Obstacle Avoidance System For Multi-quadrotor Formation Based On Safe Flight Corridor

Quadrotor is a branch of intelligent robot.Due to its excellent performance,it has been studied and improved by excellent institutions at home and abroad.The advantages are such as taking off anywhere,no run-up,fixed-point hovering,and easy control.In recent years,it has been widely used in power line inspection,environmental detection and perception,aerial photography and other industries.Compared with other UAVs,the quadrotor has a smaller payload and is difficult to complete long-term flight,which greatly limits the use of scenarios.The quadrotor coor-dinated control system came into being.When multiple aircrafts coordinate to complete a mission to a designated location,it is inevitable that obstacles appear in the path.In order to avoid obstacles,the system needs to have the functions of formation maintenance and transformation.In order to realize the obstacle avoidance function of the quadrotor cooperative control system,this paper studies this,and designs a physical platform based on the visual sensor that can realize the functions of positioning,mapping,navigation,and cooperative obstacle avoidance.The collaborative control system plans a safe flight path between the start point and the end point of the environmental map,constructs a safe flight corridor on the safe path and optimizes the formation parameters according to it,and completes avoiding obstacles to the designated location by changing the formation task.The main tasks are as follows:1.Design and develop the flight control system based on the mathematical model and force analysis of the quadrotor.The control accuracy and response speed meet the requirements of the system platform.2.Introduce the dense reconstruction algorithm of 3D real-time map.The obstacles in the surrounding environment are reconstructed by octree map,and the flight path is planned between the barrier-free area from the starting point to the target point in the visual map,and a safe flight corridor is obtained in real time by using the information of obstacles and path.3.Use the formation algorithm to achieve the formation control effect,and use the artificial potential field algorithm to achieve internal collision avoidance and improve the safety of the system.The safe flight corridor is used as an external constraint to update the formation parameters to control the formation through obstacles,and obtain the expected speed of each node and input it into the bottom flight control system.4.Select suitable racks,vision sensors,power systems,on-board computing com-ponents and other equipment to build a complete set of physical platforms.Design and develop a complete set of software processes,and complete the system software frame-work.5.Verify the feasibility of the system in MATLAB and Gazebo simulation system.Test the stable flight effect on a single quadrotor physical platform,and test the obstacle avoidance effect of multiple quadrotor cooperative control system platforms,and verify that the system platform can complete coordinatedfollow-up,change formation,avoid ob-stacles and other tasks.It proves the feasibility and stability of the experimental platform and lays the foundation for follow-up research.