A wheel circumference out-of-roundness measurement method and measurement mechanism

Abstract

The present invention belongs to the field of rail transit, and discloses a method for measuring the circumferential non-circularity of a wheel. The method can accurately measure the circumferential non-circularity of a wheel without lifting the wheel off the rail. First, a measuring circumferential surface coaxial with the wheel is set outside the wheel, and then three distance measuring sensors are equidistantly set on the measuring circumferential surface; then, a distance measuring relationship model related to the middle measuring length, two edge measuring lengths and the circumferential non-circularity of the wheel is established; finally, the circumferential non-circularity of the wheel is obtained based on the middle measuring length, the edge measuring length and the distance measuring relationship model, that is, the circumferential non-circularity of the wheel is obtained by geometric calculation according to the equidistant relationship of the distance measuring sensors and the three measuring lengths. The present invention also discloses a measuring mechanism for the circumferential non-circularity of a wheel, which is used to implement the above-mentioned method for measuring the circumferential non-circularity of the wheel, and includes a measuring component and a host computer connected to the measuring component signal, and the measuring component includes the three distance measuring sensors as mentioned above.

Description

Technical Field

[0001] The present invention belongs to the field of rail transit, and specifically relates to a measurement method and a measuring mechanism for wheel circumference non-roundness. Background Art

[0002] After a period of operation, the wheel tread of a rail vehicle will produce uneven deformation along the circumference, that is, the wheel circumference will be out of roundness. The wheel circumference out of roundness will cause additional vibration, impact, and noise to the vehicle, affecting the stability of the vehicle, thereby reducing the passenger's riding experience. If it is serious, it may even pose a serious threat to the safety of train operation. Therefore, it is necessary to regularly and accurately detect the wheel out of roundness and timely control the wheel out of roundness within a certain range by rotating the wheel.

[0003] At present, the radial runout value of the wheel is generally measured using a non-underfloor wheel lathe, that is, a special rotating lifting device is used to lift the wheel off the rail, and the radial runout value of the wheel circumference out-of-roundness of the rotating wheel is measured.

[0004] However, when implementing this measurement method, it is necessary to use special lifting equipment to lift the wheels off the rails. It is difficult to operate and is not suitable for use on site without lifting equipment. It also poses certain safety hazards. Summary of the invention

[0005] In view of the deficiencies of the prior art, the present invention provides a method and a mechanism for measuring the out-of-roundness of the wheel circumference, which can be used together to accurately measure the out-of-roundness of the wheel circumference without lifting the wheel off the rail.

[0006] To achieve the above objectives, the present invention provides the following technical solutions as follows:

[0007] A method for measuring the non-roundness of the wheel circumference, using the actual circumference of the wheel as the circumference to be measured, characterized in that it includes the following steps:

[0008] Step S1: Set the measuring circumferential surface, and the measuring circumferential surface is arranged coaxially outside the wheel;

[0009] Step S2: three distance measuring sensors are arranged equidistantly along the circumferential direction on the measuring circumferential surface, the distance measuring sensors face the circumferential surface to be measured and the measuring directions are parallel, and the measuring direction of the distance measuring sensor in the middle coincides with the diameter of the wheel, the distance measuring sensor is used as the middle distance measuring sensor, and the remaining distance measuring sensors are used as edge distance measuring sensors;

[0010] Step S3: establishing a distance measurement relationship model related to the middle measurement length of the circular surface to be measured by the middle distance measurement sensor, the two edge measurement lengths of the circular surface to be measured by the two edge distance measurement sensors, and the circumferential out-of-roundness of the wheel;

[0011] Step S4: Obtain the wheel circumference non-roundness based on the intermediate measurement length, edge measurement length and distance measurement relationship model.

[0012] Preferably, a reference wheel chord is provided on the wheel, the detection point of the distance measuring sensor on the circular surface to be measured is located within the arc formed by the reference wheel chord on the wheel, and the detection direction of the distance measuring sensor is perpendicular to the reference wheel chord.

