion of a piezoelectric actuator is in nano-meter order, so the stream is considered to be controlled precisely. The manipulator works in 3 dimensional space, that means water stream is generated in 3d space. We focused on the rotational stream generated by the glass needle 2-dimensional circular vibration. By using the resonance in a structure of the manipulator and the actuator's vibration, circular vibration can be generated by only one actuator. There is no need to use two actuators for generating circular vibration, so the structure of the manipulator is quite simple. In this paper rotational stream around the glass needle is also analyzed in 3d space using micro beads. This manipulator has the similar characteristics to the existing research of contact manipulation, so we think our method also have the capability to conduct contact manipulation.

IROS Conference 2015 Conference Paper

Releasing and accurate placing of adhered micro-objects using high speed motion of end effector

Eunhye Kim 0003
Masaru Kojima
Kazuto Kamiyama
Mitsuhiro Horade
Yasushi Mae
Tatsuo Arai

This paper presents an active release method of microobject for the improvement of the position accuracy after releasing by using 3D high speed motions of an end effector. In the micro manipulation, the release task is the challenge work due to adhesion forces. To overcome the adhesion force and to place microobject accurately on the desired location, in this paper, we propose a high speed motion by analyzing dynamic model of manipulated end effector and attached microbeads. Two fingered microhand driven by DC motors and PZT actuators is utilized for this paper. Parallel mecahnism with three PZT actuators was used for making 3D motion at high speed. To generatge high acceleration of end effector, many researchers applied simple vibration by using an additional PZT actuator. In our research, 3D high speed motion with large amplitude was achieved by only using a compacted parallel mechanism. To verify the advantage of the proposed motion, we compare five motions, 1D motions (X, Y, and Z direction) and circular motions (clockwise and counterclockwise direction), by changing the frequency and moving distance of the end effector. From these results of experiments, we conclude that the circular motion can detach microobjects with high placing accuracy after release.

ICRA Conference 2015 Conference Paper

Tracking handheld object using three layer RGB-D image space

Krishneel Chaudhary
Yasushi Mae
Masaru Kojima
Tatsuo Arai

Visual tracking of objects subjected to non-linear motion and appearance changes has shown to be a difficult task in computer vision. While research in visual object tracking has progressed significantly in terms of robust tracking of objects subjected to non-linear motion and appearance changes, these algorithms has shown limited capability for long term tracking of handheld objects during human-object interactions. The failure in tracking is a consequence of abrupt changes in the handheld object motion resulting in tracker drifting off the optimal object space. In this paper, we present a novel 3 layer RGB-D image model formulated with Bayesian filters that tracks handheld object using near constant velocity motion model. Our method divides the image into three layers of abstraction where each encodes visual information of environment, human, object and contributes toward precise localization of the handheld object during tracking. A boundary re-alignment step is introduced during tracking such that the tracker predicted object region is re-aligned to the optimal object region, therefore reducing the likelihood of tracker drifting off the object space. This compensation of the tracker prediction offset enables our algorithm to robustly track handheld object subjected to abrupt changes in motion during manipulation.

ICRA Conference 2014 Conference Paper

Autonomous acquisition of generic handheld objects in unstructured environments via sequential back-tracking for object recognition

Krishneel Chaudhary
Yasushi Mae
Masaru Kojima
Tatsuo Arai

Robots operating in human environments must have the ability to autonomously acquire object representations in order to perform object search and recognition tasks without human intervention. However, autonomous acquisition of object appearance model in an unstructured and cluttered human environment is a challenging task, since the object boundaries are unknown in prior. In this paper, we present a novel method to solve the problem of unknown object boundaries for handheld objects in an unstructured environment using robotic vision. The objective is to solve the problem of object segmentation without prior knowledge of the objects that human interacts with daily. In particular, we present a method that segments handheld objects by observing human-object interaction process, and performs incremental learning on the acquired models using SVM. The unknown object boundary is estimated using sequential back-tracking via exploitation of affine relationship of consecutive frames. The segmentation is achieved using identified optimal object boundaries, and the extracted models are used to perform future object search and recognition tasks.

ICRA Conference 2014 Conference Paper

BMI-based framework for teaching and evaluating robot skills

Christian I. Penaloza
Yasushi Mae
Masaru Kojima
Tatsuo Arai

Brain Machine Interface systems provide ways of communication and control of a variety of devices that range from domestic appliances to humanoid robots. Most BMI systems are designed exclusively to control devices using low-level commands, or high-level commands when devices with pre-programmed functionalities are available. In this paper, we build on our previous work on BMI-based Learning System in which we presented a different approach for designing BMI systems that incorporate learning capabilities that relieve the user from tedious low-level control. In this work, we extend the capabilities of our framework to allow a user to be able to teach and evaluate a robotic system by using a BMI. We provide general system architecture and demonstrate its applicability in new domains such as teaching a humanoid robot object manipulation skills and evaluating its performance. Our approach consists of 1) tele-operating robot's actions while robot's camera collects object's visual properties, 2) learning manipulation skills (i. e. push-left, lift-up, etc.) by approximating a posterior probability of commonly performed actions when observing similar properties, and 3) evaluating robot's performance by considering brain-based error perception of the human while he/she passively observes the robot performing the learned skill. This technique consists of monitoring EEG signals to detect a brain potential called error related negativity (ERN) that spontaneously occurs when the user perceives an error made by the robot. By using human error perception, we demonstrate that it is possible to evaluate robot actions and provide feedback to improve its learning performance. We present results from five human subjects who successfully used our framework to teach a humanoid robot how to manipulate diverse objects, and evaluate robot skills by visual observation.

ICRA Conference 2014 Conference Paper

Control of flagellar motor using a real-time local environment chemical stimulation system

Masaru Kojima
Takahiro Motoyoshi
Kenichi Ohara
Mitsuhiro Horade
Kazuto Kamiyama
Yasushi Mae
Tatsuo Arai

Single cell analysis has attracted much attention to reveal the localized biological information in detail. Local environmental control technique is developed to analyze the localized detail properties of single cells. In this paper, we propose the local environmental chemical stimulation system with micro dual pipettes to stimuli the local reagent concentration dynamically and automatically. Local environmental chemical stimulation by dual pipettes is applied to the rotational speed control of bacterial flagellar motor, which is a rotary molecular machine. Here, we show quick response and rotational speed control of Na-driven flagellar motor in both accelerating and relaxing directions was demonstrated by automatic switching the local spout between Na-containing and Na-free solutions with dual pipettes. It was shown that the rotational speed could be maintained by automatic controlling the spouting velocity of Na-containing and Na-free solution with multiplying the applied DC voltage. Furthermore, it was confirmed that by applying the P-control, rotational speed of flagellar motor could be controlled more stably.

IROS Conference 2014 Conference Paper

Development of chemical stimulation system for local environment control by using combination of spout and suction from dual-pipettes

Takahiro Motoyoshi
Masaru Kojima
Kenichi Ohara
Mitsuhiro Horade
Kazuto Kamiyama
Yasushi Mae
Tatsuo Arai

Single cell analysis has attracted much attention for revealing detailed and localized biological information. A local environmental control technique is desired when analyzing the detailed and localized properties of single cells. In this paper, we propose a local environmental stimulation system with micro dual-pipettes to stimulate the local reagent concentration dynamically, freely and automatically. When the local environment is controlled with chemical stimuli, the chemical solution is diffused and affects other objects. The local environment stimulation system with micro dual-pipettes can solve this problem. By using spout pipette and suction pipette, it is possible to use local stimuli without affecting other objects. For evaluating the locality of the system, we use a fluorescent substance and measure the diffusion of the spouted solution.

ICRA Conference 2014 Conference Paper

Dynamic releasing of biological cells at high speed using parallel mechanism to control adhesion forces

Ebubekir Avci
Hiroyuki Yabugaki
Takayuki Hattori
Kazuto Kamiyama
Masaru Kojima
Yasushi Mae
Tatsuo Arai

In this paper, a dynamic releasing method for high-speed biological cell manipulation is proposed. A compact parallel mechanism, used for grasping and releasing microob-jects, was utilized for generating controllable vibration to overcome the strong adhesion forces between the end effector and the manipulated object. To reach the required acceleration of the end effector, which is necessary for the detachment of the target object, vibration in the end effector is generated by applying sinusoidal voltage to the PZT actuator of the parallel mechanism. For the necessary acceleration, we focus on the frequency of the vibration, while keeping the amplitude of the PZT actuator vibration small (14 nm) to achieve precise positioning. Releasing of microbeads and biological cells is conducted and results are compared for the first time. The effect of the air and liquid environments are also investigated. Successful releasing (97. 5%) of biological cells proves that the proposed active releasing method is an appropriate solution for the adhered biological cells during the releasing task.

IROS Conference 2014 Conference Paper

On-chip flexible scaffold for construction of multishaped tissues

Puwanan Chumtong
Masaru Kojima
Mitsuhiro Horade
Kenichi Ohara
Kazuto Kamiyama
Yasushi Mae
Yoshikatsu Akiyama
Masayuki Yamato

This paper presents a chip containing a flexible scaffold which facilitates the construction of tissues with different shapes. The chip, entirely made of Polydimethylsiloxane (PDMS), has 2 main components including actuator and channel layers. The actuator layer consists of a 6×6 array of membrane actuators, with round shapes. The channel layer has a single layered structure due to the simplicity in chip assembly and the ability to observe seeded cells via a microscope. The actuator array offers a flat surface, like a normal cell culture dish, in the rest state, while it temporarily offers a scaffold structure when actuators are activated. By changing the actuation pattern, formation of many scaffold structures is possible. To demonstrate the utility of this chip in biological application, a syringe pump is connected to all actuators to produced 2 different scaffolds, enabling the fabrication of multiple flat round and lattice shaped tissues. NIH3T3 cells with the amount of 5×10 6 were seeded on the scaffold and kept inside the incubator for 24 hours. The 25 round shaped tissues with an average diameter of 623. 87 μm were simultaneously fabricated when a scaffold with large deformed actuators was used. The lattice shaped tissue with a line width of about 300 μm was also fabricated with a different scaffold structure which has less actuator displacement. Results suggest the potential usage of this chip for the preparation of many building units with different structures, without the necessity of making a new mold for a new tissue shape.

ICRA Conference 2013 Conference Paper

Automated stable grasping with two-fingered microhand using micro force sensor

Hiroyuki Yabugaki
Kenichi Ohara
Masaru Kojima
Yasushi Mae
Tamio Tanikawa
Tatsuo Arai

Recently, with the development of life science field, micromanipulation technology has attracted attention. A two-fingered microhand system, that has been developed as a micro manipulator, can perform dexterous cell manipulation such as grasping, rotating, and transferring using two end effectors in a chopstick-like motion. The automated manipulation uses processing results based on all-in-focus (AIF) images and depth map obtained from the vision system; however, errors in the results still reduce the efficiency of the system. In this study, we introduce an automated grasping system that corrects the image processing error using the reaction force from the target object during grasping maneuvers. In our improved microhand system, micro force sensors that comprises strain gauge are attached to the two fingers of microhand. The two fingers with micro force sensor are set to be able to measure the horizontal and vertical forces to detect grasping state, precisely. Using the sensor information and the image processing results, we demonstrate that this system improves the accuracy and success rate of automated grasping.

ICRA Conference 2013 Conference Paper

BMI-based learning system for appliance control automation

Christian I. Penaloza
Yasushi Mae
Kenichi Ohara
Tatsuo Arai

In this research we present a non-invasive Brain-Machine Interface (BMI) system that allows patients with motor paralysis conditions to control electronic appliances in a hospital room. The novelty of our system compared to other BMI applications is that our system gradually becomes autonomous by learning user actions (i. e. turning on/off window, lights, etc.) under certain environment conditions (temperature, illumination, etc.) and brain states (i. e. awake, sleepy, etc.). By providing learning capabilities to the system, patients are relieved from mental fatigue or stress caused by continuously controlling appliances using a BMI. We present an interface that allows the user to select and control appliances using electromyogram signals (EMG) generated by muscle contractions such as eyebrow movement. Our learning approach consists in two steps: 1) monitoring user actions, input data from sensors distributed around the room, and Electroencephalogram (EEG) data from the user, and 2) using an extended version of the Bayes Point Machine approach trained with Expectation Propagation to approximate a posterior probability from previously observed user actions under a similar combination of brain states and environmental conditions. Experimental results with volunteers demonstrate that our system provides satisfactory user experience and achieves over 85% overall learning performance after only a few trials.

