Detection Device and Detection Method for Creep Ratio of Double-Disk Counter-Rolling Test Bench

Abstract

The present invention discloses a detection device and a detection method for the creepage rate of a double-disk rolling test bench that uses an image recognition method and can measure the creepage rate at different positions on the circumference. The detection device for the creepage rate of the double-disk rolling test bench includes: a camera for photographing the contact area of the rail disk and the wheel disk along the axial direction of the rail disk and the wheel disk; a reference calibration plate for camera calibration and determining the conversion relationship between the image pixel size and the physical size; the reference calibration plate is arranged on the axial side surfaces of the rail disk and the wheel disk and covers the contact area; a first reference ring for determining the creepage rate; the first reference ring is concentric with the rail disk; the first reference ring includes first reference sites arranged at intervals; a second reference ring for determining the creepage rate; the second reference ring is concentric with the wheel disk; the second reference ring includes second reference sites arranged at intervals.

Description

Technical Field

[0001] The present invention relates to the technical field of creepage rate detection of a dual-disk rolling test bench, and more particularly, to a detection device and a detection method for the creepage rate of a dual-disk rolling test bench. Background Art

[0002] Wheel-rail adhesion is crucial for the normal operation of trains and is the key to realizing the normal traction, braking, and curve guiding functions of trains. Therefore, in view of the wheel-rail adhesion characteristics (i.e., the wheel-rail creep force-rate relationship), a large number of scholars have carried out adhesion test research by means of a dual-disk rolling test bench. In these test benches, the measurement of the creepage rate is based on the measurement of the rotational speeds of the wheel disk and the rail disk.

[0003] For the measurement of rotational speed, the commonly used methods are divided into five categories: mechanical, electromagnetic, photoelectric, laser, and image recognition methods. Among them, the mechanical principle is simple and is suitable for contact-type test scenarios with low requirements for detection accuracy. The electromagnetic and photoelectric methods are non-contact detections and are mostly used for the detection of shaft-end rotational speeds, with higher detection accuracy. The laser and image recognition methods are new detection methods developed in recent years, which are also non-contact detections, with high detection accuracy, and can measure the rotational speed at any position on the surface of an object, but the test process is complex.

[0004] Currently, the measurement of rotational speed based on the electromagnetic and photoelectric methods is the main method for obtaining the creepage rate in a dual-disk rolling test bench, while the laser and image recognition methods have not been further developed for the creepage rate detection of a dual-disk rolling test bench. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a detection device and a detection method for the creepage rate of a dual-disk rolling test bench that uses the image recognition method and can measure the creepage rate at different positions on the wheel circumference.

[0006] To achieve the above object, according to the first aspect of the present invention, a detection device for the creepage rate of a dual-disk rolling test bench is provided, and the technical solution is as follows:

[0007] A detection device for the creepage rate of a dual-disk rolling test bench, the dual-disk rolling test bench includes a rail disk for simulating a rail and a wheel disk for simulating a train wheel, and the rotational directions of the rail disk and the wheel disk are opposite; the detection device includes:

[0008] A camera for photographing the contact area of the rail disk and the wheel disk along the axial direction of the rail disk and the wheel disk;

[0009] A reference calibration plate for camera calibration and determining the conversion relationship between the image pixel size and the physical size; the reference calibration plate is arranged on the axial side surface of the rail disk and the wheel disk and covers the contact area;

[0010] The first reference ring is used to determine the creep ratio; the first reference ring is concentric with the rail disk; the first reference ring includes first reference sites arranged at intervals;

[0011] The second reference ring is used to determine the creep ratio; the second reference ring is concentric with the wheel disk; the second reference ring includes second reference sites arranged at intervals.

