Finite-gain L2 Stability of Anti-windup Adaptive Tracking Control for Euler-Lagrange Systems with Actuator Saturation

The present paper describes finite-gain L-2 stability guaranteed locally by the proposed anti-windup adaptive law for Euler-Lagrange systems with actuator saturation. All constant parameters of the robot system are estimated for an arbitrary target orbit. In order to achieve finite-gain L-2 stability and ensure adaptive tracking performance, an output saturation function of the tracking error is introduced. The finite L-2 gains are derived considering four actuator saturation cases, and finite-gain L-2 stability is guaranteed locally based on passivity. The control performance is verified through numerical simulations using a two-link robot arm.