Lateral Parameter-Varying Modelling and Control of a UAV on-Ground

Lateral modelling and control of a UAV on-ground is one of the critical phases of its flight. In this paper, a linear parameter-varying (LPV) mathematical model is proposed for the taxi phase. First, a complete non-linear taxi model has been derived, which includes the forces generated by both the aerodynamics and the interaction of the tyres and runway. The model is explicitly dependent on forward velocity of the UAV which continuously varies during take-off and landing both. Since, a single H0c loop shaping controller designed at a particular velocity point does not suffice the design requirements of all other velocity points, so parameter-varying Hoc loop shaping controllers are developed. It utilizes the observer plus state feedback structure of H0o loop shaping controller. A comprehensive control law in the parametric form in which the controller and observer gain matrices are explicitly dependent on the forward velocity has been derived. This control law is successfully evaluated 011 a real world example of a test UAV and actual results are in good comparison with the simulation.