Fault-tolerant attitude tracking control for a quadrotor aircraft

A quaternion-based attitude tracking scheme for a quadrotor subject to external disturbances and partial loss of rotor effectiveness faults is proposed in this paper. In attitude tracking controller design, the indirect robust adaptive control technique is employed to compensate the external disturbances and gyroscopic term, and stable attitude trajectory tracking is achieved. Then, the desired attitude tracking torques are maintained by designing the motor torques in the case of partial loss of rotor effectiveness faults. Based on the on-line estimation of the rotor effectiveness factor, an adaptive fault-tolerant controller is proposed to generate motor torques, where the rotor faults are handled without using the fault detection and diagnosis (FDD) mechanism. Simulation results are provided to demonstrate the performance of the proposed scheme against rotor faults.