Sliding mode control for a near space autonomous airship

The near space autonomous airship represents a unique and promising solution for many applications ranging from surveillance, communication utilities and scientific exploration. In attempt to complete the various missions, the near space airship first requires an accurate control system for autonomous flight. This paper presents an improved sliding mode control method for autonomous flight, considering the characteristics of nonlinearity, strong coupling and uncertainty of an airship. Firstly, the dimensional motion mathematical model of an airship is derived, including kinematics and dynamics equations. Then the controller for autonomous flight is designed by use of an improved variable structure control method, which adopts the boundary layer sliding mode control approach. Finally simulation results illustrate the effectiveness of the proposed method. The proposed control method is robust to parameter uncertainties and external disturbances, and provides an effective approach to design flight control system of a near space airship.