[0012] To achieve the above object, according to the second aspect of the present invention, a detection method for the creep ratio of a double-disk rolling test bench is provided, and the technical solution is as follows:

[0013] A detection method using the detection device for the creep ratio of the double-disk rolling test bench described in the first aspect above includes the following steps:

[0014] (1) Collect and input the calibration image: Install the reference calibration board and make the reference calibration board located at the center of the camera's field of view, and then collect the calibration image; Remove the reference calibration board after calibration;

[0015] (2) Collect and input the contact area image: Start the rotation of the rail disk and the wheel disk and make the camera take pictures of the contact area, and any frame of the image is recorded as image I0; Among them, the number of frames taken satisfies that the moving distances of each first reference site and second reference site during the shooting interval are less than their arrangement pitch;

[0016] (3) Preprocess the calibration image: Process the calibration image and obtain the internal parameter matrix and distortion parameter matrix of the camera;

[0017] (4) Preprocess the contact area image: Correct and binarize image I0 to obtain image I0'; Combine the actual physical size of the reference calibration board and the pixel size of the reference calibration board in image I0' to obtain the conversion relationship between the pixel size unit pixel and the physical size unit mm, denoted as 1 pixel = λ mm, and further obtain the conversion ratio λ: Perform edge detection and denoising processing on image I0' to obtain image I;

[0018] (5) According to image I i Calculate the creep ratio of each circumferential reference point pair in the image, and the calculation expression is:

[0019]

[0020] In the formula, is the creep ratio of the jth circumferential reference point pair; Image I i is the ith frame of image I; and constitute the speed of the jth circumferential reference point pair, and One of them is the calculation result, and the other is the linear interpolation result. When it is the calculation result, the calculation result is equal to the circumferential linear velocity of the corresponding first reference point or second reference point extending along the diameter direction to the circumference. When it is the linear interpolation result, the linear interpolation result is obtained by linearly interpolating the circumferential linear velocities of two adjacent points.

[0021] The detection device and method of the present invention have low cost and are simple and easy to operate. By using the image recognition method to measure the rotational speeds of the rail disk and the wheel disk in the double-disk rolling test bench and then developing the image recognition method to the creepage rate detection, it not only provides a new auxiliary detection means for the adhesion test, but also can measure the creepage rate at different positions on the circumference, obtain the distribution result of the creepage rate along the circumference under any frame of image and the change of the creepage rate at different positions on the circumference with time, and can better reflect the wheel-rail adhesion characteristics, having good practicability.

[0022] The following further describes the present invention in conjunction with the drawings and specific embodiments. The additional aspects and advantages of the present invention will be partially given in the following description, partially become obvious from the following description, or be understood through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings constituting a part of the present invention are used to assist in understanding the present invention. The content provided in the drawings and the related descriptions in the present invention can be used to explain the present invention, but do not constitute an improper limitation to the present invention. In the drawings:

[0024] Figure 1 is a perspective view of the detection device for the creepage rate of the double-disk rolling test bench of the present invention.

[0025] Figure 2 is a schematic structural view of the first circular arc strip or the second circular arc strip in the detection device for the creepage rate of the double-disk rolling test bench of the present invention.

[0026] Figure 3 is a side view of the assembled state of the detection device for the creepage rate of the double-disk rolling test bench of the present invention.

[0027] Figure 4 is a side view of the calibration state of the detection device for the creepage rate of the double-disk rolling test bench of the present invention.

[0028] Figure 5 is a side view of the test state of the detection device for the creepage rate of the double-disk rolling test bench of the present invention.

[0029] Figure 6 is Figure 5 an enlarged view of part A in

[0030] Figure 7 is Figure 5 an enlarged view of part B in

[0031] Figure 8 Contact area images collected at speeds of 50 to 200 km / h during the test.

[0032] Figure 9 It is the image I on the rail disc i and the image I i-1 The corresponding relationship diagram of each first reference point in it.

[0033] Figure 10 It is the image I on the rail disc i The distribution model diagram of the first reference point, the second reference point and the wheel circumference reference point pair in it.

[0034] Figure 11 It is the specific distribution diagram of the wheel circumference reference point pair in the embodiment of the present invention.

[0035] Figure 12 It is Figure 11 The creepage rate distribution diagram of 20 wheel circumference reference point pairs in it.

[0036] Figure 13 It is Figure 11 The curve of the creepage rate of the wheel circumference reference point pair in different regions in it changing with time.

