阅读说明：本技术 一种列车转向架轮径约束的平行度测量装置及方法 (Parallelism measuring device and method for wheel diameter constraint of train bogie ) 是由 张爽 侯岱双 高金刚 王�华 祝国凯 陈儒 赵伟甫 郭于龙 于 2019-09-30 设计创作，主要内容包括：本发明公开了一种列车转向架轮径约束的平行度测量装置及方法,该装置包括：四组测量组件,每一组测量组件包括：支撑架Ⅰ、位移升降系统Ⅱ和测量子系统Ⅲ；所述支撑架Ⅰ包括支架和支撑板；所述支撑板固定设置在所述支架的一侧；所述位移升降系统Ⅱ上安装所述测量子系统,所述位移升降系统Ⅱ与所述支撑板滑动连接。该装置的构成部件减少,简化了测量过程,可快速准确的完成列车转向架轮径约束的平行度测量。该测量方法简化了测量时由于重构信息数据多,导致后续运算困难的问题,仅需通过平移3次或3次以上,即可实现列车转向架轮径及平行度的测量。(The invention discloses a parallelism measuring device and method for train bogie wheel diameter constraint, the device comprises: four sets of measurement components, each set of measurement components comprising: the device comprises a support frame I, a displacement lifting system II and a measurement subsystem III; the support frame I comprises a support and a support plate; the supporting plate is fixedly arranged on one side of the bracket; and the measurement subsystem is arranged on the displacement lifting system II, and the displacement lifting system II is connected with the supporting plate in a sliding manner. The device has the advantages of reducing the number of components, simplifying the measurement process and quickly and accurately completing the parallelism measurement of the train bogie wheel diameter constraint. The measuring method simplifies the problem that the subsequent operation is difficult due to the fact that a large amount of reconstructed information data exist in the measuring process, and the wheel diameter and the parallelism of the train bogie can be measured only by translating for 3 times or more than 3 times.)

1. The utility model provides a parallelism measuring device of train bogie wheel footpath restraint which characterized in that includes: four sets of measurement components, each set of measurement components comprising: the device comprises a support frame I, a displacement lifting system II and a measurement subsystem III;

the support frame I comprises a support and a support plate; the supporting plate is fixedly arranged on one side of the bracket;

and the measurement subsystem is arranged on the displacement lifting system II, and the displacement lifting system II is connected with the supporting plate in a sliding manner.

2. The parallelism measuring device for the wheel diameter constraint of the train bogie as recited in claim 1, wherein the displacement lifting system II comprises: the device comprises a guide rail slide block 3, a displacement lifting plate 4, an electric pushing cylinder 5 and a displacement connecting block 6;

the electric pushing cylinder is vertically arranged, and one end of a pushing rod of the electric pushing cylinder is provided with the displacement connecting block; the displacement lifting plate is arranged on the displacement connecting block; at least one guide rail sliding block is arranged on one side surface of the displacement lifting plate;

the supporting plate is provided with a sliding groove matched with the guide rail sliding block; the guide rail sliding block is connected with the supporting plate in a sliding mode through the sliding groove; the measurement subsystem is arranged on the displacement lifting plate.

3. The train bogie wheel diameter constrained parallelism measuring apparatus of claim 2, wherein the measurement subsystem iii comprises: two sets of measuring units; each set of measurement units includes: the sensor comprises a sensor connecting plate and a line-structured light sensor;

the line-structured light sensor is arranged on the sensor connecting plate;

and the two groups of sensor connecting plates are respectively and symmetrically arranged on the same side surface of the displacement lifting plate and synchronously move along with the displacement lifting plate.

4. A parallelism measuring method for train bogie wheel diameter constraint is characterized by comprising the following steps:

step 1, conveying a train bogie to be detected to a detection station, and stopping at a detection position; the four groups of measuring assemblies are symmetrically positioned at the inner sides of the two wheel sets of the train bogie to be detected in pairs;

step 2, a measurement subsystem III of each group of measurement assemblies acquires tread contour information of two sides of a corresponding train bogie wheel pair;

step 3, the measurement subsystem III moves along with the displacement lifting system II d₁Distance, recording the tread profile information and displacement d of the two sides of the wheel of the train bogie wheel pair at the moment₁；

