Anti-windup adaptive tracking control for Euler-Lagrange systems with actuator saturation

The present paper proposes an anti-windup adaptive law for Euler-Lagrange systems with actuator saturation. For an arbitrary target orbit, all constant parameters of the robot system are estimated by the proposed anti-windup adaptive law. In order to ensure tracking performance with actuator saturation, the input saturation state is classified into four saturation cases, and an adaptive law is given for each case. Switching of the adaptive law according to saturation case is proposed. Two Lyapunov functions, such as hybrid control, are derived and global asymptotic stability is ensured by energy dissipation between the two Lyapunov functions. The control performance is verified through numerical simulations using a two-link robot arm.