[0013] Preferably, the spacing between the two edge distance measuring sensors is greater than two orders of magnitude of the wheel circumferential out-of-roundness, the detection point of the middle distance measuring sensor on the circular surface to be measured is used as the middle detection point, the detection point of the edge distance measuring sensor on the circular surface to be measured is used as the end detection point, the line connecting the two end detection points is used as the detection line, the shortest distance from the middle detection point to the reference wheel chord is used as the point-chord distance, the part of the point-chord distance between the detection line and the reference wheel chord is used as the middle chord distance, and the shortest distances from the two end detection points to the reference wheel chord are used as the edge chord distances respectively; the expressions of the middle chord distance D1 and the edge chord distances D2 and D3 are: D1=(D2+D3) / 2.

[0014] Preferably, the wheel rotates relative to the measuring circumferential surface, a first fitting model of all intermediate chord distances on the measured circumferential surface is established, and a second fitting model of all reference deviation values ​​on the measured circumferential surface is established. The relationship between the first fitting model f(x) and the second fitting model M(x) is as follows:

[0015] M(x)=f(x)-[f(xl / 2)+f(x+l / 2)] / 2;

[0016] l is the length of the line connecting the detection points of the two edge distance measuring sensors on the circumferential surface to be measured.

[0017] Preferably, the present invention further includes step S5: fitting all wheel periphery non-circumferentiality into a full-circumferential non-circumferential fitting model, and removing interference values ​​from the full-circumferential non-circumferential fitting model through a deinterference function.

[0018] Preferably, the interference removal function is an inverse filtering model.

[0019] A wheel circumferential out-of-roundness measuring mechanism for implementing the above-mentioned wheel circumferential out-of-roundness measuring method, wherein the wheel is mounted on a vehicle bottom frame, and is characterized in that it comprises: a fixing assembly for connecting to the vehicle bottom frame; a driving assembly, comprising a fixing base, a moving assembly and a measuring fixing plate, wherein the fixing base is arranged on the fixing assembly, the measuring fixing plate is arranged on the fixing base via the moving assembly, and the measuring fixing plate is movably arranged relative to the fixing base along the traveling direction of the wheel; a measuring assembly, comprising the three distance measuring sensors as mentioned above; and a host computer, which is signal-connected to the measuring assembly.

[0020] Preferably, the present invention also includes a collection component connected to the upper computer signal, the collection component includes a close crank, a synchronous wheel and a rotary encoder, one end of the close crank is restorably set on the measuring component through an elastic member, and the elastic force recovery direction is toward the circumferential surface of the wheel, the synchronous wheel is rotatably set at the other end of the close crank, and is frictionally coupled with the circumference of the wheel, and the rotary encoder is torque coupled with the synchronous wheel.

[0021] Preferably, the measuring assembly further comprises a measuring fixing frame, which is arranged on the measuring fixing plate, and three ranging sensors, rotary encoder and clamping crank are arranged on the measuring fixing frame.

[0022] Preferably, the moving assembly includes a driving motor, a driven worm and a driving gear. The driven worm is arranged on the measuring fixed plate along the travel direction of the wheel, the driving gear is arranged on the fixed base, and the driven worm cooperates with the driving gear. The driving motor is used to drive the measuring fixed plate to move through the driven worm.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. The method for measuring the wheel circumference out-of-roundness of the present invention firstly sets a measuring circumferential surface coaxial with the wheel outside the wheel, and then sets three distance measuring sensors equidistantly on the measuring circumferential surface; then, establishes a distance measuring relationship model related to the middle measuring length, the two edge measuring lengths and the wheel circumference out-of-roundness; finally, the wheel circumference out-of-roundness is obtained based on the middle measuring length, the edge measuring length and the distance measuring relationship model, and the three projection points of the three distance measuring sensors on the surface of the circumferential surface to be measured, the wheel circumference out-of-roundness at the middle projection point, that is, the deviation distance of the middle projection point relative to the line connecting the other two projection points, that is, the wheel circumference out-of-roundness is obtained by geometric calculation based on the equidistant relationship of the distance measuring sensors and the three measuring lengths. Therefore, the present invention can accurately measure the wheel circumference out-of-roundness without lifting the wheel off the rail.

