Robust Adaptive Fault-Tolerant Control for Hypersonic Flight Vehicles with Multiple Faults

Abstract

This paper proposes a robust adaptive strategy for longitudinal dynamics of generic hypersonic flight vehicles with uncertainties and faults. Flight vehicles are generally subjected to disturbances and multiple faults, which should be compensated for to preclude performance degradation. To solve this problem, considering fast abrupt faults such as actuator stuck faults, an adaptive fault observer is added into the nominal dynamic inversion controller to accommodate the effects of faults with discrete function patterns. In addition, since the above observer is designed only for fast abrupt faults, an online support vector machine compensator is proposed to learn the state error caused by other faults. As the error contains both dynamic uncertainties and slow variation faults, additional controllers are not required to get rid of the unwanted faults. Stability of the overall closed-loop system is analyzed with the Lyapunov stability theory, and output tracks the expected trajectory. The simulation is presented with multiple faults to verify the effectiveness and feasibility of the proposed scheme.