Multi-UAV Cooperative Formation Control Algorithm Based On Multi-area Hierarchical Structure

With the rapid development of science and technology,the Unmanned Aerial Vehicle(UAVs)playing an increasingly important role in the military and civilian fields.Compared with a single UAV,multi-UAV formation has higher efficiency,better robustness,greater service range and functions,but currently there are still many restrictions in the practical application of multi-UAV formation.The ability to perform missions is often determined by the size of multi-UAV formation.With the expansion the size of multi-UAV formation,how to improve the accuracy and efficiency of multiUAV formation control,avoiding flight path conflicts and collision accidents,and become an important direction for multi-UAV collaborative formation control research.In this paper,the fourrotor UAV is used as the research object,and the shortcomings of maintenance and obstacle avoidance of multi-UAV formation are analyzed.The main research contents and achievements are as follows:Firstly,the research status of related multi-UAV formation maintenance and obstacle avoidance control problems are investigated by referring to the important research results at home and abroad.The achievements that researchers at home and abroad have achieved in the field of multi-UAV collaborative formation control and the existing problems and future directions of the formation control methods are analyzed.This paper studies the flight control problem of multi-UAV cooperative formation in an ideal environment.Based on the multi-UAV position consistency theory,an areabased multi-UAV formation control algorithm is proposed.This algorithm uses each UAV to establish a communication topology diagram and area objective function based on graph theory.The information exchange between adjacent UAVs is realized,so as to achieve the purpose of adjusting the flight status according to the position of adjacent UAVs.The area-based multi-UAV formation control algorithm has good robustness and expansion ability.That is,when the UAVs fly away or fly into the formation,the algorithm can maintain the stability of the formation formation in real time.Secondly,aiming at the difficulty of multi-UAV cooperative formation flight control in largescale,multi-task and complex environments,this paper proposes a multi-region hierarchical UAV cooperative formation control algorithm based on distributed control strategy.The basic idea of the algorithm is used to study the multi-UAV cooperative formation flight control.By establishing a multi-area hierarchical UAV formation control architecture,the complex multi-UAV formation control problem is decomposed into task assignment between formation areas and task coordination within the formation area.It reduces the communication pressure between the member machines in the multi-UAV formation,realizes the coordination among different levels in the formation,meets the needs of multi-UAV cooperative formation flight control,and the accuracy and flexibility of multi-UAV formation in flight control,avoiding the path conflicts and collisions.Finally,in order to avoid the collision of the multi-UAV formation with the obstacles during flight,the adaptability of the UAV formation in the uncertain flight environment is improved.For the artificial potential field method,it is easy to fall into the local optimal problem and the unrelated external interference problem when planning the UAV formation path.An avoidance control algorithm for multi-UAV formation based on improved cone-potential field method is proposed.The algorithm mainly solves the problem of multi-UAV formation maintenance and obstacle avoidance control in three-dimensional space environment without changing the whole path.Through the independent obstacle avoidance function of each area in the formation,and finally realizes autonomous avoidance control under multi-area hierarchical formation flight with distributed control strategy.