Nonlinear rendezvous guidance law design for a receiver UAV based on the Lyapunov stability theory

Abstract

The rendezvous problem in the autonomous aerial refueling (AAR) was researched for the receiver unmanned aerial vehicle (UAV). The three-dimensional guidance model was constructed for the UAV to pursue the virtual tanker. In order to guarantee the zero miss distance and the intercept angle constraints, a nonlinear rendezvous guidance law was designed for the UAV based on the Lyapunov stability theory. The guidance law generated the normal acceleration command and the lateral acceleration command. The velocity control system was designed by the sliding mode control method. It controled the UAV’s velocity to equal to that of the virtual tanker at the end of the rendezvous phase. The simulation results validate the effectiveness of the designed nonlinear guidance law and the velocity control system.

Sliding mode guidance law for a receiver UAV in the rendezvous phase of autonomous aerial refueling

“…x y z is the UAV's coordinate in the inertial frames, U V is its velocity, U  is its elevation angle, and Figure 1 depicts the geometric relationship of the UAV tracking the virtual tanker. The physical meanings of all variables in Figure 1 are explained in 11 . According to Figure 1 and the previous achievements 11,13 , the 3D rendezvous guidance model is described as follows, cos cos cos cos…”

“…The physical meanings of all variables in Figure 1 are explained in 11 . According to Figure 1 and the previous achievements 11,13 , the 3D rendezvous guidance model is described as follows, cos cos cos cos…”

“…where the physical meanings of all variables are explained in 11 . The following equations are also given in 11 , ( )…”

“…The receiver UAV's guidance law was designed by dividing terminal angle constraint and speed constraint, and the fast terminal sliding mode control strategy was applied to design the guidance law 10 , but there existed the singular problem in the guidance law. A nonlinear rendezvous guidance law was designed for the receiver UAV based on the Lyapunov stability theory 11 , and it controlled the receiver UAV to complete favourably the rendezvous process.…”