Research And Design Of Key Technologies For Intelligent Patrol Based On Unmanned Aerial Vehicle(UAV)

With the rapid development of China's economy and society,Highway,Transportation,Communications and Power Lines are also gradually increasing,followed by the patrol task is more and more serious.At present,the inspection of above lines still mainly relies on manual regular field inspection.This method requires a lot of manpower and time,and because it is not easy for people to cross rivers and other complex terrain,It has very low patrol efficiency.Thanks to the rapid development of uav technology in recent years,the application of uav in power inspection and even inspection of other large-scale facilities is also gradually increasing,which directly promotes the shift of inspection mode of power,bridge and other large-scale facilities to aircraft inspection mode.However,unmanned aerial vehicles(uavs)also face many unpredictable problems in the actual patrol process,which brings great challenges to the extensive application of uavs in various complex environments.Limited by the interference of the surrounding environment on the sensor of uav and the absence of high-precision positioning device,it is difficult for uav to realize automatic navigation and patrol along the planning route,and it can only rely on manual observation and operation,with low precision and poor effect.At the same time,the battery life of the lithium battery used in the uav is about 30 minutes.After the battery power is exhausted,the battery needs to be replaced manually,which increases the patrol workload and reduces the patrol efficiency.This paper takes the uav power patrol as the starting point,analyzes and studies the application of uav in power patrol at home and abroad,and proposes a comprehensive intelligent patrol system design scheme for uav that can be widely used in various complex patrol environments in view of the existing problems and challenges.A charging platform is designed in the patrol terminal,and the uav can conduct continuous patrol with the charging platform as the springboard,so as to solve the endurance problem of the uav.At the same time,the patrol task is not affected by the river terrain and other environments,and the patrol distance is increased.In the process of patrol,the advanced uav flight control system and algorithm are used to make the patrol stable,safe and accurate as planned.At the same time,a dynamic calibration method of magnetometer was proposed to solve the problem that the uav could not be dynamically calibrated in the air.This design scheme can solve many problems in the inspection process of uav power,substation,bridge,reservoir and other large facilities.The main contents and results of this design scheme are as follows:1.As the core of the whole intelligent patrol system,the intelligent flight control system controls the attitude of the uav in real time to realize stable patrol and automatic landing and charging.In this paper,a set of uav intelligent flight control system is designed by using advanced processing chip and various sensor modules and integrating GPS and RTK data.In the early stage,the drawing board and proofing were carried out,and in the later stage,welding and installation were carried out.In the later test,the flight control system was found to be stable in overall operation and strong in wind and interference resistance,which met the basic requirements for the stable operation of uav in various complex environments;2.GPS/RTK technology is used to guide and land the uav at a relatively long distance.Then the airborne camera is used to realize the high-precision positioning of the uav through image processing technology,so that the uav can take off and land accurately on the automatic charging platform.The uav battery is automatically charged through the docking and positioning of the charging interface.Combined with the uav flight control system,the "leapfrog" automatic patrol is realized.Then the image processing algorithm is improved step by step to improve the landing accuracy of the uav in the experiment process;3.The ground station is the ground control center of the uav when it is flying in the air.At first,this paper use all kinds of sensors to collect airborne uav/RTK GPS coordinates,speed,flight status information,such as,the onboard computer processing,by the communication module to send to the ground station,station shows that uavs status information at this time,to monitor state of unmanned aerial vehicle(uav),a special circumstances also can be directly used to ground station taking the operation of the unmanned aerial vehicle(uav)control,guide the unmanned aerial vehicle(uav)along its airline.The ground station can also simulate the flight path and attitude of the uav,and analyze and test the reliability and stability of the uav;4.In this paper,aiming at the problem that the magnetometer of multi-rotor uav is easy to be disturbed by the magnetic field of the surrounding environment in the inspection process,a small Angle least square iterative dynamic calibration method is proposed on the basis of static calibration.In other words,the curve is fitted with the least square at a small Angle continuously and the spherical center is calculated.The spherical center coordinates are updated repeatedly to realize deviation correction and further improve the navigation accuracy of uav.Through simulation verification and experimental test,this method can effectively solve the dynamic calibration problem of multi-rotor uav magnetometer,so as to improve the navigation accuracy of uav patrol in a variety of complex environments.