Compensation of discrete contact state errors in regrasping experiments with the TUM-hand

In this paper we present an approach to compensate for discrete contact state errors in regrasping tasks with multi-fingered robotic hands. An adaptation of reference trajectories connected with a hybrid discrete-continuous control architecture allows to keep stable grasps even if moving fingers cannot contact at the desired position on a grasped object. We propose a robust control setup that allows to perform multiple regrasping tasks of objects using this compensation strategy and contact force optimization. Experimental results with the hydraulic robotic hand of the TUM verify the proposed approach and illustrate the increase in robustness for multi-fingered manipulation.