Robust control design based on sliding mode control for hover flight of a mini tail-sitter Unmanned Aerial Vehicle

In this paper, the modeling and robust control design of a vertical flight attitude control for a mini tail-sitter with variable pitch propeller is discussed. Tail-sitters vertical take-off and landing - unmanned aerial vehicles (VTOL-UAVs) have the operational flexibility of a typical helicopter while having the cruise performance of a fixed wing airplanes. The VTOL-UAVs configuration used in this paper is highly unstable in its natural flight state in vertical mode. First of all, a simplified attitude dynamic model that includes interval parametric uncertainty is obtained; then a control law based in the sliding mode control (SMC) technique is applied to stabilize the decoupled attitude control systems. The results are supported by simulation tests.