Nonlinear Disturbance-Observer-Based Sliding Mode Control for Flexible Air-Breathing Hypersonic Vehicles

摘要

This paper investigates a tracking problem for flexible air-breathing hypersonicvehicles (FAHVs) with composite disturbance. The composite disturbance producedby flexible effects, parameter uncertainties, and external interferences is modeledas a kind of unknown derivative-bounded disturbance in this paper. Then a novel compositecontrol strategy is presented for the nonlinear FAHV model with the compositedisturbance, which combines a nonlinear disturbance-observer-based compensator (NDOBC)and a dynamic-inversion-based sliding mode controller (DIBSMC). Specifically,the NDOBC is constructed to estimate and compensate for the composite disturbance,and the DIBSMC is designed to track desired trajectories of velocity and flight pathangle. Moreover, the uniformly ultimate boundedness of the composite system canbe guaranteed by using Lyapunov theory. Finally, simulation results on a full nonlinearmodel of FAHVs demonstrate that the proposed nonlinear disturbance-observer-basedsliding mode controller is more effective than the traditional DIBSMC. Specifically, it isshown that the chattering of traditional DIBSMC in presence of composite disturbancescan be attenuated with the NDOBC.