Observer-based optimal control method combination with event-triggered strategy for hypersonic morphing vehicle

Abstract

A morphing-attitude coupling control method based on event-triggered adaptive dynamic programming (ETADP) and a finite-time fuzzy disturbance observer (FTFDO) is proposed for a class of hypersonic morphing vehicle (HMV). Firstly, an attitude-morphing coupled dynamic model is established, and the morphing variable is treated as the state for integrated control with attitude. The control law is updated by an event-triggered mechanism, which is designed in two parts: feedforward control and feedback control. Based on the proposed FTFDO, the matched and mismatched uncertainties are estimated and compensated in finite time to solve the feedforward control input. Based on an adaptive dynamic programming algorithm, Critic-Actor dual networks are constructed to implement policy iteration for an approximate optimal feedback control policy by offline training with exploration. The Critic-Actor dual networks then adopt the ETADP algorithm to tune the weight of the networks online when triggering criteria for policy improvement are met. Event-triggered conditions are developed such that the feedforward control and feedback control are both updated by aperiodic sampling, reducing the number of controller updates required. Zeno behavior is avoided by determining the minimum sampling interval time. The stability of the closed-loop system is demonstrated theoretically. Simulation results verify the control efficiency and robustness of the proposed method.