Step 4, repeating the step 2 to the step 3, and moving the measurement subsystem III along with the displacement lifting system II d₂Distance, recording the tread profile information and displacement d of the two sides of the wheel of the train bogie wheel pair at the moment₂(ii) a According to d₁And d₂Calculating wheel diameter values of corresponding train bogie wheel pairs;

step 5, solving the spatial point cloud information of the train bogie wheel set by using the wheel diameter value of the train bogie wheel set in the step 4 as a constraint condition through system calibration to realize three-dimensional reconstruction of the train bogie wheel set;

and 6, after the three-dimensional reconstruction is finished, the parallelism measurement of the train bogie is finished through calculation.

5. The parallelism measuring method for the wheel diameter constraint of the train bogie according to claim 4, wherein the step 4 comprises the following steps:

two line-structured light sensors of the measurement subsystem III respectively emit line-structured light to the wheel set tread, and when the wheel set reaches the detection position, the distance from each of the two line-structured light sensors to the tread is H₁、H₂(ii) a At initial positions P on both sides of the wheel₁The linear structure light sensor obtains the tread A of the distance wheel at the moment₁、B₁Respectively marked as L₁、K₁(ii) a At the moment, the height between the positions of the two linear structured light sensors and the circle center of the wheel pair is recorded as s, the linear structured light sensors are translated along the vertical direction and are respectively positioned at P₂、P₃Position obtaining two sets of corresponding data return values, and the characteristic points of the wheel set tread edge are A respectively₂、B₂And A₃、B₃And the corresponding return distance is recorded as L₂、K₂And L₃、K₃Two displacements are d₁And d₂；

The following set of equations is listed:

combining the formulas (1) and (2), and eliminating S to obtain R_iComprises the following steps:

wherein l₁＝H₁-L₃、l₂＝H₁-L₂、l₃＝H₁-L₁，k₁＝H₂-K₃、k₂＝H₂-K₂、k₃＝H₂-K₁(ii) a Simultaneous equations (1) and (2) to obtain H₁、H₂、R₁、R₂、R₃、R₄、R₅、R₆；

Calculation of R₁、R₂、R₃、R₄、R₅、R₆The mean value of the wheel diameter value R_i。

6. The parallelism measuring method for the wheel diameter constraint of the train bogie according to claim 5, wherein the step 5 comprises:

simplifying the bogie wheel pair tread into a tread formed by iteration of a plurality of circular sections;

constructing a circular curve equation:

f(x,y)＝x²+y²+Dx+Ey+F (3)

wherein the center coordinates areRadius of

When a radius constraint is added, then it is expressed as

f(x,y)＝x²+y²+Dx+Ey+F+λ(R-r_k) (4)

Deduction calculation is carried out on the formula (4), and the formula is rewritten into a matrix form:

AB＝L+V (9)

using SVD decomposition equation (9), model parameter estimates are given as:

determining upper right of tread curve of wheel set of trainDiameter value R of the section of the circle and corresponding spatial circle center coordinates (a)_k,b_k,c_k) (ii) a And performing iterative calculation to realize the three-dimensional reconstruction of the train bogie wheel set.

7. The parallelism measuring method for the wheel diameter constraint of the train bogie according to claim 4, wherein the step 6 comprises the following steps:

1) selecting an initial value of a measured point, and defining the initial value as P_q(x_q,y_q,z_q)；

2) Taking the front wheel as a measurement reference, performing least square fitting by using the space circle center coordinates of the two wheels at the front side of the bogie after three-dimensional reconstruction, and taking the obtained space straight line as a reference axis; the space circle center coordinates of two wheels at the front side of the bogie are taken as a measured point P_k(k＝1～n)；

3) Calculate the measured point P_k(k is 1 to n) as an initial radius value of the target axis;

4) continuously moving the axis to obtain the minimum containing cylinder, and recording the diameter of the minimum containing cylinder as f;

5) repeating the steps 3) to 4) until the diameter of the smallest small cylinder is obtained; the smallest diameter value of the small cylinder is the value of the parallelism error sought.

Technical Field

The invention relates to the technical field of rail transit safety monitoring and machine vision, in particular to a parallelism measuring device and method for train bogie wheel diameter constraint.

