Hybrid impedance and admittance control of robot manipulator with unknown environment

This paper presents a novel impedance control strategy to improve the performance of a robot manipulator. Impedance control and admittance control have complementary effects on the stability and performance of a control system. Impedance control works well in stiff environments, whereas admittance control works well in soft environments. In this paper, we propose a hybrid impedance and admittance control strategy that switches the controller based on the switching condition. If proper switching between impedance control and admittance control is achieved, the controller will have the advantages of both the control strategies. The proposed schemes were evaluated through simulations using a 2-DOF manipulator. Experiments were conducted using an actual robot. The results of the simulation and experiments performed confirmed that the proposed control strategy improves the performance of the robot manipulator.