Prescribed Performance Control for Robotic Systems with Unknown Dynamics

Abstract

In this paper, a prescribed performance controller for robotic systems with guaranteed transient and steady-state performance is proposed. A performance function that characterizes the convergence rate, maximum overshoot and steady-state error is employed to construct a new coordinate system. Then, the tracking error of the original system can be retained within a prescribed bound by stabilizing the transformed system. The unknown dynamics are accurately estimated by an estimator. The merit of the estimator is that the structure is simple and only one parameter needs to be tuned. The stability of the control system including the prescribed performance control and the unknown dynamics estimator is proved via Lyapunov theory. Simulation results are carried out to validate the effectiveness of the proposed control scheme.