IROS Conference 2013 Conference Paper

Development of microhand utilizing singularity of parallel mechanism

Toru Ejima
Kenichi Ohara
Masaru Kojima
Mitsuhiro Horade
Tamio Tanikawa
Yasushi Mae
Tatsuo Arai

In the fields of medicine and biology, it is essential to realize fine manipulation. Therefore, micromanipulation techniques and micromanipulators such as microgrippers and optical tweezers have been developed. We have developed a two-fingered microhand which is using the parallel mechanism to realize precise and stable micromanipulation. However, the previous microhand has problems about workspace and vibration. In this paper, the development of a new microhand which solves problems of previous microhand. The characteristic of new microhand is to enlarge the workspace utilizing the singularity of the parallel mechanisms. Inverse kinematics and structural analysis are used to analyze the workspace, and we show that results of two analyses match. Vibration analysis simulates transportation task and grasping task for manipulation. The new microhand has a potential to reduce the vibration by vibration analysis results.

IROS Conference 2013 Conference Paper

Lifelogging keyframe selection using image quality measurements and physiological excitement features

Photchara Ratsamee
Yasushi Mae
Amornched Jinda-Apiraksa
Jana Machajdik
Kenichi Ohara
Masaru Kojima
Robert Sablatnig
Tatsuo Arai

Keyframe selection is the process of finding a representative frame in an image sequence. Although mostly known from video processing, keyframe selection faces new challenges in the lifelog domain. To obtain a keyframe that is close to a user-selected frame, we propose a keyframe selection method based on image quality measurements and excitement features. Image quality measurements such as contrast, color variance, sharpness, noise and saliency are used to filter high quality images. However, high quality images are not necessarily keyframes because humans also use emotions in the selection process. In this study, we employ a biosensor to measure the excitement of humans. In previous investigation, keyframe selection using only image quality measurements yielded an acceptance rate of 79. 70%. Our proposed method achieves an acceptance rate of 84. 45%.

IROS Conference 2013 Conference Paper

Social navigation model based on human intention analysis using face orientation

Photchara Ratsamee
Yasushi Mae
Kenichi Ohara
Masaru Kojima
Tatsuo Arai

We propose a social navigation model that allows a robot to navigate in a human environment according to human intentions, in particular during a situation where the human encounters a robot and he/she wants to avoid, unavoid (maintain his/her course), or approach the robot. Avoiding, unavoiding, and approaching trajectories of humans are classified based on the face orientation on a social force model and their predicted motion. The proposed model is developed based on human motion and behavior (especially face orientation and overlapping personal space) analysis in preliminary experiments. Our experimental evidence demonstrates that the robot is able to adapt its motion by preserving personal distance from passers-by, and approaching persons who want to interact with the robot. This work contributes to the future development of a human-robot socialization environment.

ICRA Conference 2013 Conference Paper

Towards high-speed automated micromanipulation

Ebubekir Avci
Chanh-Nghiem Nguyen
Kenichi Ohara
Masaru Kojima
Yasushi Mae
Tatsuo Arai

In this work, we present a high-speed pick-and-place method for cell-assembly applications. Besides range of motion and accuracy, rapidness of a manipulation system is an important parameter, which is so far underrated in related studies. To achieve high-speed micromanipulation, obtaining 3D positions of both the target microobject and the end effector rapidly is necessary. In addition, controlling the vibration of the end effector, which is greater at high speed, is another arduous task. We propose a new fast detection algorithm for both the target microobject and the end effector for achieving high-speed control of the system. Moreover, to realize the stable control for very fast movements, the vibration of the system is compensated. High-speed control of the microhand system is demonstrated with preliminary experiments consisting of pick-and-place actions of 40 to 60 μm microspheres; we aimed at performing a manipulation task in 1 second. Comparison with similar studies shows the merit of the proposed automated high-speed micromanipulation system.

ICRA Conference 2012 Conference Paper

A psychological scale for general impressions of humanoids

Hiroko Kamide
Yasushi Mae
Koji Kawabe
Satoshi Shigemi
Tatsuo Arai

This study identifies the basic general perspectives that ordinary people use to evaluate humanoids (Study 1). In addition, it develops a new psychological scale to quantify general impressions regarding humanoids based on these basic perspectives (Study 2). In Study 1, to discover the basic perspectives toward humanoids, we used 11 humanoids and collected data from 919 Japanese people ranging from teenagers to people in their 70s in three big cities. We asked people to describe their impressions in free text about the robots. Five psychologists analyzed the qualitative data to categorize all the descriptions into several categories. Then, we made the items based on the obtained descriptions to construct a new psychological scale for evaluating general impressions regarding humanoids. In Study 2, we asked 2, 624 Japanese who did not participate in Study 1 to evaluate 11 humanoids on the developed scale. Factor analysis showed that nine factors should be used for evaluating the general impressions regarding humanoids: Familiarity, Repulsion, Performance, Utility, Motion, Sound, Voice, Humanness, and Entitativity. The factor structure is clear and its reliability as a psychological scale is satisfactorily high. Finally, we discuss the usability of the new scale.

IROS Conference 2011 Conference Paper

Automated micromanipulation for a microhand with All-In-Focus imaging system

Chanh-Nghiem Nguyen
Kenichi Ohara
Ebubekir Avci
Tomohito Takubo
Yasushi Mae
Tatsuo Arai

For potential applications in bioscience, a two-fingered microhand with dexterous manipulation capability was developed. This microhand system could perform dexterous tasks such as cell rotation, single cell pick-and-place, cell patterning, and measurement of mechanical properties of living cells. However, it is a tedious task to manipulate micro objects manually. In order to improve the efficiency of the system, automated micromanipulation is required. This paper describes how to automate micromanipulation for this two-fingered microhand so that it can perform desired tasks more efficiently, more accurately, and faster. By integrating an All-In-Focus imaging system to the microhand system, 3D positions of the two microfinger tips and micro target objects can be obtained. These 3D positions are necessary for the microhand to handle the target object automatically. We demonstrate this capability by a pick-and-place task with multi-sized microspheres. Short time for object grasping and success rate over 70% for all cases could be achieved.

IROS Conference 2011 Conference Paper

Cell hardness measurement by using two-fingered microhand with micro force sensor

Daiki Kawakami
Kenichi Ohara
Tomohito Takubo
Yasushi Mae
Akihiko Ichikawa
Tamio Tanikawa
Tatsuo Arai

In the field of bioscience, such as regeneration medicine and cloning, the manipulation and analysis for cells are performed by many researchers. However, manual operation for such micro objects is not feasible and practical for beginner operators. As for the problem, we have developed a two-fingered microhand supporting manual operation. Using the microhand, we can manipulate cells i. e. , grab, rotate, carry, and so on - like when using chop sticks. The stiffness measurement of a cell is a key approach in single cell analysis techniques. It is important in indicating cell condition, because the stiffness of a cancer cell is lower than that of a normal cell as an example. However, measuring stiffness is very difficult, because deformations of cell are plasticly, and many researches to measure the stiffness of cell don't deal with plastic deformation. So, in this paper, the cell hardness is calculated instead of cell stiffness by measuring the reaction force caused in the process of cell deformation via a micro force sensor attached to the end-effector of the microhand. Our results point out that this can be one efficient measurement method for acquiring cell hardness. In this paper, three topics are discussed. First one is the fabrication of the end-effector with micro force sensor. Second one is the method of measuring hardness of cell. As a last one, the hardness of the fibroblastic cell is measured by proposed method and the effectiveness of the proposal technique is shown.

ICRA Conference 2011 Conference Paper

Comparative evaluation of virtual and real humanoid with robot-oriented psychology scale

Hiroko Kamide
Mika Yasumoto
Yasushi Mae
Tomohito Takubo
Kenichi Ohara
Tatsuo Arai

The aim of this study was to compare a robot designed using a virtual reality (VR) system (termed VR robot) with a real robot by using a psychological evaluation to investigate whether the VR robot can be used in the same manner as a real robot. To make the direct comparison between a VR and real robots possible, the same designed robots in both VR and real are used in the experiment. For evaluating the robots on a psychological basis, we focused on six basic dimensions (Utility, Clumsiness of motion, Possibility of communication, Controllability, Vulnerability, and Objective hardness) that ordinary people generally use to perceive robots. Sixty-one participants observed and evaluated a real and VR humanoid robots using a psychological scale. Results show that the real robot was evaluated to have higher scores for Utility, Possibility of communication, and Objective hardness and lower ones for Controllability as compared to a VR robot. The Vulnerability scores of the real robot and the VR robot were not significantly different. The usability of a VR robot is discussed in the paper.

IROS Conference 2011 Conference Paper

Visual and physical segmentation of novel objects

Amr Almaddah
Yasushi Mae
Kenichi Ohara
Tomohito Takubo
Tatsuo Arai

The ability to recognize novel items in complex environment is fundamental to robot intelligence and manipulation. In this work, we consider the issue of segmenting visual and physical aspects of novel objects of interest, specifically ones that are being seen for the first time and located in the proximity of unidentified obstacles. Illumination at different wavelengths and angles are projected by a robot, thus acquiring additional information about the scene and exploiting it for successful novel objects segmentation. By analyzing shades and reflections of a scene's objects, we were able to form and identify true edges and visually separate items of interest. In order to recognize the physical characteristics of segmented objects, we introduce a novel material classification technique which utilizes static electricity charge sensing. Our proposed methods do not require predefined models of target objects and assume no previously assigned targets' pose. Using extracted object visual and physical aspects, an autonomous robot manipulator successfully performed a trash separation task.

ICRA Conference 2010 Conference Paper

A new stiffness evaluation toward high speed cell sorter

Yuki Hirose
Kenjiro Tadakuma
Mitsuru Higashimori
Tatsuo Arai
Makoto Kaneko
Ryo Iitsuka
Yoko Yamanishi
Fumihito Arai

Cell stiffness could be an index for evaluating its activity. Although various systems measuring cell stiffness have been proposed so far, they are slow for adaptively connecting to cell sorters capable of handling more than 1000 [cells/sec]. This paper proposes a new approach that can indirectly evaluate the cell stiffness by measuring the passing time for a narrow channel. When a cell passes through the channel, it receives a viscous force depending upon how much deformation is exerted on the cell. We show that the stiffness is a function of both the passing time and the initial diameter of cell. We also show that the stiffness is proportional to the passing time and inversely proportional to the initial diameter, under the assumption that the thickness of fluid film is inversely proportional to the normal force. The experimental validation is given together with the basic working principle.

IROS Conference 2010 Conference Paper

Development of a scale of perception to humanoid robots: PERNOD

Hiroko Kamide
Yasushi Mae
Tomohito Takubo
Kenichi Ohara
Tatsuo Arai

In this study we explored basic dimensions used to perceive humanoid robots and developed a scale to evaluate perception of humanoid robots, PERNOD. Previous studies of perception of humanoid robots used psychological scales created for interpersonal perception between humans. This study clarified the basic dimensions of perception of humanoid robots and developed PERNOD by means of psychological methodology. The results revealed six basic dimensions of perception of humanoid robots: Utility, Clumsiness of motion, Possibility of communication, Controllability, Vulnerability, and Objective hardness. The 6 dimensions of PERNOD were originally developed for humanoid robots. Thus, these dimensions represent the organization of knowledge used in the recognition of humanoid robots. Usability of PERNOD was discussed.

