UAV Formation Reconfiguration Strategy Considering Fuel Consumption and Escape Time

Abstract

A sequential quadratic programming is used to formulate and solve a trajectory optimization problem for UAV formation reconfiguration. In this dissertation, a formation reconfiguration is designed for a UAV formation in a situation where a certain UAV in formation flight cannot perform a given mission due to a failure. In this case, the faulty UAV should leave the formation and return to the base, while its corresponding duty in the formation is transferred to another UAV in the group. The formation reconfiguration process is divided into two maneuvers: escape maneuver and replacement movement. A trajectory optimization problem is constructed for each maneuver while considering a physically reasonable cost function and constraint of collision avoidance. The escape maneuver is formulated as a minimum-time problem to reduce the possibility of collision and the replacement movement is formulated as a minimum-fuel problem to secure UAV durability. Three dimensional equations of motion are derived with respect to the formation frame. The reconfiguration process can be optimized in the general situation that the formation group is turning with time-varying angular velocity. To evaluate the optimization results, the fuel consumption for the reconfiguration is considered. For comparison, optimization of the trajectories following a three-phase reference trajectory is also performed. The overall results show that the optimized trajectories reduce fuel consumption as well as elapsed time.