A method for detecting misalignment of a laser collimator under asymmetric installation conditions

Abstract

The application discloses a kind of laser alignment instrument asymmetric installation conditions under misalignment detection method, the application establishes absolute coordinate system with initiative axle end face as center;With the center of PSD establishes coordinate system, laser and PSD are relatively placed;Any point method measures laser spot coordinate, at least two measured points;The laser spot displacement of M machine and S machine due to parallel misalignment and angle misalignment is projected on PSD;The distance of M machine and S machine to rotor center is measured respectively;Based on spot position information, the parallel misalignment and angle misalignment of two axes are calculated;Due to the factors such as limit, the distance of M machine and S machine to rotor center is different, which leads to error in misalignment calculation, the misalignment measurement method based on double LD / double PSD of the application needs to record the distance of M machine to rotor center and the distance of S machine to rotor center, which can eliminate the error caused by the asymmetric installation of alignment instrument.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of centering measurement of rotating machinery, and particularly relates to a method for detecting misalignment of a laser centering instrument under an asymmetric installation condition. BACKGROUND

[0002] A laser centering instrument is a common rotating shaft position measurement instrument, which can calculate the angle misalignment and parallel misalignment of a coupling connection position in vertical and horizontal directions according to a laser measurement result and parameters such as device related sizes input in advance. The ideal mathematical model assumes that the distance of the M machine and the S machine from the center of the rotor is the same. However, in the actual shaft centering process, due to the limited installation of the fixture or the limited rotation of the centering instrument, the installation of the centering instrument will cause certain errors due to the failure to meet this condition. The current existing laser centering instrument research records the distance U of the S machine to the rotor and the distance Z of the M machine and the S machine, which is only used for the calculation of the subsequent foot adjustment amount, and therefore, the model of the laser centering instrument and the misalignment detection method need to be improved. SUMMARY

[0003] In order to solve the above problems, the present application provides a method for detecting misalignment of a laser centering instrument under an asymmetric installation condition, particularly relates to a method for detecting misalignment of a laser centering instrument under an asymmetric installation condition for centering and debugging of a generator and a gear box in the wind power generation industry.

[0004] The method for detecting misalignment of a laser centering instrument under an asymmetric installation condition for large-scale shaft coupling analyzes the laser spot position change caused by the misalignment component e and S, the ratio of the distance of the S machine to the center of the rotor and the distance of the M machine to the center of the rotor, and the general equation group for calculating the misalignment when S exists, and then obtains the parallel misalignment and angle misalignment of the rotor according to the PSD position coordinates and angles measured by the arbitrary point method.

[0005] A method for detecting misalignment of a laser centering instrument under an asymmetric installation condition, comprising the following steps:

[0006] Step 1: establishing a coordinate system X-O-Y on the driven shaft end surface of the coupling connection;

[0007] Step 2: the measurement unit of the laser centering instrument includes an M machine and an S machine, and a coordinate system x M -o M -y M is established with the geometric center of the position sensitive detector of the M machine of the centering instrument as the origin o M , and a coordinate system x S -o S -y S is established with the geometric center of the position sensitive detector of the S machine of the centering instrument as the origin o S , wherein (xM , y M ) are M machine PSD laser coordinates, (x s , y s ) are S machine PSD laser coordinates;

[0008] Step 3: measure the S machine to the coupling center distance U, the M machine and the S machine position sensitive detector plane distance Z, and calculate the distance ratio k = (Z-U) / U;

[0009] Step 4: derive the relationship equation of S machine PSD laser coordinates (x s , y s ), M machine PSD laser coordinates (x M , y M ), distance ratio k and misalignment components e y , e x , S y , S x ;

[0010] Step 5: through the measurement unit S machine and M machine, the coordinates of the S machine rotating to any angle α1, α2 are obtained , and the coordinates of the M machine rotating to any angle α1, α2 are obtained The angles α1, α2 and the different angle coordinate values measured twice are subtracted and substituted into the relationship equation obtained in step 4, to obtain the misalignment components e y , e x , S y , S x , and the adjustment amount of the four footings of the driven machine connected by the coupling is calculated according to the misalignment components e y , e x , S y , S x , and the four footings of the driven machine are adjusted through the adjustment amount of the four footings of the driven machine.