IROS Conference 2010 Conference Paper

Gait planning for a biped robot by a nonholonomic system with difference equation constraints

Nobuya Yao
Tomohito Takubo
Kenichi Ohara
Yasushi Mae
Tatsuo Arai

New gait planning using a nonholonomic model with difference equation constraints is proposed for biped robot walking. A model of a pivoting telescopic segment is used as the kinematic foothold selection model of a bipedal robot. The repetitive and discontinuous constraints of pivoting, expanding, and contracting make up the set of walking trajectory data. The k-step reachable region is defined as the set of the k-th state that the system can reach from the initial state, and the motion planning is solved using the Jacobian matrix of the state with regard to the input series. The difference equation constraints can be discussed as a digital control of continuous-time nonholonomic systems. The gait planning is modified based on the limiting condition for the HRP-2 humanoid robot. Energy consumption is evaluated based on the linear-pendulum model and the gait planning is optimized. The feasibility of the proposed walking planning is demonstrated through a numerical simulation and an experiment involving the HRP-2 humanoid robot.

IROS Conference 2009 Conference Paper

Automated initial setup method for two-fingered micro hand system

Izumi Hatta
Kenichi Ohara
Tatsuo Arai
Yasushi Mae
Tomohito Takubo

A two-fingered micro hand has been available for use for years and allows dexterous manipulation of a single cell: grabbing, positioning, rotating and releasing. The end-effector of this micro hand consists of two glass needles; however, the glass tips must be finely adjusted and the micro hand must be calibrated prior to use. Because these initial procedures require highly skilled human operators and a great deal of time, a fine adjustment module (FAM) has been developed for assisting with the fine adjustment work and was successfully shown to make the initial setup easier. However, problems with the calibration process and with the dependence on a user of the FAM control are still present. One means of improving the system for users is to automate the initial setup. The detection of the glass tips in a wide range of Z directions from a microscopic image having a small depth of focus requires robust calibration and must be possible using an automated FAM control. From this perspective, the tip position detection algorithm using the evaluation function, Image Quality Measurement (IQM), is proposed in this paper. Based on this algorithm, the automated initial setup method is explained and its effectiveness is experimentally evaluated.

IROS Conference 2009 Conference Paper

Detection sensor for flowing particles in micro channel

Ichiro Okuda
Tatsuo Arai
Tomohito Takubo
Akiyuki Hasegawa
Yasushi Mae
Kenichi Ohara

In this paper, we propose a sensor for detecting particles flowing in a micro channel fabricated with polydimethylsiloxane (PDMS) chip. A light source placed at one side of a micro channel irradiates the micro channel through plastic optical fibers (POF), and a detector placed at the opposite side of the micro channel receives light transmitted through the POF. Since this sensor simultaneously detects plural particles with a diameter of around 100 ¿m flowing in a micro channel, it can be implemented in automatic measurement systems of cells in desktop bio plant, on which automated embryonic cell manipulation is achieved using micro robotics technology.

IROS Conference 2009 Conference Paper

Interoperable RT component for object detection and 3D pose estimation for service robots

Jaeil Choi
Hideyasu Takahashi
Yasushi Mae
Kenichi Ohara
Tomohito Takubo
Tatsuo Arai

Finding objects and tracking their poses are essential functions for service robots, in order to manipulate objects and interact with humans. We present an approach for object detection and 3D pose estimation for autonomous mobile robots, that is suitable for general uses in a modularized robot control system. Our approach extracts local features from the input images, searches for the reference pattern, and then produces the 3D pose in camera coordinate system, using only a single reference image and the 6-DOF pose in it. We have created an RT (Robot Technology) component that can be used in any RT-based system, and developed an algorithm that can extend the range of detection and produce robust pose estimation. For evaluation, we have integrated our vision component in an autonomous robot system with a search-and-grasp task, and tested it with several objects that are found in ordinary domestic environment. We present the details of our approach, the design of our modular component design, and the results of the experiments in this paper.

IROS Conference 2009 Conference Paper

NDT scan matching method for high resolution grid map

Tomohito Takubo
Takuya Kaminade
Yasushi Mae
Kenichi Ohara
Tatsuo Arai

A new convergence calculation method of the normal distributions transform (NDT) scan matching for high resolution of grid maps is proposed. NDT scan matching algorithm usually has a good effect on large grids, so it is difficult to generate the detailed map with small grids. The proposed method employs interactive closest point (ICP) algorithm to find corresponding point, and it also enlarges the convergence area by modifying the eigenvalue of normal distribution so that the evaluation value is driven effectively for the pairing data. In addition, outlier elimination process is implemented to the scanning for sub-grid scale object. The scanning data from laser range finder (LRF) have error but its set of detected small object can be clustered to determine the center of mass (CoM) and the outlier data. The outlier commonly locates behind true points and it can be eliminated when the robot observes from other point. Experimental result shows the effectiveness of the proposed convergence algorithm and outlier elimination method.

ICRA Conference 2009 Conference Paper

Rough terrain walking for bipedal robot by using ZMP criteria map

Tomohito Takubo
Yoshinori Imada
Kenichi Ohara
Yasushi Mae
Tatsuo Arai

A new method for bipedal walking on rough terrain by using ZMP criteria map is proposed. The rough terrain walking is classified to “step up” and “step down” by landing timing of a swing leg. The walking pattern is modified in real-time according to the difference between the ideal timing and the measured timing by a force sensor on the foot. In the case of “step up”, the landing timing is faster than the ideal, and the swing leg trajectory should be change to follow the step so that the ZMP based balance of the sudden caused double support phase is kept. In the case of “step down”, the landing timing is later than the ideal, and the swing leg trajectory should be change to seek the ground so that the balance of the unknown future double support phase is kept. The modified walking pattern is decided based on the ZMP criteria map. The ZMP criteria map can indicate a safe landing timing and landing position of a swing leg. By referring the ZMP criteria map, the robust walking pattern can be planned. The proposed method is implemented to HRP-2, and the effectiveness is confirmed through experiments.

IROS Conference 2009 Conference Paper

Self-Controlled Cell Selection and Loading System for & microfluidic systems

Huseyin Uvet
Akiyuki Hasegawa
Kenichi Ohara
Tomohito Takubo
Yasushi Mae
Tatsuo Arai

In this paper, we presented a design for an automated cell supply system that can be used with complex microfluidic applications requiring single cell loading such as the current nuclear transplantation method. The aim of the system is to automatically transfer mammalian donor (~15 ¿m) or egg (~100 ¿m) cells one by one from a container to a PDMS micro-channel and then transport them to other modules. The system consists of two main parts; a single cell suction module, and a PDMS-based microfluidic chip controlled by an external pump. The desired number of vacuumed cells can be directed into the microfluidic chip and stored in a docking area. From the batch, they can be moved to next module by activating pneumatic pressure valves located on two sides of the chip.

IROS Conference 2008 Conference Paper

Detection of screws on metal-ceiling structures for dismantling tasks in buildings

Sergio Rolando Cruz-Ramírez
Yasushi Mae
Tomohito Takubo
Tatsuo Arai

In the renewal process of office interiors, a robotic system is needed in order to assist the human workers engaged in this kind of job. Regarding the items in the ceiling side, after the dismantling task of the ceiling panels, it is necessary to remove carefully the screws that once held these boards to the Light Gauge Steel (LGS), with the purpose of reusing. The proposed methodology to achieve the task consists at first of the LGS detection. Such detection is useful as a first approach to detect the screws because a trajectory under and near of that metal-ceiling structure can be generated for a scanning process. In both tasks, a stereo camera configured as an eye-in-hand system is necessary. During the motion under the structure, the screws are detected by applying a multi-template matching process to every caught image. A multi-frame integration increases the robustness in the screw detection process. The results of all the processed images along the trajectory are analyzed in order to measure both the true and the false positive detection rates of the screws attached to the LGS and to measure the 3D position of each one.

ICRA Conference 2008 Conference Paper

Development of a compact vision system for "automated nuclear transplantation project"

Huseyin Uvet
Tatsuo Arai
Yasushi Mae
Tomohito Takubo

This paper describes research and development of a compact vision system for real-time cell detection and manipulation in a capillary in order to apply on the “Automated Nuclear Transplantation” project which will achieve sort of cell manipulation tasks such as positioning, cutting, sizing, and so on, automatically between different interconnected modules. Here, we propose a vision system boarded on a PDMS based silicon chip, which can be utilized in a complex network for continuous monitoring of mammalian egg and donor cells of sizes in the range of 10 to 100 micron. The developed prototype has sufficient resolution and is accompanied with a robust detection method for cell-based microfluidic applications.

ICRA Conference 2008 Conference Paper

Dismantling interior facilities in buildings by human robot collaboration

Sergio Rolando Cruz-Ramírez
Yuusuke Ishizuka
Yasushi Mae
Tomohito Takubo
Tatsuo Arai

New robotic systems will be playing an essential role in the future dismantling service for renewing office interiors facilities in buildings. In our study, the dismantling task would be achieved by proper collaboration between human workers and robots utilizing mobile arms, interface devices and software. This paper describes an overview of the proposed dismantling system as well as its requirements. The real experiments presented are focused on the disassembling task of a ceiling lamp panel (LP). In the disassembling task, a robot arm collaborates with the human worker holding the LP, accomplishing an assisting function. At first, in order to approach the robot to the holding position, the worker controls the robot using interface devices which are also evaluated in their usability aspect. Then, a laser pointer fixed at the robot’s tip is used both as a guidance in the teleoperation process and as a first indicator of the holding position. As a second step toward the target, the control program applies model-based 3D object recognition techniques to calculate the final position. At this stage the information of an stereo camera, configured as an eye-in-hand system, is necessary. On the last part of the task, the robot reaches the estimated position automatically by using the results of its kinematic analysis. The experimental results show the effectiveness of the proposed methodology.

ICRA Conference 2008 Conference Paper

Ladder climbing control for limb mechanism robot "ASTERISK"

Shota Fujii
Kenji Inoue
Tomohito Takubo
Yasushi Mae
Tatsuo Arai

A ladder climbing motion for limb mechanism robot “ASTERISK” is proposed. This robot has six legs. The upper three legs hold on the upper rung from its both sides alternately, just like pinching it. The lower three legs hold on the lower rung in the same way. Hence the robot can climb the ladder stably. Depending on the posture of the robot, when it lifts up its body, the robot automatically selects the legs supporting the robot’s weight and distributes the weight to these legs based on their force margins. The legs which cannot support forces are controlled to always contact with the rungs so that the robot holds the ladder firmly. The advantages of proposed gait and control method are verified by the analysis of the supporting range and the torque, and by experiment on force distribution.

ICRA Conference 2008 Conference Paper

The generation of environmental map based on a NDT grid mapping -Proposal of convergence calculation corresponding to high resolution grid-

Takuya Kaminade
Tomohito Takubo
Yasushi Mae
Tatsuo Arai

The paper presents a new convergence calculation method of the Normal Distributions Transform (NDT) scan matching for high resolution grid map. The proposed method employs Interactive Closest Point(ICP) algorithm to find corresponding point, even if the input scan points are in the outside of the reference grid area. It also enlarges the convergence area by modifying the eigenvalue of normal distribution so that the evaluation value can be driven effectively by all the pairing data for improving convergence speed. In the normal NDT scan matching algorithm, the grid size especially has much effect on the capability of convergence area and speed. Thus, it is difficult to generate the detailed map with small grids. The proposed convergence approach can solve the problem by the phased adjustment of convergence area. Experimental result shows the feasibility of the detailed environmental map generated by the NDT grid mapping.

