Stabilization of a nonlinear underactuated autonomous airship-a combined averaging and backstepping approach

A strategy to design a time-varying stabilizing controller of the position and the orientation of an underactuated autonomous airship is proposed. The dynamic modelling of the airship involves six equations with only three inputs. This airship cannot be stabilized to a point using continuous pure-state feedback law. However, the stabilization problem is solved with an explicit homogeneous time-varying control law, based on an averaging approach. We prove that the origin of the system is locally exponentially stable.