Control system of airship based on nonlinear disturbance observer

A variable structure control scheme based on nonlinear disturbance observer is proposed for the position control of the stratospheric airship according to the uncertainties of its attitude control system. Firstly, the mathematic model of the pitch channel in stratospheric airship is built by considering the uncertainties including system model error and disturbance under the flight environment. Secondly, with the help of introducing the nonlinear disturbance observer, the control system of pitch channel is derived from the method of variable structure control with a sliding mode. Finally, the nonlinear simulation is used to show that the control scheme can estimate effectively the uncertainties, and the robustness and dynamic performance of the control system is met.