Distributed Visibility Preservation for Hybrid Nonholonomic Leader-Follower Formation with General Network Structure

This paper studies leader-follower formation tracking problem for hybrid multiple nonholonomic robots with visibility constraints. With onboard vision sensors on follower robots and inter-robot communication, a new distributed controller for leader-follower formation is proposed based on dynamic surface control method. Our presented controller can make tracking errors of relative distances and bearing angles between each leader-follower pair in the robot team arbitrarily small by adjusting parameters. In addition, the visibility sensor constraints and connectivity of communication graph are preserved all the time. Unlike most of papers which can merely cope with the condition where one leader tracks only one leader, our methods can be suitable to more general network structure with multiple leaders as well. Furthermore, the proposed method is adaptive to different kinds of robots including first-order and second-order multi-robot systems. Also, it can be robust to actuator faults and abrupt disturbance in second-order robots. Lyapunov stability analysis and several numerical simulation are presented to verify the correctness and effectiveness of our proposed controller.