On-line testing method for longitudinal force and adhesion coefficient of railway vehicle wheel rail

Abstract

The invention discloses a railway vehicle wheel rail longitudinal force and adhesion coefficient on-line test method, which comprises the following steps of: establishing a force balance equation and a moment balance equation by analyzing the stress of a wheel set; according to the axle box vibration longitudinal / transverse / vertical acceleration collected by the acceleration sensor installed on the axle and the primary longitudinal / transverse / vertical displacement on the two sides of the axle, the vertical force and the longitudinal force of the wheel rail are worked out, and the adhesion coefficient is calculated. The problems that the adhesion saturation effect is neglected, the vertical force time-varying characteristic of the wheel rail is not considered, and the testing precision of the longitudinal force and the adhesion coefficient is insufficient in an existing testing method are solved.

Description

Technical Field

[0001] The invention relates to the field of rail contact force measurement, and in particular to an online testing method for railway vehicle wheel-rail longitudinal force and adhesion coefficient. Background Art

[0002] When the wheels of railway vehicles come into contact with the rails, contact spots are generated. The contact spots include adhesion areas and sliding areas. In the adhesion area, the wheel-rail materials are in a pure rolling state without relative sliding; in the sliding area, the wheel-rail is in a sliding state without rolling. The wheel-rail adhesion state directly determines the saturation limit of the wheel-rail longitudinal force, and directly determines the traction and braking performance of the train. When the wheel-rail longitudinal force is lower than the traction force, the wheels will spin, causing abnormal wear of the wheels and rails; when the wheel-rail longitudinal force is lower than the braking force, the wheels will slip, resulting in an increase in the braking distance of the train, seriously affecting the safety of train operation.

[0003] The wheel-rail adhesion coefficient is mainly affected by the third medium. Under conditions of moisture, oil, frost, fallen leaves, etc., the wheel-rail adhesion coefficient decreases rapidly. The adhesion coefficient of the dry and clean wheel-rail interface is higher. The adhesion coefficient can also be increased by appropriately spreading sand.

[0004] The wheel-rail adhesion coefficient can be measured on a rolling test bench. The wheel-rail longitudinal creep rate is calculated by the speed difference between the roller and the wheel, and the wheel-rail tangential force is calculated by the torque signal. The ratio of the tangential force to the vertical force is the adhesion coefficient. It is difficult to test the wheel-rail adhesion coefficient online. The existing technology mainly estimates it through braking force or traction force, but it is not applicable in the case of adhesion saturation. In addition, the time-varying wheel-rail vertical force information is lacking, making it difficult to accurately obtain the wheel-rail adhesion coefficient of different sections of the entire line. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the present invention provides an online testing method for the longitudinal force and adhesion coefficient of the wheel-rail of a railway vehicle.

[0006] In order to achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is:

[0007] An online testing method for the longitudinal force and adhesion coefficient of a railway vehicle wheel-rail comprises the following steps:

[0008] S1. Establishing a group of wheelset balance equations based on the stress state of the wheelset when the train is running;

[0009] S2. Collect the longitudinal, lateral and vertical acceleration of the axle box vibration on the train running line, and collect the longitudinal, lateral and vertical displacements on both sides of the axle;

[0010] S3, calculating the wheel-rail vertical force and the wheel-rail longitudinal force on the left and right sides of the wheelset according to the equilibrium equations established in S1 and the data collected in S2;

[0011] S4. Based on the wheel-rail vertical force and wheel-rail longitudinal force obtained in S3, the wheel-rail adhesion coefficients on the left and right sides are calculated according to the adhesion coefficient formula.

