Local control strategy for moving-target-enclosing under dynamically changing network topology

This paper studies the moving-target-enclosing problem for a group of autonomous mobile robots, which can be seen as the requirement of achieving a formation surrounding a moving target whose movement is not known a priori. A local information control law is proposed to solve the problem utilizing only the relative position information from the target and its neighbors. The derivation of the controller is based on the idea of decoupling the task of target tracking and the task of inter-robot coordination. It is shown that the group of autonomous mobile robots collaboratively estimates the moving velocity of the target and asymptotically reaches a regular polygon formation to keep the moving target as its centroid. The neighbor topology may dynamically change as the system evolves. Hence, a non-smooth version of LaSalle’s invariance principle is used to show the convergence.