Wheel-rail adhesion-creep behavior and rail corrugation comprehensive measurement device and method

Abstract

The present invention relates to a comprehensive measuring device and method for wheel-rail adhesion-slip behavior and rail corrugation. The comprehensive measuring device for wheel-rail adhesion-slip behavior and rail corrugation includes a left fixing frame, a right fixing frame, a linear driving motor, a lead screw transmission assembly, a lead screw slider, a mounting plate, a vertical loading platform, a configuration block, a rotary driving motor, a measuring wheel, a first rotary encoder, a torque sensor, a second rotary encoder, and a laser displacement sensor. The creep ratio can be calculated according to the moving speed of the vertical loading platform and the linear rotation speed of the measuring wheel. The adhesion coefficient can be calculated according to the pressure applied to the rail and the torque during the rotation of the measuring wheel. The data of the wavy wear of the rail (rail corrugation) can be measured by the laser displacement sensor. The beneficial effect of the present invention is that while detecting the wheel-rail adhesion-slip behavior, the corrugation data of the rail can be obtained, and further the collaborative analysis of the relationship between the adhesion-slip curve and the rail corrugation state can be realized.

Description

Technical Field

[0001] The present invention relates to the technical field, and particularly relates to a comprehensive measuring device and method for wheel-rail adhesion-creep behavior and rail corrugation. Background Art

[0002] The basic principle of train operation is to achieve traction and braking by means of the rolling contact of the driving wheels / axles on the rail, and this process completely depends on the adhesion characteristics between the wheel-rail interfaces. Wheel-rail contact adhesion is a special rolling friction problem, which is not only related to factors such as contact patch pressure, contact object materials, relative wheel-rail motion state, surface roughness of the contact surface, environmental state, etc., but also affected by wheel-rail creep, wheel rolling speed, and vibration of the drive system. Many researchers have carried out a large number of research works on the adhesion characteristics between wheel and rail by means of adhesion-creep curves both theoretically and experimentally.

[0003] Rail corrugation refers to the longitudinal unevenness of the rail, which means the unevenness in the vertical direction of the rail surface after being worn by the wheel-rail contact, and it will cause vibration, noise, and safety problems for train operation.

[0004] At present, most of the experimental studies on wheel-rail adhesion are simulated experiments carried out in the laboratory. However, the surface conditions of the actual track vary greatly under dry conditions, lubricated conditions, and states such as water, oil, and sand particles. It is very difficult to simulate the surface conditions equivalent to the field track in the laboratory. At the same time, existing on-site test equipment can either not monitor the creep rate or has too high test costs. Therefore, it is of great significance to develop a convenient and fast on-site test device that can detect the adhesion-creep curve to study wheel-rail adhesion behavior. In addition, when existing measuring equipment detects wheel-rail adhesion-creep behavior, it cannot obtain the corrugation data of the rail at the same time, and thus cannot conduct a collaborative analysis of the relationship between the adhesion-creep curve and the rail corrugation state. In this regard, creating a comprehensive measuring device and method for wheel-rail adhesion-creep behavior and rail corrugation has important theoretical and practical significance and is worthy of further research. Summary of the Invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a comprehensive measuring device and method for wheel-rail adhesion-creep behavior and rail corrugation, which can obtain the corrugation data of the rail while detecting the wheel-rail adhesion-creep behavior, and thus realize the collaborative analysis of the relationship between the adhesion-creep curve and the rail corrugation state.

[0006] The purpose of the present invention is achieved by the following technical solutions:

[0007] An integrated measurement device for wheel-rail adhesion-creep behavior and rail corrugation, comprising a left fixing frame, a right fixing frame, a linear driving motor, a lead screw transmission assembly, a lead screw slider, a mounting plate, a vertical loading platform, a configuration block, a rotary driving motor, a measuring wheel, a first rotary encoder, a torque sensor, a second rotary encoder, and a laser displacement sensor. The left fixing frame and the right fixing frame are respectively erected at both ends of a rail (31). The linear driving motor is arranged on the left fixing frame. The linear driving motor drives the lead screw slider to make a linear reciprocating movement along the rail between the left fixing frame and the right fixing frame through the lead screw transmission assembly. The mounting plate is erected at the bottom of the lead screw slider. The vertical loading platform is arranged on one side of the mounting plate and can slide up and down. The laser displacement sensor is arranged on the other side of the mounting plate. The rotary driving motor and the configuration block are arranged on the top of the vertical loading platform. The measuring wheel is rotatably arranged at the bottom of the vertical loading platform through a wheel shaft. A first rotary encoder is arranged at the output end of the linear driving motor. The torque sensor and the second rotary encoder are respectively arranged at both ends of the wheel shaft. The output end of the rotary driving motor is connected to the second rotary encoder.

