A distributed reconfigurable control law for escorting and patrolling missions using teams of unicycles

Abstract—Recent years have seen rapidly growing interest in the development of networks of vehicles for which adaptive cooperation and autonomous execution become a necessity. In the paper, we develop a distributed reconfigurable control law to distribute unicycle-type vehicles evenly on a circle surrounding a moving target for the escorting and patrolling missions. The even distribution of the vehicles provides the best overall coverage of the target in its surroundings. It is shown that as the target moves, the group formation moves and rotates around the target to keep the target around the formation centroid. When some vehicles in the group are lost due to faults, the remaining vehicles recognize the loss and adaptively reconfigure themselves to a new evenly distributed formation

Cooperative Target Tracking in Balanced Circular and Elliptical Formations

This paper extends our earlier results on cooperative target tracking in cyclic pursuit using a group of mobile robots by further prescribing the formation radius and achieving an elliptical formation pattern. Prescribing the formation radius of a balanced circular formation is achieved by adjusting a parameter in the existing control input to each robot. The new elliptical formation pattern is obtained via a transformation matrix. Both single-integrator and double-integrator robot models are considered. The effectiveness of the proposed schemes is demonstrated by simulation examples

COOPERATIVE TARGET TRACKING IN CONCENTRIC FORMATIONS

This paper considers the problem of coordinating multiple unmanned aerial vehicles (UAVs) in a circular formation around a moving target. The main contribution is allowing for versatile formation patterns on the basis of the following components. Firstly, new uniform spacing control laws are proposed that spread the agents not necessarily over a full circle, but over a circular arc. Uniform spacing formation controllers are proposed, regulating either the separation distances or the separation angles between agents. Secondly, the use of virtual agents is proposed to allow for different radii in agents’ orbits. Thirdly, a hierarchical combination of formation patterns is described. A Lyapunov analysis is conducted to study the stability characteristics. This paper also addresses the practical issue of collision avoidance that arises while UAVs are developing formations. An additional control component is added that repels agents to steer away from each other once they get too close. All UAVs have constant linear velocities. Control of the UAV is via its yaw rate. The proposed extensions to formation on a portion of a circle, circling on different radii for different agents, formation in local geometric shapes, and inter-vehicle collision avoidance, provide more complete solution to cooperative target tracking in concentric formations