Dynamic Visual Measurement Of Medium And Low Speed Maglev Contact Rail Geometric Parameters

With the rapid development of urbanization in China,the problem of traffic congestion in big cities has become more and more serious,which has brought about serious negative impact on people's lives.The low-speed maglev train is part of urban rail transit.With its many advantages such as its environmental protection,energy saving,and high efficiency,it has become an important way to solve the current situation of urban congestion and ease the pressure of urban public traffic.At present,Changsha Maglev Express have been completed and put into operation.At the same time,planning and construction are being carried out on multiple lines across the country.It is the key to ensure the normal operation of the train to ensure that the maglev train is stably receiving flow during operation.The Changsha Maglev Express lines have been built to take flow through the contact between the contact shoses and the contact rails.In order to maintain the normal function and smooth contact between the rail shoes,the public works department needs to periodically check the geometry parameters of the contact rails(Including the height of the contact rails,and the stagger value of the contact rails),and take appropriate maintenance measures to repair the track.The artificial detection of the geometric parameters of the geometry parameters of the contact rails is inefficient,the workload is large,and the accuracy is difficult to guarantee.Therefore,a dynamic detection device capable of quickly detecting the geometric parameters of the flow track of the maglev line is urgently needed.According to the requirements of the actual maintenance of the contact rails in the middle and low speed maglev lines in Changsha,based on the principle of vision measurement,a laser imaging sensor is proposed to detect the geometric parameters of the contact rails.Aiming at the requirements of real-time and high-precision in the dynamic detection process,this paper proposes a set of methods for detecting the geometric parameters of flow paths.The main tasks are as follows:(1)Analyze the imaging principle of the laser imaging sensor and establish a mathematical model of the sensor.The sensor is calibrated using planar targets and needle targets to solve the model parameters.Through analyzing the image captured by the laser imaging sensor,a suitable image preprocessing method and light bar center extraction algorithm are adopted to obtain the track detection profile data.(2)In order to solve the problem of high-accuracy extraction of feature points in the presence of erroneous orbital surface during orbital processing,a feature extraction algorithm based on constraint points is proposed.The algorithm is based on the matching of the detection profile with the standard profile of the track,and uses the method of fitting the curve and the line where the constraint point locates to obtain the intersection point,which effectively solves the problem of the accuracy of feature point extraction.At the same time,in order to meet the requirements of real-time and high-precision,the classical matching algorithm used in the detection process of profile registration has been improved,and a data matching algorithm for track profile registration has been proposed.The profile registration algorithm effectively improves the matching efficiency and accuracy.(3)To study vehicle vibration types that have an impact on the test results during vehicle operation.Through the analysis of the vehicle structure,a vehicle vibration compensation formula is derived.Then,the two sensors on the same side of the vehicle are statically calibrated.Based on the static calibration results and the vehicle vibration compensation formula,the calculation method of the geometric parameters of the contact rails is deduced.(4)According to the geometric parameters detection requirements of the middle and low speed maglev contact rails,the middle and low speed maglev flow receiving rail detection software was developed based on the MFC library.Using the developed detection system,static precision experiments and dynamic repeatability precision experiments were performed on the medium and Changsha Maglev Express in Changsha.The experimental results show that the proposed method can meet the accuracy requirements for detection of geometric parameters of medium-low speed maglev contact rails.