[0025] 2. Because a reference wheel chord is provided on the wheel of the present invention, the detection point of the distance measuring sensor on the circular surface to be measured is located within the arc formed by the reference wheel chord on the wheel, and the detection direction of the distance measuring sensor is perpendicular to the reference wheel chord, so that the two projection points formed by the edge distance measuring sensor on the reference wheel chord and the two projection points of the edge distance measuring sensor on the circular surface to be measured are respectively the four corner points of a right trapezoid, and the distance between the distance measuring sensor and its projection point on the reference wheel chord and the detection distance of the distance measuring sensor to the circular surface to be measured can be easily obtained. Therefore, the present invention measures the out-of-roundness of the wheel based on the reference wheel chord, which can greatly simplify the relevant calculation process.

[0026] 3. Because the distance between the two edge distance measuring sensors of the present invention is two orders of magnitude greater than the circumferential out-of-roundness of the wheel, the detection point of the middle distance measuring sensor on the circumferential surface to be measured is taken as the middle detection point, the detection point of the edge distance measuring sensor on the circumferential surface to be measured is taken as the end detection point, the line connecting the two end detection points is taken as the detection line, the shortest distance from the middle detection point to the reference wheel chord is taken as the point-chord distance, the part of the point-chord distance between the detection line and the reference wheel chord is taken as the middle chord distance, the shortest distances from the two end detection points to the reference wheel chord are taken as the edge chord distances; the middle chord distances The expression of the distance D1 and the edge chord distances D2 and D3 is: D1=(D2+D3) / 2. Therefore, after the reference wheel chord is determined, the center chord distance and the edge chord distance can be obtained by subtraction operation. The uneven circular surface to be measured makes the two edge chord distances often different in essence. The out-of-roundness of a predetermined point on the circular surface to be measured is the difference between the shortest distance from the projection point on the circular surface to be measured to the wheel reference chord when the intermediate distance measuring sensor is located at the point and the center chord distance. Therefore, the present invention can accurately obtain the distance from the circular surface to be measured to the reference wheel chord through the right-angle trapezoid centerline operation.

[0027] 4. Because the present invention also includes step S5, all wheel circumference out-of-roundness are fitted to form a full-circumference out-of-roundness fitting model, and the interference value of the full-circumference out-of-roundness fitting model is removed by the interference removal function, and the interference removal function is an inverse filtering model, through the out-of-roundness fitting of the full circumference of the wheel, the deviation value of the overall deviation of the circular surface to be measured from the standard circular surface and the out-of-roundness of the full circumference of the wheel can be obtained, and the interference value caused by the deviation caused by vibration of the distance measuring sensor relative to the wheel can be effectively removed by the interference removal function. Therefore, the present invention can accurately measure the out-of-roundness of the full circumference of the wheel when the external environment is disturbed.

[0028] 5. Because the wheel circumferential non-roundness measuring mechanism of the present invention includes a fixing component, a driving component, a measuring component and a host computer, the fixing component is used to connect with the vehicle bottom frame; the measuring component includes three distance measuring sensors equidistantly arranged on the measuring circumferential surface as mentioned above; the host computer is signal-connected with the measuring component, therefore, the wheel circumferential non-roundness measuring mechanism of the present invention can better implement the above-mentioned wheel circumferential non-roundness measuring method.

[0029] 6. Because the measuring assembly of the present invention also includes a measuring fixture, the measuring fixture is arranged on the measuring fixing plate, and the three distance measuring sensors, the rotary encoder and the close crank are all arranged on the measuring fixture. Therefore, the present invention measures and samples the entire wheel circumference with a predetermined collection step length through the rotary encoder, thereby obtaining the out-of-roundness data on the entire wheel circumference. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1A schematic diagram of the steps of a measuring method for the wheel circumference of an embodiment of the present invention;

[0031] Figure 2 Schematic diagram for measuring the non-roundness of the wheel periphery according to an embodiment of the present invention;

[0032] Figure 3 A schematic diagram of the application of a measuring mechanism for the non-roundness of the wheel in an embodiment of the present invention;

[0033] Figure 4 Schematic diagrams of fixing and driving components of embodiments of the present invention;

[0034] Figure 5 Schematic diagrams of measurement components and acquisition components of embodiments of the present invention.

