Cooperative circumnavigation of a moving target with multiple nonholonomic robots using backstepping design

The problem of cooperative circumnavigation of a moving target with multiple nonholonomic robots is addressed in this paper. The goal for the multi-robot system is to circumnavigate the moving target with prescribed radius, circular velocity, and inter-robot angular spacing. Two distributed control strategies respectively in Cartesian coordinates and polar coordinates are proposed using backstepping techniques, in which some virtual signals are introduced to facilitate the control design. Under some mild assumptions on the velocity of the target, the proposed controllers ensure asymptotic convergence of the robot team to the desired motion. Explicit stability and convergence analyses are presented using Lyapunov tools. The effectiveness of the proposed control strategies is demonstrated through numerical simulations.