Research On Formation Control Method Of Multiple Quadrotor UAVs

In recent years,academic research on quadrotor unmanned aerial vehicles has been extensive.It is widely used in disaster relief,military reconnaissance,express transportation,aerial photography and other fields due to its simple structure and flexible maneuverability.However,with the continuous deepening of research,the defects of single quadrotor unmanned aerial vehicles with limited load and insufficient fault-tolerant ability to perform complex tasks have also become increasingly apparent.Therefore,the formation of multiple quadrotor unmanned aerial vehicles to perform tasks in collaboration has gradually become the focus of scholars’ research.In this paper,multiple quadrotor UAV systems are taken as the research objects,and the system’s attitude coordination,formation flying,collision avoidance and communication maintenance are studied.This paper first describes the background,research status and research significance of the quadrotor UAV formation,and analyzes its structure and flight principle.Then,based on the idea of double closed-loop control,a quadrotor UAV system model is established,which is divided into a position subsystem and an attitude subsystem.Based on the mathematical model,the attitude coordination and position formation control of multi-quadrotor aircrafts are studied respectively.Specifically,for the attitude subsystem of the quadrotor,first,based on the backstepping method,a multi-quadrotors attitude coordination controller is designed to achieve attitude synchronization of multiple quadrotors.Then,based on the homogeneity theory,a limited time attitude cooperative control law is proposed,so that the attitudes of multiple quadrotor UAV systems can be synchronized within a limited time.Then,for the position and attitude subsystems of the quadrotor,based on the proportional differential control and communication topology theory,a distributed position formation control strategy and an improved finite-time attitude tracking control law are proposed respectively.This allows all quadrotor UAVs to form formations and fly along the desired trajectory.Finally,based on the previous research,a formation controller with collision avoidance and communication maintenance functions is proposed.In order to achieve this function,this paper adds a potential energy function to the controller,and defines the communication area and collision area for each quadrotor UAV centered on itself.When the distance between the quadrotor aircraft isless than the collision radius defined in the collision area,the potential energy function term can generate a repulsive force to keep the quadrotor away from the other quadrotor;when the distance between the quadrotor unmanned aerial vehicle is greater than the communication retention radius defined in the communication area.At this time,the potential energy function term can generate suction force,and pull the quadrotor back into the formation,thereby achieving the safe flight of multiple quadrotor formations.In summary,the main contribution of this paper is to propose a finite-time attitude cooperative controller,position formation controller,and formation energy controller with potential energy function for multi-quadrotor UAVs with a leader-follower structure.Based on the above controllers,the problems of attitude synchronization,formation flying,communication connectivity maintenance and collision avoidance of multi-quadrotor aircrafts are solved respectively.Among them,the simulation results of each chapter separately verify the effectiveness of the above controllers.