Adaptive fault-tolerant attitude tracking control of hypersonic vehicle subject to unexpected centroid-shift and state constraints

Abstract

This paper presents a study on hypersonic vehicle (HSV) with unexpected centroid shift, actuator fault, system input saturation and state constraints, aiming to investigate the adaptive fault-tolerant control method for stability recovery of HSV. By analysis, the influence of unexpected centroid shift mainly reflects in three aspects: 1) uncertainties of the system, 2) eccentric moments, 3) variation of system inertial matrix. For system uncertainties, eccentric moments and actuator fault, the radial basis function neural network (RBFNN) and adaptive estimator are utilized to obtain those unknown nonlinearities. For the bad effects of actuator faults, system input constraints and variation of inertial matrix, an adaptive estimator combined with Nussbaum gain is designed to cope with that problem. In addition, the barrier Lyapunov function is adopted in order to limit the amplitude of the attitude angles ensuring the safety of HSV. Then, the fault-tolerant controller is established using the backstepping technology to synthesize various control strategies. At last, the boundedness of whole closed-loop system signals and stability of system are demonstrated by Lyapunov theory of stability. The simulation results illustrate the effectiveness of the proposed control strategies in this paper.