  This paper proposes a method for the deployment of a multi-agent system of
unmanned aerial vehicles (UAVs) as a shield with potential applications in the
protection of infrastructures. The shield shape is modeled as a quadric surface
in the 3D space. To design the desired formation (target distances between
agents and interconnections), an algorithm is proposed where the input
parameters are just the parametrization of the quadric and the number of agents
of the system. This algorithm guarantees that the agents are almost uniformly
distributed over the virtual surface and that the topology is a Delaunay
triangulation. Moreover, a new method is proposed to check if the resulting
triangulation meets that condition and is executed locally. Because this
topology ensures that the formation is rigid, a distributed control law based
on the gradient of a potential function is proposed to acquire the desired
shield shape and proofs of stability are provided. Finally, simulation and
experimental results illustrate the effectiveness of the proposed approach.
