Cooperative moving path following for multiple fixed-wing unmanned aerial vehicles with speed constraints

This paper is to address a cooperative moving path following (CMPF) problem, in which a fleet of fixed-wing unmanned aerial vehicles (UAVs) are required to converge to and follow a desired geometric moving path while satisfying prespecified speed and spatial constraints. A representative application of the CMPF problem is the challenging mission scenario where a group of UAVs are tasked to track a moving ground target. The proposed methodology is based on the insight that a vehicle can follow a given path only through attitude control, thus leaving its speed as an extra input to be used at the coordination level. To deal with moving path following (MPF) of a single UAV, a non-singular control law is derived to steer the vehicle along the desired moving path which avoids the singularity problem in the previous MPF strategy. For multi-UAV coordination, a pursuit strategy is employed with the introduction of a virtual leader. To account for speed constraints and collision avoidance, conditions are derived under which the combined MPF and multi-UAV coordination closed-loop system is asymptotically stable while speed and spatial constraints are satisfied. Further simulation has been performed to demonstrate the effectiveness of the proposed method.