Robust Stabilization of Elastic Joint Robots by ESP and PID Control: Theory and Experiments

This work addresses the problem of global set-point control elastic joint robots by combining structure preserving (ESP) with non-collocated integral action. Despite popularity and extensive research on PID for rigid robots, such schemes largely evaded adoption to robots. is mainly due underactuation inherent these systems, which impedes direct implementation (link position) feedback. We remedy this issue using recently developed concept “quasi-full actuation,” achieve a link-side “delayed” The design follows philosophy ESP ensures asymptotic stability local passivity closed loop. A key feature proposed controller switching logic action that enables combination excellent positioning accuracy in free motion compliant manipulation contact environment. Its performance evaluated an testbed robot arm. results demonstrate may comparable