[0037] The relevant markings in the above-mentioned drawings are as follows:

[0038] 100 - rail disc, 110 - first reference ring, 120 - first reference point, 200 - wheel disc, 210 - second reference ring, 220 - second reference point, 230 - rotating shaft, 300 - camera, 400 - reference calibration plate, 510 - first circular arc bar, 511 - first through hole, 512 - first limiting block, 520 - second circular arc bar, 521 - second through hole, 522 - second limiting block, 600 - support frame, 610 - column, 620 - cross bar, 700 - supplementary light. Detailed implementation manners

[0039] The present invention will be clearly and completely described below with reference to the drawings. Those of ordinary skill in the art will be able to implement the present invention based on these descriptions. Before describing the present invention with reference to the drawings, it should be particularly noted that:

[0040] The technical solutions and technical features provided in each part including the following description in the present invention can be combined with each other without conflict.

[0041] In addition, the embodiments of the present invention involved in the following description are generally only a part of the embodiments of the present invention, rather than all the embodiments. Therefore, all other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0042] Regarding the terms and units in the present invention. The terms "comprising", "having" and any variations thereof in the specification, claims and relevant parts of the present invention are intended to cover non-exclusive inclusion.

[0043] Figure 1 It is a perspective view of the detection device for the creepage rate of the double-disk rolling test bench of the present invention. Figure 2 It is a schematic structural view of the first circular arc strip or the second circular arc strip in the detection device for the creepage rate of the double-disk rolling test bench of the present invention. Figure 3 It is a side view of the assembled state of the detection device for the creepage rate of the double-disk rolling test bench of the present invention. Figure 4 It is a side view of the calibration state of the detection device for the creepage rate of the double-disk rolling test bench of the present invention. Figure 5 It is a side view of the test state of the detection device for the creepage rate of the double-disk rolling test bench of the present invention. Figure 6 is Figure 5 the enlarged view of part A in Figure 7 is Figure 5 the enlarged view of part B in

[0044] As Figure 1-7 shown, the double-disk rolling test bench includes a rail disk 100 for simulating a rail and a wheel disk 200 for simulating a train wheel, and the rotation directions of the rail disk 100 and the wheel disk 200 are opposite; the detection device for the creepage rate of the double-disk rolling test bench includes a camera 300, a reference calibration plate 400, a first reference ring 110, a second reference ring 210, a first marking caliper, a second marking caliper, a ground control platform (not shown in the figure) and a support frame 600.

[0045] The camera 300 is used to photograph the contact area between the rail disk 100 and the wheel disk 200 along the axial direction of the rail disk 100 and the wheel disk 200; the camera 300 adopts a high-definition high-speed camera, which is black and white imaging, with a maximum pixel resolution of 1024*1024 and a maximum frame rate of 200000fps. In order to improve the clarity of the image, supplementary lights 700 can be arranged on both radial sides of the rail disk 100 and the wheel disk 200.

[0046] The reference calibration plate 400 is used for calibrating the camera 300 and determining the conversion relationship between the image pixel size and the physical size; the reference calibration plate 400 is arranged on the axial side surfaces of the rail disk 100 and the wheel disk 200 and covers the contact area; the shape of the reference calibration plate 400 projected axially along the rail disk 100 and the wheel disk 200 is square, and the side length is 16 - 50 mm; the reference calibration plate 400 is provided with a grid.

[0047] The first reference ring 110 is used for determining the creep rate; the first reference ring 110 is concentric with the rail disk 100; the first reference ring 110 includes first reference sites 120 arranged at intervals; the second reference ring 210 is used for determining the creep rate; the second reference ring 210 is concentric with the wheel disk 200; the second reference ring 210 includes second reference sites 220 arranged at intervals. The first reference sites 120 and / or the second reference sites 220 are black dots with a diameter of 1 - 3 mm; the distance between the first reference sites 120 and / or the second reference sites 220 and the wheel circumference is 2 - 5 mm; the first reference sites 120 and the second reference sites 220 are distributed according to the same central angle, and the central angle is preferably 1 - 3°, so that an appropriate number of reference sites can be obtained.

