A coaxiality error calibration device and its calibration method based on laser collimation measurement.

Abstract

This invention discloses a coaxiality error calibration device and its calibration method based on laser collimation measurement. It is used to calibrate the coaxiality error of a laser collimation measurement system. The calibration device consists of a base, a horizontal turntable, an X-axis long guide rail, an X-axis moving platform, a Y-axis displacement stage, a connector, and a Z-axis displacement stage. The X-axis long guide rail can adjust the distance between the laser and the receiving target in the laser collimation measurement system. The laser rotates in a full circle with the horizontal turntable. The trajectory of the laser spot is measured at different distances on the receiving target. The center of the laser spot trajectory is obtained by least squares fitting. Furthermore, the rotation axis equation of the laser collimation measurement system is calibrated using the coordinates of the center at different distances. The coaxiality error of the laser collimation measurement system at any distance can be calculated using the axis equation. This invention has high measurement efficiency, simple operation, and is suitable for dynamic continuous measurement and compensation of coaxiality errors in laser collimation measurement systems.

Description

Technical Field

[0001] This invention relates to the field of instrument calibration technology, specifically to a coaxiality error calibration device and its calibration method based on laser collimation measurement. Background Technology

[0002] Coaxiality is one of the key geometric tolerance parameters, used to ensure that the axes of the driving shaft and the driven shaft are always on a straight line when shaft components rotate at high speed.

[0003] With the development of laser collimation measurement technology, the measurement accuracy of coaxiality has also improved. For high-precision coaxiality measurement of large shaft systems or two shaft systems that are far apart, the laser collimation measurement method has advantages that traditional coaxiality measurement methods such as dial indicators cannot replace. Compared with non-traditional measurement methods such as coordinate measuring machine method, machine vision measurement method, and optical collimation method, although the latter can meet the coaxiality measurement requirements of general shaft components, they are limited by measurement efficiency, measurement range and inability to meet on-site measurement. The laser collimation measurement method has a wider range of applications, higher measurement efficiency, and is suitable for various application scenarios such as on-site measurement.

[0004] The laser collimation measurement method is constrained by the coaxiality error introduced by the installation error of the laser collimation measurement system during the coaxiality measurement process. It cannot effectively separate the error and inevitably introduces measurement error during the coaxiality measurement process, which further limits the manufacturing and assembly accuracy of large electromechanical equipment. Summary of the Invention

[0005] The present invention aims to provide a coaxiality error calibration device and its calibration method based on laser collimation measurement, so as to realize the dynamic continuous measurement of the rotation axis of the laser collimation measurement system and the coaxiality error calibration, thereby further improving the coaxiality measurement accuracy of the laser collimation measurement system.

[0006] This invention is achieved through the following technical solution:

[0007] The coaxiality error calibration device based on laser collimation measurement includes a base, a horizontal turntable, an X-axis long guide rail, an X-axis moving platform, a Y-axis displacement stage, a connector, and a Z-axis displacement stage. The horizontal turntable is installed at one end of the base, and its rotating working surface is used to install the laser of the laser collimation measurement system. The X-axis long guide rail is installed on the base to provide displacement in the X-axis direction. The X-axis moving platform is installed on the X-axis long guide rail. The Y-axis displacement stage is installed on the X-axis moving platform to provide displacement in the Y-axis direction. The Z-axis displacement stage is installed on the Y-axis displacement stage via the connector to provide displacement in the Z-axis direction. The working surface of the Z-axis displacement stage is used to install the receiving target of the laser collimation measurement system.

[0008] The coaxiality error calibration method based on laser collimation measurement is implemented through the aforementioned coaxiality error calibration device, and specifically includes the following steps:

[0009] S1: The laser is coaxially mounted with the working surface of the horizontal rotary table's rotation axis. The coordinate system o0x0y0z0 is established with the laser's mounting position as the origin o0. The positive direction of axis x0 is the movement direction of the long guide rail of the X-axis, the positive direction of axis z0 is vertically upward, and the positive direction of axis y0 is determined by the right-hand rule. The receiving target is mounted on the working surface of the Z-axis displacement stage. The receiving target can be moved in the Y-axis and Z-axis directions through the Y-axis displacement stage and the Z-axis displacement stage, so that the receiving target and the laser are always aligned with the laser throughout the entire range.

[0010] S2: Select m measurement positions on the X-axis guide rail to measure the motion trajectory of the laser spot, with the target mounting position as the origin of the coordinate system. i Establish a coordinate system o parallel to the coordinate system o0x0y0z0. i x i y i z i Origin of coordinate system i The distance from the origin o0 of the coordinate system is L i (i = 1, 2, 3L m).