Background

The bogie wheel set is used as a core component of the rail train, and the quality of the bogie wheel set directly influences the running safety and the transportation capacity of the train. The wheel set is one of the parts directly contacted with the rail, and bears large impact and load, and under an ideal state, 2 bogies of the same train respectively meet the condition that the outline dimensions of the wheels are the same, namely the wheel diameters are the same.

With the continuous improvement of the speed per hour of the rail train, parameters of a train bogie are stricter and stricter, but in practice, due to the limitation of a processing technology and mechanical precision in a production process, the actual diameter of a wheel set is deviated from a standard value, so that the deviation of the parallelism between the bogie wheel sets is indirectly caused, and the running performance of the train is influenced. The traditional method for detecting the wheel diameter and the parallelism of the bogie adopts a two-dimensional method for measurement, and although the measurement method solves the problem that the wheel diameter and the parallelism of the bogie are difficult to measure, the two-dimensional projection method cannot detect the unparallel problem of the train bogie caused by the wheel diameter deviation.

Disclosure of Invention

The invention aims to provide a parallelism measuring device and method for wheel diameter constraint of a train bogie, which can solve the problem that the parallelism measurement of the train bogie can not be comprehensively reflected by factors such as wheel diameter difference and the like in the two-dimensional detection of the train bogie at present.

In a first aspect, an embodiment of the present invention provides a parallelism measuring apparatus for wheel diameter constraint of a train bogie, including: four sets of measurement components, each set of measurement components comprising: the device comprises a support frame I, a displacement lifting system II and a measurement subsystem III;

the support frame I comprises a support and a support plate; the supporting plate is fixedly arranged on one side of the bracket;

and the measurement subsystem is arranged on the displacement lifting system II, and the displacement lifting system II is connected with the supporting plate in a sliding manner.

In one embodiment, the displacement lift system ii comprises: the device comprises a guide rail slide block, a displacement lifting plate, an electric pushing cylinder and a displacement connecting block;

the electric pushing cylinder is vertically arranged, and one end of a pushing rod of the electric pushing cylinder is provided with the displacement connecting block; the displacement lifting plate is arranged on the displacement connecting block; at least one guide rail sliding block is arranged on one side surface of the displacement lifting plate;

the supporting plate is provided with a sliding groove matched with the guide rail sliding block; the guide rail sliding block is connected with the supporting plate in a sliding mode through the sliding groove; the measurement subsystem is arranged on the displacement lifting plate.

In one embodiment, the measurement subsystem iii comprises: two sets of measuring units; each set of measurement units includes: the sensor comprises a sensor connecting plate and a line-structured light sensor;

the line-structured light sensor is arranged on the sensor connecting plate;

and the two groups of sensor connecting plates are respectively and symmetrically arranged on the same side surface of the displacement lifting plate and synchronously move along with the displacement lifting plate.

In a second aspect, the present invention further provides a parallelism measuring method for wheel diameter constraint of a train bogie, including:

step 1, conveying a train bogie to be detected to a detection station, and stopping at a detection position; the four groups of measuring assemblies are symmetrically positioned at the inner sides of the two wheel sets of the train bogie to be detected in pairs;

step 2, a measurement subsystem III of each group of measurement assemblies acquires tread contour information of two sides of a corresponding train bogie wheel pair;

step 3, the measurement subsystem III moves along with the displacement lifting system II d₁Distance, recording the tread profile information and displacement d of the two sides of the wheel of the train bogie wheel pair at the moment₁；

Step 4, repeating the step 2-3, and measuring the subsystem IIIDisplacement elevator system ii moves d₂Distance, recording the tread profile information and displacement d of the two sides of the wheel of the train bogie wheel pair at the moment₂(ii) a According to d₁And d₂Calculating wheel diameter values of corresponding train bogie wheel pairs;

step 5, solving the spatial point cloud information of the train bogie wheel set by using the wheel diameter value of the train bogie wheel set in the step 4 as a constraint condition through system calibration to realize three-dimensional reconstruction of the train bogie wheel set;

and 6, after the three-dimensional reconstruction is finished, the parallelism measurement of the train bogie is finished through calculation.

