Research On Automatic Track Detection System Of Tank Floor Based On UWB Positioning

Large storage tanks are widely used oil and gas storage equipment in petrochemical enterprises.Under the action of internal storage medium and external environment,the upper and lower surfaces of the tank bottom plate are prone to different degrees of corrosion defects,which seriously threaten its safe operation.Therefore,it is imperative to regularly inspect the quality of tank floor.At present,the application of magnetic flux leakage detection system for tank floor is relatively mature.However,the existing detection system mostly adopts manual operation,which not only has high labor intensity,but also does not allow operators to work too long in the sealed environment of the tank.Therefore,based on the development of automatic magnetic flux leakage detection device for tank floor,according to the technical requirements of defect location,UWB positioning technology is proposed to be applied to the system in order to achieve the purpose of automatic track inspection of tank floor magnetic flux leakage detection trolley.Firstly,combined with the technical difficulties of automatic magnetic flux leakage detection of tank floor,the UWB positioning scheme is compared and analyzed,and the positioning method based on signal arrival time difference is determined.In order to improve the accuracy of positioning coordinates,the classical UWB positioning algorithm is studied.Through theoretical analysis and simulation calculation,it is found that Chan positioning algorithm is more suitable for the research needs of this paper.Secondly,according to the requirements of tank floor automatic track inspection system,a specific system framework is designed,including differential steering three-wheel mobile structure,positioning device based on DWM1000 chip,motion control system based on STM32F4 microprocessor,Ethernet data transmission module based on TCP/IP protocol and Hall array magnetic flux leakage detection module.On the basis of establishing the kinematics model of differential steering three-wheel structure,the principle and control method of automatic track patrol are studied.At the same time,the hardware circuit of the tank floor automatic track inspection system is designed,and the software programs of the lower and upper computer of the system are compiled.Finally,based on the designed system scheme,the UWB positioning parameters are optimized from the number of base stations and the spacing of the base stations,and the PID control parameters are optimized from the adjustment path and the adjustment time.In order to verify the validity of the designed system,a system test experiment was carried out under laboratory conditions to simulate the detection environment of tank floor.The results show that the inspection car can automatically drive along the planned path,detect and accurately determine the defect location,and the defect location error is within±5 cm,which can meet the basic requirements of magnetic flux leakage detection of the tank bottom plate.