[0012] Furthermore, the balance equation group in S1 includes: a longitudinal balance equation, a lateral rolling balance equation, and a lateral shaking balance equation, which are expressed as:

[0013] F=ma

[0014]

[0015] m w a z ·l c / 2+Q s1 l1-Q s2 ·l2+G·l c / 2-Q1·l c +H·r0=0

[0016] m w a z ·l c / 2+Q s2 l1-Q s1 ·l2+G·l c / 2-Q2·l c -H·r0=0

[0017] Where m is the unsprung mass, m w is the axle mass, G is the axle weight, F is the longitudinal external force, is the axle moment of inertia, L C is the distance between the wheels on both sides, L s is the distance between the axle boxes on both sides, l1 is the distance between the wheel and the axle box on the other side, l2 is the distance between the wheel and the axle box on the same side, a is the longitudinal acceleration, is the angular acceleration, F XR is the right longitudinal force, F XL is the longitudinal force on the left side, F y is the lateral force, Q s1 is the vertical force of the left axle box, Q s2 is the vertical force of the right axle box, a z is the vertical acceleration, H is the wheel-rail lateral force, Q xl is the left wheel-rail vertical force, Q xr is the right wheel-rail vertical force.

[0018] Furthermore, in S2, the longitudinal / lateral / vertical acceleration of the axle box vibration is collected by an acceleration sensor installed on the axle, the longitudinal / lateral / vertical displacements of the two sides of the axle are collected by a displacement sensor, and the three-dimensional acceleration of the wheelset is calculated by derivation of the three-dimensional displacement of the wheelset.

[0019] Furthermore, the wheel-rail vertical force and the wheel-rail longitudinal force on the left and right sides in S3 are calculated as follows:

[0020] Q xl =(k s d zl +c d d′ zl )·(l s / 2+l c / 2) / l c -(k s d zr +c d d′ zr )·(l s / 2-l c / 2) / l c +G / 2+m w a z / 2+H·r0 / l c Q xr =(k s d zr +c d d′ zr )·(l s / 2+l c / 2) / l c -(k s d zl +c d d′ zl )·(l s / 2-l c / 2) / l c +G / 2+m w a z / 2+H·r0 / l c

[0021]

[0022] In the formula, Q xl is the left wheel-rail vertical force, Q xr is the right wheel-rail vertical force, F xl is the left wheel-rail longitudinal force, F xr is the right wheel-rail vertical force, d xl ,d xr is the longitudinal displacement and vertical displacement of the left wheel pair, d zl ,d zr is the longitudinal displacement and vertical displacement of the right wheelset, d y is the lateral displacement of the wheelset, d′ xl , d′ xr is the longitudinal speed and vertical speed of the left wheel pair, d′ zl , d′ zris the longitudinal speed and vertical speed of the right wheelset, d′ y is the lateral speed of the wheelset, a l 、a r is the longitudinal acceleration of the left and right axle boxes, k x , k y , k z is the longitudinal / lateral / vertical stiffness of a system, c x 、c y 、c z is a series of longitudinal / lateral / vertical damping, L c Indicates the distance between the left and right wheels, L s Indicates the distance between the left and right axle boxes, m is the unsprung mass, m w is the axle mass, G is the axle weight, and H is the wheel-rail lateral force.

[0023] Furthermore, the calculation method of the adhesion coefficient in S4 is:

[0024]

[0025] In the formula, μ l , μ r are the left and right wheel-rail adhesion coefficients, F xl is the left wheel-rail longitudinal force of the wheelset, Q xl is the left wheel-rail vertical force of the wheelset, F xr is the right wheel-rail longitudinal force of the wheelset, Q xr Vertical wheel-rail force on the right side of the wheelset.

[0026] The present invention has the following beneficial effects:

[0027] The present invention solves the problems that the existing test method ignores the adhesion saturation effect, does not consider the time-varying characteristics of the wheel-rail vertical force, and has insufficient accuracy in testing the longitudinal force and the adhesion coefficient. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The figure is a flow chart of the on-line testing method for the longitudinal force and adhesion coefficient of the wheel-rail of a railway vehicle according to the present invention.

[0029] Figure 2a It is a schematic diagram of the comparison results between the left longitudinal force calculated in the simulation verification of the straight-line working condition of an embodiment of the present invention and the actual left longitudinal force.

[0030] Figure 2b It is a schematic diagram of the comparison results between the right longitudinal force calculated in the simulation verification of the straight-line working condition of an embodiment of the present invention and the actual right longitudinal force.

[0031] Figure 2c It is a schematic diagram of the comparison results between the left adhesion coefficient calculated in the simulation verification of the straight line working condition of the embodiment of the present invention and the actual left adhesion coefficient.

