Adaptive hybrid formation-search and track controller of UAVs

In this paper, a novel search and track scheme is developed through adaptive hybrid formation- search and track controller of networked unmanned aerial vehicles (UAVs). The search and the track algorithm is carried out with antennas placed on at least four UAVs that kept the ‘+’ formation on the x-y plane. The x-axis is assumed to lie in the east–west direction and the y-axis in the north–south direction. UAVs flying in the ‘+’ formation are divided into 4 main groups: east, west, north, and south. UAVs on the x-axis are driven from the difference in signal strengths of the east group and the west group, and on the y-axis from the difference in signal strengths of the north and south groups respectively. The hybrid controller consists of two discrete modes: (1) formation mode (2) search and track mode. The back-stepping formation controller is derived through Lyapunov stability criteria to make the UAVs fly in ‘+’shape and at a fixed altitude. Then, received signal power consensus-based search and track controller is developed for networked UAV groups flying in a desired ‘+’ formation. Simulation results verify our theoretical claims.