Predictor‐Based Adaptive Robust Control for Input Delay Systems With Lipschitz Nonlinear Uncertainties and Disturbances

ABSTRACT This article proposes a predictor‐based adaptive robust tracking controller for input delay systems with unknown plant parameters, Lipschitz nonlinear uncertainties and disturbances. The underlying robust controller, with a predictor‐based structure to compensate for the effect of input delay, comprises the feedforward compensation and predictor feedback with prior knowledge about the bounds of unknown parameters, uncertainties and disturbances. At the same time, projection‐type adaptation laws are designed to reduce parametric uncertainties. Lyapunov functions are constructed to prove the semi‐global stability of the closed‐loop system in the sense that the tracking error is upper bounded by a known function which exponentially converges to a certain range as long as the control parameters meet specified conditions. In particular, when there are only parametric uncertainties including constant disturbances, the tracking error is guaranteed to converge to zero asymptotically. Simulations with a second‐order plant demonstrate the effectiveness of the proposed controller.