In one embodiment, the step 4 comprises:

two line-structured light sensors of the measurement subsystem III respectively emit line-structured light to the wheel set tread, and when the wheel set reaches the detection position, the distance from each of the two line-structured light sensors to the tread is H₁、H₂(ii) a At initial positions P on both sides of the wheel₁The linear structure light sensor obtains the tread A of the distance wheel at the moment₁、B₁Respectively marked as L₁、K₁(ii) a At the moment, the height between the positions of the two linear structured light sensors and the circle center of the wheel pair is recorded as s, the linear structured light sensors are translated along the vertical direction and are respectively positioned at P₂、P₃Position obtaining two sets of corresponding data return values, and the characteristic points of the wheel set tread edge are A respectively₂、B₂And A₃、B₃And the corresponding return distance is recorded as L₂、K₂And L₃、K₃Two displacements are d₁And d₂；

The following set of equations is listed:

combining the formulas (1) and (2), and eliminating S to obtain R_iComprises the following steps:

wherein l₁＝H₁-L₃、l₂＝H₁-L₂、l₃＝H₁-L₁，k₁＝H₂-K₃、k₂＝H₂-K₂、k₃＝H₂-K₁(ii) a Simultaneous equations (1) and (2) to obtain H₁、H₂、R₁、R₂、R₃、R₄、R₅、R₆；

Calculation of R₁、R₂、R₃、R₄、R₅、R₆The mean value of the wheel diameter value R_i。

In one embodiment, the step 5 comprises:

simplifying the bogie wheel pair tread into a tread formed by iteration of a plurality of circular sections;

constructing a circular curve equation:

f(x,y)＝x²+y²+Dx+Ey+F (3)

wherein the center coordinates areRadius of

When a radius constraint is added, then it is expressed as

f(x,y)＝x²+y²+Dx+Ey+F+λ(R-r_k) (4)

Deduction calculation is carried out on the formula (4), and the formula is rewritten into a matrix form:

AB＝L+V (9)

using SVD decomposition equation (9), model parameter estimates are given as:

calculating the diameter value R of any circular section on the wheel tread curve of the train wheel set and the corresponding space circle center coordinate (a)_k,b_k,c_k) (ii) a And performing iterative calculation to realize the three-dimensional reconstruction of the train bogie wheel set.

In one embodiment, the step 6 comprises:

1) selecting an initial value of a measured point, and defining the initial value as P_q(x_q,y_q,z_q)；

2) Taking the front wheel as a measurement reference, performing least square fitting by using the space circle center coordinates of the two wheels at the front side of the bogie after three-dimensional reconstruction, and taking the obtained space straight line as a reference axis; the space circle center coordinates of two wheels at the front side of the bogie are taken as a measured point P_k(k＝1～n)；

3) Calculate the measured point P_k(k is 1 to n) as an initial radius value of the target axis;

4) continuously moving the axis to obtain the minimum containing cylinder, and recording the diameter of the minimum containing cylinder as f;

5) repeating the steps 3) to 4) until the diameter of the smallest small cylinder is obtained; the smallest diameter value of the small cylinder is the value of the parallelism error sought.

The embodiment of the invention provides a parallelism measuring device for train bogie wheel diameter constraint, which comprises: four sets of measurement components, each set of measurement components comprising: the device comprises a support frame I, a displacement lifting system II and a measurement subsystem III; the support frame I comprises a support and a support plate; the supporting plate is fixedly arranged on one side of the bracket; and the measurement subsystem is arranged on the displacement lifting system II, and the displacement lifting system II is connected with the supporting plate in a sliding manner. The device has the advantages of reducing the number of components, simplifying the measurement process and quickly and accurately completing the parallelism measurement of the train bogie wheel diameter constraint.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

The technical solution of the present invention is further described in detail by the accompanying drawings and embodiments.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:

FIG. 1 is a schematic diagram of a train bogie wheel pair under inspection.

Fig. 2 is a structural diagram of a parallelism measuring apparatus for wheel diameter constraint of a train bogie according to an embodiment of the present invention.

Fig. 3 is a schematic structural diagram of a measuring device according to an embodiment of the present invention during detection.

Fig. 4 is a schematic structural diagram of a support frame according to an embodiment of the present invention.

Fig. 5 is a schematic structural diagram of a displacement lifting system according to an embodiment of the present invention.

Fig. 6 is a schematic structural diagram of a measurement subsystem iii according to an embodiment of the present invention.

