Mesh stability of unmanned aerial vehicle clusters

In this paper we present a cluster controller design of a mesh of helicopters which, produces the trajectory to be tracked in terms of desired acceleration. As an intermediate step for the formation flying of a cluster of helicopters an individual helicopter controller is designed which accepts the trajectory to be tracked in terms of desired accelerations. The design uses the fact that the linear position dynamics of a helicopter are slow compared to the attitude dynamics. Next we discuss the design of a higher level cluster controller assuming simple double integrator dynamics. The results show that we need leader information to achieve mesh stability in case of point masses. The higher level mesh controller is then used for simulation of a formation flight of a cluster of helicopters. It is observed that the intuition about mesh stability obtained with simple double integrator dynamics is carried over to the case of helicopters.