Fixed-Time Observer-Based Sliding Mode Control of Air-Breathing Hypersonic Vehicles Subject to Multisource Uncertainties and Actuator Faults

A composite control scheme is proposed for an air-breathing hypersonic vehicle at the presence of multisource uncertainties and actuator faults. Firstly, the dynamic model of the vehicle is transformed into five control-oriented subsystems. Then, the improved fixed-time sliding mode observer is used to estimate the uncertainties caused by elastic effects, external disturbances and actuator faults, these uncertainties are further compensated in the integral terminal sliding mode control laws. Finally, the stability of the closed-loop system is analyzed, the result shows that the designed control system is asymptotically stable. Compared with the disturbance observer-based robust backstepping control system, the designed control system has great advantages in settling time and control efforts, and has strong robustness to multisource disturbances and actuator faults.