[0035] In the figure: S100, a method for measuring the out-of-roundness of a wheel, C, a wheel, C1, a circular surface to be measured, C2, a measuring circular surface, X, a reference wheel chord, G, a wheel out-of-roundness, l, a detection line, 100, a mechanism for measuring the out-of-roundness of a wheel, P, a vehicle bottom frame, 10, a fixing component, 11, an electromagnet, 20, a driving component, 21, a fixing base, 22, a moving component, 221, a driven worm, 222, a driving gear, 23, a measuring fixing plate, 23a, an extending fixing rod, 30, a measuring component, 31, a measuring fixing frame, 32, a distance measuring sensor, 33, a crank fixing seat, 40, a collecting component, 41, a close crank, 42, a close spring, 43, a synchronous wheel, 44, a rotary encoder. DETAILED DESCRIPTION

[0036] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the following embodiments and the accompanying drawings specifically illustrate a method and a mechanism for measuring the circumferential non-roundness of a wheel of the present invention. It should be noted that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention.

[0037] like Figure 1 and Figure 2 As shown in the measurement method S100 of the wheel circumference in this embodiment, the actual peripheral surface of the wheel C is used as the circumference C1 to be measured, and the circumference C1 to be measured is a non-standard circumference due to use loss.

[0038] The measurement method S100 of the wheel circumference is composed of the following steps:

[0039] Step S1: Set the measuring circumferential surface C2, and the measuring circumferential surface C2 is arranged coaxially outside the wheel C.

[0040] Step S2: three distance measuring sensors 32 are arranged on the measuring circular surface C2 at equal intervals along its circumference, the distance measuring sensors 32 face the circular surface C1 to be measured and the measuring directions are parallel, and the measuring direction of the distance measuring sensor 32 in the middle coincides with the diameter of the wheel C. The distance measuring sensor 32 is used as the middle distance measuring sensor, and the remaining distance measuring sensors 32 are used as edge distance measuring sensors.

[0041] Specifically, a reference wheel chord X is set on the wheel C, and the detection point of the distance sensor 32 on the measured circumferential surface C1 is located within the minor arc formed by the reference wheel chord X on the wheel C, and the detection direction of the distance sensor 32 is perpendicular to the reference wheel chord X.

[0042] The detection point of the intermediate distance measuring sensor on the circumferential surface C1 to be measured is used as the intermediate detection point, and the detection point of the edge distance measuring sensor on the circumferential surface C1 to be measured is used as the end detection point.

[0043] The line connecting the two end detection points is taken as the detection line l, the shortest distance from the middle detection point to the reference wheel chord is taken as the point-chord distance, and the partial point-chord distance between the detection line l and the reference wheel chord X is taken as the intermediate chord distance. The out-of-roundness G of the predetermined point on the measured circular surface C1 is the difference between the shortest distance from the projection point on the measured circular surface C1 to the wheel reference chord X when the middle distance measuring sensor is located at the point and the center chord distance. The spacing between the two edge distance measuring sensors is two orders of magnitude larger than the wheel circumference out-of-roundness, that is, the spacing between the two edge distance measuring sensors is much larger than the wheel circumference out-of-roundness G.

[0044] The shortest distances from the two end detection points to the reference wheel chord X are respectively taken as the edge chord distances. Since the measured circular surface C1 is a non-standard circular surface and is not smooth, the two edge chord distances are often different in essence. Therefore, the two projection points formed by the edge distance sensor on the reference wheel chord X and the two projection points of the edge distance sensor on the measured circular surface C1 constitute the four corner points of the same right-angle trapezoid, that is, the expressions of the middle chord distance D1 and the edge chord distances D2 and D3 are:

[0045] D1 = (D2 + D3) / 2.

[0046] Step S3: establishing a distance measurement relationship model related to the middle measurement length of the circular surface C1 to be measured by the middle distance measurement sensor, the two edge measurement lengths of the circular surface C1 to be measured by the two edge distance measurement sensors, and the wheel circumference out-of-roundness G.

[0047] Specifically, the wheel C rotates relative to the measuring circumferential surface C2. In order to comprehensively describe the multiple out-of-roundness G of the entire wheel circumference, a first fitting model f(x) of all intermediate chord distances on the measuring circumferential surface C1 is established, and a second fitting model of all reference deviation values, i.e., out-of-roundness G, on the measuring circumferential surface C1 is established. The relationship between the first fitting model f(x) and the second fitting model M(x) is as follows:

[0048] M(x)=f(x)-[f(xl / 2)+f(x+l / 2)] / 2 (1);

[0049] l is the length of the line connecting the detection points of the two edge distance measuring sensors on the circumferential surface to be measured.

