Estimation of Track Irregularity Based on Genetic Algorithm and Unscented Kalman Filtering

2012 ◽  
Author(s):  
Hongmei Shi ◽  
Zujun Yu
Keyword(s):  
Genetic Algorithm ◽  
Kalman Filtering ◽  
High Speed ◽  
Measurement Data ◽  
Estimation Method ◽  
Coupling Model ◽  
Dynamic Responses ◽  
The Real ◽  
True Value ◽  
Track Irregularity

Track irregularity is the main excitation source of wheel-track interaction. Due to the difference of speed, axle load and suspension parameters between track inspection train and the operating trains, the data acquired from the inspection car cannot completely reflect the real status of track irregularity when the operating trains go through the rail. In this paper, an estimation method of track irregularity is proposed using genetic algorithm and Unscented Kalman Filtering. Firstly, a vehicle-track vertical coupling model is established, in which the high-speed vehicle is assumed as a rigid body with two layers of spring and damping system and the track is viewed as an elastic system with three layers. Then, the static track irregularity is estimated by genetic algorithm using the vibration data of vehicle and dynamic track irregularity which are acquired from the inspection car. And the dynamic responses of vehicle and track can be solved if the static track irregularity is known. So combining with vehicle track coupling model of different operating train, the potential dynamic track irregularity is solved by simulation, which the operating train could goes through. To get a better estimation result, Unscented Kalman Filtering (UKF) algorithm is employed to optimize the dynamic responses of rail using measurement data of vehicle vibration. The simulation results show that the estimated static track irregularity and the vibration responses of vehicle track system can go well with the true value. It can be realized to estimate the real rail status when different trains go through the rail by this method.

scholarly journals Application of KLE-PEM for Random Dynamic Analysis of Nonlinear Train-Track-Bridge System

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Lizhong Jiang ◽  
Xiang Liu ◽  
Tuo Zhou ◽  
Ping Xiang ◽  
Yuanjun Chen ◽  
...  
Keyword(s):  
High Speed ◽  
Linear Models ◽  
Estimation Method ◽  
Point Estimation ◽  
Random Response ◽  
Train Track ◽  
Track Irregularity ◽  
Track Bridge ◽  
Point Estimation Method ◽  
Bridge System

A nonlinear train-track-bridge system (TTBS) considering the random track irregularity and mass of train is discussed. Based on the Karhunen–Loéve theory, the track irregularity is expressed and input into the TTBS, and the result of random response is calculated using the point estimation method. Two cases are used to compare and validate the applicability of the proposed method, which show that the proposed method has a high precision and efficiency. Then, taking a 7-span bridge and a high-speed train as an example, the calculation results of random response of the nonlinear and linear wheel-rail model are compared, and the results show that for the bridge and rail response, the nonlinear and linear models are almost the same. Finally, comparing the calculated probability distribution results with the test results, it shows that the method can be applied to the prediction of actual response range.

Study on Methods of Lateral Deviation of Track for Static Inspecting in High-Speed Railway

2014 ◽  
Vol 638-640 ◽  
pp. 1195-1206
Author(s):  
Yang Teng Long Li ◽  
Min Yi Cen ◽  
Xuan Bai
Keyword(s):  
Newton’S Method ◽  
Newton's Method ◽  
High Speed ◽  
Measurement Data ◽  
Railway Track ◽  
Transition Curve ◽  
Lateral Deviation ◽  
High Speed Railway ◽  
Track Irregularity ◽  
Circular Curve