Fig. 7 is a schematic diagram of wheel diameter calculation according to an embodiment of the present invention.

Fig. 8 is a schematic diagram of parallelism measurement according to an embodiment of the present invention.

Detailed Description

Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

Referring to fig. 1, the device is a train bogie wheel set to be detected; referring to fig. 2, a parallelism measuring apparatus for a wheel diameter constraint of a train bogie according to an embodiment of the present invention includes: four sets of measurement components, each set of measurement components comprising: the device comprises a support frame I, a displacement lifting system II and a measurement subsystem III;

the four groups of measuring assemblies are symmetrically arranged and are respectively arranged on the inner sides of two wheel pairs of the train bogie, as shown in fig. 3.

Referring to fig. 4, the support frame i is composed of a profile support frame 1 and a support plate 2, for example, the profile support frame is constructed by standard aluminum profiles 60 x 60, for example, the profile support frame is detachably connected by bolts and is responsible for supporting and positioning the measuring device; the supporting plate 2 is arranged on the side face of the section bar supporting frame 1 and is responsible for providing mounting support for the displacement lifting system II.

Further, referring to fig. 5, the displacement lifting system ii is composed of a rail block 3, a displacement lifting plate 4, an electric pushing cylinder 5, and a displacement connecting block 6, wherein the electric pushing cylinder 5 is vertically arranged, and the displacement connecting block 6 is installed at one end of a pushing rod thereof. Wherein, servo/step motor or drive assembly can be joined in marriage to the electric push cylinder, can realize quick, flexible location in this embodiment, keeps higher precision and stability.

A displacement lifting plate 4 is arranged on the displacement connecting block 6; one side surface of the displacement lifting plate 4 is provided with at least one guide rail slide block 3; in order to enhance the stability, 2 guide rail sliding blocks can be arranged at two ends of one side surface of the displacement lifting plate 6. A sliding groove matched with the guide rail sliding block 3 is arranged on the supporting plate 2; the number of the sliding grooves is the same as that of the guide rail sliding blocks. The guide rail sliding block slides in the sliding groove, sliding connection of the support frame I and the displacement lifting system II is achieved, and the guide rail sliding block slides in the sliding groove and is responsible for providing guidance for the displacement lifting system.

The measurement subsystem III is arranged on the displacement lifting plate 6, the electric pushing cylinder 5 is connected with the displacement lifting plate 4 through a displacement connecting block 6, wherein the electric pushing cylinder 5 is responsible for providing lifting power for the displacement lifting system II, and the displacement connecting block 6 is responsible for connecting the electric pushing cylinder 5 with the displacement lifting plate 4.

Further, referring to fig. 6, the measurement subsystem iii is composed of a sensor connection board 7, 2 line structured light sensor 8. The sensor connecting plate 7 is arranged on the displacement lifting plate 4 on the displacement lifting system II and is responsible for providing support for the line-structured optical sensor and ensuring synchronous motion along with the displacement lifting system II; the line structured light sensors are arranged on two sides of the displacement lifting plate 4 in a symmetrical structure and are responsible for system measurement.

In the embodiment, the parallelism measuring device for the wheel diameter constraint of the train bogie respectively obtains the profile information of the train bogie wheel corresponding to the moving position on the tread by the linear structure optical sensor of the measuring subsystem III moving for multiple times and different displacement distances under the driving of the electric pushing cylinder 5 of the displacement lifting system II; then, calculating the wheel diameter value of the bogie wheel pair of the train by utilizing the displacement relation between the wheel pair tread contour information of the bogie wheel pair of the train for many times; then, by system calibration, the calculated wheel diameter value is used as a constraint condition, and the spatial point cloud information of the train bogie wheel set is solved, so that the three-dimensional reconstruction of the train bogie wheel set is realized; and finally, solving the axis of the train bogie wheel pair after three-dimensional reconstruction, thereby realizing the measurement of the relevant parameters of the train bogie. In addition, the number of the components of the device is reduced, the measuring process is simplified, and the parallelism measurement of the train bogie wheel diameter constraint can be quickly and accurately completed.