[0011] The present application establishes an absolute coordinate system with the driving shaft end face as the center; a coordinate system is established with the position sensitive detector (PSD) center, and the laser and the PSD are relatively placed; the laser spot coordinates are measured by the arbitrary point method, and the measured points are at least two; the laser spot displacement of the M machine and the S machine due to parallel misalignment and angle misalignment is projected onto the PSD; the distances of the M machine and the S machine to the rotor center are measured; the parallel misalignment amount and the angle misalignment amount of the two shafts are calculated based on the spot position information; due to the limitation of the actual alignment operation and other factors, the distances of the M machine and the S machine to the rotor center are different, thereby causing errors in the misalignment calculation, and the alignment measurement method based on the double LD / double PSD of the present application needs to record the distance of the M machine to the rotor center and the distance of the S machine to the rotor center, and can eliminate the errors caused by the asymmetric installation of the alignment instrument.

[0012] In step 1, the coordinate system X-O-Y is established based on the center of the driving shaft end face as the origin O, and the 0 o'clock direction of the driving shaft end face is the positive direction of the Y axis and the 3 o'clock position is the positive direction of the X axis.

[0013] In step 2, the measurement unit S of the laser alignment instrument is installed on the driving shaft, and the measurement unit M of the laser alignment instrument is installed on the shaft of the driven machine.

[0014] In step 4, the relationship equation is as follows:

[0015]

[0016] Wherein, a is the sine difference of the two measurement angles, b is the cosine difference of the two measurement angles, ΔY S is the y value difference of the two measurement values of the S machine, ΔY s is the y value difference of the two measurement values of the M machine, ΔX m is the x value difference of the two measurement values of the S machine, ΔX M is the x value difference of the two measurement values of the M machine. S s m M

[0017] In step 5, the angles α1 and α2 measured twice and the different angle coordinate values are subtracted and substituted into the relationship equation obtained in step 4, which specifically includes:

[0018] and are substituted into the relationship equation obtained in step 4.

[0019] Further preferably, a method for detecting misalignment of a laser alignment instrument under an asymmetric installation condition, comprising the following steps:

[0020] Step 1: establishing an absolute coordinate system based on the driving shaft end face;

[0021] Step 2: the laser alignment instrument includes M machine and S machine, establishing the PSD relative coordinate system x M -o M -y M of the alignment instrument M machine, and the PSD relative coordinate system x S -o S -y S of the alignment instrument S machine;

[0022] The laser alignment instrument includes M machine and S machine, which is established according to the double LD-double PSD mathematical model, the structure of the S machine is an upper laser and a lower position sensitive detector, which is installed on the driving shaft; the structure of the M machine is an upper position sensitive detector and a lower laser, which is installed on the driven shaft;

[0023] ​​​​​Step 3: measure the distance U from the M machine to the coupling center, the distance Z from the M machine to the S machine PSD, and calculate the distance ratio k;

[0024] Step 4: based on the laser coordinate change caused by the misalignment component, establish the relationship equation of the S machine PSD laser coordinates (x s ,y s ), the M machine PSD laser coordinates (x M ,y M ) and the misalignment components e y , e x , S y , S x ;

[0025] Step 5: through the relationship equation, obtain the coordinates of the S machine when turning to any angle a1, a2 and the coordinates of the M machine when turning to any angle a1, a2 Subtract the coordinate values corresponding to different angles to obtain an equation group;

[0026] Step 6: measure the actual laser spot position information by using the arbitrary point method, and the measured points are at least two;

[0027] Step 7: substitute the angles a1, a2 and the coordinates of the two actual measurement points into the equation group to obtain the parallel misalignment component e and the angle misalignment component S.

[0028] Step 8: through the measurement unit S machine and M machine, obtain the coordinates of the S machine when turning to any angle a1, a2 and the coordinates of the M machine when turning to any angle a1, a2 Subtract the angles a1, a2 and the coordinate values corresponding to different angles measured two times and substitute them into the relationship equation obtained in step 4 to obtain the misalignment components e y , e x , S y , S x , and calculate the adjustment amount of the four anchor points of the driven machine connected by the coupling according to the misalignment components e y , e x , S y , S x , and adjust the four anchor points of the driven machine through the adjustment amount of the four anchor points of the driven machine.

