Quadrotor actuator fault diagnosis and accommodation based on nonlinear adaptive state observer

This chapter presents a nonlinear adaptive state observer-based fault-tolerant tracking control system for a quadrotor unmanned aerial vehicle. The developed control system includes the fault detection module, fault diagnosis module, and accommodation unit against actuator faults. The fault detection and diagnosis (FDD) architecture consist of a nonlinear fault detection estimator and a bank of nonlinear adaptive fault diagnosis estimators. Adaptive thresholds for FDD are designed to enhance fault sensitivity and the robustness of the fault-tolerant control algorithm. Moreover, fault-tolerant tracking control is developed to accommodate the fault effect by virtue of the fault parameter estimated by the FDD algorithm. Finally, numerical simulation and flight test are carried out to validate the effectiveness and applicability of the algorithms.