Research And Application Of UAV Path Planning Method For Electric Patrol Line

With the rapid development of China’s power industry,the scale of power grids has grown and the traditional way of patrolling can no longer meet the needs.As a safe and efficient technology,UAV inspection technology has received extensive attention in many fields,such as forest fire patrol,electric power patrol,oil field patrol,meteorological investigation and so on.At present,the use of unmanned aerial vehicle inspection task is mainly based on the manual remote control by the operator.If the UAV is fully autonomous,the efficiency of inspection will be further improved.However,UAV path planning is a key technology to realize the full autonomous flight of UAV.Therefore,it is of great significance to study the path planning method of UAV and apply it to the inspection of the transmission line,to realize the autonomous flight of the unmanned aerial vehicle and to improve the inspection efficiency.UAV path planning is to use a certain path planning algorithm to search out an optimal or near-optimal flight path that meets the constraints between the starting point and the target point.In this paper,the path planning method of UAV is studied under the background of transmission line inspection,and the main contents are as follows:Firstly,the problems of UAV path planning and environmental modeling are studied according to the requirements of UAV transmission line inspection tasks and the environmental characteristics.The content of inspection is determined to be the corridor monitoring of transmission lines and fixed wing UAV is selected as the inspection model.Besides,the constraints are analyzed and determined,and the track representation is selected.The obstacle model and the terrain model are established by using the geometric description method and the functional simulation method,respectively,so that the flight environment model is set up,to lay the foundation for the implementation of follow-up path planning.Secondly,Rapidly-exploring Random Tree(RRT)is selected as track search algorithm.Aiming at the defects of RRT algorithm,a Goal-bias Bidirectional Connection RRT*(GBCRRT*)algorithm is proposed.In the proposed algorithm,the selection strategy of random nodes is improved to increase the search efficiency and convergence speed of the algorithm.Two search trees are set up at the starting point and target point,respectively,and the searching speed of the algorithm is improved by using the connective extension method.Furthermore,the method of collision detection based on fast rejection test and cross vertical test is used to avoid obstacles.The cost function is introduced in the expansion of search trees to obtain an approximate optimal track and improve the quality of the track.Through simulation experiments,the GBCRRT* algorithm is compared with other improved methods to verify its effectiveness.Finally,combined with the inspection content,the path planning is realized on the established environment model.In this paper,the overall steps of route planning are given,and the trajectory planning is divided into two steps: the global static track planning before takeoff and the replanning of the local track during the flight process.In the global static track planning,the goal-bias bidirectional connection RRT* algorithm is used to plan the reference track.Then the redundant nodes in the reference track are deleted,and the B spline curve method is used to smooth the reference track after the deletion of the redundant route points,so that the track is more flyable.In local path replanning,the connected bidirectional RRT algorithm based on the improved random nodes selection strategy and the RRT algorithm based on kinematics equations are used to evade the static threats and dynamic threats,respectively.The feasibility of the path planning method is verified by simulation experiments.