Robust impedance control of a robot manipulator with exponential tracking error convergence

The authors develop a robust position/force controller based on the impedance approach without requiring exact knowledge of the robot dynamics. The controller is designed so that a desired positional trajectory can be followed along the surface of the environment while the forces exerted on the environmental surface are regulated according to a target impedance. A global exponential stability result is obtained for the position tracking error and the force regulation error (i.e. the error between the actual manipulator impedance and the desired target impedance). The controller only requires measurement of the end effector force, joint velocity, and joint position