According to the critical factor of railway track geometric irregular, the deformations of track can be controlled. The lateral deviation is the key to determine the railway track irregularity. Currently, in the static inspected methods, the combined method of geodetic surveys and track surveying trolleys (inspecting instruments for static geometry parameter of track) is widely used in high-speed railway. Depending on some tests, the model of track irregularity in track surveying trolleys can be reconstructed by another method. According to the special features of track of high-speed railway, it is necessary to study on the accurate and effective lateral deviation algorithm which is suitable for the precise track inspection of high-speed railway. Based on some existing methods of construction layout in highway, the primary contents of this paper are: (1) reduces those methods to three algorithms, such as the Longitudinal Deviation Algorithm with Composite Simpson rule (LDACS), the Distance Function Algorithm of Newton’s method (DFAN) and Normal Perpendicular to Tangent Algorithm of Newton’s method (NPTAN), and (2) completes the algorithm steps of DFAN and NPTAN on circular curve, and proves the results of two algorithms on circular curve same, and (3) proposes the three algorithms to calculate lateral deviation and mileage of any rail detection points for inspecting the static geometric state of track in high-speed railway. Depending on some simulation data, the experimental results are: (1) the calculations of DFAN, NPTAN and LDACS, in which the number of subintervals of equal greater than or equal to five, meet the accuracy of the precise track detection of high-speed railway, and (2) the difference mileage and lateral deviation between DFAN and NPTAN are less than 0.001 mm, and (3) the efficiency of those algorithms is very considerable and the efficiency of DFAN is basically the same with NPTAN and higher than LDACS, and (4) the longer the transition curve is, the lower the efficiency and accuracy of DFAN and NPTAN are. The bigger the radius is, the higher the accuracy of LDACS is. According to the measurement data of the Chengdu Dujiangyan Railway Line (Cheng Guan Line), the above mentioned results of (1) and (2) can be proved correctly.

scholarly journals Rail Corrugation Detection of High-Speed Railway Using Wheel Dynamic Responses

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Jianbo Li ◽  
Hongmei Shi
Keyword(s):  
High Speed ◽  
Estimation Error ◽  
Estimation Method ◽  
Dynamic Responses ◽  
Support Vector ◽  
Vibration Acceleration ◽  
High Speed Railway ◽  
Rail Corrugation ◽  
Reconstructed Signal ◽  
Wheel Vibration

Rail corrugation often occurs on the high-speed railway, which will affect ride comfort and even the train operation safety in severe condition. Detection of rail corrugation wavelength and depth is absolutely essential for maintenance and safety. A novel method using wheel vibration acceleration is proposed in this paper, in which ensemble empirical mode decomposition (EEMD) is employed to estimate the wavelength, and bispectrum features are extracted to recognize the depth with support vector machine (SVM). Firstly, a vehicle-track coupling model considering the rail corrugation of high-speed railway is established to calculate the wheel vibration acceleration. Secondly, the estimation algorithm of wavelength is studied by analyzing the main frequency with EEMD. The optimal parameters of EEMD are selected according to the orthogonal coefficient of decomposition results and the distribution of the extreme points of signal. The depth detection is transformed to a classification problem with SVM. Bispectrum features, which are extracted from the reconstructed signal using the high-frequency components of wheel vibration acceleration, combining with train speed and corrugation wavelength are input into SVM to recognize the rail corrugation depth. Finally, numerical simulation is carried out to verify the accuracy of the proposed estimation method. The simulation results show that the proposed detection algorithm can accurately identify rail corrugation, the estimation error of rail corrugation wavelength is less than 0.25%, and the classification accuracy of rail corrugation depth is more than 99%.

Dynamic Responses Analysis of Vehicle and Track Based on Different Train Speed

2013 ◽  
Vol 706-708 ◽  
pp. 1314-1318
Author(s):  
Hong Mei Shi ◽  
Zu Jun Yu
Keyword(s):  
High Speed ◽  
Rapid Development ◽  
Coupling Model ◽  
Dynamic Responses ◽  
High Speed Railway ◽  
Vertical Coupling ◽  
Railway Infrastructure ◽  
Train Operation ◽  
Vibration Responses ◽  
Train Speed

