Robotic Time Varying Force Tracking in Position Based Impedance Control

Abstract

This paper presents a unified control framework for both setpoint and timevarying force control of robot manipulator by introducing an improved positionbased impedance control (IPBIC). In order to essentially achieve accurate force control, especially timevarying force tracking, a new target impedance function compensated by a force controller is presented. The essence of the improved method in realizing timevarying force tracking, as well as the coupled stability of the manipulator–environment system is investigated. To further improve the force control performance, the Newtontype iterative learning control (ILC) is introduced upon the closedloop system. A case study on a twolink robot model demonstrates the effectiveness of this method.