[0050] Step S4: Obtain the wheel circumference non-roundness based on the intermediate measurement length, edge measurement length and distance measurement relationship model.

[0051] Step S5: Fit all wheel circumference non-roundness G to form a full-circumference non-roundness fitting model, and remove the interference value of the full-circumference non-roundness fitting model through the deinterference function.

[0052] Specifically, considering that in actual scenarios, the overall distance sensor 32 will inevitably produce vibration offset due to the installation method and external interference, the measuring direction of the distance sensor 23 is often offset from the diameter direction of the wheel C, resulting in a deviation angle, which makes the calculation result of the full-circle non-circularity fitting model inaccurate. Therefore, the inverse filtering model is used as the interference removal function to remove the interference value.

[0053] In this embodiment, the first fitting model f(x) is expanded as:

[0054] f(x) = Asin(2π / λ)x (2);

[0055] Substituting (2) into (1), we obtain

[0056] M(x)=Asin(2π / λ)x–(1 / 2)[Asin(2π / λ)(xl / 2)+Asin(2π / λ)(x+l / 2)](3)=Asin(2π / λ)x(1-cos(2π / λ)l / 2) (3);

[0057] Let H(x) = 1-cos(π / λ) (4);

[0058] Based on (4), (3) is transformed into the frequency domain to obtain:

[0059] M(Ω)=H(Ω)f(Ω) (5);

[0060] Spatial angular frequency Ω=2π / λ.

[0061] Through analysis of H(Ω), we can find that H(Ω) is not always equal to 1, and only when its value is equal to 1, M(x)=f(x), so it needs to be removed through the inverse filtering model.

[0062] The transfer functions Hi(Ω) and H(Ω) of the inverse filter model are inverse relationships, as follows:

[0063] H(Ω)Hi(Ω)=1·e -jαΩ Ω 1 ≤Ω≤Ω 2

[0064] H i (Ω)=0Other

[0065] Among them, α represents the phase, Ω 1 ,Ω 2 They are the lower and upper limits of the frequency change respectively.

[0066] like Figure 3 As shown, the wheel circumferential non-roundness measuring mechanism 100 in this embodiment is used to implement the above-mentioned wheel circumferential non-roundness measuring method S100, and the wheel C is installed on the vehicle bottom frame (not marked in the drawings), including a fixing component 10, a driving component 20, a measuring component 30, a host computer (not shown in the drawings) and a collection component 40.

[0067] like Figure 4 As shown, the fixing assembly 10 is used for connection with the vehicle bottom frame, and in particular, the fixing assembly 10 includes two electromagnets 11 which are adsorbed on the vehicle bottom frame.

[0068] The drive assembly 20 includes a fixing base 21 , a moving assembly 22 , and a measuring fixing plate 23 .

[0069] The fixed base 21 is disposed on the fixed assembly 10 , and the measurement fixed plate 23 is disposed on the fixed base 21 via the moving assembly 22 . The measurement fixed plate 23 is movably disposed along the traveling direction of the wheel C relative to the fixed base 21 .

[0070] Specifically, the electromagnet 11 is installed at the bottom of the fixed base 21, and the moving assembly 22 includes a driven worm 221, a driving gear 222 and a driving motor (not shown in the drawings). The driven worm 221 is arranged on the bottom of the measuring fixed plate 23 along the travel direction of the wheel C, and the driving gear 222 is arranged on the fixed base 21, and the driven worm 221 cooperates with the driving gear 222. The driving motor is used to drive the measuring fixed plate 23 to move through the driven worm 221.

[0071] In this embodiment, the driven worm 221 is threadedly connected to the bottom of the measurement fixing plate 23. The driven worm 221 can drive the measurement fixing plate 23 to move by self-rotation. The upper surface of the measurement fixing plate 23 is provided with two extended fixing rods 23a extending toward the wheel C.