[0048] The first marking caliper has a first arc-shaped strip 510 adapted to the first reference ring 110, and the first arc-shaped strip 510 is provided with first through holes 511 adapted to the first reference sites 120; the second marking caliper has a second arc-shaped strip 520 adapted to the second reference ring 210, and the second arc-shaped strip 520 is provided with second through holes 521 adapted to the second reference sites 220. At the outer edge of the first arc-shaped strip 510, there is a first limiting block 512 adapted to the outer edge of the rail disk 100; at the outer edge of the second arc-shaped strip 520, there is a second limiting block 522 adapted to the outer edge of the wheel disk 200. The central angle at both ends of the outer edges of the first arc-shaped strip 510 and the second arc-shaped strip 520 is 30° - 75°; the first marking caliper has at least two rows of first through holes 511; the second marking caliper has at least two rows of second through holes 521; the first marking caliper and the second marking caliper are formed by 3D printing.

[0049] The ground control platform is used to control the start and stop of the camera 300 and receive the images captured by the camera 300, and the ground control platform communicates with the camera 300 through a wired or wireless network; the ground control platform includes an image receiving module, an image processing module, and a data storage and export module.

[0050] The support frame 600 has four columns 610 and a cross bar 620 arranged along the axial direction of the track disc 100 and the wheel disc 200. The cross bar 620 can slide up and down along the columns 610. The camera 300 is installed on the cross bar 620 and can slide along the axial direction of the track disc 100 and the wheel disc 200. The rotating shaft 230 of the wheel disc 200 passes through the support frame 600 under the cross bar 620 and is connected to the motor.

[0051] The detection method of the creepage rate of the double-disc rolling test bench using the above detection device includes the following steps:

[0052] (1) Collect and input the calibration image: First, draw a first reference circle 110 on the track disc 100 with the assistance of the first marking caliper, and draw a second reference circle 210 on the wheel disc 200 with the assistance of the second marking caliper. Then install the reference calibration plate 400 and make the reference calibration plate 400 located at the center of the camera 300's field of view, and then collect the calibration image. After calibration, remove the reference calibration plate 400;

[0053] (2) Collect and input the contact area image: Start the rotation of the track disc 100 and the wheel disc 200 and make the camera 300 take pictures of the contact area. Any frame of the image is denoted as image I0. Among them, the number of shooting frames satisfies that the moving distance of each first reference point 120 and second reference point 220 during the shooting interval is less than their arrangement pitch;

[0054] Figure 8 The contact area image collected at a test speed of 50 - 200 km / h. As Figure 8 shown, at each speed, each reference point is clearly visible and well-defined. It should be noted that in order to capture the instantaneous change of the dynamic creepage rate as much as possible, an appropriate number of shooting frames is set during shooting, so that at each test speed, the first reference point 120 and the second reference point 220 move at most about 2 mm within each frame time interval.

[0055] (3) Preprocess the calibration image: Process the calibration image and obtain the internal parameter matrix and distortion parameter matrix of the camera;

[0056] (4) Preprocess the contact area image: Correct and binarize the image I0 to obtain the image I0'. Combine the actual physical size of the reference calibration plate and the pixel size of the reference calibration plate in the image I0' to obtain the conversion relationship between the pixel size unit pixel and the physical size unit mm, denoted as 1 pixel = λ mm, and further obtain the conversion ratio λ. Perform edge detection and denoising processing on the image I0' to obtain the image I;

[0057] (5) According to the image I i the creepage rate of each pair of circumferential reference points on the wheels is calculated, and the calculation expression is:

[0058]

[0059] In the formula, is the creep ratio of the j-th circumferential reference point pair; the image I i is the i-th frame of the image I; and constitute the velocity of the j-th circumferential reference point pair. Since the matching of the circumferential reference point pairs satisfies the principle of equal abscissa (x), therefore, to ensure that the abscissa positions of the circumferential reference point pairs corresponding to each pair of velocities in the image I i are consistent, the present invention makes and one of them is the calculation result and the other is the linear interpolation result; when it is the calculation result, the calculation result is equal to the circumferential linear velocity of the corresponding first reference site 120 or the second reference site 220 extending along the diameter to the circumference; when it is the linear interpolation result, the linear interpolation result is obtained by linearly interpolating the circumferential linear velocities of two adjacent circumferences.

