Cooperative Unmanned Air Vehicle Mission Planning and Collision Avoidance

Multiple UAVs can combine capabilities to maximize mission effectiveness. However, many UAVs operating in close proximity increases the likelihood of collision, which causes damage to property and personnel, and at a minimum jeopardizes the mission. Therefore, it is desired to have a method of planning a collision free path for each UAV. The example considered herein involves using multiple UAVs in a surveillance orbit to continuously monitor a target. Nevertheless, the techniques presented herein will apply in a general sense to a myriad of problems. The goal is for the UAVs to arrive in their orbit position as quickly as possible without colliding. This presents a nontrivial problem. The example assumes the UAVs will be launched at different locations, simulating a ground launch tactic. The mission planning portion must solve for the optimal minimum time trajectory for each UAV to arrive on the surveillance orbit with a tangent velocity. Since the vehicles are operating simultaneously, and independently, it is necessary to ensure there is a safety collision avoidance bubble around each UAV at all times. This problem statement reduces to a dynamic constrained optimization problem. Pseudospectral Methods, as implemented through the General Pseudospectral Optimal Control Software (GPOPS ) 1 in this study, serve as a means of transcribing the continuous time optimization problem into a more easily solved discrete non-linear programming (NLP) problem. The software, GPOPS , is open-source and publically available for download.