Wheel-Rail Force Continuous Measurement Method And Out-Of-Round Wheel Detection And Identification

Real-time safety monitoring of train key component is an important means to ensure the security of train operation. Through the real-time recording, analysis and diagnosis, timely detect vehicles which exists serious safety hazard and find out the location of the fault and its reason, furthermore, implement of vehicle maintenance, which has a very positive role in the protection of railway traffic safety and significant social and economic benefits. This paper is in the context of the leaps and bounds development of the China railway, use the wheel-rail dynamic impact as the theme, from the point of view vehicle and track overall system, comprehensively research vehicle-track dynamic interaction security issue. This paper mainly carries out the following research works:(1) Realization of wheel-rail force continuous measurementAccording to wheel-rail interaction characteristics and the restriction condition of track, the single point measure of wheel-rail vertical force and lateral force are studied by means of simulation calculation, rail response change when load moves and stain outputs of measure points in different position are detailed analysed, finally the measure points arrangement position of continuous measurement is determined, and simulation results are verified by laboratory experiment. On this basis, a radial basis function neural network and a combination model based on the grey system, genetic algorithm and neural work based wheel-rail force continuous measure method is put forward. It has been proved their high precision and feasibility through field test and reduces the influence of sensor failures on measure results.(2) Research of wheel-rail force decoupingStudy strain outputs of wheel-rail vertical force measure point under the action of lateral force and strain outputs of lateral force measure point under the action of vertical force by simulation, the results show that wheel-rail vertical force and lateral force exist crosstalk, at the same time, this phenomenon is found in laboratory test. Aim at this problem, this paper proposes to use an improved independent component analysis algorithm to decouple the crosstalk of wheel-rail vertical force and lateral force, this method provides a new approach for high precision wheel-rail force measurement.(3) Establish of vehicle-track coupling dynamics modelOn the basis of the theory of vehicle-track coupling dynamics, with high speed train as research object, railway vehicle dynamics simulation technology is used to systematically analyse wheel-rail contact and interaction of vehicle-track coupling system, a mechanical model of vehicle and track structure and dynamics simulation model are established respectively, the Hertz contact theory and Kalker rolling contact theory are employed to research wheel-rail interaction process and wheel-rail force of out-of-round wheel, which provides a basis for the study the influence of out-of-round wheel on wheel-rail dynamic characteristics.(4) Analysis of the influence of out-of-round wheel on wheel-rail dynamic actionOut-of-round wheel is a serious hidden danger for vehicle running safety. This paper defines and classifies the forms of out-of-round wheel, combines with the established vehicle-track coupling dynamics model to study wheel-rail impact and vibration characteristic caused by different out-of-round wheel styles, such as wheel flats and wheel periodic polygon, which provides a theoretical basis for the establishment of wheel-rail force real-time monitoring system.(5) Identification of out-of-round wheel through wheel-rail forceVehicle-track coupling dynamics model is used to calculate wheel-rail impact force caused by80groups of wheel flat with different length and depth, and the wheels are divided into3styles according to the amplitude of wheel-rail force, there are normal wheels, fault wheels and severe fault wheels. Compress the original data through feature extraction firstly to avoid the curse of dimensionality, and then analyses three different classifiers:BP neural network, learning vector quantization neural network and support vector machine for wheel classification case in detail.(6) Identification of out-of-round wheel through axle box vibration accelerationOut-of-round wheel could cause abnormal vibration of the axle box, we could identify potential wheel defect through axle box vibration information. This paper uses measured data and simulation results, puts forward a Hilbert spectrum method based on improved EMD to qualitative identify out-of-round wheel effectively, the method can not only determine whether the wheel exists defect, but also judge the wheel defect is whether wheel flat or wheel polygon regardless of the speed. At the same time, quantitatively judge defect degree by means of wavelet package decomposition.