Mignon Park

ICRA Conference 2005 Conference Paper

A New Facial Features and Face Detection Method for Human-Robot Interaction

• Taigun Lee
• Sung-Kee Park
• Mignon Park

We propose an effective facial features detection method for human– robot interaction (HRI) with indoor mobile robot. In case of human-robot interaction, its vision system has to manage such difficult problems as pose variations, illumination changes, and complex backgrounds, which is caused by the mobility of robot. In this paper, in order to overcome such difficult problems, we suggest a facial feature detection method based on local image area and direct pixel-intensity distributions, in which we propose two novel concepts; the directional template for evaluating intensity distributions and the edge-like blob map with multiple strength intensity. Using this proposed blob map, we show that the locations of major facial features – two eyes and a mouth – can be successfully estimated. Without the information of facial area boundary, final candidate face region is determined by both obtained locations of facial features and weighted correlations with stored facial templates. Our approach is also a flexible algorithm that can be applicable to both color and gray image. In case of color image, faster detection of both facial features and face is feasible by using the chromatic property of facial color. Experimental results from many color images and well-known gray level face database images prove the usefulness of proposed algorithm in human– robot interaction applications.

IROS Conference 2004 Conference Paper

Passivity control of a passive haptic device

• Beom-Seop Kim
• Mignon Park
• Chang-Soon Hwang
• Mun Sang Kim
• Changhyun Cho

In this paper, we propose an energy-based stability control of a passive haptic device equipped with passive actuators such as an electric brake. Unstable behavior is observed even in the passive haptic system due to time delay mainly arising from the slow update rate of the virtual environment. The force approximation, one of the major limitations of the passive haptic device, is explained in the passive FME analysis. The ideal force display of passive haptic device is investigated, and it is shown that the passive haptic system frequently obtains the pullback capability due to the force approximation. The indirect force control scheme is proposed in that the change rate of passivity is controlled to simulate the ideal force display. To avoid the increase of the passivity due to the rate controller, which is not correlative to stability, passivity feedback is established. An experiment was conducted with a 2-link passive haptic device equipped with two electric brakes. From the experiment, the proposed control method showed satisfactory performance in displaying a plain virtual wall.

IROS Conference 2004 Conference Paper

ROBHAZ-DT3: teleoperated mobile platform with passively adaptive double-track for hazardous environment applications

• Woosub Lee
• Sungchul Kang
• Mun Sang Kim
• Mignon Park

In this paper, design and integration of the ROBHAZ-DT3 are introduced which is a newly developed mobile robot system with double tracks. It is designed to curry out military and civilian missions in various hazardous environments. The rotational passive adaptation mechanism equipped between the front and rear body enables the ROBHAZ-DT3 to have good adaptability to uneven terrain including stairways. The passive adaptation mechanism reduces energy consumption in moving on uneven terrain as well as it offers simplicity in design and teleoperation. Based on this new design concept, dynamic simulation was conducted to determine the significant parameters such as optimal track size and allowable attack angle. Also dynamic effects in vehicle turning are investigated to assess proper load torque. The ROBHAZ-DT3 system developed was successfully experimented in stair climbing case.

IROS Conference 1999 Conference Paper

A new exoskeleton-type masterarm with force reflection: controller and integration

• Sooyong Lee
• Jangwook Lee
• Woojin Chung
• Mun Sang Kim
• Chong-Won Lee
• Mignon Park

For robot teleoperation, a lot of research has been done to control the slave robot from a remote site using a masterarm. The concept of a distributed controller architecture for the masterarm is introduced in the paper. To reduce possible non-uniform time delay and to have higher position command update rate, the host controller with distributed satellite controllers is developed. Each satellite controller measures the corresponding joint angle, while the host controller performs initial calibration, inverse kinematics calculation, and position commands generation. The host controller and the satellite controllers are networked via a SPI (serial peripheral interface) protocol. For force feedback, the host controller solves the joint torque relations based on the kinematics of the masterarm and the satellite controller controls each joint's torque. This distributed controller greatly reduces calculation and control loads and makes the electrical wiring very simple. In order to measure finger movement of the operator, the master hand is developed using infrared light. A similar slave satellite controller for this master hand is interfaced to the host controller via a SPI network. For teleoperation of the KIST humanoid robot which has two arms and two hands, the masterarm controller with one host controller and 16 satellite controllers is implemented. Force feedback with less than 2 msec update rate is achieved. This masterarm/hand is also integrated with a graphic model instead of using the slave robot. The experimental results show the performance of the distributed controller.

