|
Sign In to gain access to subscriptions and/or personal tools.
|
The International Journal of Robotics Research, Vol. 24, No. 4,
311-327 (2005)
DOI: 10.1177/0278364905049469
© 2005 SAGE Publications
Coping with the Grasping Uncertainties in Force-closure Analysis
Yu Zheng
Robotics Institute, Shanghai Jiao Tong University, Shanghai, China 200030, yuzheng007{at}sjtu.edu.cn
Wen-Han Qian
Robotics Institute, Shanghai Jiao Tong University, Shanghai, China 200030, whqian{at}sh163.net
Friction uncertainty and contact position uncertainty may have a disastrous effect on the closure properties of grasps. This paper reflects our approach to handling these uncertainties in force-closure analysis. The former uncertainty is measured by the possible reduction rate of friction coefficients, while the radius of contact regions is used to quantify the latter uncertainty. The actual contact point may deviate from the desired position but not farther than S, the supremum of without loss of force-closure, indicates the grasp tolerance to contact position uncertainty. For investigating the above uncertainties systematically, we propose three new problems in force-closure: whether a grasp with given and achieves force-closure, what value S equals if is given, and how S varies versus . To facilitate their solutions, we extend the scope of the infinitesimal motion approach from form-closure analysis to force-closure. A necessary and sufficient condition for force-closure is deduced by means of the duality between some convex cones, which play the key role in solving the problems. Finally, efficient algorithms are developed and applied to two illustrative examples.
Key Words: duality force-closure grasping uncertainty infinitesimal motion approach multifingered robot hand

CiteULike Connotea Del.icio.us Digg Reddit Technorati What's this?
|