[0029] Compared with the prior art, the present application has the following advantages:

[0030] The present application can eliminate the error of the laser alignment instrument caused by the unsymmetrical installation under the actual working conditions, and obtain more accurate misalignment components. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly introduced. Obviously, the drawings in the following description only constitute some embodiments of the present application, and for those skilled in the art, other drawings can be obtained without creative labor based on these drawings.

[0032] Figure 1 is a flow chart of the centering detection method of the asymmetric installation of the laser centering instrument of the present application;

[0033] Figure 2 is a schematic diagram of the installation of the laser centering instrument when there is a parallel misalignment amount e (mm) in the present application;

[0034] Figure 3 is a schematic diagram of the installation of the laser centering instrument when there is a parallel misalignment amount S (mm / 100 mm) in the present application.

[0035] Figure 4 is a schematic diagram of the relationship between the relative model error and the distance ratio of the misalignment measurement method of the present application. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the drawings of the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the present application.

[0037] The present application will be described below in combination with the drawings and specific implementation examples.

[0038] A misalignment detection method under the asymmetric installation condition of a laser centering instrument, as an embodiment, the method is used for the case that the laser centering instrument cannot be installed symmetrically due to actual operation conditions, such as Figure 1 as shown, specifically comprising:

[0039] Step 1: Establish an absolute coordinate system based on the active shaft end face, view the active shaft end face, and according to the clock scale, the 0 point direction is the positive direction of the Y axis, and the 3 point position is the positive direction of the X axis;

[0040] Step 2: The laser centering instrument includes M machine and S machine, and the PSD relative coordinate system x M -o M -y M of the centering instrument S machine is established; S -o S -yS ;

[0041] As Figure 3 shown, taking the angle misalignment in the vertical direction as an example, when only the angle misalignment amount S exists, the laser spot will be offset from the original position by S*100 (mm), S is the distance from the S machine to the rotor center, and Z = 2*U when Z is unchanged and U is the distance from the S machine to the coupling center, S m = S s , if the distance Z of the M machine and the S machine changes to Z2, the spot coordinates obtained by the S machine PSD will not change, but the M machine PSD spot position will change, S m2 ≠ S s , and the results of the two calculations will also be different;

[0042] Step 3: Measure the distance U (mm) from the S machine to the coupling center and the distance Z (mm) from the M machine to the S machine PSD, and calculate the distance ratio k, as follows:

[0043]

[0044] The laser offset coordinates caused by parallel misalignment and angle misalignment in the horizontal and vertical directions of the PSD projection are generated when there are misalignment components e y , e x , S y , and S x , respectively, and the laser coordinate diagram of the M machine PSD and the laser coordinate diagram of the S machine are shown in Figure 2 and Figure 3 ,

[0045] According to the principle of similar triangles, the angle misalignment amount S s of the S machine and the distance ratio are used to obtain the angle misalignment amount S m of the M machine:

[0046] S m = k*S s

[0047] Step 4: Based on the laser coordinate changes caused by misalignment components, the relationship equations between the S machine PSD laser coordinates (x s , y s ), the M machine PSD laser coordinates (x M , y M ), and the misalignment components e y , e x , S y , and S x are established:

[0048]

[0049] Step 5: Through the relationship equations, the coordinates of the S machine when rotating to any angle a1 and a2 can be obtained Coordinates of M machine when rotating to any angle α1, α2 The equation group is obtained by subtracting the coordinate values corresponding to different angles:

[0050]

[0051] The left side column vector is expanded as

[0052] The coefficient matrix a, b of the right side equation group is expanded:

[0053]

[0054] Step 6: The laser spot position information is measured by the arbitrary point method, and the measured points are at least two;

[0055] Step 7: Substitute the actual measured point angles α1, α2 and coordinates Solve the equation group to get the vertical parallel misalignment e y (mm) horizontal parallel misalignment e x (mm), and vertical angle misalignment S y (mm / 100mm) and horizontal angle misalignment S x (mm / 100mm), and the formula is as follows:

[0056]

[0057] Step 8: The coordinates of the S machine when rotating to any angle α1, α2 are obtained by the measuring unit S machine and the M machine and the coordinates of the M machine when rotating to any angle α1, α2 Subtract the measured angles α1, α2 and the coordinate values corresponding to different angles, and substitute them into the relationship equation obtained in step 4 to obtain the misalignment component e y , e x , S y , S x According to the misalignment components e y , e x , S y , S x , the adjustment amount of the four anchor points of the driven machine connected by the coupling is calculated, and the four anchor points of the driven machine are adjusted through the adjustment amount of the four anchor points of the driven machine.

