Hover autopilot design for an un-crewed helicopter using static output feedback controller

Design of linear matrix inequality-based static output feedback controller for an un-crewed helicopter in hover flying mode is presented. The six degrees of freedom linear time-invariant state-space model of the vehicle is developed analytically from first principles considering the force and moments acting on it without the usual simplifying approximations. Since access to full state information is not a situation in practice, output feedback-based controller is an appealing solution for the autopilot design. Here, two separate static output feedback controllers are developed for the fast inner-loop and the slow outer-loop dynamics of the vehicle. As the number of variables to be fedback is reduced, the proposed scheme is simpler compared to conventional state feedback controller. Numerical simulation studies validate that the proposed controller exhibits fast transient performance and robustness when subjected to wind disturbances acting in the three fuselage axes during the hover flight.