Research On Obstacle Avoidance Path Planning And Tracking Control Of Rotor UAV For Cable Tower Inspection Of Cable-stayed Bridge

With the rapid development of China’s transportation,more and more long-span bridges have been built and put into use.In order not to interfere the ship passage on the original channel,the cable-stayed bridge is the main type of long-span bridges.For the scheduled inspection and maintenance of cable-stayed bridges,especially for the inspection of cable-stayed towers,the traditional methods possess low inspection efficiency and low inspection accuracy,so more and more unmanned aerial vehicle(UAV)are used in the inspection of cable tower of cable-stayed bridges.However,cable tower inspection with the UAV is usually manipulated by human,rarely optimizing the inspection path for the UAV and without in-depth study of the tracking control algorithm of inspection path.Thus,this above-mentioned work can not promote the intelligent level of cable tower inspection.Therefore,in order to improve the safety and efficiency of cable tower inspection of cable-stayed bridge with the rotor UAV,this thesis studies the obstacle avoidance path planning and tracking control of the rotor UAV for cable-stayed bridge tower inspection,and the main research work and contributions can be summarized as follows:(1)Aiming at path planning of the rotor UAV for cable tower inspection of cable-stayed bridge,a path planning algorithm of multi-rotor UAV for cable tower inspection of cable-stayed bridge is designed.The algorithm utilizes the genetic algorithm improved by the information entropy theory to obtain the pylon inspection path with the least energy consumption,and uses the double-arc obstacle avoidance strategy to re-plan the local area with cable stay obstacles on the path,so the UAV obtains good obstacle avoidance characteristics,which enables it to acquire the surface images of the cable-stayed bridge tower safely and efficiently.(2)For solving the tracking control problem of cable tower inspection of cable-stayed bridge with the rotor UAV,a novel type of tracking control algorithm is proposed based on particle swarm optimization(PSO)and fuzzy immune PID.The algorithm combines the traditional PID control,fuzzy control and immune control,and introduces the PSO algorithm with linearly decreasing weights to achieve the parameter optimization of the immune control part.The tracking efficiency is improved while ensuring the accuracy of the track tracking,and simulation results demonstrate the correctness and reliability of the proposed path tracking algorithm.(3)In order to verify the path planning algorithm and tracking control algorithm of the rotor UAV for cable-stayed bridge tower inspection,the hardware and software environment of four-rotor UAV is built.By using the Tower open source framework and Px4 firmware for secondary development,programs for path planning and tracking control are written,respectively.Finally,the correctness and validity of the algorithm are validated by the software simulation and actual flight test.