The kinematics of multi-fingered manipulation

Previously, general models of the kinematics of multi-fingered manipulation have only treated instantaneous motion (i.e., velocities). However, such models, which ignore the underlying configuration (or state) space, are inherently incapable of capturing certain properties of the fingers-plus-object system important to manipulation. In this paper, we derive a configuration-space description of the kinematics of the fingers-plus-object system. To do this, we first formulate contact kinematics as a “virtual” kinematic chain. Then, the system can be viewed as one large closed kinematic chain composed of smaller chains, one for each finger and one for each contact point. We examine the underlying configuration space and two ways of moving through this space. The first, kinematics-based velocity control, is a generalization of some previous velocity-based approaches. The second, hyperspace jumps, is a purely configuration-space concept. We conclude with a discussion of how these concepts can be used to understand the task of twirling a baton [6].