Author name cluster

Yan-Bin Jia

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.

32 papers

1 author row

ICRA Conference 2025 Conference Paper

Patch Tree: Exploiting the Gauss Map and Principal Component Analysis for Robotic Grasping

Yan-Bin Jia
Yuechuan Xue
Ling Tang

Grasp planning must consider an object's local geometry (at the finger contacts), for the range of applicable wrenches under friction, and its global geometry, for force closure and grasp quality. Most everyday objects have curved surfaces unamenable to a pure combinatorial approach but treatable with tools from differential geometry. Our idea is to “discretize” such a surface in a top-down fashion into elementary patches (e-patches), each consisting of points that would yield close enough wrenches. Preprocessing based on Gaussian curvature decomposes the surface into strictly convex, strictly concave, ruled, and saddle patches. The Gauss map guides the subdivision of any patch with a large variation in the contact force direction, with the aid of a Platonic solid. The principal component analysis (PCA) further subdivides any patch that has a large variation in torque. The final structure is called a patch tree, which stores e-patches at its leaves, and force or torque ranges at its internal nodes. Grasp synthesis and optimization operates on the patch tree with a stack to efficiently prune away non-promising finger placements. Simulation and experiment with a Shadow Hand have been conducted over everyday items. The patch tree exhibits different levels of surface granularity. It has a good promise for efficient planning of finger gaits to carry out grasping and tool manipulation.

ICRA Conference 2024 Conference Paper

Robotic Manipulation of Hand Tools: The Case of Screwdriving

Ling Tang
Yan-Bin Jia
Yuechuan Xue

Despite decades of steady research progress, the robotic hand is still far behind the human hand in terms of dexterity and versatility. A milestone in this quest for human-level performance will be possessing the skills of manipulating hand tools, for their non-trivial geometries and for the intricacies of controlling their contact-based interactions with objects, which are the final targets of manipulation. This paper investigates screwdriving by a robotic arm/hand pair, dealing with the chain of contacts connecting the substrate, screw, screwdriver, and fingertips. Considering rolling contacts and finger gaits, our force control scheme is derived through backward chaining to leverage the dynamics of the screwdriver and arm/hand. To maintain the fastening effort, estimations are carried out sequentially for the screwdriver’s pose via optimization under visual and kinematic constraints, and for its applied wrench on the screw via solution drawing upon dynamics. This wrench, adjusted based on position/force feedback, is mapped by the grasp matrix to the desired fingertip forces, which are then used for computing torques to be exerted by the arm and hand to close the loop. Simulation and experiments with a Shadow Hand have been conducted for validations.

IROS Conference 2023 Conference Paper

Dynamic Finger Gaits via Pivoting and Adapting Contact Forces

Yuechuan Xue
Ling Tang
Yan-Bin Jia

For over three decades, finger gaiting has remained largely a subject for theoretical inquiries. Successful execution of a sequence of finger gaits does not simply reduce to planning collision-free paths for the involved fingers. A major issue is how to move the gaiting finger without losing the finger contacts with the object, which will most likely undergo a motion as the contact forces need to be adapted during the gait. This paper focuses on a single finger gait executed on a tool by an anthropomorphic hand driven by an arm. To improve stability, the tool's tip is leveraged as a pivot on the supporting plane. The gait consists of three stages: removal, during which the contact force on the gaiting finger gradually decreases to zero; relocation, during which the finger follows a pre-planned path (relative to the moving object) to establish a new contact; and addition, during which the contact force on the relocated finger increases to some desired level. Hybrid position/impedance control employs reference finger forces that satisfy the friction cone constraints and are dynamically consistent with the object's motion, which in turn provides reference poses for the fingertips to maintain their contacts during the gait. Finger gaits have been demonstrated on a kitchen knife and a screwdriver with an Adept SCARA robot and a Shadow Dexterous Hand.

