A composite Fault Tolerant Control based on fault estimation for quadrotor UAVs

This paper proposed a novel composite Fault Tolerant Control (FTC) approach based on fault estimation for quadrotor actuator fault. Firstly, an Adaptive Thau Observer is used to estimate the actuator fault magnitudes, and then faults with different time-varying natures are classified into corresponding fault severity levels based on the predefined fault-tolerant bounds. Secondly, a composite FTC strategy including passive and active FTC is designed to compensate fault for different fault severity levels. Unlike former single passive and active FTC, our proposed FTC can compensate fault in a way of Condition-Based Maintenance (CBM) and is more suitable for complex and time-varying fault, which is general in practice. Finally, Different simulations have been carried out to show the performance and effectiveness of the proposed method.