[0058] As Figure 4 ​The relative error diagram of the original model due to the distance ratio k is shown. The true value of the misalignment is set. By changing the ratio k of the distance from the M machine to the coupling center and the distance from the S machine to the coupling center, the actual coordinate difference is calculated, and then the misalignment is obtained by substituting the original model, and the difference with the true value is obtained. Because the error will change with the size of the true value of the misalignment, the relative error obtained by dividing the error by the true value is used to judge the effect of the improved detection method. It is difficult to ensure that the distance from the M machine and the S machine to the center of the coupling is 1:1 during installation. The distance ratio is generally between 0.8 and 1.2. The relative error of the misalignment is 10%. The misalignment detection method of the present application can effectively eliminate this error.

[0059] The above description is only a specific embodiment of the present application, which enables those skilled in the art to understand or implement the present application. Various modifications of these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features applied herein.

Claims

1. A method for detecting misalignment of a laser collimator under asymmetric mounting conditions, characterized in that, The method comprises the following steps: Step 1: establishing a coordinate system X-O-Y at the end surface of the driving shaft of the coupling; Step 2: The measurement unit of the laser alignment instrument consists of an M-machine and an S-machine. The origin is established with the geometric center of the position-sensitive detector of the M-machine as the reference point. M coordinate system x M -o M -y M The origin is taken as the geometric center of the position-sensitive detector of the centering instrument S. S coordinate system x S -o S -y S , where (x M ,y M ) represents the PSD laser coordinates of the M-machine, (x s ,y s () represents the PSD laser coordinates of the S-machine; Step 3: measuring the distance U from the S machine to the center of the coupling, the distance Z from the S machine to the plane of the position-sensitive detector of the M machine, and calculating the distance ratio k=(Z-U) / U; Step 4: Derive the relationship equations of S-machine PSD laser coordinates (x s ,y s ), M-machine PSD laser coordinates (x M ,y M ), distance ratio k and misalignment components e y ,e x ,S y ,S x ; Step 5: get the coordinates of S machine when it rotates to any angle α1, α2 and the coordinates of M machine when it rotates to any angle α1, α2 by measuring units S and M and M machine when it rotates to any angle α1, α2 Subtract the measured angles α1, α2 and the different angle coordinate values and substitute them into the relational equation obtained in step 4 to obtain the misalignment component e y , e x , S y , S x According to the misalignment component e y , e x , S y , S x , calculate the adjustment amount of the four anchor points of the driven machine connected by the coupling, and adjust the four anchor points of the driven machine through the adjustment amount of the four anchor points of the driven machine.

2. The method according to claim 1, wherein In step 1, the coordinate system X-O-Y takes the center of the end surface of the driving shaft as the origin O, and the 0 o'clock direction is the positive direction of the Y axis and the 3 o'clock position is the positive direction of the X axis according to the clock scale on the end surface of the driving shaft.

3. The method of claim 1, wherein the method further comprises: In step 2, the measuring unit S machine of the laser aligning instrument is installed on the driving shaft, and the measuring unit M machine of the laser aligning instrument is installed on the shaft of the driven machine.

4. The method of claim 1, wherein the method further comprises: In step 4, the relationship equation is as follows: where a is the difference in sine of the two measured angles, b is the difference in cosine of the two measured angles, ΔY S is the difference in y values for two measurements by the S machine s m is the difference in y values for two measurements by the M machine M is the difference in x values for two measurements by the S machine S is the difference in x values for two measurements by the S machine s is the difference in x values for two measurements by the M machine m is the difference in x values for two measurements by the M machine M is the difference in x values for two measurements by the M machine​ 5. The method of claim 1, wherein the method further comprises: In step 5, the angles α1 and α2 measured twice and the corresponding coordinate values at different angles are subtracted and substituted into the relationship equation obtained in step 4, which specifically includes: Substituting and into the relationship equation obtained in step 4.

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