ICRA Conference 2023 Conference Paper

Robotic Fastening with a Manual Screwdriver

Ling Tang
Yan-Bin Jia

The robotic hand is still no match for the human hand on many skills. Manipulation of hand tools, which usually requires sophisticated finger movements and fine controls, not only poses a clear technical challenge but also carries a great potential for enabling the robot to assist humans in a wide range of tasks accomplishable using tools. This paper takes a first step to investigate how a robotic arm mounts a rigidly attached screwdriver onto a screw (pre-mounted in a tapped hole) and then tightens it using the tool. Mounting begins with sliding the screwdriver tip on the screw head along preplanned paths to search for the drive and follows with rotating the screwdriver to drop the tip into the drive. Prevention of a slip off the screw head is achieved via impedance control to install a “virtual fence” along its boundary. Turning of the screw is conducted via hybrid position/admittance control based on modeling the reaction force between the screw and the substrate. Simulation results with a KUKA Arm demonstrate the smoothness of the entire action.

ICRA Conference 2022 Conference Paper

Physical Property Estimation and Knife Trajectory Optimization During Robotic Cutting

Xiaoqian Mu
Yan-Bin Jia

Dexterous robotic cutting needs to demonstrate a skill level with smooth and efficient knife movements. The work performed by the knife mainly generates fracture and overcomes the blade-material friction. This paper presents a recursive least-squares method that repeatedly estimates relevant physical parameters such as Poisson's ratio, fracture toughness, and coefficient of friction, all varying with the knife's movement when cutting a natural food, from force sensor readings. Furthermore, we show that these estimates can be used for generating the knife's trajectory on the fly to either maximize the ease of fracturing or to minimize the rate of work.

ICRA Conference 2021 Conference Paper

Robotic Slicing of Fruits and Vegetables: Modeling the Effects of Fracture Toughness and Knife Geometry

Prajjwal Jamdagni
Yan-Bin Jia

Slicing is an important skill for a robot to learn as it is more efficient and results in less deformation in comparison with cutting by pressing. Cutting experiments with foods have indicated that the ease of slicing is caused by a decrease in fracture toughness. In this paper, we formally characterize this decrease based on the work needed to maintain the critical strain for fracture. Forces generating fracture and deformation and overcoming friction are predicted using the finite element method (FEM) and based on fracture mechanics. Extending our previous work [1] on cutting by pressing with a straight knife edge, we model general slicing and knife geometry (i. e. , a curved edge). Experiments over potatoes and eggplants have demonstrated the accurate modeling of the overall cutting force during slicing, which could be leveraged for control of cutting by the robot to demonstrate human-level skills in the near future.

IROS Conference 2020 Conference Paper

Gripping a Kitchen Knife on the Cutting Board

Yuechuan Xue
Yan-Bin Jia

Despite more than three decades of grasping research, many tools in our everyday life still pose a serious challenge for a robotic hand to grip. The level of dexterity for such a maneuver is surprisingly "high" that its execution may require a combination of closed loop controls and finger gaits. This paper studies the task of an anthropomorphic hand driven by a robotic arm to pick up and firmly hold a kitchen knife initially resting on the cutting board. In the first phase, the hand grasps the knife's handle at two antipodal points and then pivots it about the knife's point in contact with the board to leverage the latter's support. Desired contact forces exerted by the two holding soft fingers are calculated and used for dynamic control of both the hand and the arm. In the second phase, a sequence of gaits for all the five fingers is performed quasi-statically to reach a power grasp on the knife's handle, which remains still during the period. Simulation has been performed using models of the Shadow Hand and the UR10 Arm.

IROS Conference 2019 Conference Paper

Robotic Cutting of Solids Based on Fracture Mechanics and FEM

Prajjwal Jamdagni
Yan-Bin Jia

Cutting skills are important for robots to acquire not only because of a need from kitchen automation, but also because of the technical challenge for robotic manipulation. Modeling of fracture and deformation during a cutting action, often based on the finite element method (FEM), provides the force and shape information used in knife control to implement a skill such as slice, chop, or dice. However, an object’s 3D mesh model can be computationally prohibitive for achieving a desired accuracy since numerous tiny elements must be used near the knife’s moving edge. To address this issue, we represent the object as evenly spaced slices normal to the cutting plane such that cutting of each slice requires only a 2D mesh. Fracture and force can be then interpolated between every two adjacent slices. Experiment with an Adept arm and an ATI force/torque (F/T) sensor has demonstrated reasonable accuracy in force ad shape modeling.