[0008] Further, the lead screw transmission assembly includes a ball screw and a cylindrical guide rail. Both ends of the ball screw are respectively rotatably arranged on the left fixing frame and the right fixing frame through first support seats. The output end of the linear driving motor is connected to the ball screw through a coupling. The cylindrical guide rail is arranged on both sides of the ball screw. Both ends of the cylindrical guide rail are respectively fixed on the left fixing frame and the right fixing frame through second support seats. The lead screw slider is threadedly sleeved on the ball screw. Connecting plates are arranged on both sides of the lead screw slider. The cylindrical guide rail passes through the connecting plates and is slidably connected to the connecting plates through bearings.

[0009] Further, a vertical linear guide rail is arranged on one side of the mounting plate. A linear slider slidably connected to the linear guide rail is arranged on the vertical loading platform.

[0010] Further, five laser displacement sensors are provided. The probes of the five laser displacement sensors are respectively vertically corresponding to the midpoints of five arc segments located at the rail top in the cross-section of the rail.

[0011] Further, a driving wheel is arranged at the output end of the rotary driving motor. A driven wheel is arranged on the rotating shaft of the second rotary encoder. The driving wheel and the driven wheel are connected through a synchronous belt.

[0012] Further, the integrated measurement device for wheel-rail adhesion-creep behavior and rail corrugation further includes a host computer and a data acquisition card. The linear driving motor and the rotary driving motor are both electrically connected to the host computer. The first rotary encoder, the torque sensor, the second rotary encoder, and the laser displacement sensor are all electrically connected to the input end of the data acquisition card. The output end of the data acquisition card is electrically connected to the host computer.

[0013] Further, both sides of the bottom of the left fixing frame and both sides of the bottom of the right fixing frame are connected by a fixing plate. Support frames are provided at the bottom of the left fixing frame and the bottom of the right fixing frame, and a base is provided at the bottom of the support frame. The base is clamped to the bottom of the rail by fastening bolts.

[0014] Further, the present invention also provides a comprehensive measurement method for wheel-rail adhesion-creep behavior and rail corrugation, including:

[0015] Configuring the initial setting values of experimental parameters, where the experimental parameters include the moving speed of the measuring wheel, the moving distance of the measuring wheel, the creep ratio control range, the creep ratio increase amount, the number of reciprocating motions, the normal pressure, and the experimental simulation conditions;

[0016] Starting the linear drive motor and the rotary drive motor through the host computer, causing rolling contact and slippage between the measuring wheel and the rail, and detecting the moving speed v of the vertical loading platform through the first rotary encoder r , detecting the torque T when the measuring wheel rotates through the torque sensor, and detecting the rotational linear speed v of the measuring wheel through the second rotary encoder w , collecting data on v r and v w through the data acquisition card and transmitting the collected data to the host computer;

[0017] The host computer calculates the rotational linear speed v of the measuring wheel according to the set creep ratio s and the moving speed v of the vertical loading platform r , and controls the measuring wheel according to the measured v w value to make v w < v w to simulate the braking condition, or make v r > v w > v r to simulate the traction condition;

[0018] For different simulation conditions, the host computer changes the creep ratio according to the creep ratio increase amount, and then calculates the adhesion coefficient μ under different creep ratio conditions according to the torque T when the measuring wheel rotates under different creep ratio conditions, and draws the adhesion-creep curve under different simulation conditions according to the calculation results;

[0019] By adjusting the installation positions of the left fixing frame and the right fixing frame on the rail, the contact position between the measuring wheel and the rail surface is adjusted. For different contact positions, the host computer changes the creep ratio according to the creep ratio increase amount, and then calculates the adhesion coefficient μ under different creep ratio conditions according to the torque T when the measuring wheel rotates under different creep ratio conditions, and draws the adhesion-creep curve under different contact positions according to the calculation results;

