UAVs Cooperative Formation Flight Based On Intelligent Technology

The unmanned aerial vehicle(UAV) has a wide range of applications in the military field because of its many advantages. In the transformation process of multi UAV formation, the formation system can be divided into three parts, which are formation massing, formation holding and formation reconstruction. And formation forming, formation holding are the key point in this paper.In order to achieve the goal of the minimum formation massing time and the same time to reach the requirements of multi UAV assembly area, the measures, mainly regulating air-route, regulating speed and waiting around as a supplement, are adopted to plan real-time path online on the basis of the position of each UAV in the formation of multi UAV. The adjustment of the assembly time is realized by changing the radius of the arc to regulate air-route and changing the engine thrust to adjust the flight speed. Besides, the mean of Single or multiple UAV waiting around in circles is adopted to revise the UAV assembly time when the air-range adjustment and flight speed adjustment can’t meet the consistency of the assembly timeThe control law based on single Leader and multi Follower formation holding when cooperative flight is designed according to the relative kinematics model of multi UAV and the control strategy of multi UAV formation holding studied in this paper. The control law is that treating the Leader UAV path as the constantly changing base line, multi Follower UAV use offset position of base line as target path and formation holding is achieved by the correction of heading angle and speed.By using the roll angle control as the basic motion, the Followers can adjust their lateral relative positions to the Leader; By using the engine’s thrust to adjust their velocity, the Followers can adjust their distance to the Leader, all help to realize the multi UAV formation flight. The formation keeping control loop is multi-parameter control, in which the drift angle, lateral separation, longitudinal separation, altitude difference and rate of change in altitude all have their control gains. So, we adopt intelligent optimizing parameter algorithm based on chemical reactions to ensure the value of each control gain which is to achieve a reasonable formation flight.Based on the requirements of the task of UAV drone formation flight, we designed an overall implementation control plan of two UAV drone formation flight and conducted the formation flight test. The results verify the feasibility of the strategy of formation forming and formation holding.