ICRA Conference 2019 Conference Paper

Robotic Cutting: Mechanics and Control of Knife Motion

Xiaoqian Mu
Yuechuan Xue
Yan-Bin Jia

Effectiveness of cutting is measured by the ability to achieve material fracture with smooth knife movements. The work performed by a knife overcomes the material toughness, acts against the blade-material friction, and generates shape deformation. This paper studies how to control a 2-DOF robotic arm equipped with a force/torque sensor to cut through an object in a sequence of three moves: press, push, and slice. For each move, a separate control strategy in the Cartesian space is designed to incorporate contact and/or force constraints while following some prescribed trajectory. Experiments conducted over several types of natural foods have demonstrated smooth motions like would be commanded by a human hand.

ICRA Conference 2018 Conference Paper

Dexterous Manipulation by Two Fingers with Coupled Joints

Yan-Bin Jia
Yuechuan Xue

This paper studies dexterous manipulation in the plane by a two-fingered hand in the plane. The dynamics of each finger, which consists of two links with coupled joints, are derived based on Lagrangian mechanics. As an object is being manipulated, its orientation and the two independent joint angles of the hand constitute the state of the entire system. Contact kinematics, accounting for both stick and slip modes, are combined with dynamics to establish a dependence of the object's linear and angular accelerations on joint accelerations. This allows control of joint torques, under a proportional-derivative (PD) law, to move the object to a target position in a desired orientation.

IROS Conference 2016 Conference Paper

Batting flying objects to the target in 2D

Matthew Gardner 0003
Yan-Bin Jia
Huan Lin

This paper presents a planning algorithm for a 2-DOF robotic arm to bat a flying 2D object to a targeted location. Impact dynamics are combined with trajectory kinematics and manipulator dynamics to compute the evolving set of states (poses and velocities) of the arm able to achieve the task as the object is flying. Planning is conducted under the arm's dynamic and kinematic constraints. At the time of hit, the robot executes an action to minimize its total energy. Simulation and Experiments have been conducted using a Whole Arm Manipulator (WAM) from Barrett Technology, Inc.

IROS Conference 2015 Conference Paper

Computational modeling of N-body collisions

Feifei Wang
Huan Lin
Yan-Bin Jia

This paper presents an impulse-based model for n-body collisions with or without friction. In the frictionless case, impulses at all the contacts, initialized via solution of a non-linear system, accumulate over different phases (compression and restitution) tracked through numerical integration. Experiment over Newton's cradle, using vision-based velocity estimation, achieves a close agreement with simulation. The presence of friction requires a contact mode analysis via solution of a linear system to check for contact mode consistencies with Coulomb's friction law. Simulation of nine-ball break shots, drawing upon a recent trajectory study [6], yields realistic scenarios. The modeling approach is part of our efforts toward planning for robotic manipulation strategies using impulsive forces.

ICRA Conference 2015 Conference Paper

Planning finger movements to lift up deformable 2D objects

Feng Guo 0004
Yan-Bin Jia

This paper describes a strategy to lift up a deformable 2D object resting on a horizontal plane. Inspired by human hand lifting behavior, the strategy plans grasping trajectories of two fingertips using modified Rapidly-exploring Random Trees (RRT). Compared to a straight squeeze, a planned finger movement not only enlarges the graspable region, but also minimizes the work. Improvements on control complexity and robustness are made through modifications to RRT. The introduced strategy is applicable to both hollow and solid 2D objects, and is extendable to 3D ones.