[0020] The distance between the probe of the laser displacement sensor and the midpoint of the corresponding circular arc segment is detected by the laser displacement sensor. The second rotary encoder measures the running mileage by recording the generated number of pulses. The data acquisition card collects the measured distance and running mileage data and transmits them to the host computer. The host computer removes outliers from the data through digital signal processing, and then calculates the chord measurement value y(x) of the midpoint of the corresponding circular arc segment according to the formula where f(x) is the rail unevenness function, a is the horizontal distance from the starting point of the chord to the chord measurement point, b is the horizontal distance from the ending point of the chord to the chord measurement point, f(x - a) is the value of the rail unevenness function at the starting point of the chord, f(x + b) is the value of the rail unevenness function at the ending point of the chord, and L is the chord length of the corresponding circular arc segment;

[0021] For the chord measurement value calculated by the host computer, first, the low-frequency band signal and the high-frequency band signal are decomposed by empirical wavelet transform, then the trend term in the low-frequency band signal is removed by ensemble empirical mode decomposition, and then an inverse filter with different amplitude responses is designed based on the least squares method to process the chord measurement value, and the corrugation data of the corresponding band of the track is restored. Finally, the corrugation data is filtered in different wavelength sections by a band-pass filter to obtain the waveform diagrams of different wavelength sections.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. The present invention drives the vertical loading platform equipped with measuring wheels to move through a linear drive motor, and then simulates the train running speed through the moving speed of the vertical loading platform; drives the measuring wheels to rotate through a rotary drive motor, and then simulates the train wheel speed through the speed of the measuring wheels; by controlling the rotational speeds of the linear drive motor and the rotary drive motor, creep is generated between the wheel and the rail, and the magnitude of the creep rate is regulated. At the same time, the adhesion coefficient between the wheel and the rail is measured. Finally, the adhesion coefficient at different creep rates is repeatedly measured through the reciprocating movement of the measuring wheels, and an adhesion-creep curve is plotted.

[0024] 2. The present invention can control the creep rate range from 0 to 100%. The required creep rate can be input through the host computer to ensure that the creep rate during each test is the one required for the experiment, which has the advantages of a large control range and high control accuracy.

[0025] 3. The present invention can control the running speed of the vertical loading platform through the host computer to ensure that the running speed during each test is the one required for the experiment, which has the advantage of high control accuracy.

[0026] 4. The present invention can conduct adhesion experiments under traction conditions and braking conditions. When the host computer controls the rotational linear speed of the measuring wheels to be greater than the moving speed of the vertical loading platform, it can simulate the traction condition; when the rotational linear speed of the measuring wheels is controlled to be less than the moving speed of the vertical loading platform, it can simulate the braking condition.

[0027] 5. The present invention can change the contact position between the measuring wheel and the rail surface by adjusting the installation positions of the left fixing frame and the right fixing frame on the rail, so as to conduct adhesion experiments at different lateral contact positions on the rail surface.

[0028] 6. Through the arrangement of five laser displacement sensors, the present invention can synchronously collect the rail surface corrugation data when the vertical loading platform is running. Brief Description of the Drawings

[0029] Figure 1 It is a schematic diagram of the overall structure of the wheel-rail adhesion-creep behavior and rail corrugation comprehensive measurement device in the present invention;

[0030] Figure 2 It is a front view schematic diagram of the structure of the wheel-rail adhesion-creep behavior and rail corrugation comprehensive measurement device in the present invention;

[0031] Figure 3 It is a side view schematic diagram of the structure of the wheel-rail adhesion-creep behavior and rail corrugation comprehensive measurement device in the present invention;

[0032] Figure 4 It is an installation schematic diagram of the right fixing frame on the rail in the present invention;

[0033] Figure 5 It is a layout schematic diagram of the five laser displacement sensors in the present invention;

[0034] Figure 6 It is a flow chart of the test control method and data acquisition of the device in the present invention;

[0035] Figure 7 It is a schematic diagram of the adhesion-creep curve results under traction and braking conditions in the present invention;

[0036] Figure 8 It is a schematic diagram of the adhesion-creep curve results of the test wheel at different lateral contact positions in the present invention;

[0037] Figure 9 It is a schematic diagram of the displacement-amplitude curve results of the corrugation data measured by the laser displacement sensor 1 (mm) corresponding to the inner R13 arc section in the present invention;

[0038] Figure 10 It is a schematic diagram of the displacement-amplitude curve results of the corrugation data measured by the laser displacement sensor 2 (mm) corresponding to the inner R80 arc section in the present invention;

[0039] Figure 11 It is a schematic diagram of the displacement-amplitude curve results of the corrugation data measured by the laser displacement sensor 3 (mm) corresponding to the middle R300 arc section in the present invention;

[0040] Figure 12It is a schematic diagram of the displacement-amplitude curve result of the corrugation data measured by the laser displacement sensor 4 (mm) corresponding to the outer R80 arc segment in the present invention;

[0041] Figure 13 It is a schematic diagram of the displacement-amplitude curve result of the corrugation data measured by the laser displacement sensor 5 (mm) corresponding to the outer R13 arc segment in the present invention.