ICRA Conference 2007 Conference Paper

Emergent walking stop using 3-D ZMP modification criteria map for humanoid robot

Tomohito Takubo
Takeshi Tanaka
Kenji Inoue
Tatsuo Arai

Real-time emergent stop walking motion is necessary for humanoid robots. We propose a new emergent stop method using modification criteria map. The stable gait change is generated by adjusting the amount of the ZMP modification according to the timing of stop command. The modified ZMP trajectory is given so that the humanoid robot can change the current motion without falling down. The modification criteria are defined from the relation between the predicted ZMP trajectory using a preview controller and the support polygon. The preview controller employs table-cart model and it derives center of mass (CoM) trajectory from ZMP reference in real-time. We make the map of relation among the ZMP modification length, the modification timing and the timing of the stop command for stable gait modification. The robot can execute the best motion referring to the predefined map. In this method, the humanoid robot can stop immediately within one step or zero step to avoid a collision, if humans or objects appeared unexpectedly in front of the walking humanoid robot. The stop motion is typically divided two phase: single leg support phase and double leg support phase. In the single leg support phase, the next landing position and timing are decided according to command time of the stop signal. In the double leg support phase, the humanoid robot can stop anytime without changing standing position. The validity of the proposed method is confirmed by experiment using a humanoid robot HRP-2.

ICRA Conference 2007 Conference Paper

Encountered-type Visual Haptic Display Using Flexible Sheet

Tsuyoshi Furukawa
Kenji Inoue
Tomohito Takubo
Tatsuo Arai

An encountered-type visual haptic display using flexible sheet is proposed; it allows users to feel like seeing and pushing virtual soft objects directly. Both edges of a translucent flexible sheet such as rubber is attached to two manipulators. They apply bias tension to the sheet by pulling it from both sides, thus varying the sheet compliance. A user can feel the compliance of a virtual soft object by pushing the sheet with his finger directly. The motion of the finger tip is measured by stereo cameras. The manipulators also change the pose of the sheet along the object's surface together with the finger tip motion. The user can touch different points of the object and feel like stroking it with his finger. This sheet is also used as a rear projection screen. From the measured finger tip position, the deformation of the object is calculated by FEM. An LCD projector projects the CG image of the deformed object stereoscopically on the sheet from its back. The user can see the 3D image through stereoscopic glasses and touch the image directly. A method of correcting the CG image distortion caused by the movement of the sheet and the depression of the pushed sheet is proposed. A virtual soft cylinder is expressed by a prototype display: the stroking of the cylinder and the correction of its 3D image are evaluated.

ICRA Conference 2006 Conference Paper

Calibration Method for Parallel Mechanism using Micro Grid Pattern

Wataru Tanaka
Tatsuo Arai
Kenji Inoue
Tomohito Takubo
Choong Sik Park

This paper investigates a calibration of a parallel mechanism stage which is set up under the microscope. The calibration method uses the measurement data of the translation movement in the plane of the end-effector and rotation about the axis perpendicular to it using measurement method with the micro grid pattern. This paper discusses its calibration method with experiments for the stage constructed a fixed linear actuated parallel mechanism. The results show that the calibration using limited data is possible and has good performance

IROS Conference 2006 Conference Paper

Design Optimization of a Compact 3-DOF Parallel Micro/Nano Finger Manipulator

Ahmed A. Ramadan
Kenji Inoue
Tatsuo Arai
Tomohito Takubo

A compact and yet economical 3-DOF micro/nano finger manipulator based on micro parallel kinematics structure is presented in this paper. It uses three piezo-electric actuators and two types of flexure joints, one is a revolute joint and the other is a ball joint, as its main mechanism. The problem of inverse kinematics between end effector position and actuator displacements along with the Jacobian matrix for this design is derived. A glass needle of 3 to 10 cm length is used as the end effector to increase the workspace of the micro/nano manipulator. As the length of the glass needle end effector is decreased, the resolution and accuracy of the manipulator is increased while the workspace volume is decreased. The design parameters are optimally chosen so that the manipulator will obtain maximum workspace volume. The simulation results illustrate that the proposed model has a large workspace and in the same time it will be small in size using the proposed architecture

IROS Conference 2006 Conference Paper

Emergent stop for Humanoid Robots

Takeshi Tanaka
Tomohito Takubo
Kenji Inoue
Tatsuo Arai

This paper describes a real-time gait change for a walking humanoid robot. We propose a control method to change the gait motion by modifying a pre-defined zero moment point (ZMP) trajectory in real time. The stable gait change is generated by adjusting the amount of the ZMP modification according to the timing of stop command. The modified ZMP trajectory is given so that the humanoid robot can change the current motion without falling down. The modification criteria is defined from the relation between the predicted ZMP trajectory using a preview controller and the support polygon. The preview controller employs table-cart model and it derives center of mass (CoM) trajectory from ZMP reference in real-time. We make the map of relation between the ZMP modification and the timing of command for stable gate modification. The robot executes the best motion referring to the map. In this method, the humanoid robot can stop immediately within one step to avoid a collision, if humans or objects appeared unexpectedly in front of the walking humanoid robot. The stop motion is typically divided two mode; single leg stop motion and double leg stop motion. The stop mode and the next landing position are decided according to the command time of the stop signal. The validity of the proposed method is confirmed by experiment using a humanoid robot HRP-2

IROS Conference 2006 Conference Paper

Omni-directional Gait of Limb Mechanism Robot Hanging from Grid-like Structure

Kenji Inoue
Taisuke Tsurutani
Tomohito Takubo
Tatsuo Arai

A method for limb mechanism robots of omni-directional gait hanging from grid-like structure is proposed. Grid-like structure consists of many bars assembled in a matrix in a horizontal plane; its grid spacing is not always constant and unknown. A robot has six legs, and each foot has a hemispherical shape for hooking on the bar. The robot moves in any direction as commanded by tripod gait; it hangs from the grid-like structure using two sets of three legs alternately. The leg gropes for the bar so as to take as long stroke as possible. By increasing joint compliance, the foot contacts the bar softly and detects the contact. Then, using a foot force sensor, the robot ascertains that the foot hooks on the bar. The developed robot ASTERISK can perform omni-directional gait hanging from experimental grid-like structure by the proposed method

IROS Conference 2006 Conference Paper

Wholebody Teleoperation for Humanoid Robot by Marionette System

Tomohito Takubo
Kenji Inoue
Tatsuo Arai
Kazutoshi Nishii

Marionette system provides an intuitive teleoperation system for the difficulty controlling whole-body motion of a multi-joint robot and the complicated observation of its condition. This system employs a small robot which has similar form to a control target as an operating/displaying device, so that the device provides an operational feeling like manipulating a doll, so it is named Marionette device. Since the characteristics of the Marionette device and the target robot are synchronized bilaterally in the system, the operation of the Marionette device is reflected intuitively in the target, and the robot motion is also displayed simultaneously by the Marionette device. In this paper, we develop a humanoid type device as a Marionette device in order to operate a humanoid robot HRP-2 and implement a wholebody teleoperation method. The remote walking and manipulation experiments in an unknown environment are introduced. In this experiment, the operator should guess the remote environment using head camera view and control legs and arms by the Marionette device. We propose a new operation method for controlling the foot position and leg joints with the Marionette device. It makes possible to walk by pointing a foot stamp step by step in a stable place

IROS Conference 2005 Conference Paper

Measurement of the mechanical properties of living cell using micro hand and developed AFM system

Daisuke Nishi
Tatsuo Arai
Kenji Inoue
Tomohito Takubo

In this paper, the mechanical properties of yeast cell are determined by means of the developed two-fingered micro hand and an atomic force microscope (AFM). The micro hand has excellent absolute positioning accuracy after the elaborated calibration, and is typically capable of obtaining less than several hundred nanometer of positioning accuracy by human tele-operation. The authors also developed an AFM system of our own composition. The AFM consists of a laser diode module, a cantilever, a 4-segment photodiode and output circuit. The task to measure the mechanical properties of cells include moving of the fingers from the home position to the target object (cell), then picking and grasping it, moving it to a target position (AFM tip), and finally pushing it against the cantilever tip. However, since it is difficult to stabilize the sample, the authors utilized the capillary phenomenon, i. e. the liquid inside the tube-shaped object ascends the inner wall in order to stabilize the sample strongly. And force-indentation relation was obtained applying a force to individual yeast cells by moving the sample to the cantilever tip. Force is automatically calculated from the cantilever deflection measured with a laser beam and a quadrature photodiode, while indentation is obtained from the difference between the movement of the micro hand and that of the cantilever tip caused by cantilever deflection. The mechanical properties of yeast cells is finally determined using the produced force-indentation curves, the Hertz model and FIEL (force indentation to equal limits) mapping, which is an analytical way for determining relative microelastic properties from force volumes of viscoelastic materials.

ICRA Conference 2005 Conference Paper

Pushing an Object Considering the Hand Reflect Forces by Humanoid Robot in Dynamic Walking

Tomohito Takubo
Kenji Inoue
Tatsuo Arai

This paper discusses pushing a heavy object by a humanoid robot. We modify the whole body motion considering the hand reflecting forces for the walking pattern of a humanoid robot. By assuming that linear and angular momentum of a humanoid robot are calculated, we define the projection of the Center of the Mass(CoM) as” Dynamically Complemental Zero Moment Point(DCZMP)”, when external forces act to the end-effectors. We propose a new method using the DCZMP for the modification control of CoM position with balancing control. The robot can keep the dynamical balance considering the DCZMP and the walking velocity in both single and double support phase. In addition, for controlling pushing force, we implement an impedance controller with the manipulation and walking velocity controller. The effectiveness of the proposed method is confirmed by simulations and experiments.

IROS Conference 2005 Conference Paper

Pushing operation for humanoid robot using multipoint contact states

Tomohito Takubo
Kenji Inoue
Tatsuo Arai

In this paper, we propose new method for the task of pushing an object by a humanoid robot. First, a humanoid robot leans against the task object whose mass and shape are known, and it makes multipoint contact states which the whole body is supported by both hands and feet. We focus on two support polygons which consist of the both hands and one foot, and we make them include the center of mass (CoM). In this case, the humanoid robot doesn't need to move the CoM for walking and it is easily possible to make stable gate motion. The force control considering the pushing force and the acceleration control of the CoM are implemented for the gate velocity control. Experimental results show the effectiveness of the proposed method.

ICRA Conference 2005 Conference Paper

Wide-Area Recognition Using Hybrid Motion Stereo

Shun Nishide
Tomohito Takubo
Kenji Inoue
Tatsuo Arai

In this paper, a wide-area recognition technique for mobile robots, which proves to be specifically effective with biped robots, using Hybrid Motion Stereo is presented. The proposed technique uses several cameras and divides the field of view into two groups, namely, areas visible in more than two cameras (MCVA: Multiple Camera Visible Area) and areas visible in only a single camera (SCVA: Single Camera Visible Area). Positional informations contained in MCVA can be computed constantly by stereo vision, while those contained in SCVA require movement of the camera to be computed by motion stereo. Estimation of the movement of cameras can be obtained by calculating the movement of immobile objects in MCVA. The measure of precision in computation by motion stereo depends on the magnitude of the movement of points in the image. Thus, high precision in SCVA can be obtained by lateral or longitudinal motions of the cameras. One such motion can be generated with biped robots for its lateral cyclic motion caused by the movement of the center of gravity for stability retainment. The authors have implemented these methods into the humanoid robot HRP-2 and evaluated the effectivity of the technique.

IROS Conference 2005 Conference Paper

Wide-area recognition using hybrid motion stereo outlier rejection for motion stereo: outlier rejection for motion stereo using sequential data

Shun Nishide
Tomohito Takubo
Kenji Inoue
Tatsuo Arai

Robots working in complex environment require accurate perception of a wide field of view. Using cameras, hybrid motion stereo, which combines the computations by stereo vision and motion stereo, is capable of acquiring positional information of the whole field of view. However, the technique generates errors in computation by motion stereo when tracking feature points fails. This paper describes a method to reject the outliers to avoid erroneous recognition. The method uses computation results from several previous images, computing the spatial deviation and temporal deviation of points, and rejecting those considered to be deviated. The evaluation function is composed with a weighted average of the sequential results, each with a weight of the total number of points existing in the neighboring space, which represents the spatial deviation. Experimental results using the humanoid robot HRP-2 denote the effectiveness of the method.

