Optimal leader allocation in UAV formation pairs ensuring cooperation

This paper considers the problem of optimally allocating the leader task between pairs of selfish un-manned aerial vehicles (UAVs) flying in formation. The UAV that follows the other achieves a fuel benefit. The noncooperative nature of the agents makes it necessary to arbitrate leader-allocation mechanisms that induce collaboration so that the fuel consumption benefits of flying in formation can be realized. Formulated as a nonlinear program, our problem poses two distinct challenges: on the one hand, given a fixed number of leader switches, determine the optimal leader allocation and, on the other, find the optimal number of leader switches. Even though the first problem is nonconvex, we identify a suitable restriction of its feasible set that makes it convex while maintaining the same optimal value. Regarding the second problem, our analysis of the optimal value of the problem as a function of the number of switches allows us to design a search algorithm which is guaranteed to find the solution in logarithmic time. Several simulations illustrate our results. (C) 2013 Elsevier Ltd. All rights reserved.