ICRA Conference 2015 Conference Paper

Planning the motion of a sliding and rolling sphere

Yan-Bin Jia

This paper investigates the free motion of a sphere with initial velocity and angular velocity on a plane under sliding and rolling friction. The sphere will first slide along a parabolic trajectory (with a constant direction of its contact velocity), and then roll along a straight trajectory. Such a curved trajectory can be utilized for obstacle avoidance in path planning. A one-to-one correspondence exists between trajectories connecting two specified locations and pairs of sliding and rolling directions within some 2-dimensional region, called the trajectory space, which is then used for planning. A plane sweep algorithm operating in this space is presented to find all collision-free trajectories in the presence of cylindrical obstacles that are vertically oriented.

ICRA Conference 2014 Conference Paper

Picking up soft 3D objects with two fingers

Huan Lin
Feng Guo 0004
Feifei Wang
Yan-Bin Jia

This paper describes a simple strategy for a robot hand to grasp and lift a deformable 3D object resting on a table. Inspired by the human hand grasping, the strategy employs two rigid hemispherical fingers to first squeeze the object until a secure grip is achieved under contact friction, and then translate vertically upward. During the squeeze, a lift test is repeatedly conducted to determine if the maximum hypothetical liftable weight of the object reaches its real weight. Actual lifting follows when the test is passed. The object's deformation and configuration of contact with the fingers and the plane are tracked using the finite element method (FEM) in an event-driven manner, based on varying contact displacements induced by the finger movements. The gravitational force acting on the object is accounted for. Slips inside the contact regions are determined from solving quadratic systems. Experiment has been conducted to demonstrate the efficiency and accuracy for this sensorless grasping approach.

IROS Conference 2013 Conference Paper

Optimal two-finger squeezing of deformable objects

Yan-Bin Jia
Huan Lin
Feng Guo 0004

This paper gives an in-depth analysis of two-finger squeeze grasping of deformable objects introduced in our previous work [6] with a focus on two special classes: stable squeezes, which minimize the potential energy of the system among squeezes of the same magnitude, and pure squeezes, which eliminate all possible Euclidean motions from the resulting deformations. Next, the paper characterizes the best resistance by a grasp to an adversary finger under known translation, as the one that minimizes the work done by the grasping fingers. An optimization scheme is offered to deal with the general case of frictional segment contact. Simulation and experimental results are presented.

ICRA Conference 2013 Conference Paper

Squeeze grasping of deformable planar objects with segment contacts and stick/slip transitions

Feng Guo 0004
Huan Lin
Yan-Bin Jia

Robotic grasping of a deformable object is difficult not simply due to the high computational cost of deformable modeling. More fundamentally, the difficulty lies in a wrench space that changes under deformation, with growing contact areas, and subject to varying slip/stick modes in these areas. This paper presents a grasping strategy by squeezing the object with two fingers. An analysis based on the finite element method (FEM) proves equilibrium and uniqueness of deformation during the action, and leads to a (improved) quadratic time deformation update from the displacements of as few as two contact nodes. An event-driven algorithm is then presented to track the contact regions during a squeeze, and determine the stick/slip mode of every node in contact. The contacts supply the constraints needed for deformation update using FEM. Several experiments with a Barrett Hand have been conducted for validation.

ICRA Conference 2011 Conference Paper

On two-finger grasping of deformable planar objects

Yan-Bin Jia
Feng Guo 0004
Jiang Tian

Grasping a deformable object instantaneously requires maintaining equilibrium of its pre- and post-deformed shapes using the same set of forces. This paper studies the type of grasps generated by squeezing a planar object with two fingers. It is shown that the success of such a grasp is independent of the applied forces in the case of small deformation. Numerical algorithms are introduced to compute sets of squeeze grasps with small and large deformations modeled using the finite element method (FEM) based on the linear and nonlinear elasticity theories, respectively.