IROS Conference 2004 Conference Paper

Building 3D map for localization using human action

Yukinobu Sakaguchi
Yasushi Mae
Naoki Sasao
Tomohito Takubo
Kenji Inoue
Tatsuo Arai

This paper proposes a method of building a 3D map composed of static objects for localization of mobile robots using recognition of human actions. In the monitoring systems with fixed cameras and also moving cameras, high-precision localization of moving cameras is required for measuring human actions in detail and precisely. A 3D map of the environment composed of static objects such as walls, desks and shelves is useful for high-precision localization of moving cameras in 3D space, because salient features in the environment are used as landmarks. Furthermore, the 3D map is required for generation of monitoring motion of the moving cameras and recognition of human actions in the relation of the environmental objects. In order to generate a 3D map automatically by measuring 3D points in an environment, points on static objects have to be selected from measured points, because there are dynamic objects such as chairs, books, and other mobile things in the environment. The proposed method generates a 3D map for localization by selecting points on static objects from measured 3D points based on recognition of human actions. Experimental results show feasibility of our proposed method.

ICRA Conference 2004 Conference Paper

Evaluation of Human Sense of Security for Coexisting Robots using Virtual Reality. 1st Report: Evaluation of Pick and Place Motion of Humanoid Robots

Seri Nonaka
Kenji Inoue
Tatsuo Arai
Yasushi Mae

When robots coexisting with humans are designed, it is important to evaluate the influence of the shape and size of the robots and their motions on human sense of security. For this purpose, an evaluation system of human sense of security for coexisting robots using virtual reality is discussed. Virtual robots are visually presented to a human subject through a head mounted display; the subject and the robots coexist in the virtual world. Some kinds of physiological indices of the subject are measured, he answers the questionnaire about his impression of the robots, and his sense of security is evaluated. Because of using virtual reality technique, the shape and size of the robots and their motions can be easily changed and tested. In the present report, pick and place motion of humanoid robots is evaluated. As a result of analyzing the questionnaire, it is found that turning the body coordinating with the arm gives good impression on humans.

IROS Conference 2004 Conference Paper

Integrated visual and haptic display translucent and flexible sheet

Kenji Inoue
Reiko Uesugi
Ryouhei Sasama
Tatsuo Arai
Yasushi Mae

An integrated visual and haptic display using translucent and flexible sheet such as rubber is proposed. This display varies the compliance of the sheet in the normal direction by changing the bias tension of the sheet: tightly stretched sheet feels hard, and loosely stretched sheet feels soft Hence a user can feel compliance of various virtual objects when he pushes the sheet. This sheet is also used as a rear projection screen; an LCD projector projects the image on the sheet from its back. When the user's finger pushes the sheet, the position and deformation of the pushed point are measured by stereo vision. The deformation of the virtual object is calculated by FEM, and the graphical model of the deformed object is generated. The user sees both the image of the object projected on the sheet and his own finger pushing the image. As a result, the proposed visual and haptic display allows users to feel like pushing virtual soft objects with their fingers directly. It is ascertained that the developed display can generate variable compliance and simulate the compliance of a real soft object. Human subjects feel like seeing and pushing a virtual object directly.

IROS Conference 2004 Conference Paper

Marionette system for operating and displaying robot whole-body motion development of similar humanoid-type device

Tomohito Takubo
Kazutoshi Nishii
Kenji Inoue
Yasushi Mae
Tatsuo Arai

We propose "marionette system" as a master slave teleoperation. The operation/display device which presents form and posture equivalent to the remote robot is named "marionette device". In the system, it is possible, making exact discrimination, to control flexibly the remote robot by using marionette device. Marionette system is the operation/presentation technique which not only enables to operate flexibly all movable joints but to discriminate correctly by checking the marionette device. Since the condition of the marionette device is made almost equivalent to the remote robot, the operator can check and operate the device as treating a doll for judgments of operation. Thus, we named the control system "marionette system. " In this paper, we develop the humanoid-robot (HR) type device as an example of the remote control of the humanoid robot. When a humanoid robot is set as an operation target, it becomes easy to transpose and image a robot pattern from human motion. HR type device used as operation/display equipment enables intuitive approach in operation. In order to verify the validity of the proposed system, we have carried out various experiments comparing two types of device. One is conventional the method employing graphic simulators and a joystick, the other is a proposed control/display device employing humanoid type device. The effectiveness of the proposed system is confirmed by the experimental results.

IROS Conference 2004 Conference Paper

Mobile manipulation of humanoid robots - control method for CoM position with external force

Tomohito Takubo
Kenji Inoue
Kotaro Sakata
Yasushi Mae
Tatsuo Arai

Mobile manipulation control method for humanoid robots provides good manipulability and stability on manipulation tasks. This method leads whole body motion and locomotion, when the manipulator tip trajectory is decided. For the dexterous manipulation, the robot has to cope with the unexpected forces acting to the hands. By assuming the statistical balance, we define the projection of the CoM as "complement zero moment point (CZMP)", when the external forces act to the end-effectors. We propose to use the CZMP for the modification control of CoM with balancing control. The method is implemented to the mobile manipulation control method and the effectiveness is confirmed by the experimental results.

ICRA Conference 2004 Conference Paper

Omni-directional Gait of Multi-legged Rescue Robot

Kenji Kamikawa
Tatsuo Arai
Kenji Inoue
Yasushi Mae

This paper proposes a gait control algorithm for limb-mechanism robot on rough terrains and slopes. The concept of the "limb-mechanism" is to integrate functions of legged locomotion and arm manipulation. A limb can be used as a leg and an arm according to different situations. Each limb radiates out in six directions and the robot has a symmetrical configuration in horizontal and vertical directions. The robot can walk into any direction using a simple motion planning where the same trajectory is assumed in each leg. This trajectory is generated on a cylindrical volume which is defined in the leg workspace. The robot has a touch sensor at the tip of each leg. The sensor can detect the contact with the ground, and the legs can stay on the ground stably. When the robot walks on a rough terrain, the body is inclined in parallel to the virtual plane defined by leg supporting points in order to use the leg workspace effectively. The stability margin of the robot can be also improved easily by changing the leg trajectory.

IROS Conference 2003 Conference Paper

Mobile manipulation of humanoid robots -control method for accurate manipulation

Yusuke Nishihama
Kenji Inoue
Tatsuo Arai
Yasushi Mae

A control method for humanoid robots of mobile manipulation is proposed: this method allows accurate manipulation using hands, even when the robots move around. A robot controls its body pose and steps so that manipulabilities of both arms and robot stability can increase, coordinating with the motion of both hands for performing objective tasks. Because of the vibration caused by the impact of foot landing and the slip of the feet, the accuracy of the hand positions and robot stability decrease. For this problem, the robot measures real hand positions and body orientation with its camera and gyroscope. Then the hand positions errors are transformed to correcting joint angles of the arms using arm Jacobian matrices. Adding the calculated joint angles to the desired joint angles of the arms, the arms can compensate the hand positions. New desired joint angles of the legs are calculated by inverse kinematics from real foot positions and desired shoulder position. Adding the correcting joint angles to the desired joint angles of the legs, the legs can compensate the shoulder position, thus increasing robot stability. The effectiveness of the proposed method is ascertained by simulations.

ICRA Conference 2003 Conference Paper

Remote actuation mechanism for mr-compatible manipulator using leverage and parallelogram - workspace analysis, workspace control, and stiffness evaluation

Yoshihiko Koseki
Noriho Koyachi
Tatsuo Arai
Kiyoyuki Chinzei

In this paper, a novel mechanism of remote actuation was proposed and its mechanical problems were discussed. This mechanism consists of leverage and parallelogram mechanism and transmits 3 d. o. f translational and 3 d. o. f rotational motions from the input to output. Such a remote actuation is significantly useful for robotic assist around MRI where the strong and precise magnet is used for imaging, because mutual effect between MRI and robot are inverse proportional to the distance. In this paper, the basic ideas of mechanism were introduced firstly. The discussions of its stiffness and workspace conclude their trade-off. Our new idea of workspace control for mechanical safety is preliminary discussed.

IROS Conference 2002 Conference Paper

Automated calibration for micro hand using visual information

Tatsuo Arai
Akihiro Suzuki
Yousuke Kato
Yasushi Mae
Kenji Inoue
Tamio Tanikawa

An automated calibration for micro-hand is proposed to obtain high quality micromanipulation system. The calibration is based on automatic focusing of micro-object and its position detection in the microscope frame using microscope images. The automatic focusing works well even in the tracking of moving target using chromatic aberration. The finger position can be detected automatically by integrating focusing and identification of the micro-hand finger wherever it is in the microscope view. These automated processes are implemented in the actual system. The experiment shows the system can attain around 2[/spl mu/m] in absolute positioning accuracy.

ICRA Conference 2002 Conference Paper

Control of Walk and Manipulation by a Hexapod with Integrated Limb Mechanism: MELMANTIS-1

Noriho Koyachi
Hironori Adachi
Makoto Izumi
Takeshi Hirose
Naofumi Senjo
Ryoji Murata
Tatsuo Arai

Describes dual mode control of walk and manipulation of a prototype hexapod with integrated limb mechanism, named MELMANTIS-1. MELMANTIS-1 uses six-bar linkages with four degrees-of-freedom as an integrated limb mechanism with dual use for a leg and for an arm. Omni-directional drive control is introduced to the hexapod walk with alternative tripod gait. The transformation from hexapod walking style into the combination of dual arms and quadruped platform is introduced. A remote control to handle an object by dual arms is experimented with in a simple application of a trash pitcher.

IROS Conference 2002 Conference Paper

Design of 3-DOF parallel mechanism with thin plate for micro finger module in micro manipulation

Tamio Tanikawa
Motohide Ukiana
Kazuhiro Morita
Yoshihiko Koseki
Kohtaro Ohba
Kazuhiro Fujii
Tatsuo Arai

A dexterous micro manipulation system was developed for applications such as assembling micro machines, manipulating cells, and micro surgery. We (1996, 1999) have proposed a concept of a two fingered micro hand, and designed and built a prototype. We succeeded in performing basic micro manipulations, including the grasp, release, and rotation of a microscopic object. The two-fingered micro hand prototype needs to be more miniaturized for higher accuracy and use in the small chamber of SEM. In this paper, we propose a new 3-DOF parallel mechanism for the micromanipulator in order to achieve low cost and small size. The new mechanism is only used for punching holes and bending a thin plate. The two-fingered micro hand with the mechanism was designed and a prototype developed. An experiment shows the excellent micro capability of the mechanism.

ICRA Conference 2002 Conference Paper

Mechanism Configuration Evaluation of a Linear-Actuated Parallel Mechanism using Manipulability

Takanori Masuda
Motoyoshi Fujiwara
Norihiko Kato
Tatsuo Arai

The linear-actuated parallel mechanism that changes the motion characteristic according to the actuator configuration is known. The authors previously (2000) reported on the kinematics and the motion characteristic on the basis of the motion transmissibility. In this report, we analyze the changed in motion characteristics using the measures of manipulability. Indices of manipulability are given with components of the value determined by the singular value decomposition. The typical index is a volume of the manipulability ellipsoid. We clarify the features of the motion characteristics according to a change in the actuator configuration using these indices. Finally, we show the recommended application examples that are designed for mechanisms using the obtained result.

ICRA Conference 2002 Conference Paper

Mobile Manipulation of Humanoid Robots - Body and Leg Control for Dual Arm Manipulation

Kenji Inoue
Yusuke Nishihama
Tatsuo Arai
Yasushi Mae

A control method for humanoid robots of mobile manipulation is proposed. A robot autonomously steps or controls its body pose while performing various manipulation tasks with its hands; that enables dexterous and stable manipulation. Two hands always move along their desired trajectories by impedance control for carrying out a given task. Coordinating with this motion of the hands, the robot controls its body and legs so that arm manipulability and robot stability may increase. It determines the next foothold by evaluating manipulabilities of both arms, shape of stable region and moving direction. An evaluation function consisting of manipulabilities of both arms and static stability of the robot is defined, and the robot steps if the new double support state is better than the current one. Both in double and single support states, the robot controls its body pose using the support leg(s) so that this evaluation may be optimal. Various motions of a humanoid robot by the proposed method are simulated.

