Integrated fault‐tolerant control system design based on continuous model predictive control for longitudinal manoeuvre of hypersonic vehicle with actuator faults

Abstract

In this study, an integrated fault-tolerant control (IFTC) approach with a two-layer structure is proposed for longitudinal manoeuvre of the hypersonic vehicle with elevator deflection faults. On the top, longitudinal manoeuvre trajectory optimisation problem being subjected to state and input constraints is formulated. The minimum oscillation is taken as the objective function, and the direct collocation method is introduced to calculate the optimal manoeuvre reference trajectory online. On the bottom, diverse elevator deflection faults of the hypersonic vehicle are considered. The faulty longitudinal model is reformulated by input–output feedback linearisation, and the faults are equivalently lumped into additional uncertainties. For the lumped uncertainties and high-order derivatives of velocity and altitude of manoeuvre feasible trajectory, an extended state observer is used for online estimation. The fault-tolerant control based on continuous model predictive control is designed, where predictive models are derived by Taylor expansion approximation. To guarantee that the control inputs do not violate constraints, the analytical control law is improved by the optimal-aim distance criterion. The stability of the closed-loop control system and boundedness of observation errors are proved. The simulations verify the effectiveness of the proposed IFTC approach.