In the measuring process, the measured train bogie does not need to be subjected to reverse resetting movement, the measured train bogie only needs to be stopped at the detection position, and the measuring subsystem III only needs to be subjected to multiple displacements under the control, so that the wheel diameter and the parallelism of the train bogie can be measured; the device can simplify the problem that subsequent operation is difficult due to the fact that reconstruction information data are large in quantity during measurement, measurement of the wheel diameter and the parallelism of the train bogie can be achieved only by translating for 3 times or more than 3 times, the quantity of acquired information data is small, accuracy of an operation result is improved in a constrained mode, the problem of large operation quantity during reconstruction is solved, and meanwhile the purpose of measuring the wheel diameter and the parallelism of the train bogie by an enterprise can be met.

Based on the parallelism measuring device for the wheel diameter constraint of the train bogie, the invention also provides a parallelism measuring method for the wheel diameter constraint of the train bogie, which is shown in figure 7 and comprises the following steps:

step 1, conveying a train bogie to be detected to a detection station, and stopping at a detection position; the four groups of measuring assemblies are symmetrically positioned at the inner sides of the two wheel sets of the train bogie to be detected in pairs; during specific execution, for example, an operator can issue a detection starting instruction on the upper computer to convey the detected train bogie to the detection station.

Step 2, a measurement subsystem III of each group of measurement assemblies acquires tread contour information of two sides of a corresponding train bogie wheel pair;

step 3, the measurement subsystem III moves along with the displacement lifting system II d₁Distance, recording the tread profile information and displacement d of the two sides of the wheel of the train bogie wheel pair at the moment₁. Namely: the measurement subsystem III moves under the action of an electric pushing cylinder of the displacement lifting system II₁A distance;

step 4, repeating the step 2 to the step 3, and moving the measurement subsystem III along with the displacement lifting system II d₂Distance, recording the tread profile information and displacement d of the two sides of the wheel of the train bogie wheel pair at the moment₂(ii) a According to d₁And d₂Calculating wheel diameter values of corresponding train bogie wheel pairs;

step 5, solving the spatial point cloud information of the train bogie wheel set by using the wheel diameter value of the train bogie wheel set in the step 4 as a constraint condition through system calibration to realize three-dimensional reconstruction of the train bogie wheel set;

and 6, after the three-dimensional reconstruction is finished, the parallelism measurement of the train bogie is finished through calculation.

In the embodiment, the train bogie does not need to be reversely moved, the train bogie only needs to be stopped at the position to be detected, and the measurement subsystem only needs to carry out multiple displacements under the control of the system, so that the measurement of the wheel diameter and the parallelism of the train bogie can be realized; the method simplifies the problem of difficult subsequent operation caused by more reconstructed information data during measurement, and can realize the measurement of the wheel diameter and the parallelism of the train bogie only by translating for 3 times or more than 3 times.

The wheel diameter calculation method in the step 4 is as follows:

when the train bogie wheel pair arrivesWhen the position is detected, the two line-structured light sensors on the measurement subsystem III respectively emit line-structured light to the wheel set tread, for example, a diameter measurement position 70mm away from the inner side surface of the wheel set is selected for explanation, and when the wheel set reaches the detection position, the distance from each of the two line-structured light sensors to the tread is H₁、H₂At initial positions P on both sides of the wheel₁The linear structure light sensor obtains the tread A of the distance wheel at the moment₁、B₁Respectively marked as L₁、K₁At the moment, the height between the positions of the two linear structured light sensors and the circle center of the wheel pair is recorded as s, the linear structured light sensors are translated along the vertical direction and are respectively positioned at P₂、P₃Position obtaining two sets of corresponding data return values, and the characteristic points of the wheel set tread edge are A respectively₂、B₂And A₃、B₃And the corresponding return distance is recorded as L₂、K₂And L₃、K₃Two translation distances d₁And d₂。

Referring to FIG. 7, the following set of equations may be listed:

the equations (1) and (2) are combined, and after s is eliminated, R can be obtained_iComprises the following steps:

wherein l₁＝H₁-L₃、l₂＝H₁-L₂、l₃＝H₁-L₁，k₁＝H₂-K₃、k₂＝H₂-K₂、k₃＝H₂-K₁(ii) a Simultaneous equations (1) and (2) to obtain H₁、H₂、R₁、R₂、R₃、R₄、R₅、R₆；

To make the calculation result closer to the true value, R is calculated₁、R₂、R₃、R₄、R₅、R₆The mean value of the wheel diameter value R_i。

In the above step S5, the three-dimensional reconstruction process is as follows:

by analyzing the characteristics of the tread of the bogie wheel pair and machining the tread by a lathe, the tread can be regarded as being formed by iteration of a plurality of circular sections, and therefore, relevant data can be calculated by calculating the diameter of the circular section of the corresponding position of the tread of the bogie wheel pair.