ICRA Conference 2002 Conference Paper

Mobile Manipulation of Humanoid Robots - Optimal Posture for Generating Large Force Based on Statics

Haruyuki Yoshida
Kenji Inoue
Tatsuo Arai
Yasushi Mae

The optimal posture of a humanoid robot for generating large desired force at its hands is discussed. The robot is required to stand stably and to support the force and its weight under the constraint of maximum joint torques. Furthermore, it is important to keep the robot controllable against sudden change in the force. From this point of view, an evaluation function for the task with large force based on statics is proposed; we focus on Jacobian matrices of two arms and legs to give the robot adaptability to force change. Then the method of obtaining the optimal posture, footholds and joint torques of the robot is described. Effectiveness of the method are verified through computer simulations.

ICRA Conference 2002 Conference Paper

Simplified Kinematic Calibration for a Class of Parallel Mechanism

Wataru Tanaka
Tatsuo Arai
Kenji Inoue
Yasushi Mae
Choong Sik Park

Calibration methods and parameter estimation analyses of a class of parallel mechanisms are discussed in order to achieve a nano-modon stage applied in the machining of high quality optical devices. The paper includes mechanical structure of Delta type parallel mechanism, its kinematics analyses for calibration, two calibration methods and their comparisons in the aspects of parameter errors, final achieved accuracy and simple procedure. Exclusion of orientation data will be also discussed for the simplicity of measurements in the calibration procedure.

ICRA Conference 2001 Conference Paper

Adaptive Relocation of Environment-Attached Storage Device by Multiple Robots

Tomohiro Umetani
Yasushi Mae
Kenji Inoue
Tatsuo Arai

We propose a method of relocating storage devices attached to the environment for sharing knowledge efficiently among multiple robots. If a robot stores acquired knowledge into the storage device, other robots can achieve the task by using the knowledge. Since the memory size of the storage device is limited, usefulness of the knowledge is evaluated with respect to the reducible cost. A memory unit containing useless knowledge is removed from the storage device and added to the device where more useful knowledge is required. Then, the robots can store useful knowledge for the whole environment and the memory units are flexibly relocated according to the change of a series of the tasks. The simulation results of multiple robots navigation for repetitive transportation tasks show the effectiveness of our method.

IROS Conference 2001 Conference Paper

Error analysis of dead reckoning of multi-legged robots

Yasushi Mae
Toru Masuda
Tatsuo Arai
Kenji Inoue

This paper describes a method of analyzing the error of dead reckoning of multilegged robots. In dead reckoning of multilegged robots, the body posture and contact positions of legs are alternately estimated. The estimated error is accumulated in locomotion. We derive the basic equations for estimation of the error of body posture and the contact positions based on the small displacement analysis. The 3D distribution of the error is analyzed by singular value decomposition.

ICRA Conference 2001 Conference Paper

Force Control System for Autonomous Micro Manipulation

Tamio Tanikawa
Masashi Kawai
Noriho Koyachi
Tatsuo Arai
Takayuki Ide
Shinji Kaneko
Ryo Ohta

A dexterous micro-manipulation system was developed for applications such as assembling micro-machines, manipulating cells, and micro-surgery. We proposed a concept of a two-fingered micro-hand, and designed and built a prototype. We succeeded in performing basic micro-manipulations, including the grasp, release, and rotation of a microscopic object. The micro-hand is controlled by a position controller only. The accuracy of the micro-manipulation depends on the skill of the operator. For automatic manipulation, it is necessary to measure the micro-forces between the finger and the object. A micro force sensor has developed for the force control in micro-manipulation. In this paper, we describe the micro force sensor and perform an automatic micro-manipulation and force control with the sensor. The basic experiment performed shows excellent micro-capability.

IROS Conference 2000 Conference Paper

Application of locomotive robot to rescue tasks

Yasushi Mae
Atsushi Yoshida
Tatsuo Arai
Kenji Inoue
Kunio Miyawaki
Hironori Adachi

The research aim is to apply locomotive robots to rescue tasks, such as searching for sufferers and removing obstacles to save sufferers. The paper discusses the exploitation of arm and leg integrated robots and basic experiments of infrared probing sensor, in the application of rescue tasks. First, the limb mechanism is introduced and discussed in the aspect of locomotion capability and stability in rough terrain of disaster area. Then, the probing sensor is evaluated in the aspect of its detection range and capability. Assuming the sensor is mounted on the tip of robot arm for probing, the probing algorithm is proposed to find quickly and locate precisely a sufferer. The basic experiments have been carried out using a parallel arm to confirm the applicability and the usefulness of the proposed rescue system.

IROS Conference 2000 Conference Paper

Development of multi-limb robot with omnidirectional manipulability and mobility

Yuuya Takahashi
Tatsuo Arai
Yasushi Mae
Kenji Inoue
Noriho Koyachi

In order to develop a high performance working robot, we design and develop a new robot based on the concept of "limb mechanism " for integration of legged locomotion and arm manipulation. The robot developed has six limbs which can be used for both locomotion and manipulation. The six limbs are set on vertices of regular hexagonal body so that this robot can have omnidirectional manipulability and mobility. We evaluate the stroke and the stability margin in all walking directions on six-legged and four-legged locomotion. As a result, this robot has higher omnidirectional mobility than conventional mechanisms.

IROS Conference 2000 Conference Paper

Hybrid drive parallel arm and its motion control

Hirofumi Kamishima
Tatsuo Arai
Kei Yuasa
Yasushi Mae
Kenji Inoue
Kunio Miyawaki
Noriho Koyachi

A hybrid cylinder/cable drive parallel arm and its motion control are discussed. The basic idea of the hybrid parallel arm is to make the best use of the mixture of the high power cable drive and the cylinder actuation to obtain a heavy-duty manipulator in construction and ship building applications. A prototype arm has been designed and built based on the analysis and the comparative study of several types of hybrid drive mechanisms, the Stewart platform, and a wire drive mechanism. The tension of wire has to be maintained properly in the hybrid mechanism during its motion. The proposed hybrid arm is a kind of actuation-redundant mechanism and its internal force can be freely controlled. The proposed control algorithm is to give wires proper tension during its motion by exploiting the internal force, The required tension and cylinder force can be obtained by compensating each link position command based on its compliance. The repeatability tests show the effectiveness of the proposed algorithm in maintaining the overall stiffness of the arm.

IROS Conference 2000 Conference Paper

Kinematic analysis of translational 3-DOF micro parallel mechanism using matrix method

Yoshihiko Koseki
Tamio Tanikawa
Noriho Koyachi
Tatsuo Arai

We apply the matrix method to kinematic analysis of our translational 3-DOF micro parallel mechanism for an instance of general flexure mechanisms. The matrix method has been well developed in architecture to analyze a frame structure. We found that this method is well applicable to such a flexure mechanism with circular notched hinges as our micro parallel mechanism because it is approximate to the Rahmen structure. Our matrix method can calculate a compliance matrix with less nodes of matrix than conventional finite element method. First, the compliance matrices of a circular notched hinge and some other beams are defined and the coordinate transformations of compliance matrix are introduced. Next, an analysis of our micro parallel mechanism is demonstrated.

IROS Conference 2000 Conference Paper

Mobile manipulation of humanoid robots-analysis of manipulability and stability in mobile manipulation

Haruyuki Yoshida
Kenji Inoue
Tatsuo Arai
Yasushi Mae

This paper describes mobile manipulation of humanoid robots. A humanoid robot is a kind of integrated machines: two arm and two leg mechanism. It could be well applied to mobile manipulation in nonroutine task automation. The main objective of the mobile manipulation is to obtain versatile and efficient manipulation by the arms. In this respect the legs are required to assist the arms obtaining their high manipulability by changing step length and timing of step motion. Accordingly, the required motion of the legs in mobile manipulation is different from conventional biped locomotion. From this point of view, the relationship between manipulability of the arm and various leg motions is analyzed and evaluated by computer simulations.

ICRA Conference 2000 Conference Paper

Mobile Manipulation of Humanoids: Real-Time Control Based on Manipulability and Stability

Kenji Inoue
Haruyuki Yoshida
Tatsuo Arai
Yasushi Mae

A real-time control method for a humanoid in mobile manipulation, doing tasks with its arms while moving, is proposed. The arm tips always follow their desired position with external force applied by impedance control, for carrying out a given task with the arms. An evaluation function consisting of not only stability but also arm manipulability-both are important for mobile manipulation-is defined; the humanoid controls its body and legs so that this evaluation may be optimal. As a result, the humanoid autonomously steps or keeps standing, coordinating with the arm tips motion. The effectiveness and usefulness of the proposed method are ascertained by computer simulations on a humanoid of human-size and experiments using a small experimental robot.

IROS Conference 2000 Conference Paper

Parallel mechanisms with adjustable link parameters

Tatsuo Arai
Kazunari Takayama
Kenji Inoue
Yasushi Mae
Yoshihiko Koseki

There has been always a workspace problem with parallel mechanisms. This paper discusses the workspace of the parallel mechanisms and its enlargement by adjusting their link parameters. The basic idea is to cover a whole required range of workspace with small pieces of one. A fixed linear type mechanism is selected to analyze and to evaluate its adjustable workspace. The analyses of simple 2 DOF plane model show that additional spaces are obtainable, which cannot be reached by the conventional mechanism due to its singularity. More detailed analyses and evaluations are discussed based on a 6 DOF spatial model.

IROS Conference 2000 Conference Paper

Presentation of push button switches with manipulators for virtual operating environment

Kenji Inoue
Yusuke Takao
Tatsuo Arai
Yasushi Mae

The concept of virtual operating environment (VOE) used for teleoperation of various machines is proposed. A virtual cockpit for each machine is constructed within a computer: it consists of virtual input devices such as switches and joysticks, meters or indicators, and TV monitors displaying the images from the machine-mounted cameras. The cockpit is displayed to an operator through a head-mounted display. In the real world, a manipulator presents the virtual input devices by turns; the operator handles the end-effector of the manipulator, regarding it as the input device. VOE can provide different types of operating environment for various machines simply by switching softwares. One of the most important techniques for VOE is the simulation and presentation of various input devices with a manipulator. The manipulator simulates the switch using the obtained impedance model. It is ascertained by experiment that the manipulator can present two different switches.

IROS Conference 2000 Conference Paper

Specific kinematic changes in a linear-actuated parallel mechanism according to differences in actuator arrangement

Takanori Masuda
Motoyoshi Fujiwara
Tatsuo Arai

Parallel mechanisms driven by fixed linear actuators promise high speed and high output, thanks to lightweight movable parts. Several types of mechanism applying this mechanical principle are already known. Although these have different methods of actuator arrangement, they may be considered the same mechanism since they can be treated using the same kinematics. However, it is not known how the output characteristics differ with differences in actuator arrangement. The article first shows the general kinematics that can be applied regardless of actuator arrangement. Next, changes are shown in the output characteristics occurring with changes in the actuator layout angle in a linear-actuated parallel mechanism with validity arranged actuators. The movable space and motion transmission indexes were used to determine the output characteristics. A total transmission index integrating the transmission index into the movable space is proposed, and the effects of design parameters other than actuator layout angle were investigated while giving weight to the motion transmissibility. The results show that the best actuator layout angle is 45-75 (deg).

