Visionbased Localization of Leader-Follower Formations

Abstract — This paper deals with vision-based localization for leader-follower formation control. Each unicycle robot is equipped with a panoramic camera which only provides the view-angle to the other robots. The localization problem is studied using a new observability condition valid for general nonlinear systems, and based on the Extended Output Jacobian. This allows us to identify those robot motions that preserve the system observability and those that render it non-observable. The state of the leader-follower system is estimated via the extended Kalman filter and an input-state feedback control law is designed to stabilize the formation. Simulations as well as real-data experiments confirm the theoretical results and show the effectiveness of the proposed formation control. Index Terms — Mobile robots, nonlinear observability, forma-tion control, panoramic cameras, feedback linearizatio