With the rapid development of high-speed railway, dynamic interaction between vehicles and track is correspondingly strengthened. Therefore, dynamic responses analysis of the high-speed vehicles and track become more and more important to the train operation safety, riding comfort as well as the maintenance of railway infrastructure. In this paper, vehicle and track vibration equations are separately established based on the vehicle track vertical coupling model. Taking the CRH vehicle running on the existing line as an example, the random vibration responses of the vehicle and track under different running speed are analyzed in time domain through numerical integral method and MATLAB program. According to the results, the velocity of train has more influence on the vibration property of rail and wheelsets than bogie and carbody.

scholarly journals Insights into the Effect of WJ-7 Fastener Rubber Pad to Vehicle-Rail-Viaduct Coupled Dynamics

2020 ◽  
Vol 10 (5) ◽  
pp. 1889 ◽  
Author(s):  
Linya Liu ◽  
Zhiyuan Zuo ◽  
Yunlai Zhou ◽  
Jialiang Qin
Keyword(s):  
High Temperature ◽  
High Speed ◽  
Coupling Model ◽  
Peak Frequency ◽  
Dominant Frequency ◽  
Dynamic Responses ◽  
Temperature Sensitive ◽  
Temperature Dependent ◽  
Vertical Coupling

The high-speed railway (HSR) has been a long-term hotspot in both scientific and engineering societies to enhance the long-term high quality HSR service. This study aims to investigate the WJ-7B type small resistance fastener rubber pad applied in HSR, and temperature sweep test is applied to determine the mechanical parameters of the fastener rubber pad, which are hereafter introduced into the vehicle-track-viaduct vertical coupling model via dynamic flexibility method. The track irregularity spectrum is considered as fixed-point excitation to investigate the temperature-dependent effect of fastener rubber pad on the dynamic responses. The results reveal that the rigidity of the fastener rubber pad is low temperature sensitive and high temperature stable, and the temperature variation has little effect on the vertical dynamic responses of the vehicle. The dynamic flexibility of the rail increases in amplitude and the dominant frequency decreases as the temperature of the fastener rubber pad increases. The vertical dynamic responses of the wheel-rail force, the wheelset and the rail-viaduct system gradually decrease as the temperature of the fastener rubber pad increases, and the peak frequency follows the similar rule. While under high temperature circumstances, the temperature dependent stiffness of the fastener rubber pad has little influence on the peak of the dominant frequency in the vertical dynamic response of the track-viaduct system.

Vibration Analysis of High-Speed Vehicles under the Condition of Track Random Irregularity

2011 ◽  
Vol 211-212 ◽  
pp. 525-529 ◽  
Author(s):  
Hong Mei Shi ◽  
Jia Liang Zhou
Keyword(s):  
Differential Equation ◽  
Numerical Simulation ◽  
Vibration Analysis ◽  
High Speed ◽  
Simulation Method ◽  
Coupling Model ◽  
Vertical Coupling ◽  
Vehicle Components ◽  
Track Irregularity ◽  
Random Irregularity

Track irregularity is the most important excitation source of wheel-rail system. The vibration characteristics of vehicle components and track components are analyzed in this paper under the condition of track irregularity by establishing the vehicle - track vertical coupling model. And the establishment of vibration differential equation and numerical simulation method for solving vibration response are described in detail. Finally, the results are given by MATLAB. The method is of great significance for evaluating the dynamic track irregularity and vehicle’s vibration at different running speeds.

Application of Genetic Algorithm in Neutron Spectrum Unfolding

2010 ◽  
Author(s):  
Dong Wang ◽  
Bin He ◽  
Quanhu Zhang
Keyword(s):  
Genetic Algorithm ◽  
Response Function ◽  
Fitness Function ◽  
Measurement Data ◽  
Neutron Energy Spectrum ◽  
Neutron Spectrometer ◽  
The Real ◽  
Neutron Dosimeter ◽  
Ill Posed ◽  
The Individual