The circle is a special form of a quadratic curve, which is expressed in the form:

f(x,y)＝x²+y²+Dx+Ey+F (3)

wherein the center coordinates areRadius of

When a radius constraint is added, then it is expressed as

f(x,y)＝x²+y²+Dx+Ey+F+λ(R-r_k) (4)

Where λ is a constraint coefficient, r_kIs the constraint radius.

Rewriting the above formula (4) to

x²+y²＝-Dx-Ey-F-λ(R-r_k) (5)

let-D-m, -E-n, -F-t, - λ -p, - λ r_k＝q

x²+y²＝mx+ny+t+pR+q (6)

Let the data point coordinate be (x)_i,y_i) 1,2, …, n, and an approximate value of the parameter m₀、n₀、t₀、p₀、q₀The error correction numbers of x and y are respectively v_xi,v_yiRoot of Chinese ginsengNumber error is respectively_m、_n、_t、_p、_q。

(x_i+v_xi)²-(y_i+v_yi)²＝(m₀+_m)(x_i+v_xi)+(n₀+_n)(y_i+v_yi)+(t₀+_t)+(p₀+_p)R+(q₀+_q)

(7)

The above equation (7) is expanded and truncated by quadratic terms, expressed in matrix form as follows:

(2x_i-m₀-_m)v_xi+(2y_i-n₀-_n)v_yi＝x_{i m}+y_{i n}+_q-L_i

(8)

(8) in the formula, L_i＝x_i ²+y_i ²-m₀x_i-n₀y_i-q

Rewriting the above equation (8) into a matrix form:

AB＝L+V (9)

in the formula (I), the compound is shown in the specification,

v_i＝(2x_i-m₀-_m)v_xi+(2y_i-n₀-_n)v_yi

from the above, it can be obtained:

(10) in the formula (I), the compound is shown in the specification,

Q_v＝diag((2x₁-m₀-_m)²+(2y₁-n₀-_n)²)+…+((2x_n-m₀-_m)²+(2y_n-n₀-_n)²))

solving equation (9) by SVD decomposition method

From this, model parameter estimates can be obtained as

So far, the diameter value R of any circular section on the tread curve of the train wheel set and the corresponding space circle center seat (a) can be obtained_k,b_k,c_k) And repeating the steps to complete the three-dimensional reconstruction of the rectified and modified wheel, and establishing a finished bogie wheel model.

In the step 6, the parallelism calculation process is as follows:

1) referring to FIG. 8, the initial value of the selected measured point is defined as P_q(x_q,y_q,z_q)；

2) A reference axis is constructed. The front wheels are taken as measuring references, so that least square fitting is carried out by using the space circle center coordinates of the two wheels at the front side of the bogie after three-dimensional reconstruction, and the obtained space straight line is taken as a reference axis; the space circle center coordinates of two wheels at the front side of the bogie are taken as a measured point P_k(k＝1～n)；

3) Calculate the measured point P_k(k 1-n) to a reference axisAs an initial radius value of the target axis; wherein (a)₀,b₀,c₀) Is the direction vector of the reference axis, (x)_q,y_q,z_q) The initial value of the measured point is defined;

4) continuously moving the axis to obtain the minimum containing cylinder, and recording the diameter of the minimum containing cylinder as f;

5) repeating the steps 3) to 4) until the diameter of the smallest small cylinder is obtained; the smallest diameter value of the small cylinder is the parallelism error value sought.

According to the train bogie wheel diameter constraint parallelism measuring method provided by the invention, in the measuring process, the obtained information data amount is less, the accuracy of the operation result can be increased in a constraint mode, the problem of large operation amount in reconstruction is solved, and meanwhile, the aim of measuring the train bogie wheel diameter and the parallelism by enterprises can be fulfilled.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.