[0042] In the figure: 1. First support seat; 2. Cylindrical guide rail; 3. Bearing; 4. Connecting plate; 5. Lead screw slider; 6. Second support seat; 7. Left fixing frame; 8. Linear drive motor; 9. Fixing plate; 10. Mounting plate; 11. Right fixing frame; 12. Linear guide rail; 13. Driving wheel; 15. Coupling; 17. Driven wheel; 18. Linear slider; 19. Wheel shaft; 20. Second rotary encoder; 21. Synchronous belt; 22. Rotary drive motor; 23. Configuration block; 24. Vertical loading platform; 26. Torque sensor; 27. Measuring wheel; 28. Support frame; 29. Tightening bolt; 30. Base; 31. Rail; 32. Ball screw; 33. Laser displacement sensor. Specific embodiments

[0043] The present invention will be further described below in conjunction with the accompanying drawings, but the protection scope of the present invention is not limited to the following.

[0044] As Figures 1-5 shown, a comprehensive measurement device for wheel-rail adhesion-creep behavior and rail corrugation includes a left fixing frame 7, a right fixing frame 11, a linear drive motor 8, a lead screw transmission assembly, a lead screw slider 5, a mounting plate 10, a vertical loading platform 24, a configuration block 23, a rotary drive motor 22, a measuring wheel 27, a first rotary encoder, a torque sensor 26, a second rotary encoder 20, and a laser displacement sensor 33. The left fixing frame 7 and the right fixing frame 11 are respectively installed at both ends of the rail 31. The linear drive motor 8 is installed on the left fixing frame 7. The linear drive motor 8 drives the lead screw slider 5 to make a linear reciprocating movement along the rail 31 between the left fixing frame 7 and the right fixing frame 11 through the lead screw transmission assembly. The mounting plate 10 is vertically fixed at the bottom of the lead screw slider 5. A vertical linear guide rail 12 is fixed on one side of the mounting plate 10. A linear slider 18 slidably connected to the linear guide rail 12 is fixed on the vertical loading platform 24, so that the vertical loading platform 24 can slide up and down along the linear guide rail 12. The laser displacement sensor 33 is installed on the other side of the mounting plate 10. The rotary drive motor 22 and the configuration block 23 are installed on the top of the vertical loading platform 24. The measuring wheel 27 is rotatably installed at the bottom of the vertical loading platform 24 through a wheel shaft 19. The output end of the linear drive motor 8 is connected to a first rotary encoder. The torque sensor 26 and the second rotary encoder 20 are respectively connected to both ends of the wheel shaft 19. The output end of the rotary drive motor 22 is connected to the second rotary encoder 20.

[0045] In this embodiment, the torque sensor 26 is a TR1055 type dynamic torque sensor; the laser displacement sensor 33 is an LDK60-882-3Hz type laser displacement sensor.

[0046] As Figure 2 shown, the lead screw drive assembly includes a ball screw 32 and a cylindrical guide rail 2. Both ends of the ball screw 32 are rotatably mounted on the left fixed frame 7 and the right fixed frame 11 through the first support seats 1 respectively. The output end of the linear drive motor 8 is connected to the ball screw 32 through a coupling 15. The cylindrical guide rails 2 are arranged on both sides of the ball screw 32. Both ends of the cylindrical guide rails 2 are fixed to the left fixed frame 7 and the right fixed frame 11 through the second support seats 6 respectively. The lead screw slider 5 is threadedly sleeved on the ball screw 32. Connecting plates 4 are fixed on both sides of the lead screw slider 5. The cylindrical guide rail 2 passes through the connecting plate 4 and is slidably connected to the connecting plate 4 through a bearing 3.

[0047] As Figure 2 、 Figure 3 shown, a driving wheel 13 is installed at the output end of the rotary drive motor 22, a driven wheel 17 is installed on the rotating shaft of the second rotary encoder 20, and the driving wheel 13 and the driven wheel 17 are connected by a synchronous belt 21, so that the measuring wheel 27 can be driven to rotate by the rotary drive motor 22.

