Design of sliding mode attitude control system for stratospheric airship

For the case of attitude control for stratospheric airship,a new robust nonlinear sliding mode control system is proposed. Firstly,the nonlinear dynamics is built with the consideration of the uncertainties due to flight environment and the model error and couplings among different channels. Secondly, several sliding modes and control law with robustness are derived by applying the backstepping method, and the reachability and stability of sliding mode is strictly proven by Lyapunov stability theory. The influence of mismatched uncertainties on system performance is eliminated,and the problem of differential expansion in traditional backstepping is avoided. Finally,the simulation results demonstrate that the controller could meet the performance of control system and adapt well to stratospheric environment and unknown disturbances.