Cooperative Fencing Control of Multiple Vehicles for a Moving Target With an Unknown Velocity

In this article, we investigate a moving-target-fencing problem for multiple vehicles using nearest neighbor rules where the target moves with an unknown constant velocity. Without a predefined stand-off distance or formation, two local cooperative controllers are proposed using only the relative position information from the target and its neighbors within its local frame of reference. The controllers consist of three functionalities. The repulsive term between a vehicle and its neighbors is used to avoid collision. The attractive term between a vehicle and the target drives the vehicle toward the target. The adaptive term amounts to estimate the target's velocity. Specifically, with the first controller, the vehicles follow the target's velocity in the average sense resulting in rotation about the target; with the second controller, each vehicle is able to follow the target's velocity resulting in a rigid formation. Furthermore, a decentralized estimator is applied to handle the case where only a portion of vehicles can access the target's position. Both controllers assure target fencing. The results are proved by rigorous theoretical analysis and verified by extensive numerical simulation.