[0032] Figure 2d It is a schematic diagram of the comparison results between the right adhesion coefficient calculated in the simulation verification of the straight line working condition of the embodiment of the present invention and the actual right adhesion coefficient.

[0033] Figure 3a It is a schematic diagram of the comparison results between the left longitudinal force calculated in the simulation verification of the R2800m working condition of the embodiment of the present invention and the actual left longitudinal force.

[0034] Figure 3b It is a schematic diagram of the comparison results between the right longitudinal force calculated in the simulation verification of the R2800m working condition of the embodiment of the present invention and the actual right longitudinal force.

[0035] Figure 3c It is a schematic diagram of the comparison results between the left adhesion coefficient calculated in the simulation verification of the R2800m working condition of the embodiment of the present invention and the actual left adhesion coefficient.

[0036] Figure 3d It is a schematic diagram of the comparison results between the right-side adhesion coefficient calculated in the simulation verification of the R2800m working condition of the embodiment of the present invention and the actual right-side adhesion coefficient.

[0037] Figure 4a A side view of the arrangement of sensors according to an embodiment of the present invention.

[0038] Figure 4b This is a front view of the sensor arrangement position according to an embodiment of the present invention. DETAILED DESCRIPTION

[0039] The specific implementation modes of the present invention are described below to facilitate those skilled in the art to understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0040] An online testing method for the longitudinal force and adhesion coefficient of the wheel-rail of a railway vehicle, such as Figure 1 As shown, the following steps are included:

[0041] S1. Establishing a group of wheelset balance equations based on the stress state of the wheelset when the train is running;

[0042] In this embodiment, according to the force state analysis, the wheelset longitudinal balance equation, the lateral rolling balance equation, and the sway balance equation are established:

[0043] F= ma (1)

[0044]

[0045] m w a z ·l c / 2+Q s1 l1-Q s2 ·l2+G·l c / 2-Q1·l c +H·r0=0 (3)

[0046] m w a z ·l c / 2+Q s2 l1-Q s1 ·l2+G·l c / 2-Q2·l c -H·r0=0 (4)

[0047] The meanings of the parameters in the above formula are as follows:

[0048] F=F XR +F XL (5)

[0049] F XR =F xr +k x d xr +c x d′ xr (6)

[0050] F XL =F xl +k x d xl +c x d′ xl (7)

[0051] F y =k y d y +c y d′ y (10)

[0052]

[0053] Q sl =k z d zl +c z d′ zl (13)

[0054] Q sr =k z d zr +c z d′ zr (14)

[0055] Where d xl ,d xr ,d zl ,d zr is the longitudinal displacement and vertical displacement of the left and right wheels, d y is the lateral displacement of the wheelset, d′ xl , d′ xr , d′ zl , d′ zr is the longitudinal speed and vertical speed of the left and right wheels, d′ y is the lateral speed of the wheelset, a l 、a r is the longitudinal acceleration of the left and right axle boxes, k x , k y , k z is the longitudinal / lateral / vertical stiffness of a system, c x 、c y 、c z is a series of longitudinal / lateral / vertical damping, L c Indicates the distance between the left and right wheels, L s Indicates the distance between the left and right axle boxes

[0056] S2. Collect the longitudinal, lateral and vertical acceleration of the axle box vibration on the train running line, and collect the longitudinal, lateral and vertical displacements on both sides of the axle;

[0057] In this embodiment, the required parameters are measured on the running line: three-dimensional acceleration of the axle box and three-dimensional displacement / velocity of the first system. The acceleration sensor installed on the axle collects the longitudinal / lateral / vertical acceleration of the axle box vibration, and the displacement sensor collects the longitudinal / lateral / vertical displacement of the first system on both sides of the axle. The three-dimensional speed of the wheelset can be obtained by derivatizing the three-dimensional displacement. In this embodiment, longitudinal / lateral / vertical acceleration sensors are arranged on the axle boxes on the left and right sides of the bogie, and longitudinal / lateral / vertical displacement sensors are arranged on the left and right first systems. The sensor layout diagram is shown in the figure. Figure 4a and Figure 4b As shown, the longitudinal / vertical displacement sensors need to be arranged symmetrically on both sides, and the lateral displacement sensor can be arranged on one side to collect the longitudinal / lateral / vertical acceleration of the axle box and a series of longitudinal / lateral / vertical displacements.

