Fixed-Wing UAV Attitude and Altitude Control via Adaptive Second-Order Sliding Mode

Abstract

This paper proposes an advanced control approach applied to a fixed-wing Unmanned Aerial Vehicle (UAV) to ensure the stabilization of its angular and vertical positions (attitude and altitude). Actually, the UAV is represented by a dynamic model and is controlled by a robust control law which is the adaptive super-twisting algorithm. This controller based on a second-order sliding mode (SOSM) control is justified by the fact that the fixed-wing UAV has a complex nonlinear, strongly coupled model and undergoes external disturbances. The proposed approach overcomes these problems and ensures finite time convergence. It should be noted that gain adaptation reduces chatter. The performance and effectiveness of the proposed controller are tested by simulations in trajectory tracking mode and compared to classical sliding and classical super-twisting controllers.