Adaptive hybrid impedance control of robot manipulators: A comparative study

Abstract

This article presents an adaptive hybrid impedance control approach for robot manipulators. The proposed scheme, consists of an outer hybrid impedance control loop that generates a target acceleration to an inner adaptive controller in order to linearize the robot dynamics and track the desired force/position. In order to analyse the performance of the proposed control scheme, two distinct adaptive control algorithms in the inner control loop are tested. The performance of the hybrid impedance strategy is illustrated by computer simulations with a 2-DOF PUMA 560 robot, in which the end-effector is forced to move along a frictionless surface in the vertical plane. The results obtained for both adaptive algorithms, reveal an accurate force tracking and impedance control in robotic tasks that require force tracking capability in an rigid environment with a time varying stiffness profile.