Back-stepping sliding mode control method for quadrotor UAV with actuator failure

In this article, a fault tolerant controller (FTC) based on back-stepping sliding mode is proposed for a quadrotor unmanned aerial vehicle (UAV) with single-rotor failure. According to the working mechanism of the quadrotor, the control system of UAV is divided into position subsystem and attitude subsystem. Then, the yaw control is abandoned because of the increased underactuation. The controller is designed by the back-stepping sliding mode control (BSMC). BSMC is robust to system uncertainties and external disturbances. Sliding mode reaching law is designed. Therefore, it can reduce system chattering. Based on the Lyapunov function method, the proposed FTC approach makes the faulty UAV stable and realises position control accuracy. Finally, simulation results show that the quadrotor UAV can reach the desired position and maintain the hover state, which verifies the effectiveness of the proposed method.