Adaptive sliding mode control of non-linear non-minimum phase system with input delay

This study proposes an adaptive sliding mode control (SMC) design method for multi-input multi-output non-linear non-minimum phase system with input delay. The problem is challenging, not only because of the unstable internal dynamics of the non-minimum phase system, but also the existence of input delay. The partially linearised model of the original non-linear system is obtained through input/output linearisation, and a state tracking model is constructed based on the computed ideal internal dynamics. A filtered tracking error is introduced to handle the input delay. A SMC strategy is proposed for the stability of filtered tracking error system, and an adaptive law is designed to estimate the upper bound of perturbations. Finally, comparison simulation results on vertical takeoff and landing aircraft are provided to verify the efficiency of the proposed method.