Connectivity-maintaining obstacle avoidance approach for leader-follower formation tracking of uncertain multiple nonholonomic mobile robots

This paper investigates a connectivity-maintaining obstacle avoidance problem for guaranteed-performance-based leader-follower formation tracking of uncertain multiple nonholonomic mobile robots with communication and sensing range constraints. All nonlinearities in the robot dynamics are assumed to be unknown. The desired relative angles among robots for preserving connectivity between the leader and the follower while avoiding obstacles are derived to develop a novel connectivity-maintaining obstacle avoidance strategy. Then, a leader-follower formation tracker using these desired relative angles and connectivity-preserving and collision-avoiding performance functions is designed for accomplishing connectivity maintenance, collision avoidance, and obstacle avoidance among robots. The performance-functions-based avoidance starting range for the connectivity-maintaining obstacle avoidance achievement is induced from the Lyapunov stability analysis. Furthermore, the proposed formation tracking strategy does not require any potential-functions-based approaches and adaptive approximation techniques. Finally, simulation studies clarify and verify the proposed theoretical approach.