Stability of planar grasps

It is well established that all form closed grasps are stable. However, not all stable grasps are form closed, including many common and easily obtainable grasps. This is especially true in whole arm manipulators and multi-fingered hands where, in many cases, it is difficult or impossible to effect a form closed grasp. Thus it is necessary to establish a general framework for the determination of stability for any equilibrium grasp. In order to analyze the stability of grasps with multiple contacts, we first model the compliance at each contact. We develop expressions for the changes in contact forces as a function of the rigid body relative motion between the fingers and a grasped planar object. The stability of a grasp is shown to depend on the local curvature of the contacting bodies as well as the magnitude and arrangement of the contact forces. We then derive results providing simple criteria to determine the stability of almost any grasped planar object, including the special but important limiting case of rigid bodies where the contact compliance is zero.<<ETX>>

[1]  J. Burdick,et al.  A configuration space analysis of bodies in contact. I: 1st order mobility , 1995 .

[2]  Imin Kao,et al.  Computing and controlling compliance of a robotic hand , 1989, IEEE Trans. Robotics Autom..

[3]  H. Hanafusa,et al.  Stable Prehension by a Robot Hand with Elastic Fingers , 1977 .

[4]  David J. Montana,et al.  The Kinematics of Contact and Grasp , 1988, Int. J. Robotics Res..

[5]  Joel W. Burdick,et al.  Towards planning with force constraints: on the mobility of bodies in contact , 1993, [1993] Proceedings IEEE International Conference on Robotics and Automation.

[6]  Van-Duc Nguyen,et al.  Constructing Stable Grasps , 1989, Int. J. Robotics Res..

[7]  Mark R. Cutkosky,et al.  Friction, Stability and the Design of Robotic Fingers , 1986 .

[8]  N. Sarkar.  Control of mechanical systems with rolling contacts: applications to robotics , 1993 .

[9]  Jeffrey C. Trinkle,et al.  On the stability and instantaneous velocity of grasped frictionless objects , 1992, IEEE Trans. Robotics Autom..

[10]  Matthew T. Mason,et al.  Robot Hands and the Mechanics of Manipulation , 1985 .

[11]  B. Mishra,et al.  Some discussion of static gripping and its stability , 1989, IEEE Trans. Syst. Man Cybern..

[12]  David J. Montana,et al.  The condition for contact grasp stability , 1991, Proceedings. 1991 IEEE International Conference on Robotics and Automation.

[13]  Vijay Kumar,et al.  A minimum principle for the dynamic analysis of systems with frictional contacts , 1993, [1993] Proceedings IEEE International Conference on Robotics and Automation.