Adaptive terminal sliding mode attitude control law of elastic flying wing UAV with backstepping

An attitude control strategy based adaptive terminal sliding mode backstepping was proposed for the flying wing layout and unmanned aerial vehicle (UAV) rigid/elastic coupled dynamic model with the nonlinear, strong coupling, parameter uncertainties and external disturbance. Firstly, the actual control and the virtual control were designed with the backstepping design system derived directly from applying Lyapunov stability theory. Secondly, in virtual control, it employed the adaptive norm switch sliding mode to eliminate the negative effects from the uncertainties and resilient-rigid coupling. Furthermore, it utilized integral item of feedback system to reinforce robustness and dynamic characteristic. In the actual control input, it injected the robust adaptive terminal sliding mode to eliminate the uncertainty and disturbance effects and solved the calculating explosion problems of back stepping method and control buffeting problems, improved the control accuracy and robustness of the system. Finally, according to Lyapunov theory, it proves that the tracking error astringes to arbitrarily small field. The simulation results indicate that the method has robustness to the model uncertainty, aero elasticity, gust and external disturbance effect and can realize high precision position tracking control.