[0048] By driving the ball screw 32 to rotate through the linear drive motor 8, the vertical loading platform 24 and the measuring wheel 27 can be driven to move synchronously along the rail 31 through the lead screw slider 5. Furthermore, the linear moving speed of the vertical loading platform 24 and the measuring wheel 27 can simulate the train running speed; by driving the measuring wheel 27 to rotate through the rotary drive motor 22, the rotational linear speed of the measuring wheel 27 can simulate the wheel speed of the train; by simultaneously operating the linear drive motor 8 and the rotary drive motor 22, creep can be generated between the measuring wheel 27 and the track, and the magnitude of the creep rate can be adjusted. At the same time, the adhesion coefficient between the measuring wheel 27 and the track can also be measured. Furthermore, during the reciprocating movement of the measuring wheel 27, the adhesion coefficient under different creep rate conditions can be measured and an adhesion-creep curve can be plotted.

[0049] As Figure 1 、 Figure 4 shown, both sides of the bottom of the left fixed frame 7 and both sides of the bottom of the right fixed frame 11 are connected by a fixing plate 9. Support frames 28 are fixed to the bottom of the left fixed frame 7 and the bottom of the right fixed frame 11. A base 30 is fixed to the bottom of the support frame 28. The base 30 is clamped to the bottom of the rail 31 through a fastening bolt 29. By changing the installation positions of the left fixed frame 7 and the right fixed frame 11 on the rail 31, the contact position between the measuring wheel 27 and the rail surface can be changed, and thus adhesion experiments at different lateral contact positions on the rail surface can be carried out.

[0050] In this embodiment, asFigure 1 , Figure 5 As shown in Figure 5 , there are five laser displacement sensors 33, which are respectively denoted as Laser Displacement Sensor 1 (mm), Laser Displacement Sensor 2 (mm), Laser Displacement Sensor 3 (mm), Laser Displacement Sensor 4 (mm), and Laser Displacement Sensor 5 (mm). The probes of the five laser displacement sensors 33 are respectively vertically corresponding to the midpoints of five arc segments located at the rail top in the cross-section of the rail. The five arc segments are divided into an inner R13 arc segment, an inner R80 arc segment, a middle R300 arc segment, an outer R80 arc segment, and an outer R13 arc segment according to the radius. Laser Displacement Sensor 1 (mm) corresponds to the inner R13 arc segment, Laser Displacement Sensor 2 (mm) corresponds to the inner R80 arc segment, Laser Displacement Sensor 3 (mm) corresponds to the middle R300 arc segment, Laser Displacement Sensor 4 (mm) corresponds to the outer R80 arc segment, and Laser Displacement Sensor 5 (mm) corresponds to the outer R13 arc segment. During the experiment on the above wheel-rail adhesion-creep behavior, the corrugation data of each arc segment on the rail surface can be synchronously collected through the laser displacement sensors 33.

[0051] To facilitate the above experiment, the wheel-rail adhesion-creep behavior and rail corrugation comprehensive measurement device of the present invention further includes a host computer and a data acquisition card. The linear drive motor 8 and the rotary drive motor 22 are both electrically connected to the host computer. The first rotary encoder, the torque sensor 26, the second rotary encoder 20, and the laser displacement sensors 33 are all electrically connected to the input end of the data acquisition card. The output end of the data acquisition card is electrically connected to the host computer.

[0052] The moving speed v of the vertical loading platform 24 can be measured through the first rotary encoder r , and the linear velocity v of the measurement wheel 27 can be detected through the second rotary encoder 20 w . The data acquisition card collects the data of v r and v w and transmits the collected data to the host computer. The host computer can then calculate the creep ratio s according to the formula . The torque T when the measurement wheel 27 rotates can be measured through the torque sensor 26. The data acquisition card collects the data of T and transmits the collected data to the host computer. The host computer can then calculate the adhesion coefficient according to the formula , where R is the radius of the measurement wheel 27, and N is the normal pressure exerted by the measurement wheel 27 on the rail 31. The normal pressure is a fixed value and is obtained by converting the total weight of the vertical loading platform 24 and all the structures installed on the vertical loading platform 24.

[0053] Before conducting experiments with the above-mentioned wheel-rail adhesion-creep behavior and rail corrugation comprehensive measurement device, first configure the initial parameters of the device. The initial parameters of the device include the number of pulses per revolution of the motor, the range and voltage range of the torque sensor, the range and voltage range of the encoder, the range and voltage range of the laser displacement sensor, the diameter of the measuring wheel, and the experimental simulation conditions. Among them, the number of pulses per revolution of the motor, the range and voltage range of the torque sensor, the range and voltage range of the encoder, and the diameter of the measuring wheel are fixed values and can be set according to the specific situation of the device. By modifying the experimental simulation conditions, it is possible to determine whether the experiment simulates the traction or braking condition for this time.

