Adaptive tracking control of a class of nonlinear time-delay systems with NN actuator saturation compensation

In this paper, adaptive tracking control is investigated for a class of nonlinear time-delay systems with actuator saturation nonlinearity. The uncertain time-delay function is bounded by a nonlinear function with unknown coefficients. The actuator saturation nonlinearity is assumed to be nonsymmetric and unknown. Neural network approximation techniques are utilized to compensate the saturation nonlinearity and the NN saturation compensator is placed in a feed-forward path, which is easy to be implemented. Based on Lyapunov approach, the resulting closed-loop control system performance and the boundedness of the NN weights are derived and guaranteed, and the tracking error exponentially converges to a small adjustable neighborhood of zero. Simulation studies are included to demonstrate the effectiveness of the proposed approach.