IROS Conference 1999 Conference Paper

Tracking control of a robot manipulator using a direct model reference adaptive fuzzy control

• Young-Wan Cho
• Eung-Sun Kim
• Kichul Lee
• Mignon Park

A direct model reference adaptive fuzzy control (MRAFC) scheme is developed for the plant model whose structure is represented by the Takagi-Sugeno model. The MRAFC scheme is proposed to provide asymptotic tracking of a reference signal for the systems with uncertain or slowly time-varying parameters. The developed control law and adaptive law guarantee the boundedness of all signals in the closed-loop system. In addition, the plant state tracks the state of the reference model asymptotically with time for any bounded reference input signal. The suggested design technique is applied to tracking control of a two-link robot manipulator.

IROS Conference 1999 Conference Paper

Tracking control of a robot manipulator using sliding mode controller with fast and accurate performance

• Chang-Woo Park
• Jaehoon Kim
• Cheol Kwon
• Mignon Park

In a variable structure control algorithm, sliding mode makes the closed loop system insensitive to modelling uncertainties and external disturbances. However due to imperfections in switching, the system trajectory chatters, which is very undesirable, and the insensitivity property of a sliding mode controller is present only when the system is in the sliding mode. To overcome this shortcoming, a sliding mode control algorithm using time-varying sliding surface and PID-like structure is proposed. This controller guarantees robustness during the whole period of control and removes chattering and also reduces steady state error of the system. To demonstrate its performance, the proposed control algorithm is applied to a two link robot manipulator.

IROS Conference 1998 Conference Paper

Variable structure control of manipulator using linear time-varying sliding surfaces

• Heejin Lee
• Hyunseok Shin
• Euntai Kim
• Seungwoo Kim
• Mignon Park

This paper proposes a new variable structure controller (VSC) for the accurate tracking control of a manipulator using the variable boundary layer. Up to now, VSC applying the variable boundary layer did not remove chattering from an arbitrary initial state of the system trajectory because VSC has used the fixed sliding surface. But, by using the linear time-varying sliding surfaces, the scheme has the robustness against chattering from all states. This scheme can be applied to the second-order nonlinear systems with parameter uncertainty and extraneous disturbances, and have better tracking performance than the conventional method. To demonstrate its performance, the proposed control algorithm is applied to a two-link manipulator.

IROS Conference 1996 Conference Paper

Navigation control of mobile robot using distance profile histogram

• Hyuntae Kim
• Kichul Lee
• Kangyuel Ryu
• Mignon Park

A new local path planning algorithm using DPH (distance profile histogram) is suggested in this paper. The proposed method makes a grid type world map using distance values acquired from multiple ultrasonic sensors and generates local points through which the mobile robot can avoid obstacles safely. The DPH (distance profile histogram) represents geometrical arrangement of obstacles around the robot in a local polar coordinate system which is assumed to be attached to the robot. To control the robot's navigation a three-layered control structure is adopted. The validity of the proposed method is demonstrated through several experiments.

IROS Conference 1995 Conference Paper

A stiffness control of a manipulator using a fuzzy model

• Moon Ju Kim
• Cheol Kwon
• Minkee Park
• Mignon Park

In this paper, we suggest a method of deciding the PD gains of a stiffness controller using an identification method based on the Takagi-Sugeno's fuzzy model. It is difficult to perform a compliance task due to the characteristics of the robot itself and an uncertain work environment. Therefore, in this paper, we identify a fuzzy model by dividing the relationship of input-output data into several piecewise-linear equations using the Hough transform, which is an image processing method, and by fine-tuning the parameters of the fuzzy model using the gradient-descent method. By using this fuzzy model, we propose a method of designing the PD gains of the stiffness controller. Finally we show the validity of this method by a surface tracking experiment using a paper box.

