Research On F-rail Track Irregularity Detection And Evaluation Of Medium And Low Speed Maglev

The medium and low speed maglev line in Changsha is the first mid low speed maglev transportation system with fully independent intellectual property rights and has been put into operation in China.The track irregularity of the maglev line affects the safety of the train and the comfort of the passengers.At present,the track irregularity depends mainly on the manual detection.This detection method is low efficiency and heavy workload.The measurement accuracy is not guaranteed by the influence of human and environmental factors,and the middle and low speed Maglev tracks are mostly elevated.The suspension on both sides of the track makes it dangerous for manual detection.In order to meet the daily inspection and maintenance needs of the operation line,the development of track irregularity dynamic detection device is imminent.According to the actual needs of Maglev inspection and operation environment of medium low speed maglev vehicle,this paper proposes a scheme of string measurement based on machine vision,and develops a vehicle non-contact low and medium speed maglev F rail dynamic detection device.A non-linear calibration model of the camera is established for the laser camera,the calibration method of the needle type target is adopted and the parameters of the nonlinear model of the camera are solved by the least square method.For the joint detection of three laser pickup sensors,a global calibration method suitable for three point string measurement is proposed.The outline drawing of F track is collected by three group of equal distance co linear laser camera sensors,and the center extraction is carried out by the gray center of gravity method.The coordinates of the feature points are processed to obtain the initial chord positive vector value,and the string unequal value is obtained by the method of "Using Small Fetch Big" and Newton Interpolation.According to the overall scheme of middle and low speed maglev F rail track irregularity detection,the front,middle and back end measuring frames of the vehicle are tested as the main frame of the hardware structure.Each detection device is assembled on the measuring frame.Based on the Windows development environment,a middle and low speed maglev track irregularities system detection software is written to realize the functions of real-time display of unsmoothed data and export of report data.The unevenness repeat experiment on the magnetic floating test line is carried out.The data collected by the 4m and 10 m string measurement unevenness data meet the requirements of the dynamic irregularity data detection precision of the maglev track,and the feasibility of the scheme is verified.Based on the maintenance method of traditional railway and the actual situation of middle and low speed maglev lines in Changsha,this paper puts forward a method of combining the dynamic evaluation of local repetitive difference and the evaluation of the mean value evaluation in the area.On the basis of a large number of measured data,the F track irregularity data are statistically analyzed,the track characteristics of the Changsha maglev line are obtained,and the corresponding track irregularity management values are discussed,which can provide reference for the scientific evaluation of the middle and low speed maglev track irregularity.