[0054] As Figure 6 shown, the experimental parameters for experimental configuration include the moving speed of the measuring wheel, the moving distance of the measuring wheel, the creep rate control range, the creep rate increase, the number of reciprocating motions, the number of experiments, and the normal pressure. These parameters are determined according to the experimental requirements. During the operation of the program started by the host computer, the data acquisition card will collect torque, rotational speed, creep rate, and adhesion coefficient. At the end of the experiment, the host computer program automatically saves the collected and calculated data.

[0055] When conducting specific experiments with the above-mentioned wheel-rail adhesion-creep behavior and rail corrugation comprehensive measurement device, it includes the following experimental processes:

[0056] Configure the initial set values of the experimental parameters. The experimental parameters include the moving speed of the measuring wheel, the moving distance of the measuring wheel, the creep rate control range, the creep rate increase, the number of reciprocating motions, the normal pressure, and the experimental simulation conditions.

[0057] Start the linear drive motor 8 and the rotary drive motor 22 through the host computer, so that rolling contact and slippage occur between the measuring wheel 27 and the rail 31. Detect the moving speed v of the vertical loading platform 24 through the first rotary encoder r , detect the torque T when the measuring wheel 27 rotates through the torque sensor 26, and detect the linear velocity v of the rotation of the measuring wheel 27 through the second rotary encoder 20 w , and collect data on v r and v w through the data acquisition card and transmit the collected data to the host computer.

[0058] The host computer calculates the linear velocity v of the rotation of the measuring wheel 27 according to the set creep rate s and the moving speed v of the vertical loading platform 24 r , and controls the measuring wheel 27 according to the measured value of v w , so that v w < v w r thereby simulating the braking condition, or making v w > v r thereby simulating the traction condition.

[0059] For different simulated working conditions, the host computer changes the creepage rate according to the increase in the creepage rate, and then calculates the adhesion coefficient μ under different creepage rate conditions based on the torque T when the measuring wheel 27 rotates under different creepage rate conditions, and draws the adhesion-creepage curve under different simulated working conditions according to the calculation results.

[0060] By adjusting the installation positions of the left fixing frame 7 and the right fixing frame 11 on the steel rail 31, the contact position between the measuring wheel 27 and the surface of the steel rail 31 is adjusted. For different contact positions, the host computer changes the creepage rate according to the increase in the creepage rate, and then calculates the adhesion coefficient μ under different creepage rate conditions based on the torque T when the measuring wheel 27 rotates under different creepage rate conditions, and draws the adhesion-creepage curve under different contact positions according to the calculation results.

[0061] The distance between the probe of the laser displacement sensor 33 and the midpoint of the corresponding arc segment is detected by the laser displacement sensor 33. The second rotary encoder 20 measures the travel mileage by recording the generated number of pulses. The data acquisition card collects the measured distance and travel mileage data and transmits them to the host computer. The host computer removes the outliers from the data through digital signal processing, and then according to the formula the chord measurement value y(x) of the midpoint of the corresponding arc segment is calculated. In the formula, f(x) is the rail unevenness function, a is the horizontal distance from the starting point of the chord to the chord measurement point, b is the horizontal distance from the ending point of the chord to the chord measurement point, f(x - a) is the value of the rail unevenness function at the starting point of the chord, f(x + b) is the value of the rail unevenness function at the ending point of the chord, and L is the chord length of the corresponding arc segment.

[0062] For the chord measurement value calculated by the host computer, the low-frequency band signal and the high-frequency band signal are first decomposed by empirical wavelet transform, then the trend term in the low-frequency band signal is removed by ensemble empirical mode decomposition, and then an inverse filter with different amplitude responses is designed based on the least square method to process the chord measurement value, and the corrugation data of the corresponding band of the track is restored. Finally, the corrugation data is filtered in different wavelength bands by a band-pass filter to obtain the waveform diagrams of different wavelength bands.

[0063] As Figure 7 shown, the adhesion-creepage curve obtained by testing the present invention is similar to the results of previous studies. The adhesion coefficients under both braking and traction conditions increase with the increase in the creepage rate, and then tend to be stable, and the maximum adhesion coefficient is between 0.3 and 0.6.

