Multi-robot enclosing formation for moving target capture

In a problem of target capturing for multiple robots, it is an issue that the target is fixed or movable. When the target is fixed, the problem is solved by enclosing the target. However, it is useless if the target moves. We have investigated the restrictive velocity of the target that the robots can maintain the enclosing formation. The velocity of the target is supposed to be constant and smaller than the maximum velocity of the robots. Simulations demonstrate the restrictive condition for the target by showing the enclosing formation is not maintained when the restrictive condition is not satisfied.