[0072] like Figure 5 As shown, the measuring assembly 30 includes a measuring bracket 31, three distance measuring sensors 32 of the above-mentioned wheel circumference out-of-roundness measuring method S100, and a crank fixing seat 33. In this embodiment, the distance measuring sensor 32 is a laser distance measuring sensor.

[0073] The measuring fixture 31 is arranged on the measuring fixture plate 23, and the three distance measuring sensors 32 and the crank fixing seat 33 are all arranged on the measuring fixture 31. The three distance measuring sensors 32 are arranged on a virtual measuring circular surface C2 coaxial with the wheel C as described in the above-mentioned wheel circumferential non-circularity measuring method S100. In the present embodiment, the measuring fixture 31 is fixedly arranged at the end of the extended fixing rod 23a, and the tread of the wheel C is the circular surface C1 to be measured described in the above-mentioned wheel circumferential non-circularity measuring method S100.

[0074] The host computer is connected to the distance sensor 32 of the measuring component 30 for receiving data information of the distance measurement sensor 32 on the measured circumferential surface C1 and executing the calculation of the relevant model and relational expression described in the above wheel circumferential non-circularity measurement method S100.

[0075] The acquisition component 40 is connected to the upper computer signal, and the acquisition component 40 includes a close crank 41, a close spring 42, a synchronous wheel 43 and a rotary encoder 44. Specifically, the close crank 41 and the rotary encoder 44 are both arranged on the measurement fixed frame 31.

[0076] One end of the clamping crank 41 is restorably set on the measuring component 30 by means of a clamping spring 42 as an elastic member, and the elastic force recovery direction is toward the circumferential surface of the wheel C. The synchronous wheel 43 is rotatably set at the other end of the clamping crank 41 and is frictionally coupled with the circumference of the wheel C. The rotary encoder 44 is torque coupled with the synchronous wheel. Specifically, when the wheel C rotates, the synchronous wheel 43 rotates synchronously, so that the rotary encoder 44 can send a pulse signal to the host computer according to the predetermined collection step length of the rotation of the circular surface C1 to be measured by the vehicle, so that the host computer measures the out-of-roundness of the wheel circumference according to the predetermined collection step length based on the distance data uploaded by the distance measuring sensor 32.

[0077] In this embodiment, the two ends of the clamping spring 42 are respectively arranged on the measurement fixed frame 31 and the synchronous wheel 43. The synchronous wheel 43 is frictionally coupled with the circumferential surface C1 to be measured, that is, the tread of the wheel C. The length of the reference wheel chord X is 80 mm, and the predetermined acquisition step length is 0.5 mm.

[0078] The following describes the positioning process of the measuring mechanism 100 with the non-roundness of the wheel circumference:

[0079] First, the wheel circumferential non-circularity measuring mechanism 100 is fixed on the vehicle bottom frame by the electromagnet 11, and the three distance sensors 32 are located above the wheel C at the same time; then, the measuring component is moved by the moving component 22, so that the three distance sensors 32 move along the travel direction of the wheel C; finally, when the difference between the two edge measurement lengths measured by the distance sensor is within the predetermined fault tolerance distance range, the upper computer controls the predetermined visual or auditory feedback, at this time, the positioning of the wheel circumferential non-circularity measuring mechanism 100 is completed, and then, the wheel circumferential non-circularity measuring mechanism 100 is implemented to measure the wheel circumferential non-circularity by the wheel circumferential non-circularity measuring method S100.

[0080] The above-mentioned implementation modes are preferred cases of the present invention and are not used to limit the protection scope of the present invention. Various deformations or modifications that can be made by ordinary technicians in this field without creative work within the scope of the attached claims are still within the protection scope of this patent.