Bonner Spheres neutron spectrometer has been widely applied as neutron dosimeter, however the derivation of neutron energy spectrum from its measurement data is still a significantly difficult task. This unfolding problem is proved to be ill-posed, under-determined and have no exact solution. Two major require of the unfolding methods are accuracy and stability. Most unfolding methods try to search the solution that best fit the measurement data and the response function. As a universal optimization tool Genetic Algorithm shows its potential to solve this kind of problem. Through gene operation of every generation, GA could find the global optimal among the searching space. A new fitness function which contains a distance part and a penalty part was constructed in this research. The distance part is the square distance between the individual and the measurement data. The penalty part which is a function associated with the continuity of individual is used to avoid intensively change of unfolded data. Five classical neutron spectra were chosen as benchmark input spectra. The product of the benchmark spectra and the response function played as input measurement data of the unfolding program. The unfolded results showed good agreement with the real ones. The measurement data could be well reproduced by the unfolded results though the results had some difference with the real spectra.

Impact of Rail Fastener Looseness on Vertical Dynamic Responses of High-Speed Vehicle and Ballastless Track

2021 ◽  
Author(s):  
Jianbo Li ◽  
Hongmei Shi
Keyword(s):  
Dynamic Response ◽  
Detailed Analysis ◽  
Frequency Domain ◽  
High Speed ◽  
Vibration Response ◽  
Dynamic Responses ◽  
Time Frequency ◽  
Ballastless Track ◽  
Track System ◽  
Track Irregularity

The fastener system is an essential component of the high-speed ballastless track system. A detailed analysis for the effect of fastener looseness on the vertical dynamic response of the vehicle–track coupling system is conducted from the time domain, frequency domain and time–frequency domain in this paper. A fine fastener system model is employed, which includes two spring rods and one rail pad. The preloaded force is proposed to simulate the defect of the fastener, and a looseness coefficient is defined to represent the loose degree of the fastener. First, three fastener system models are introduced into the model, respectively, and the difference in the vehicle–track dynamic is analyzed and compared. The results show that the proposed model is more consistent with the real situation and more suitable to simulate fastener defects. Then, the detailed analysis of vehicle and track dynamic responses is explored in the case of different degrees of loose fasteners and the case of completely loose fasteners. According to the simulation results, there is little impact on the dynamic response of the vehicle–track system when the looseness coefficient is less than 0.9. When the fasteners are completely loosened, the dynamic response of the wheelset and the rail significantly increases. The vibration responses of rail and wheelset enhance with the increase of the number of the completely loose fastener. The loose fasteners affect the low-frequency part of the wheelset vibration response and the high-frequency part of the rail vibration response. Finally, a time–frequency analysis method is used to analyze the system vibration response under the combined effect of the completely loose fastener and the track irregularity. The track irregularity still dominates the excitation of the system, and the vibration response of the wheelset and the rail is more sensitive to the fastener defect at low speed.

scholarly journals Relation Between Track Irregularity of Speed-Increased Railway and Dynamic Speed Limits Through Simulation

2014 ◽  
Vol 8 (1) ◽  
pp. 197-200 ◽  
Author(s):  
Wang Zhi-Chen ◽  
Song Ying ◽  
Wang Jian-Xi
Keyword(s):  
High Speed ◽  
Simulation Software ◽  
Dynamic Responses ◽  
System Model ◽  
Railway Vehicle ◽  
Operation Speed ◽  
Coupling System ◽  
Different Types ◽  
Speed Management ◽  
Track Irregularity

Based on the vehicle-track coupled dynamics theory and the corresponding simulation software ADAMS/Rail software package, a vehicle-track coupling system model is established, and the track irregularity is introduced to the coupling system model as an excitation source. Firstly, the dynamic responses of speed-increased railway vehicle and track components due to different types of track irregularity are obtained. Secondly, the sensitive wavelength of different track irregularities in high-speed operation is discussed. Finally, suggestions about the maximum operation speed to meet the standards value of daily maintenance target, comfortable value, emergency repair and speed management target are put forward.

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