ICRA Conference 2009 Conference Paper

Modeling deformable shell-like objects grasped by a robot hand

Jiang Tian
Yan-Bin Jia

This paper models (large) deformations of shelllike objects under the grasping of a robot hand. Classical nonlinear theory of thin shells [21, pp. 186-194] is generalized to shells with arbitrary parametric middle surfaces, using a method introduced in our earlier work [13]. An experimental study demonstrates higher modeling accuracy using the nonlinear elasticity theory than its linear counterpart. Given that many deformable objects undergo sizable shape changes when they are grasped, our result supports the application of nonlinear elasticity theory in the future design of grasp strategies for this type of objects.

IROS Conference 2008 Conference Paper

Deformations of general parametric shells: Computation and robot experiment

Yan-Bin Jia
Jiang Tian

A shell is a body enclosed between two closely spaced and curved surfaces. Classical theory of shells [38], [33], [16] assumes a parametrization along the lines of principal curvature on the middle surface of a shell. Such a parametrization, while always existing locally, is not known for many surfaces, and deriving one can be very difficult if not impossible. This paper generalizes the classical strain-displacement equations and strain energy formula to a shell with an arbitrary parametric middle surface. We show that extensional and shearing strains can all be represented in terms of geometric invariants including principal curvatures, principal vectors, and the related directional and covariant derivatives. Computation of strains and strain energy is also described for a general parametrization. The displacement field on a shell is represented as a B-spline surface. By minimization of potential energy, we have simulated deformations of algebraic surfaces under applied loads, and performed experiments on an aluminum soda can and a stretched cloth using a three-fingered Barrett Hand. The measured deformations on each object match those in the simulation with good accuracy. The presented work is an initial step in our research on robot grasping of deformable objects.

ICRA Conference 2006 Conference Paper

Surface Patch Reconstruction via Curve Sampling

Yan-Bin Jia
Liangchuan Mi
Jiang Tian

This paper introduces a method that reconstructs a surface patch by sampling along three concurrent curves on the surface with a touch sensor. These data curves, each lying in a different plane, form a "skeleton" from which the patch is built in two phases. First, the Darboux frame at the curve intersection is estimated to reflect the local geometry. Second, polynomial fitting is carried out in the Darboux frame. The use of total (absolute) Gaussian curvature effectively prevents unnecessary folding of the surface normally expected to result from fitting over one-dimensional data. The reconstructed patch attains remarkable accuracy as demonstrated through experiments. This work carries a promise for in-hand manipulation. It also has potential application in building accurate models for complex curved objects which can cause occlusion to a camera or a range sensor

IROS Conference 2006 Conference Paper

Surface Recognition by Registering Data Curves from Touch

Rinat Ibrayev
Yan-Bin Jia

Model-based recognition of an object typically involves matching dense 3D range data. The computational cost is directly affected by the amount of data of which a transformation needs to be found before carrying out the match against a model. This paper investigates recognition using "one-dimensional" data, more specifically, points sampled along three concurrent curves on the surface of an object. The introduced method determines the quality of match against a model in two steps. First, the Gaussian and mean curvatures at the curve intersection point are estimated and used in a table lookup to find multiple candidate points on the model that have similar local geometry. Second, starting at each point, local optimization is conducted to search for a possible location of the curve intersection on the model as well as an orientation that leads to a good match of all data points. The best match between the model and the data curves is chosen over the results obtained from all candidate points. The quality of this match is used for comparison against other models. Simulation and experiment have been conducted to validate the recognition approach

IROS Conference 2004 Conference Paper

High precision contour tracking with a joystick sensor

Liangchuan Mi
Yan-Bin Jia

High performance contour tracking is achievable with simple sensing and control. We describe a system that tracks unknown shapes with a joystick sensor mounted on an Adept SCARA robot. The joystick's limited force sensing is combined with the Adept's high positional accuracy to yield precise contact measurements. Force control is carried out with a simple feedback loop to avoid unnecessary oscillations. Due to contact friction and random sensor noise, prediction of the tangential motion from force measurements alone is unreliable. A position control strategy is devised to update the tracking direction based on a quadratic t to local turning of the contour. Fitting yields more accurate shape approximation while the use of local data keeps the computational cost low for constant updates. The result is fast tracking with hardly any loss of shape accuracy.