[0064] As Figure 8As shown, in this embodiment, adhesion experiments were carried out at three contact positions: the running line of the rail, the middle of the rail, and the non-running line of the rail. The adhesion coefficients at the three contact positions all increase rapidly first and then increase slowly with the increase of the creep rate. Moreover, the maximum adhesion coefficients at the three contact positions are between 0.3 and 0.6, but the maximum adhesion coefficients at the three contact positions are different.

[0065] As Figures 9-13 shown, based on the above five arc segments, there are varying degrees of corrugations on each part of the rail surface. It can be seen that the severity of the corrugations in the R13 arc segment, the R80 arc segment, and the R300 arc segment gradually increases. Moreover, the amplitude of the corrugations in the R13 segment is concentrated within 0.03 mm, the amplitude of the corrugations in the R80 segment is concentrated within 0.07 mm, and the amplitude of the corrugations in the R300 segment is concentrated within 0.1 mm.

[0066] The above test results show that through the measuring device and measuring method of the present invention, a complete adhesion-creep curve and an accurate displacement-amplitude curve for corrugations can be accurately obtained. This tester can be used for the comprehensive test and measurement of the adhesion-creep behavior and rail corrugations under on-site lines.

[0067] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A comprehensive measuring device for wheel-rail adhesion-creep behavior and rail corrugation, characterized in that: The invention comprises a left fixed frame (7), a right fixed frame (11), a linear drive motor (8), a screw transmission assembly, a screw slider (5), a mounting plate (10), a vertical loading platform (24), a configuration block (23), a rotary drive motor (22), a measuring wheel (27), a first rotary encoder, a torque sensor (26), a second rotary encoder (20), and a laser displacement sensor (33). The left fixed frame (7) and the right fixed frame (11) are respectively mounted on two ends of a steel rail (31). The linear drive motor (8) is mounted on the left fixed frame (7). The linear drive motor (8) drives the screw slider (5) to move linearly back and forth between the left fixed frame (7) and the right fixed frame (11) along the steel rail (31) through the screw transmission assembly. The mounting plate (10) is vertically mounted on the bottom of the screw slider (5). The vertical loading platform (24) is mounted on one side of the mounting plate (10) and can slide up and down. The laser displacement sensor (33) The invention is arranged on the other side of the mounting plate (10), the rotary drive motor (22) and the configuration block (23) are arranged on the top of the vertical loading platform (24), the measuring wheel (27) is arranged on the bottom of the vertical loading platform (24) through the wheel shaft (19), the output end of the linear drive motor (8) is provided with a first rotary encoder, the torque sensor (26) and the second rotary encoder (20) are respectively arranged at both ends of the wheel shaft (19), the output end of the rotary drive motor (22) is connected to the second rotary encoder (20), the output end of the rotary drive motor (22) is provided with a driving wheel (13), the rotating shaft of the second rotary encoder (20) is provided with a driven wheel (17), the driving wheel (13) and the driven wheel (17) are connected through a synchronous belt (21), and five laser displacement sensors (33) are provided, and the probes of the five laser displacement sensors (33) respectively correspond vertically to the midpoints of five circular arc segments located at the rail top in the cross section of the rail (31).

2. The wheel-rail adhesion-creep behavior and rail corrugation comprehensive measuring device according to claim 1, characterized in that: The screw transmission assembly comprises a ball screw (32) and a cylindrical guide rail (2). The two ends of the ball screw (32) are rotatably arranged on a left fixing frame (7) and a right fixing frame (11) through a first support seat (1). The output end of the linear drive motor (8) is connected to the ball screw (32) through a coupling (15). The cylindrical guide rail (2) is arranged on both sides of the ball screw (32). The two ends of the cylindrical guide rail (2) are respectively fixed on the left fixing frame (7) and the right fixing frame (11) through a second support seat (6). The screw slider (5) is threadedly sleeved on the ball screw (32). Connecting plates (4) are arranged on both sides of the screw slider (5). The cylindrical guide rail (2) passes through the connecting plate (4) and is slidably connected to the connecting plate (4) through a bearing (3).

3. The wheel-rail adhesion-creep behavior and rail corrugation comprehensive measuring device according to claim 1, characterized in that: A vertical linear guide rail (12) is provided on one side of the mounting plate (10), and a linear slide block (18) slidably connected to the linear guide rail (12) is provided on the vertical loading platform (24).

