Adaptive Control for Output-Constrained Nonlinear Systems with Input Delay

This paper concerns the adaptive tracking control for more general nonlinear systems with multiple uncertainties containing output constraint, input delay, unknown parameter uncertainty and external disturbances for the first time. Firstly, the adaptive backstepping technique is combined with the parameter separation technique to solve the parametric nonlinearities. To deal with the serious uncertainties caused by output constraint and input delay, the barrier Lyapunov function (BLF) and the Pade approximation method are employed in a unified framework. Then, the universal adaptive state-feedback control strategy merged with rigorous stability analysis is proposed, which guarantees all the signals in the closed-loop system are uniformly ultimately bounded. In addition, the system output is driven to track the reference signal to a compact set of the origin and the output constraint is not violated. Finally, a simulation example is given to demonstrate the effectiveness of the proposed scheme.