Robust control of an uncertain underactuated airship with asymptotic rejection against wind disturbance

This paper considers the problem of controlling both the planar position and the orientation of an underactuated airship with a reduced number of actuators in the presence of a unknown persistent wind disturbance. The airship is a nonholonomic system described by a set of nonlinear equations and the dynamics are subjected to bounded uncertainties. A smooth and time-varying coordinate transformation is proposed to reduce the disturbance rejection problem of the airship to that of a simple linear time-invariant system. A new adaptive robust feedback controller provides global stabilization and asymptotical rejection against the unknown wind disturbance under the plant uncertainties. The proposed design method is simple and straightforward. Some flight simulations using a real blimp are performed to validate the effectiveness of the proposed controller.