[0060] Among them, in step (5), the calculation process of the calculation result in the velocity includes the following steps:

[0061] Step100, find the pixel indexes of each first reference site 120 and the second reference site 220 in the image I i , determine the centroid coordinates of each first reference site 120 and the second reference site 220 in the image I i , and then determine the corresponding relationship of each first reference site 120 and the corresponding relationship of each second reference site 220 in the image I i and the image I i-1 ;

[0062] Among them, the centroid coordinates of the first reference site 120 on the rail disk 100 are denoted as the centroid coordinates of the second reference site 220 on the wheel disk 200 are denoted as

[0063] Figure 9 is the corresponding relationship diagram of each first reference site 120 in the image I i and the image I i-1 on the rail disk 100. As Figure 9 shown, since a sufficiently large number of shooting frames f are set, the moving distance of each first reference site 120 during the shooting interval is less than the distance between adjacent first reference sites 120. Therefore, the first reference site (labeled m) in the i-th frame of the image I i always matches the first first reference site in the (i - 1)-th frame of the image I i-1 whose centroid abscissa is greater than . On the wheel disk 200, the image Ii and image I i-1 The matching method for the corresponding relationship with each second reference point 220 in [it] is the same.

[0064] Step200, according to image I i and image I i-1 Based on the centroid coordinates, the number of shooting frames f, and the conversion ratio λ of the first reference point 120 and the second reference point 220 in [it], calculate the linear velocity of the first reference point 120 and the second reference point 220 in image I i ; among them,

[0065] The linear velocity of each first reference point 120 (unit: m / s) The calculation expression is:

[0066]

[0067] The linear velocity of each second reference point 220 (unit: m / s) The calculation expression is:

[0068]

[0069] Step300, calculate the circumferential linear velocity of the first reference point 120 and the second reference point 220 extending along the diameter direction to the wheel circumference; among them,

[0070] The circumferential linear velocity of each first reference point 120 extending along the diameter direction to the wheel circumference The calculation expression is:

[0071]

[0072] The circumferential linear velocity of each second reference point 220 extending along the diameter direction to the wheel circumference The calculation expression is:

[0073]

[0074] In the formula: r r is the radius of the track disk 100; d1 is the distance from the center of the first reference point 120 to the wheel circumference; r w is the radius of the wheel disk 200; d2 is the distance from the center of the second reference point 220 to the wheel circumference.

[0075] Figure 10 is image I i In [it], it is the distribution model diagram of the first reference point 120, the second reference point 220, and the wheel circumference reference point pair, where the first reference point 120 is represented by m, the second reference point 220 is represented by n, and the wheel circumference reference point pair is represented by j.

[0076] like Figure 10 As shown in the figure, for the second wheel reference point pair (j=2), the velocity is the calculation result, that is (m=2), Calculated by equation (1) and equation (3); for the velocity is the result of linear interpolation. and After linear interpolation, we get: and They are calculated by equation (2) and equation (4) respectively.

[0077] For the third wheel reference point pair (j=3), is the result of linear interpolation. and After linear interpolation, we get: and Calculated by equation (1) and equation (3) respectively; is the calculation result, that is It is calculated by equation (2) and equation (4).

[0078] By analogy, the creep rate of each wheel reference point pair can be calculated by the formula in step (5), and then the creep rate distribution of each wheel reference point pair in each frame image and the change of creep rate over time can be obtained.

[0079] Example

[0080] Figure 11 The specific distribution diagram of the wheel reference point pairs in the embodiment of the present invention is shown. The test parameters are: the track disc motor speed is 665.6rpm, the wheel disc motor speed is 739.5rpm, the center angles of two adjacent first reference points 120 and two adjacent second reference points 220 are both 1.5° (the center distance between two adjacent reference points is about 5mm), d1 is 2.4mm, d2 is 2.4mm, and the radius r of the track disc 100 is 2.4mm. r is 199 mm; the radius r of the wheel 200 w The focal length is 174mm, the shooting frame number f is 6400fps, and the conversion ratio λ is 0.06993.

[0081] Figure 12 for Figure 11 Creep rate distribution diagram of 10 pairs of wheel circumference reference points. Figure 13 for Figure 11 Curves showing the variation of creep rate of wheel circumference reference point pairs in different regions with time.