ICRA Conference 1999 Conference Paper

Design and Analysis of a 3-DOF Micromanipulator

James Nielsen
Tamio Tanikawa
Tatsuo Arai

A unique design for a 3-DOF micromanipulator is presented. The new design contains only revolute joints, and it incorporates rotation of the upper platform of the mechanism, which effectively uses the length of the end-effector to increase workspace volume. The forward and inverse kinematics problems for the device are solved, and a method for calculating the Jacobian is presented. Finally, a prototype of the manipulator was fabricated and tested experimentally to compare with the theoretical results.

IROS Conference 1999 Conference Paper

Development of 3-DOF finger module for micro manipulation

Yoshiki Ohya
Tatsuo Arai
Yasushi Mae
Kenji Inoue
Tamio Tanikawa

A compact and economical 3-DOF finger module for micro manipulation is developed; it is designed for a two-finger micro manipulator which can manipulate micrometer-size objects dexterously like chopsticks. A 3-DOF parallel mechanism for this finger is proposed, and its inverse kinematics between the end effector position and the actuator displacements is formulated. The design parameters are determined so that its workspace volume may be as large as possible. A prototype using three piezo-electric actuators and two types of flexure joints, which are proposed for realizing a compact finger, is developed. The Jacobian matrix used for calculating the actuator displacements corresponding to the given end effector position is obtained by experiments. The repeatability and absolute positioning accuracy-about 2. 0 /spl mu/m-of this prototype are evaluated.

IROS Conference 1999 Conference Paper

Development of a spiral structure for an active catheter-overview of the spiral structure and its kinematic configuration

Yoshihiko Koseki
Noriho Koyachi
Tatsuo Arai

We propose a special structure for an active catheter: a spiral structure. It consists of a flexible belt on which actuators, sensors, and/or control units are built. The belt is spiraled or put spirally around flexible tube to work as a catheter. The actuators on one roll of the spiral move the next roll to realize the bending, twisting, and/or expanding motion of the catheter. With this method, minute and complicated actuators, sensors, and circuits can be precisely machined with very high density, fabricated and wired together in one continuous plane with silicon processes. The advantage of this method will be simple and high-density fabrication. In the paper, the overview and kinematic analysis of the spiral-structure active catheter are discussed and some types of active catheters are proposed.

IROS Conference 1999 Conference Paper

Development of small-sized 3 DOF finger module in micro hand for micro manipulation

Tamio Tanikawa
Tatsuo Arai
Noriho Koyachi

A dexterous micro manipulation system was developed for applications such as assembling micro machines, manipulating cells, and micro surgery. We have proposed a concept of a two-fingered microhand, and designed and built a prototype. We succeeded in performing basic micro manipulations, including the grasp, release, and rotation of a microscopic object. The two-fingered micro hand prototype should be more miniaturized for higher accuracy and combination in small chamber of SEM. In this paper, we will propose a small-sized 3-DOF finger module with a parallel mechanism. An optimized link mechanism for miniaturization is used to the finger module. A photo fabrication system is used to fabrication of the finger module. Basic experiment shows excellent micro capability.

IROS Conference 1999 Conference Paper

Hybrid drive parallel arm for heavy material handling

Kei Yuasa
Tatsuo Arai
Yasushi Mae
Kenji Inoue
Kunio Miyawaki
Noriho Koyachi

A new hybrid cylinder/wire drive parallel arm (simply called "a hybrid arm") for manipulating heavy materials in construction and ship building works is proposed. Various hybrid arms with different combination of cylinders and wires are compared with the conventional Stewart platform and a multiwire drive mechanism. Their workspaces considering orientation are evaluated. The most suitable hybrid arm for heavy material handling is the mechanism with three cylinders, four wires, and one connecting rod between the cylinders and the end plate. This hybrid arm is modified into a mechanism with a variable length rod for the application of manipulating a precasting concrete board with a size of 3/spl times/6/spl times/0. 2 m/sup 3/ and a weight of 10 t which is used in automatic building construction systems; a prototype of this arm has been designed and developed.

IROS Conference 1999 Conference Paper

Mechanism and control of a leg-wheel hybrid mobile robot

Hironori Adachi
Noriho Koyachi
Tatsuo Arai
A. Shimiza
Yashiroh Nogami

Describes the mechanism and control of a leg-wheel hybrid mobile robot. Legged locomotion has high adaptability for rough terrain, and wheeled locomotion possesses speed and efficiency. A locomotion mechanism that combines legs and wheels is proposed, and a prototype mobile robot that adopts the mechanism is introduced. The robot has four legs, and a wheel is attached at the end of each leg. The front leg has three joints and a passive wheel. The rear leg has one joint and an active wheel. In order to make the best of the mechanism, three locomotion modes, wheel mode, hybrid mode, and step mode, are developed. In the wheel mode, four wheels are used on flat terrain. On rough terrain, the hybrid mode is selected, and two legs and two active wheels are used for locomotion. To climb or descend a large step, the step mode is used.

IROS Conference 1999 Conference Paper

Real-time obstacle avoidance for robot arm using collision Jacobian

Hajime Kaneko
Tatsuo Arai
Kenji Inoue
Yasushi Mae

A real-time robot arm control method for obstacle avoidance is proposed. If links are close to and approaching obstacles, the end-effector velocity is modified so that collision is avoided and the error between the desired and modified end-effector velocity can be minimized. For this purpose, a new matrix called the "collision Jacobian", which relates the approaching velocity of the links to the obstacles with the end-effector velocity, is proposed. Because the modified velocity can be calculated without an iterative algorithm, the proposed method is effective for real-time obstacle avoidance. This method is applied to collision avoidance between the links of a parallel arm.

IROS Conference 1998 Conference Paper

An upper limb motion assist system: experiments with arm models

Keiko Homma
Satoshi Hashino
Tatsuo Arai

In developing service robots, safety should be considered carefully, since robots share the space with people who do not have technical backgrounds on the operation of robots. A powered orthosis is one of the most severe examples. We have been studying an upper limb motion assist system. The aim of the system is to help a disabled person move his/her arm by his/her own will, by hanging the arm with strings and changing the length of each string. We have built an experimental system to examine the motion obtained with this system.

ICRA Conference 1998 Conference Paper

Design and Accuracy Evaluation of High Speed and High Precision Parallel Mechanism

Yoshihiko Koseki
Tatsuo Arai
Kouichi Sugimoto
Toshiyuki Takatuji
Mitsuo Goto

We have developed a precise and high-speed arm applied to assembly processes in electrical product and machine industries. The arm is designed based on the requirement from Japanese major industries. The paper addresses the background of the development, the required specification for the robot arm, and the brief introduction of the prototype arm and evaluations of accuracy. We test the repeatability of parallel mechanism. Then we calibrate the kinematic model of parallel mechanism to improve its absolute accuracy using laser tracking coordinate measuring system.

IROS Conference 1998 Conference Paper

Micro drops for adhesive bonding of micro assemblies and making a 3-D structure "micro scarecrow"

Tamio Tanikawa
Yoshiyuki Hashimoto
Tatsuo Arai

A dexterous micro manipulation system was developed for applications such as assembling micro machines, manipulating cells, and micro surgery. We have proposed a concept of a two-fingered micro hand, and designed and built a prototype. We succeeded in performing basic micromanipulations, including the grasp, release and rotation of a microscopic object. If a bonding technique for microscopic parts can be applied to our current system, the assembly of various micro 3D structures will be achieved. Various bonding techniques have been researched for assembly of micro 3D structures, including anodic bonding, direct bonding, adhesive bonding, and others. We apply the adhesive bonding technique to micro parts with micro assembly, since this method can be applied to micro parts with various material qualities. In adhesive bonding, one difficulty is how to obtain a microscopic drop of adhesive agent smaller than the micro parts. In this paper, we will propose a method to obtain a micro drop by applying the capillary phenomenon. By using this technique, a micro drop only a few microns in size could be obtained. Combining the micro drop method with our current micromanipulation system, we succeeded in building a 3D structure "Micro scarecrow".

IROS Conference 1997 Conference Paper

Development of vision system for two-fingered micro manipulation

Tamio Tanikawa
Tatsuo Arai
Yoshiyuki Hashimoto

A dexterous micro manipulation system is developed for application in assembling micro machines, manipulating cells, and micro surgery. We have proposed a concept of a two-fingered micro hand, and designed and built a prototype. In the micro manipulation, the system to observe microscopic objects is important as well as a system for actually manipulating a microscopic object. An optical microscope or SEM (scanning electron microscope) is typically used to observe micro motion of fingers in the micro hand. In high scale magnification, its focusing range is limited and the finger tip may often go out of the sight. We propose and develop a vision system using auto focus by processing CCD image data in order to obtain a fine image of the finger tip and microscopic object in a micro task.

IROS Conference 1997 Conference Paper

High speed and high precision parallel mechanism

Tatsuo Arai
Hiroaki Funabashi
Yoshihiko Nakamura
Yukio Takeda
Yoshihiko Koseki

We have established a research collaboration project to develop a precise and high-speed arm applied to assembly process in electrical product and machine industries, supported by the International Robots and Factory Automation Foundation (IROFA). The paper addresses the background of the development, the required specification for the robot arm, and the brief introduction of the prototype arm.

IROS Conference 1997 Conference Paper

Human-operated walking control of a quadruped by event-driven method

Hironori Adachi
Noriho Koyachi
Tatsuo Arai
Yoshihiro Shinohara

This paper describes a walking control scheme for a quadruped robot. In conventional walking control scheme, the leg motion is generated from the robot moving trajectory beforehand and it is difficult to control in real time. The proposed control scheme employs a real time command from a human operator instead of the moving trajectory. The operator gives a current planar moving velocity command to the robot. Body propulsive action is basically continued according with the command unless a problem arises. When a foot reaches the border of the work space of the leg, the body propulsive actions is interrupted and a supporting foot pattern is changed. That is, a foot's arrival at the border is considered as an event to trigger a recovery action for the body propulsion. The recovery actions are decided to converge to the intermittent crawl gait when straight walking command is continued. The proposed control scheme is evaluated using actual walking robot.

ICRA Conference 1997 Conference Paper

Maximum velocity analysis of parallel manipulators

Patrick Huynh
Tatsuo Arai

In order to analyse the maximum velocity of parallel manipulators in operational space, a graphical method based on the analysis of the algebraic inequalities describing the constraints on the kinematics model is presented. We consider a general 6 d. o. f parallel manipulator and assume that all articular velocities are bounded by the same limit. The method is then applied to the conventional Stewart platform chosen as a reference and a new parallel manipulator for their performance comparisons. For these two parallel manipulators, respective formula of Jacobian matrix is also given.

IROS Conference 1997 Conference Paper

Optimal velocity based control of a parallel manipulator with fixed linear actuators

Patrick Huynh
Tatsuo Arai
Noriho Koyachi
Tomokazu Sendai

High speed motion and positioning accuracy are the most important performance requirements of robot manipulators for the pick and place and assembly tasks. This paper focuses on the kinematic central system applied to a new parallel manipulator (NPM) with fixed linear direct drive actuators specially designed for high-speed trajectory applications. An optimal velocity based control method for high speed straight line trajectory of the NPM is proposed. The method is based on the maximum velocity zones analysis consisting of algebraic inequalities describing the constraints on the kinematics model. The proposed control algorithm is then implemented in off-line trajectory planning and in real time position servoing for kinematic control in the sense of achieving optimal trajectory performance. Digital PD control structure of the NPM is presented in order to satisfy the requirements in the actual manufacturing automation. The experimental straight line trajectory is satisfactorily controlled at a speed of 1. 5 m/s with no reduction in accuracy.

IROS Conference 1996 Conference Paper

Control of a manipulator mounted on a quadruped

Hironori Adachi
Noriho Koyachi
Tatsuo Arai
Ken-ichiro Nishimura

This paper describes a control method of a manipulator mounted on a quadruped walking robot. One of the advantages of legged robots is the capability to change the body position and posture without changing the foot points. When a manipulator is mounted on a legged robot, it obtains extra motion from the body. By coordinating leg motion and manipulator motion, the end-effector has more sophisticated motion. When six degrees of freedom velocity command of the end-effector is supplied the proposed control method gives each joint velocity of the manipulator and the legs. This control method is experimentally evaluated using actual robot.

