Unmanned Aerial Vehicles (UAVs) are gaining wide acceptance as tools in various industries, in civil as well as military applications. Many UAV systems are expensive and require substantial amounts of personnel and equipment on the ground to support any mission. The deployment of an UAV involves risk and critical applications. These risks include damage to the airframe particularly during take off and landing, damage to the flight control system and damage to the mission payload. This paper aims at showing how backstepping algorithm is effective in developing automatic glide and flare path control when compared to existing algorithms. In this paper the glide-slope control and flare path control are compared with conventional Proportional-Integral-Derivative controller design. The key idea of the backstepping algorithm is to benefit the design from the better knowledge of naturally stabilizing aerodynamic forces acting on the aircraft. The resulting state feedback control laws thereby rely on less knowledge of these forces compared to control laws based on Proportional- Integral-Derivative controller design. For that purpose the flight path angle control, the glide slope tracking is designed first via backstepping algorithm. A candidate controller structure for an aircraft glide slope tracking as well as flare path are presented. The derived glideslope control law is much simpler and easier to construct with localizer controller. Nonlinear 6DOF simulation results demonstrate that the backstepping tracking law can effectively guide the aircraft along the glideslope centerline until the flare control before touchdown.
展开▼