[0082] like Figure 13As shown, the mean value of the creepage rate is close to a straight line, which is adapted to the stable creepage rate value calculated from the motor speed, indicating that the present invention has a certain degree of accuracy.

[0083] Figure 13 and Figure 11 The corresponding relationships are as follows: the curve "overall" corresponds to all circumferential reference point pairs (j = 1 - 20), the curve "contact area" corresponds to the circumferential reference point pair with j = 10, the curve "leaving the contact area" corresponds to the circumferential reference point pairs with j = 1 - 9, and the curve "not entering the contact area" corresponds to the circumferential reference point pairs with j = 11 - 20.

[0084] The above has described the relevant content of the present invention. Those of ordinary skill in the art will be able to implement the present invention based on these descriptions. Based on the above content of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present invention.

Claims

1. A device for detecting creep rate of a double-disc rolling test bench, the double-disc rolling test bench comprising a rail disc (100) for simulating a steel rail and a wheel disc (200) for simulating a train wheel, wherein the rail disc (100) and the wheel disc (200) rotate in opposite directions; the device is characterized in that: The detection device includes: A camera (300) is used to photograph a contact area between the rail disc (100) and the wheel disc (200) along the axial direction of the rail disc (100) and the wheel disc (200); A reference calibration plate (400) is used for calibrating the camera (300) and determining the conversion relationship between the image pixel size and the physical size; the reference calibration plate (400) is arranged on the axial side surfaces of the track disc (100) and the wheel disc (200) and covers the contact area; A first reference ring (110) is used to determine the creep rate; the first reference ring (110) is arranged concentrically with the rail disc (100); the first reference ring (110) includes first reference points (120) arranged at intervals; A second reference ring (210) is used to determine the creep rate; the second reference ring (210) is arranged concentrically with the wheel disc (200); the second reference ring (210) includes second reference points (220) arranged at intervals; A first marking caliper, the first marking caliper having a first arc-shaped strip (510) adapted to the first reference circular ring (110), the first arc-shaped strip (510) being provided with a first through hole (511) adapted to the first reference point (120); A second marking caliper, wherein the second marking caliper has a second arc-shaped bar (520) adapted to the second reference ring (210), and the second arc-shaped bar (520) is provided with a second through hole (521) adapted to the second reference point (220).

2. The device for detecting creep rate of a double-disc rolling test bench according to claim 1, characterized in that: A first limit block (512) adapted to the outer edge of the track disc (100) is provided at the outer edge of the first arc-shaped strip (510); and a second limit block (522) adapted to the outer edge of the wheel disc (200) is provided at the outer edge of the second arc-shaped strip (520).

3. The device for detecting creep rate of a double-disc rolling test bench according to claim 1, characterized in that: The central angles of the two ends of the outer edges of the first arc-shaped strip (510) and the second arc-shaped strip (520) are 30° to 75°; the first marking caliper has at least two rows of first through holes (511); the second marking caliper has at least two rows of second through holes (521); and the first marking caliper and the second marking caliper are formed by 3D printing.

4. The device for detecting creep rate of a double-disc rolling test bench according to claim 1, characterized in that: The first reference point (120) and / or the second reference point (220) are black dots with a diameter of 1 to 3 mm; the distance between the first reference point (120) and / or the second reference point (220) and the circumference is 2 to 5 mm; the first reference point (120) and the second reference point (220) are distributed at the same central angle.

5. The device for detecting creep rate of a double-disc rolling test bench according to claim 1, characterized in that: The reference calibration plate (400) is in a square shape when projected along the axial direction of the rail disc (100) and the wheel disc (200), with a side length of 16 to 50 mm; and a grid is provided on the reference calibration plate (400).

6. The device for detecting creep rate of a double-disc rolling test bench according to claim 1, characterized in that: The detection device also includes a ground control platform for controlling the start and stop of the camera (300) and receiving images captured by the camera (300), wherein the ground control platform communicates with the camera (300) via a wired or wireless network; the ground control platform includes an image receiving module, an image processing module, and a data storage and export module.