IROS Conference 1995 Conference Paper

Hybrid force/position robot control using an adaptive fuzzy control method

• Seungwoo Kim
• Heung-Sik Noh
• Dong-Min Woo
• Mignon Park

A fuzzy adaptive controller, which is able to solve the problems of classical adaptive controllers and conventional fuzzy adaptive controllers, is suggested in this paper. The suggested design method is applied to hybrid robot control. The architecture of a fuzzy adaptive controller using the robust property of a fuzzy controller is explained. A design procedure which can be carried out mathematically and systematically from the model of an objective system is suggested. This fuzzy adaptive controller is used in the control algorithm which is adaptive to the parametric uncertainty in hybrid force/position robot system, and its practicality is confirmed by an experiment on hybrid force/position robot system.

IROS Conference 1993 Conference Paper

A new fuzzy adaptive controller using a robust property of fuzzy controller

• S. W. Kim
• Euntai Kim
• Mignon Park

A fuzzy adaptive controller which is able to solve the problems of classical adaptive controllers and conventional fuzzy adaptive controller is suggested. The architecture of a fuzzy adaptive controller using the robust property of a fuzzy controller is explained. A design procedure which can be carried out mathematically and systematically from the model of an objective system is suggested, and related mathematical theorems and their proofs are also given. The performance of the proposed adaptive control algorithm is analyzed through a DC motor control simulation and experiments on a compliant robot system.

IROS Conference 1992 Conference Paper

Cooperative Mobile Robots Using Fuzzy Algorithm

• Hyuntae Kim
• Seungwoo Kim
• Mignon Park
• Heung-Sik Noh

IROS Conference 1992 Conference Paper

The Acquisition Of Distance And Orientation Of A Mobile Robot With A Concept Of Virtual Corner Point

• Minkee Park
• Hyunduck Kim
• Dong-Min Woo
• Mignon Park

IROS Conference 1991 Conference Paper

Automated shadow mask inspection using DSP

• Dong-Min Woo
• Mignon Park

Presents a new shadow mask inspection method which can detect the very small hole defects reliably and rapidly; the shadow mask line image data is periodical. The inspection method mainly depends on the fact that a small defect can be significantly emphasized in terms of the comparison between the image pixels departed by the period. In this paper, this comparison is implemented as the digital filtering algorithms, which can be rapidly processed by a DSP chip. In terms of the high speed line image sensing and fast algorithm by DSP, the whole inspection scheme sufficiently supports the real time shadow mask handing. From the experimental results, this scheme shows a reliable inspection capability for all types of individual hole defects.

IROS Conference 1991 Conference Paper

Fuzzy compliance robot control

• Seungwoo Kim
• Mignon Park

Proposes a compliance robot control algorithm using fuzzy adaptive controller and fuzzy compliance vector generator. In the compliance robot control, one needs more adaptivity because the linear modeling in robot dynamics is getting more difficult by contact with external environment. Existing adaptive controllers have difficulty in realtime processing. So in order to overcome it, the authors adopt fuzzy adaptive controller and propose fuzzy compliance vector generator for flexible compliant motion. They analyze and confirm the proposed algorithm by surface processing experiment with a control system implemented by VME system.

IROS Conference 1990 Conference Paper

A study on compliance control for manipulator

• Misun Do
• Yang Hee Yee
• Hyunduck Kim
• Mignon Park

The compliant motion control of a manipulator is proposed by the self-tuning adaptive control method. Compliant motion is needed in such complicated and accurate fields as assembly operation in which several parts are mated. Among compliant motion control methods, the hybrid control is used so that force and position control is processed selectively through a closed feedback loop. In case of contacting with environment, uncertainties of manipulator are more serious. In order to satisfy the desired operation, self-tuning controller which adapts to various dynamic response is applied to compliant motion control. Finally, the applicability of the suggested algorithm by simulation results of the contour tracking task of four-joint manipulator is confirmed.