Computing and controlling compliance of a robotic hand

The authors express the compliance of the grasp of a robotic hand as a function of grasp geometry, contact conditions between the fingers and the grasped object, and mechanical properties of the fingers. It is argued that the effects of structural compliance and small changes in the grasp geometry should be included in the computation. Factors are then examined that can lead a grasp to become unstable, independently of whether it satisfies force closure. Finally, the authors examine the reverse problem of how to specify servo gains at the joints of a robotic hand so as to achieve, as nearly as possible, a desired overall grasp compliance. It is shown that coupling between the joints of different fingers is useful in this context.>