7. The device for detecting creep rate of a double-disc rolling test bench according to claim 1, characterized in that: The detection device also includes a support frame (600), wherein the support frame (600) has four columns (610) and a cross bar (620) arranged along the axial direction of the track plate (100) and the wheel plate (200), wherein the cross bar (620) can slide up and down along the columns (610), and the camera (300) is mounted on the cross bar (620) and can slide along the axial direction of the track plate (100) and the wheel plate (200); and the rotating shaft (230) of the wheel plate (200) passes through the support frame (600) along the bottom of the cross bar (620) and is connected to the motor.

8. A detection method using the device for detecting the creep rate of a double-disc rolling test bench according to any one of claims 1 to 7, characterized in that: The following steps are involved: (1) Acquiring and inputting a calibration image: installing a reference calibration plate (400) and placing the reference calibration plate (400) at the center of the field of view of the camera (300), and then acquiring a calibration image; After the calibration is completed, remove the reference calibration plate (400); (2) collecting and inputting the contact area image: the track plate (100) and the wheel plate (200) start to rotate and the camera (300) takes a picture of the contact area, and any frame of the image is recorded as image I0; wherein the number of frames taken is such that the movement distance of each first reference point (120) and the second reference point (220) during the shooting interval is less than the arrangement spacing of the first reference point (120) and the second reference point (220); (3) Calibration image preprocessing: processing the calibration image and obtaining the intrinsic parameter matrix and distortion parameter matrix of the camera (300); (4) Contact area image preprocessing: Image I0 is rectified and binarized to obtain image I0'; the conversion relationship between the pixel size unit pixel and the physical size unit mm is obtained by combining the actual physical size of the reference calibration plate and the pixel size of the reference calibration plate in image I0', which is recorded as 1pixel=λmm, and then the conversion ratio λ is obtained: edge detection and denoising are performed on image I0' to obtain image I; (5) According to image I i The speed of each wheel reference point pair is calculated, and the creep rate of each wheel reference point pair is calculated. The calculation expression is: In the formula, is the creep rate of the jth wheel reference point pair; Image I i is the i-th frame image I; V wj i and V rj i The velocity of the j-th wheel reference point pair, V wj i and V rj i One of them is a calculation result and the other is a linear interpolation result. When it is a calculation result, the calculation result is equal to the wheel peripheral linear velocity extending from the corresponding first reference point (120) or the second reference point (220) along the diameter direction to the wheel periphery. When it is a linear interpolation result, the linear interpolation result is obtained by linear interpolation of two adjacent wheel peripheral linear velocities.

9. The method for detecting creep rate of a double-disc rolling test bench according to claim 8, characterized in that: In step (5), the calculation process of the speed calculation result includes the following steps: Step 100, find image I i The pixel index of each first reference point (120) and second reference point (220) in the image I is determined. i The centroid coordinates of the first reference point (120) and the second reference point (220) in the image I are determined. i and image I i-1 The corresponding relationship between each first reference point (120) and the corresponding relationship between each second reference point (220); The center of mass coordinates of the first reference point (120) on the track disk (100) are denoted as (x rm i ,y rm i ), the center of mass coordinates of the second reference point (220) on the roulette wheel (200) are denoted as (x wn i ,y wn i ); Step 200, according to image I i and image I i-1 The centroid coordinates of the first reference point (120) and the second reference point (220), the shooting frame number f and the conversion ratio λ are calculated to obtain the image I i The linear speed of the first reference point (120) and the second reference point (220); wherein, The linear velocity v of each first reference point (120) rm i The calculation expression is: The linear velocity v of each second reference point (220) wn i The calculation expression is: Step 300, calculating the wheel peripheral linear velocity extending from the first reference point (120) and the second reference point (220) along the diameter direction to the wheel periphery; wherein, The wheel peripheral linear velocity V of each first reference point (120) extending along the diameter direction to the wheel periphery rm i The calculation expression is: The wheel peripheral linear velocity V of each second reference point (220) extending along the diameter direction to the wheel periphery is wn i The calculation expression is: Where: r r is the radius of the track disk (100); d1 is the distance from the center of the first reference point (120) to the wheel circumference; r w is the radius of the wheel disk (200); d2 is the distance from the center of the second reference point (220) to the wheel circumference.

Images