Dynamic In-Hand Sliding Manipulation

This paper presents a framework for planning the motion of an n-fingered robot hand to create an inertial load on a grasped object to achieve a desired in-grasp sliding motion. The model of the sliding dynamics is based on a soft-finger limit surface contact model at each fingertip. A motion planner is derived to automatically solve for the finger motions for a given initial and desired configuration of the object relative to the fingers. Iterative planning and execution are shown to reduce the errors that occur due to the modeling and trajectory tracking errors. The framework is applied to the problem of regrasping a laminar object held in a pinch grasp. We propose a limited surface model of the contact pressure distribution at each finger to predict the sliding directions. Experimental validations are shown, including iterative error reduction and repeatability of the experiment.