Fault‐tolerant attitude tracking control of tandem rotor helicopter considering internal actuator saturation and external wind gust.

Summary: Tandem rotor helicopter is configured with two main rotors distributed along the longitudinal direction and without anti‐torque tail rotor. Therefore, the control strategy of tandem rotor helicopter can be quite different from that of traditional helicopter systems. In this article, a fault‐tolerant attitude tracking controller is presented for tandem rotor helicopter, with considerations of external wind disturbance and internal actuator problem. First, attitude control oriented dynamic model of the tandem rotor helicopter is constructed, in which both actuator fault and saturation are involved. Base on statistical characteristics of practical wind condition as well as aerodynamic properties of the helicopter rotors, a detailed wind load model is further established. Then, a fault‐tolerant attitude tracking controller is proposed for the tandem rotor helicopter system by incorporating nonsingular terminal sliding mode control with an adaptive super twisting algorithm, which allows a simultaneous regulation of the three angular motions via two propeller rotors. Finally, based on Quanser's 3‐dof helicopter system, comparative simulation tests are performed to demonstrate the effectiveness as well as advantages of the proposed fault‐tolerant controller design. [ABSTRACT FROM AUTHOR]