Research On The Path Planning For Obstacle Crossing Of 110kv Overhead Transmission Line Inspection Robot

As an indispensable part of social production activities and people’s life,electric power plays an irreplaceable role in the development of national economy,and overhead transmission line is the hub responsible for transportation in the whole power system.In order to ensure the safe and stable operation of power transportation network,it is necessary to conduct regular inspection and maintenance of high-voltage overhead transmission lines exposed to harsh natural environment all year round.Compared with manual inspection,helicopter inspection and UAV inspection,online inspection robot has the advantages of low cost,high quality and long running time.In addition to cables,tangent towers and tension towers,overhead transmission lines also include various fittings on the line,such as fittings for connecting towers and cables(suspension clamps,insulator strings,etc.)and fittings for line protection(anti vibration hammer,spacer,etc.).These fittings connected above or below the line are obstacles that the line inspection robot will encounter in the inspection work.The ability of autonomous obstacle crossing under different obstacles and different relative posture environments determines the working range and efficiency of the robot,and one of the key technologies of autonomous obstacle crossing is the ability of obstacle path planning under different obstacle environments.Therefore,the research on obstacle path planning of overhead transmission line inspection robot has great practical significance.In this thesis,research and related experiments are carried out on the obstacle crossing path planning of 110 k V overhead transmission line inspection robot.Firstly,aiming at the obstacle crossing process of single arm,the structure of line inspection robot is analyzed,and the double arm line inspection robot including parallel mechanism is equivalent to the motion model of series connecting rod;Through the geometric relationship between each push rod motor and its respective stroke range,the conversion relationship between the length of each push rod and the joint variables in the equivalent model is obtained.The equivalent link model is modeled by D-H parameter method,and the analytical solutions of the inverse kinematics of other joint variables are obtained by separating the end joint variables that only play the role of attitude adjustment.The parallel structure simulation model and equivalent series link simulation model of the line inspection robot are established respectively,and the correctness of the forward and inverse kinematics models is verified by combining them.Secondly,based on the forward kinematics of the line patrol robot,the collision detection method between the robot rod and the obstacle is established based on the relative position relationship between the respective envelope ball swept bodies,and a more accurate collision detection method between the robot’s end claw and the obstacle is established based on the relative position relationship between the point and various envelope geometry,Based on the geometric relationship of each push rod,the joint stroke range of the equivalent connecting rod model is limited to avoid the collision between the robot’s own rods.The simulation verification of collision detection is carried out under the obstacle environment of vibration damper and suspension clamp insulator string.Then,aiming at the problem that it is difficult to predict the trajectory from the motion in the joint space to the workspace of the line inspection robot,so that only the collision detection of the search node may not ensure no collision on the path,the RRT connect algorithm is improved by single joint motion and fixed extended step length to the workspace;Aiming at the problem that the obstacle crossing path planning of line patrol robot is easy to fall into local search,difficult to jump out and reduce the search efficiency,the RRT connect algorithm is improved by canceling the node expansion greedy strategy and adding the intermediate point search random tree.Combined with the previously established kinematic model and collision detection method,the improved RRT connect algorithm is applied to the obstacle crossing path planning in the joint space of the robot,and the smooth trajectory planning is carried out for the obtained push rod length sequence.Similarly,the obstacle path planning simulation is carried out in the obstacle environment of vibration damper and suspension clamp insulator string respectively.The results show that the proposed obstacle path planning method of line inspection robot is correct.Finally,based on the operation requirements of the overhead transmission line autonomous obstacle crossing line inspection robot,the overall architecture design,subsystem communication mode determination and task decomposition of the line inspection robot control system are completed,and the software and hardware architecture design and software and hardware implementation of the airborne control system,remote host computer and realtime video transmission system are completed respectively.The walking experiment,obstacle crossing experiment,remote control experiment,real-time video transmission experiment and sensor data return experiment are carried out on the overhead transmission line.The experimental results fully verify the reliability and stability of the control system of the line patrol robot.On this basis,the 110 k V overhead transmission line experimental platform is built,and the obstacle path planning experiment of line patrol robot is carried out.The experimental results show that the established obstacle path planning method can be used for the obstacle crossing of actual line patrol robot.