Adaptive Variable Impedance Control for Multi-axis Force Tracking in Uncertain Environment Stiffness with Redundancy Exploitation

Abstract

This paper presents an adaptive variable impedance control methodology forforce tracking on multi-axis robotic activity in uncertain environmental stiffness along withredundancy exploitation. The classical impedance control schemes are not effective for forcetracking in uncertain environments; therefore, a revised impedance control scheme is proposedherein. The mathematical model of the robot’s motion, including its kinematics and dynamics,alongside the proposed control scheme has been discussed in detail. The robotic system’sredundancy is exploited to avoid singularities. A series of simulations based on the practicalscenarios have been carried out on a 3R planar robot considering the uncertain environmentalstiffness. The results indicate that the proposed control approach significantly reduces the forceerror-overshoot during the transition in environmental stiffness. Besides, the manipulabilityindex is reasonably improved as well.