Claims

1. A method for measuring the out-of-roundness of a wheel, wherein the actual circumference of the wheel is used as the circumference to be measured, characterized in that: The following steps are involved: Step S1: setting a measuring circumferential surface, wherein the measuring circumferential surface is coaxially arranged outside the wheel; Step S2: three distance measuring sensors are arranged equidistantly along the circumferential direction on the measuring circumferential surface, the distance measuring sensors face the circumferential surface to be measured and the measuring directions are parallel, and the measuring direction of the distance measuring sensor in the middle coincides with the diameter of the wheel, the distance measuring sensor is used as the middle distance measuring sensor, and the remaining distance measuring sensors are used as edge distance measuring sensors; Step S3: establishing a distance measurement relationship model related to the middle measurement length of the circular surface to be measured by the middle distance measurement sensor, the two edge measurement lengths of the circular surface to be measured by the two edge distance measurement sensors, and the wheel circumference out-of-roundness; Step S4: obtaining the wheel circumference out-of-roundness based on the middle measurement length, the edge measurement length and the distance measurement relationship model, Wherein, a reference wheel chord is arranged on the wheel, the detection point of the distance measuring sensor on the circumferential surface to be measured is located within the arc formed by the reference wheel chord on the wheel, and the detection direction of the distance measuring sensor is perpendicular to the reference wheel chord, The distance between the two edge distance sensors is two orders of magnitude greater than the wheel circumference out-of-roundness. The detection point of the intermediate distance measuring sensor on the circular surface to be measured is used as the intermediate detection point, The detection point of the edge distance measuring sensor on the circular surface to be measured is used as the end detection point, and the line connecting the two end detection points is used as the detection line. The shortest distance from the middle detection point to the reference wheel chord is taken as the point-chord distance, and part of the point-chord distance between the detection line and the reference wheel chord is taken as the middle chord distance. The shortest distances from the two end detection points to the reference wheel chord are respectively used as edge chord distances; The expressions of the middle chord distance D1 and the edge chord distances D2 and D3 are: D1=(D2+D3) / 2 The wheel rotates relative to the measuring circumferential surface, Establishing a first fitting model for all the intermediate chord distances on the circular surface to be measured, Establishing a second fitting model for all the reference deviation values ​​on the circular surface to be measured, The relationship between the first fitting model f(x) and the second fitting model M(x) is as follows: M(x)=f(x)-[f(xl / 2)+f(x+l / 2)] / 2; l is the length of the line connecting the detection points of the two edge distance measuring sensors on the circular surface to be measured.

2. The method for measuring wheel circumference out-of-roundness according to claim 1, characterized in that: Also includes: Step S5: fitting all the wheel circumference out-of-circularity to form a full-circumference out-of-circularity fitting model, and removing interference values ​​from the full-circumference out-of-circularity fitting model using an interference removal function.

3. The method for measuring wheel circumference out-of-roundness according to claim 2, characterized in that: in, The interference removal function is an inverse filtering model.

4. A wheel circumference out-of-roundness measuring mechanism for implementing the wheel circumference out-of-roundness measuring method according to claim 2, wherein the wheel is mounted on a vehicle bottom frame, characterized in that: include: A fixing assembly, used for connecting with the vehicle bottom frame; A driving assembly, comprising a fixed base, a moving assembly and a measuring fixed plate, wherein the fixed base is arranged on the fixed assembly, the measuring fixed plate is arranged on the fixed base via the moving assembly, and the measuring fixed plate is movably arranged relative to the fixed base along the traveling direction of the wheel; A measuring assembly comprising three distance measuring sensors as claimed in claim 2; and A host computer is connected to the measurement component signal.

5. The wheel circumference out-of-roundness measuring mechanism according to claim 4, characterized in that: Also includes: The acquisition component is connected to the host computer signal, and the acquisition component includes a close-fitting crank, a synchronous wheel and a rotary encoder. The end close to the crank is restorably arranged on the measuring assembly through an elastic member, and the elastic force restoring direction is toward the circumference of the wheel. The synchronous wheel is rotatably arranged at the other end of the close crank and is frictionally coupled with the wheel. The rotary encoder is torque-coupled to the synchronous wheel.

6. The wheel circumference out-of-roundness measuring mechanism according to claim 5, characterized in that: in, The measuring assembly further comprises a measuring fixture, which is arranged on the measuring fixture plate. The three distance measuring sensors, the rotary encoder and the close-fitting crank are all arranged on the measuring fixed frame.

7. The wheel circumference out-of-roundness measuring mechanism according to claim 4, characterized in that: in, The moving assembly includes a driving motor, a driven worm and a driving gear. The driven worm is arranged on the measuring fixed plate along the travel direction of the wheel, the driving gear is arranged on the fixed base, and the driven worm cooperates with the driving gear. The driving motor is used to drive the measuring fixed plate to move through the driven worm.

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