ICRA Conference 2004 Conference Paper

Tactile Recognition of Algebraic Shapes using Differential Invariants

Rinat Ibrayev
Yan-Bin Jia

This paper studies the recognition and localization of 2-D shapes bounded by low-degree polynomial curve segments based on minimal tactile data. We have derived differential invariants for quadratic curves and two special classes of cubic curves. Such an invariant, independent of translation and rotation, is computed from the local geometry at any two points on the curve. Recognition of a curve class becomes verifying the corresponding invariant with more than one pairs of data points. Next, the actual curve is determined in its canonical parametric form using the same tactile data. Finally, the contact locations on the curve are computed, thereby localizing the shape completely relative to the touching hand. Simulation results support the working of the method in the presence of small noise, although real experiments need to be carried out in the future to demonstrate its applicability. The presented work distinguishes from traditional model-based recognition in its ability to simultaneously recognize as well as localize a shape from one of several classes, each consisting of a continuum of shapes.

IROS Conference 2003 Conference Paper

Contact sensing for parts localization: sensor design and experiments

Yan-Bin Jia

A 2-axis force/torque sensor has been designed for contact sensing and the localization of 2-D curved shapes. The sensor is an aluminum piece attached with two "chip sensors", each a half-bridge circuit consisting of two strain gauges. It functions like a "wrist" which uses the two chip sensors to detect bending and twisting moments, respectively. When an external force is exerted on a jaw mounted with the F/T sensor, the point of force application is linearly related to the ratio between the reading variations from the chip sensors. This principle is used for determining contact locations on the jaw after calibration. A simple strategy is later described to control the jaw to roll on a motionless 2-D object while estimating the movement of contact. Given its shape, the object's position and orientation relative to the jaw can also be estimated during the rolling motion. Experiments have been conducted with an Adept Cobra 600 manipulator.

ICRA Conference 2002 Conference Paper

Curvature-Based Computation of Antipodal Grasps

Yan-Bin Jia

It is well known that antipodal grasps can be achieved on curved objects in the presence of friction. This paper presents an efficient algorithm that finds, up to numerical resolution, all pairs of antipodal points on a closed, simple, and twice continuously differentiable plane curve. Dissecting the curve into segments everywhere convex or everywhere concave, the algorithm marches simultaneously on a pair of such segments with provable convergence and interleaves marching with numerical bisection. It makes use of new insights into the differential geometry at two antipodal points. We have avoided resorting to traditional nonlinear programming which would neither be quite as efficient nor guarantee to find all antipodal points. Dissection and the coupling of marching with bisection introduced in this paper are potentially applicable to many optimization problems involving curves and curved shapes.

IROS Conference 2001 Conference Paper

Localization on curved objects using tactile information

Yan-Bin Jia

This paper offers a computational study of finger localization on 2D curved objects using tactile data which builds on efficient numerical processing of curves. Our first algorithm localizes one rolling finger on a stationary object. It finds all boundary segments with the same arc length and total curvature computed from tactile data. The algorithm slides an imaginary segment along the object boundary by alternatively marching its two endpoints forward, stretching or contracting the segment if necessary. Through a curvature-based analysis we establish the global convergence of the algorithm to every location of such a segment and also derive the local convergence rate. The algorithm runs in time linear in the size of the discretized boundary curve domain. Based on these results, we present a global algorithm to localize two fingers rolling on a free object. The algorithm partitions the object boundary into segments over which related total curvature functions are monotonic. Then it combines bisection with forward marching to search for possible locations of the fingers within every pair of such segments.

ICRA Conference 2000 Conference Paper

Grasping Curved Objects through Rolling

Yan-Bin Jia

Grasping a curved object free in the plane may be done through rolling a pair of fingers on the object's boundary. Each finger is equipped with a tactile sensor able to record any instantaneous point contact with the object. Contact kinematics reveal a relationship between the amount of finger rotations and the total curvatures of the boundary segments of the fingers and the object respectively traversed by the two contact points during the same period of rolling. Such relationship makes it possible to localize both fingers relative to the object from a few pairs of simultaneously taken finger contacts at different time instants. A least squares formulation of this localization problem can then be solved by the Levenberg-Marquardt algorithm. Simulation results are presented. After localization, a simple open loop strategy is used to control the continual rolling of the fingers until they simultaneously reach two locations on the object's boundary where a grasp is finally performed.