IROS Conference 1996 Conference Paper

Design and control of hexapod with integrated limb mechanism: MELMANTIS

Noriho Koyachi
Tatsuo Arai
Hironori Adachi
A. Murakami

This paper describes the mechanical design and basic control of a prototype hexapod with "integrated limb mechanism", named MELMANTIS. MELMANTIS uses a six-bar linkage with four degrees of freedom as an example of integrated limb mechanism with both advantages for leg and for arm. The kinematic analysis is done for mechanical design. Basic control program of MELMANTIS is developed to experiment simple walking motion and transformation from a leg into an arm.

IROS Conference 1996 Conference Paper

Development of 3 DOF micro finger

Tatsuo Arai
Jacques M. Hervé
Tamio Tanikawa

A 3 DOF micro finger, that has pure translational motion, is proposed. The finger will be applied in the two finger micro manipulation in order to manipulate micrometer size objects dexterously. The possible configurations are considered based on the group theory. Then, the optimal configuration is proposed by taking simple machining of joint structures into account. Kinematics analysis is made in order to describe the relation between end effector and actuator displacements. The design parameters are examined by evaluating the force capability of the actuator and the work space volume. Basic experiments are made by a prototype finger module that show excellent micro motion capability.

IROS Conference 1996 Conference Paper

Development of micro manipulation system with two-finger micro hand

Tamio Tanikawa
Tatsuo Arai
Takanori Masuda

A dexterous micro manipulation system is developed for the application in assembling micro machine, manipulating cell, and micro surgery. We have proposed a concept of a two-finger micro hand, and designed and built two types of hand modules based on parallel mechanisms. In this paper, we mainly discuss the structure of a two-finger micro hand. The structure of the two-finger micro hand is strongly related to the effective work space, or the common work space of two fingers as well as its cooperation control algorithms. We design a structure to be suitable for a two-finger micro hand and made a prototype. Development of useful master device to operate the two-finger micro hand is important issue for the dextrous micro manipulation system. We developed a master device which is operated by one hand. The forefinger and thumb is generally used to manipulate objects by one hand. However, motion of each finger cannot be directly used to move the micro manipulator operational signal. We observed difference between the manipulation by two-finger hand like chopsticks and the manipulation by forefinger and thumb in human hand, and discuss operational algorithm for easy manipulation. By using this system for the micro manipulation, we evaluated effectiveness of the two-finger micro hand. In the actual micro manipulation, we succeeded to pick up, place and rotate a micro glass ball having size of 2 microns. The positioning accuracy is less than 0. 1 micron.

IROS Conference 1996 Conference Paper

Robots with integrated locomotion and manipulation and their future

Tatsuo Arai

A robot should be capable of both locomotion and manipulation when it is applied to various tasks in construction, agriculture, home, office, and hospital services. This paper describes why and how locomotion and manipulation should be integrated, what the benefits are, and what problems must be solved in terms of practical application of the robot. The paper is based mostly on discussions by the RSJ research committee.

ICRA Conference 1995 Conference Paper

Accuracy Analysis of a Modified Stewart Platform Manipulator

Timo Ropponen
Tatsuo Arai

Relation between the joint displacement errors of Stewart platform manipulators and the end effector accuracy is presented. The position errors of the joints and the actuation errors and backlash are included to the kinematic model. A closed-form forward kinematics solution of the end effector error is derived from the inverse kinematics solution. The method is applied to a modified Stewart platform manipulator, and end effector error ellipsoids are computed. The analysis shows that the method can be used in evaluating the accuracy of prismatic parallel manipulators.

ICRA Conference 1995 Conference Paper

Design of an Upper Limb Motion Assist System with Parallel Mechanism

Keiko Homma
Tatsuo Arai

An upper limb motion assist system with parallel mechanism is being developed. This system aims at assisting a patient with upper limb disability to move his/her arm in daily life or rehabilitation. It suspends an arm at its elbow and wrist with three strings each, and manipulates the arm by changing the length of each string. As a first step of development, the design parameters are evaluated using simulation.

IROS Conference 1995 Conference Paper

Geometric design of hexapod with integrated limb mechanism of leg and arm

Noriho Koyachi
Tatsuo Arai
Hironori Adachi
Ken'ichi Asami
Yoshihiro Itoh

This paper introduces a new concept for the integration of locomotion and manipulation. "the integrated limb mechanism" covers the technical fields of both the control integration and the mechanism integration necessary for the practical working robot. Here, a six-bar linkage mechanism with four degrees-of-freedom is introduced as an example of integrated limb mechanism. Kinematic analysis for the geometric and mechanical design suggests that the mechanism satisfies a contradictory conditions, not only for leg with slow heavy motion in downward posture, but also for arm with fast light motion in upward posture. The work space that two or three arms can reach is analyzed and evaluated by volume numerically for dual arm work and triple arm work. According to these analysis, a prototype hexapod with integrated limb mechanism, "MELMANTIS", was made.

ICRA Conference 1995 Conference Paper

Hexapod with Integrated Limb Mechanism of Leg and Arm

Noriho Koyachi
Tatsuo Arai
Hironori Adachi
Ken'ichi Asami
Yoshihiro Itoh

This paper provides a new concept for the integration of locomotion and manipulation, "the integrated limb mechanism". The concept covers the technical fields both of the control integration and of the mechanism integration necessary for the practical working robot. Here, a six-bar linkage mechanism with four degrees-of-freedom is introduced as an example of the integrated limb mechanism with both advantages for leg sand for arms. Computer simulation with a dynamic model is performed to verify the transformability from leg posture into arm posture of this mechanism. The kinematic analysis is done for this mechanism, and it is suggested that the kinematic analysis is useful for the geometric and mechanical design. The possibility of dual arms or triple arm work is analyzed.

ICRA Conference 1995 Conference Paper

Integrated Arm and leg Mechanism and Its Kinematic Analysys

Tatsuo Arai
Noriho Koyachi
Hironori Adachi
Keiko Homma

The concept of "limb mechanism" is proposed, consisting of several common link mechanisms which can be used for either arm or leg, selectively. Integrated kinematics is introduced for r legs and one arm mechanism. Based on the derived kinematics evaluation criteria are introduced in order to design the mechanism itself as well as a motion controller. Simulation results show how the proposed methods work effectively to analyze motion of the integrated mechanism.

IROS Conference 1995 Conference Paper

Integration of parallel arm and legged mechanism

Tatsuo Arai
Hironori Adachi
Keiko Homma
Noriho Koyachi

An excavation robot is required to build a large scale underground dome. The excavation robot is developed which is composed of a parallel manipulator and four legged locomotion machine. Although the parallel manipulator has a nice feature of producing large force required for the excavation, cooperative control should be considered to achieve effective excavation. This paper discusses integrated kinematics for r legs and parallel arm mechanism for analysis of the mechanism and its control. Based on the derived kinematics, evaluation criteria are introduced in order to design the mechanism itself as well as the motion controller. Numerical examples show how the proposed methods work effectively to analyze motion of the integrated mechanism.

ICRA Conference 1995 Conference Paper

Two-Finger Micro Hand

Tamio Tanikawa
Tatsuo Arai
Pasi Ojala
Masami Saeki

The dexterous micro manipulation system is developed for application in assembling micro machines, manipulating cells, and micro surgery. We have proposed a concept of a two-finger micro hand, and designed and built two types of hand modules based on parallel mechanisms. In this paper, we mainly discuss the structure of a two-finger micro hand. The structure of the two-finger micro hand is strongly related to the effective work space, or the common work space of two fingers as well as its cooperation control algorithms. Therefore we design the structure to be suitable for a two-finger micro hand, and made a prototype. And the control system for the micro hand should be robust in some disturbance for accurate position control. A H/sub /spl infin// controller is applied to the control system of the micro hand. The controller has a tuning parameter. By tuning the parameter, the characteristic of the control system is changed like a PID controller. In a general H/sub /spl infin// controller, the characteristics are conservative, however, good stability and fast response are obtained easily in our controller.

IROS Conference 1993 Conference Paper

A new prototype parallel manipulator: Kinematics and sensor calibration

Jeffrey C. Hudgens
Tatsuo Arai

A third generation parallel link manipulator (PLM) has been developed at the Mechanical Engineering Laboratory. The device is similar in geometry to existing prototypes in the laboratory, however, the position sensing hardware configuration for online forward position analysis has been changed. The actuators and drivetrains are also more robust to provide for more realistic task demonstrations. This paper includes a brief description of the new prototype hardware. A closed-form forward position algorithm suitable for the new sensor configuration is derived, and a practical procedure for position sensor calibration is developed and demonstrated.

ICRA Conference 1991 Conference Paper

A prototype parallel manipulator: kinematics, construction, software, workspace results, and singularity analysis

Kevin Cleary
Tatsuo Arai

A prototype parallel link manipulator is described. The kinematics of a general parallel link manipulator are discussed. The hardware and software of the prototype manipulator are presented. Some symbolic kinematic results for the prototype are given, along with a discussion of how these results might be used. The workspace of the prototype is analyzed, both by simulation and experimentation. The singularity problem for parallel manipulators is discussed, and a singular configuration for the prototype is shown. >

IROS Conference 1991 Conference Paper

Optimal sensor placement for forward kinematics evaluation of a 6-DOF parallel link manipulator

Robert S. Stoughton
Tatsuo Arai

A design for a 6-DOF parallel actuated robot is presented. The design is a generalization of the Stewart-platform, and has the potential for improved dexterity compared with the traditional design. Methods for handling the forward kinematics problem are discussed. These methods include approximate linear analysis using numerical integration of the Jacobian matrix, and the use of redundant position sensors. There are several alternative locations for placement of these sensors. The accuracy and complexity of the computations for the forward kinematics vary with different locations of the sensors. Further, for some configurations it is possible to continue operation when one more sensors are lost or damaged, leading to a more robust design for remote operations. >

IROS Conference 1990 Conference Paper

Control of robot using coupled torque between joints

Tatsuo Arai
Shih-Hsuan Chiu

In high speed motion, the coupling inertia torques and nonlinear velocity torques of a robot arm are the major components of the dynamic forces and often cause that one of the motors exceeds its torque limit. The experiment outlined in the paper utilizes 'the coupled torques' to decrease the required torque of the motor. The authors have developed a direct-drive robot arm with 3 degrees of freedom. The inertia matrix and the dynamics of the robot arm are analyzed. The authors put an extra weight on the arm to change the inertia matrix of the robot arm. To evaluate the ability of the robot arm, they introduce an evaluation function, the 'general acceleration margin' (GM) which expresses the remaining acceleration ability of the robot arm. The inertia matrix is optimally designed for the robot arm to have the largest GM. The optimization of the inertia matrix makes the robot arm realize the high speed trajectory.

IROS Conference 1990 Conference Paper

Design, analysis and construction of a prototype parallel link manipulator

Tatsuo Arai
Kevin Cleary
Tatsuya Nakamura
Hironori Adachi
Keiko Homma

The paper discusses characteristics mechanism analysis, a design method and an overview of a prototype parallel link manipulator. An evaluation criteria is introduced by analyzing the manipulator statics using the singular value decomposition to realize a well balanced parallel mechanism. Based on this criteria a new configuration is proposed and the basic characteristics of a prototype manipulator are discussed.

IROS Conference 1990 Conference Paper

Spatial image model for manipulation of shape variable objects and application to excavation

Keiko Homma
Tatsuya Nakamura
Tatsuo Arai
Hironori Adachi

Proposes a spatial image model which expresses the physical characteristics of an object whose shape may vary. This model consists of a mass of particles to represent the shape of the object and a set of production rules to predict the change of the object's shape. Models to represent gas, liquid and soil are described. A three-dimensional model for sand is used to describe the planning method based on the model. Finally, this planning method is applied to an experimental excavation of sand using an industrial manipulator with a six-axis force/torque sensor.