[0058] The data acquisition device collects data through sensors and transmits it to the computing device. The computing device analyzes and calculates the data to obtain the data at different times of the train. When there are two axle boxes on one side, the longitudinal acceleration of the axle box vibration minus the average longitudinal acceleration of the front and rear axle boxes:

[0059] a l =a lf +a lb

[0060] ar =a rf +a rb

[0061] In the formula, a lf 、a rf is the longitudinal acceleration of the left and right front axle boxes, a lb 、a rb is the longitudinal acceleration of the left and right rear axle box vibration

[0062] S3, calculating the wheel-rail vertical force and the wheel-rail longitudinal force on the left and right sides of the wheelset according to the equilibrium equations established in S1 and the data collected in S2;

[0063] Substituting (5)-(14) into (1)-(4), we can conclude that the left wheel-rail vertical force Q xl and the right wheel-rail vertical force Q xr The expression of the left wheel-rail longitudinal force F of the wheelset is xl and the right wheel-rail longitudinal force F xr The expression is:

[0064] Q xl =(k s d z1 +c d d′ z1 )·(l s / 2+l c / 2) / l c -(k s d z2 +c d d′ z2 )·(l s / 2-l c / 2) / l c +G / 2+m w a z / 2+H·r0 / l c

[0065] Q xr =(k s d z2 +c d d′ z2 )·(l s / 2+l c / 2) / l c -(k s d z1 +c d d′ z1 )·(l s / 2-l c / 2) / l c +G / 2+m w a z / 2+H·r0 / l c

[0066]

[0067] S4. Based on the wheel-rail vertical force and wheel-rail longitudinal force obtained in S3, the wheel-rail adhesion coefficients on the left and right sides are calculated according to the adhesion coefficient formula.

[0068] Substituting the measured parameters into the formula, the vertical force and longitudinal force on the left and right sides of the wheelset during train operation can be obtained. Then, according to the adhesion coefficient formula, the expression of the left and right wheel-rail adhesion coefficient can be obtained as follows:

[0069]

[0070] Simulation verification. According to the line conditions, dynamic simulation software is used for simulation analysis. Simulation is performed on the straight line and the curved R2800m line respectively, and the three-dimensional acceleration of the axle box and the three-dimensional displacement / velocity of the first system are output. The calculation is performed using the formulas in steps three and four, and compared with the longitudinal force and adhesion coefficient output by the software. Figure 2a , Figure 2b , Figure 2c , Figure 2d , Figure 3a , Figure 3b , Figure 3c , Figure 3d As shown in Figure 2, the calculated results have a small error compared to the actual results.

[0071] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0072] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0073] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0074] The present invention uses specific embodiments to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

[0075] Those skilled in the art will appreciate that the embodiments described herein are intended to help readers understand the principles of the present invention, and should be understood that the protection scope of the present invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific variations and combinations that do not deviate from the essence of the present invention based on the technical revelations disclosed by the present invention, and these variations and combinations are still within the protection scope of the present invention.

Claims

1. An online testing method for the longitudinal force and adhesion coefficient of a railway vehicle wheel / rail, characterized in that: The steps include: S1. Establishing a group of wheelset balance equations based on the stress state of the wheelset when the train is running; S2. Collect the longitudinal, lateral and vertical acceleration of the axle box vibration on the train running line, and collect the longitudinal, lateral and vertical displacements on both sides of the axle; S3, calculating the wheel-rail vertical force and the wheel-rail longitudinal force on the left and right sides of the wheelset according to the equilibrium equations established in S1 and the data collected in S2; S4. Based on the wheel-rail vertical force and wheel-rail longitudinal force obtained in S3, the wheel-rail adhesion coefficients on the left and right sides are calculated according to the adhesion coefficient formula.