ICRA Conference 1998 Conference Paper

Observing Pose and Motion Through Contact

Yan-Bin Jia
Michael A. Erdmann

Investigates how to "observe" a planar object being pushed by a finger. The pushing is governed by a nonlinear system that relates through contact the object pose and motion to the finger motion. Nonlinear observability theory is employed to show that the contact information is often sufficient for the finger to determine not only the pose but also the motion of the object. Therefore a sensing strategy can be realized as an observer of the nonlinear dynamical system, which is subsequently introduced. The observer based on the result of Gauthier et al. (1992), has its "gain" determined by the solution of a Lyapunov-like equation. Simulations have been done to demonstrate the feasibility of the observer. A sensor has been implemented using strain gauges and mounted on an Adept robot with which preliminary experiments have been conducted from a general perspective, this work presents an approach for acquiring geometric and dynamical information about a task from a small amount of tactile data, with the application of nonlinear observability theory.

ICRA Conference 1996 Conference Paper

Pose from pushing

Yan-Bin Jia
Michael A. Erdmann

In the absence of vision, grasping an object often relies on tactile feedback from the fingertips. Before force closure is formed, where on the object a fingertip touches can usually be felt from the motion of contact on the fingertip during a small amount of pushing. In this paper the authors investigate the first stage of such "blind" grasping. More specifically the authors study the problem of determining the pose of a known planar object by pushing. Assuming sliding friction in the plane, a dynamic analysis of pushing results in a numerical algorithm that compares the object pose from three instantaneous contact positions on a fingertip. Simulations and experiments (with an Adept robot) have been conducted to demonstrate the sensing feasibility. Inspired by the way a human hand grasps, this work can be viewed as a primitive step in exploring interactive sensing in grasping tasks.

IROS Conference 1995 Conference Paper

On computing optimal planar grasps

Yan-Bin Jia

The quality of a grasp can often be measured as the magnitude within which any external wrench is resistible by "unit grasp force". In this paper, we present a numerical algorithm to compute the optimal grasp on a simple polygon, given contact forces of unit total magnitude. Forces are compared with torques over the radius of gyration of the polygon. Our analysis shows that the optimal grasps may be of a continuum. We also address a grasp optimality criterion for resisting an adversary finger located possibly anywhere on the polygon boundary. The disparity between these two grasp optimality criteria are demonstrated by simulation with results advocating that grasps should be measured task-dependently. The paper assumes non-frictional contacts.

ICRA Conference 1994 Conference Paper

Sensing Polygon Poses by Inscription

Yan-Bin Jia
Michael A. Erdmann

Industrial assembly involves sensing the pose (orientation and position) of a part. Efficient and reliable sensing strategies can be developed for an assembly task if the shape of the part is known in advance. In this paper the authors investigate the problem of determining the pose of a convex n-gon from a set of m supporting cones, i. e. , cones with both sides supporting the polygon. An algorithm with running time O(nm) which almost always reduces to O(n+m log n) is presented to solve for all possible poses of the polygon. As a consequence, the polygon inscription problem of finding all possible poses for a convex n-gon inscribed in another convex m-gon, can be solved within the same asymptotic time bound. The authors prove that the number of possible poses cannot exceed 6n, given m/spl ges/2 supporting cones with distinct vertices. Experiments demonstrate that two supporting cones are sufficient to determine the real pose of the n-gon in most cases. The authors' results imply that sensing in practice can be carried out by obtaining viewing angles of a planar part at multiple exterior sites in the plane. As a conclusion, the authors generalize this and other sensing methods into a scheme named sensing by inscription. >