4. The wheel-rail adhesion-creep behavior and rail corrugation comprehensive measuring device according to claim 1, characterized in that: It also includes a host computer and a data acquisition card. The linear drive motor (8) and the rotary drive motor (22) are electrically connected to the host computer. The first rotary encoder, the torque sensor (26), the second rotary encoder (20), and the laser displacement sensor (33) are electrically connected to the input end of the data acquisition card. The output end of the data acquisition card is electrically connected to the host computer.

5. The wheel-rail adhesion-creep behavior and rail corrugation comprehensive measuring device according to claim 1, characterized in that: The two sides of the bottom of the left fixing frame (7) and the two sides of the bottom of the right fixing frame (11) are connected through a fixing plate (9), and the bottom of the left fixing frame (7) and the bottom of the right fixing frame (11) are both provided with a support frame (28), and the bottom of the support frame (28) is provided with a base (30), and the base (30) is clamped to the bottom of the rail (31) by a fastening bolt (29).

6. A comprehensive measurement method for wheel-rail adhesion-creep behavior and rail corrugation, characterized in that: include: Configuring initial setting values ​​of experimental parameters, the experimental parameters including the moving speed of the measuring wheel (27), the moving distance of the measuring wheel (27), the creep rate control range, the creep rate increase, the number of reciprocating motions, the normal pressure, and the experimental simulation conditions; The linear drive motor (8) and the rotary drive motor (22) are started by the host computer to cause rolling contact and slip between the measuring wheel (27) and the rail (31), and the moving speed v of the vertical loading platform (24) is detected by the first rotary encoder. r The torque T of the measuring wheel (27) during rotation is detected by the torque sensor (26), and the rotational linear velocity v of the measuring wheel (27) is detected by the second rotary encoder (20). w , through the data acquisition card to v r and v w Collect data and transmit the collected data to the host computer. The host computer uses the formula The creep rate s is calculated, and the host computer uses the formula The adhesion coefficient is calculated, where R is the radius of the measuring wheel (27), N is the normal pressure applied by the measuring wheel (27) to the rail (31), and the normal pressure is a fixed value, which is converted according to the total weight of the vertical loading platform (24) and all structures installed on the vertical loading platform (24); The host computer sets the creep rate s and the moving speed v of the vertical loading platform (24) according to the set r The rotational velocity v of the measuring wheel (27) is calculated as w , and according to the measured v w The value controls the measuring wheel (27) so that v w <v r To simulate braking conditions, or make v w >v r Thus simulating the traction condition; For different simulation working conditions, the upper computer changes the creep rate according to the creep rate increase, and then calculates the adhesion coefficient μ under different creep rate conditions according to the torque T when the measuring wheel (27) rotates under different creep rate conditions, and draws the adhesion-creep curve under different working conditions according to the calculation results; By adjusting the installation positions of the left fixing frame (7) and the right fixing frame (11) on the rail (31), the contact position between the measuring wheel (27) and the surface of the rail (31) is adjusted. For different contact positions, the upper computer changes the creep rate according to the creep rate increase, and then calculates the adhesion coefficient μ under different creep rate conditions according to the torque T when the measuring wheel (27) rotates under different creep rate conditions, and draws adhesion-creep curves under different contact positions according to the calculation results; The laser displacement sensor (33) detects the distance between the probe of the laser displacement sensor (33) and the corresponding arc segment midpoint. The second rotary encoder (20) measures the mileage by recording the number of pulses generated. The data acquisition card collects the measured distance and mileage data and transmits them to the host computer. The host computer removes abnormal values ​​from the data through digital signal processing, and then calculates the mileage according to the formula Calculate the chord measurement value y(x) of the midpoint of the corresponding arc segment, where f(x) is the rail irregularity function, a is the horizontal distance from the starting point of the chord to the chord measurement point, b is the horizontal distance from the end point of the chord to the chord measurement point, f(xa) is the rail irregularity function value at the starting point of the chord, f(x+b) is the rail irregularity function value at the end point of the chord, and L is the chord length of the corresponding arc segment; The upper computer first decomposes the low-frequency band signal and the high-frequency band signal through empirical wavelet transform for the calculated chord measurement values, and then removes the trend term in the low-frequency band signal through ensemble empirical mode decomposition. Then, based on the least squares method, inverse filters with different amplitude responses are designed to process the chord measurement values, and the corrugation data of the corresponding band of the track are restored. Finally, the corrugation data are filtered in different wavelength segments through bandpass filters to obtain waveform diagrams of different wavelength segments.

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