2. The method for online testing of longitudinal force and adhesion coefficient of a railway vehicle wheel-rail according to claim 1, characterized in that: The balance equation group in S1 includes: longitudinal balance equation, lateral rolling balance equation, and lateral shaking balance equation, wherein: The longitudinal equilibrium equation is expressed as: F=ma The roll balance equation is expressed as: The balance equation of the shaking head is expressed as: m w a z ·l c / 2+Q s1 ·l1-Q s2 ·l2+G·l c / 2-Q xl ·l c +H·r0=0 m w a z ·l c / 2+Q s2 ·l 14 -Q s1 ·l2+G·l c / 2-Q xr ·l c -H·r0=0 Where m is the unsprung mass, m w is the axle mass, G is the axle weight, F is the longitudinal external force, is the axle moment of inertia, L C is the distance between the wheels on both sides, L s is the distance between the axle boxes on both sides, l1 is the distance between the wheel and the axle box on the other side, l2 is the distance between the wheel and the axle box on the same side, a is the longitudinal acceleration, is the angular acceleration, F XR is the right longitudinal force, F XL is the longitudinal force on the left side, F y is the lateral force, Q s1 is the vertical force of the left axle box, Q s2 is the vertical force of the right axle box, a z is the vertical acceleration, H is the wheel-rail lateral force, Q xl is the left wheel-rail vertical force, Q xr is the right wheel-rail vertical force.

3. The method for online testing of longitudinal force and adhesion coefficient of railway vehicle wheel-rail according to claim 1, characterized in that: In S2, the longitudinal / lateral / vertical acceleration of the axle box vibration is collected by the acceleration sensor installed on the axle, the longitudinal / lateral / vertical displacement of the two sides of the axle is collected by the displacement sensor, and the three-dimensional acceleration of the wheelset is calculated by derivation of the three-dimensional displacement of the wheelset.

4. The method for online testing of longitudinal force and adhesion coefficient of a railway vehicle wheel-rail according to claim 1, characterized in that: The calculation method of the wheel-rail vertical force and the wheel-rail longitudinal force on the left and right sides in S3 is: Q xl =(k s d zl +c d d′ zl )·(l s / 2+l c / 2) / l c -(k s d zr +c d d′ zr )·(l s / 2-l c / 2) / l c +G / 2+m w a z / 2+H·r0 / l c Q xr =(k s d zr +c d d′ zr )·(l s / 2+l c / 2) / l c -(k s d zl +c d d′ zl )·(l s / 2-l c / 2) / l c +G / 2+m w a z / 2+H·r0 / l c In the formula, Q xl is the left wheel-rail vertical force, Q xr is the right wheel-rail vertical force, F xl is the left wheel-rail longitudinal force, F xr is the right wheel-rail vertical force, d xl ,d xr The longitudinal displacement and vertical displacement of the left wheel pair are respectively, d zl ,d zr The longitudinal displacement and vertical displacement of the right wheelset are respectively, d y is the lateral displacement of the wheelset, d′ xl , d′ xr The longitudinal speed and vertical speed of the left wheel pair, d′ zl , d′ zr The longitudinal speed and vertical speed of the right wheelset are d′ y is the lateral speed of the wheelset, a l 、a r They are the longitudinal acceleration of the left and right axle boxes, k x , k y , k z They are the longitudinal / lateral / vertical stiffness of the series, c x 、c y 、c z They are longitudinal / lateral / vertical damping, L c Indicates the distance between the left and right wheels, L s Indicates the distance between the left and right axle boxes, m is the unsprung mass, m w is the axle mass, G is the axle weight, and H is the wheel-rail lateral force.

5. The method for online testing of longitudinal force and adhesion coefficient of railway vehicle wheel-rail according to claim 1, characterized in that: The calculation method of the adhesion coefficient in S4 is: In the formula, μ l , μ r are the left and right wheel-rail adhesion coefficients, F xl is the left wheel-rail longitudinal force of the wheelset, Q xl is the left wheel-rail vertical force of the wheelset, F xr is the right wheel-rail longitudinal force of the wheelset, Q xr Vertical wheel-rail force on the right side of the wheelset.

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