[0011] S3: When the distance between the receiving target and the laser is L i At that time, the laser rotates in a full circle with the turntable at angular intervals of 2π / n, and the receiving target collects the laser spot at a fixed distance L in real time. i plane o i y i z i Position coordinates P on ij (y ij ,z ij (j = 1, 2, 3L n).

[0012] S4: Let the general equation for the circular trajectory of the laser spot be...

[0013]

[0014] P ij (y ij ,z ij Substituting into equation (1) and establishing an overdetermined system of equations, the sum of squares of the residual errors δ i 2 for

[0015]

[0016] When δ i 2 When the value is minimized, the partial derivative of equation (2) is 0, and the center of the circle is o.i (y i ,z i There exists a least-squares solution, that is, we have

[0017]

[0018] United achievable

[0019]

[0020] United achievable

[0021]

[0022] By combining equations (4) and (5), we can obtain

[0023]

[0024] In the formula

[0025]

[0026] The solution is obtained when the distance between the receiving target and the laser is L. i When, the parameter a of the general equation for the circular trajectory of the laser spot i b i and c i They are respectively

[0027]

[0028] The center o can be found by using the transformation relationship between the general equation and the standard equation of a circle. i (y i ,z i ) and radius R i for

[0029]

[0030] S5: Combine the center o i (y i ,z i Position L on the guide rail i The laser axis is obtained at a distance L i coordinate point p on the time axis i (x i ,y i ,z i ), where x i =L i Let the equation of the laser axis be...

[0031]

[0032] Rewrite equation (10) as follows:

[0033]

[0034] p i (x i ,y i ,z i Substituting into equation (11), an overdetermined system of equations is established, and the sum of squares of the residual errors is... and for

[0035]

[0036] make Right now

[0037]

[0038] Sum of squares of residual errors and When it is at its minimum, the partial derivative is 0, that is...

[0039]

[0040] make K1 = [AB] T K2 = [CD] T X = [x1 x2 x3 L x] n ] T Y = [y1y2y3Ly] n ] T That is,

[0041]

[0042] The parameters K1 and K2 are obtained as follows:

[0043]

[0044] S6: After solving the axis equation of the laser, when using the laser to measure coaxiality on site, it is only necessary to obtain the actual distance between the laser and the receiving target, and the coaxiality error of the laser itself at the current position can be calculated according to equation (10), thereby realizing the separation of coaxiality error from the object being measured.

[0045] The present invention has the following positive and beneficial effects:

[0046] 1. High measurement efficiency, easy to realize dynamic and continuous measurement of coaxiality error of laser collimation measurement system;

[0047] 2. The coaxiality error calibration device can measure the two-dimensional displacement indication error of the receiving target while simultaneously measuring the coaxiality error.

[0048] 3. Simple to operate and applicable to a variety of scenarios, suitable for online measurement in the assembly, debugging and daily use of laser collimation measurement systems. Attached Figure Description

[0049] Figure 1 This is a schematic diagram of the coaxiality error calibration device based on laser collimation measurement method in this invention.

[0050] Figure 2 This is a schematic diagram of the coordinate system setup during the coaxiality error calibration process in this invention.

[0051] Figure 3 This is a schematic diagram illustrating the coaxiality error measurement principle of the laser collimation measurement system in this invention.

[0052] In the diagram: 1-base, 2-horizontal turntable, 3-X-axis long guide rail, 4-X-axis moving platform, 5-Y-axis displacement stage, 6-adapter, 7-Z-axis displacement stage. Detailed Implementation

[0053] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0054] like Figure 1 As shown, the coaxiality error calibration device based on laser collimation measurement method includes a base 1, a horizontal turntable 2, an X-axis long guide rail 3, an X-axis moving platform 4, a Y-axis displacement stage 5, a connector 6, and a Z-axis displacement stage 7. The device is characterized in that 2 is installed at one end of 1, and its rotating working surface is used to install the laser of the laser collimation measurement system; 3 is installed on 1 to provide displacement in the X-axis direction; 4 is installed on 3; 5 is installed on 4 to provide displacement in the Y-axis direction; 7 is installed on 5 through 6 to provide displacement in the Z-axis direction; and the receiving target of the laser collimation measurement system is installed on the working surface of 7.

[0055] The coaxiality error calibration method based on laser collimation measurement is implemented through the aforementioned coaxiality error calibration device, and specifically includes the following steps:

[0056] S1: As Figure 2As shown, the laser is coaxially mounted with the working surface of the rotating shaft of 2. The coordinate system o0x0y0z0 is established with the laser mounting position as the origin o0. The positive direction of the x-axis is the direction of movement of the long guide rail of the X-axis, the positive direction of the z-axis is vertically upward, and the positive direction of the y-axis is determined by the right-hand rule. The receiving target is mounted on the working surface of 7. The receiving target can be moved in the Y-axis and Z-axis directions through 5 and 7 so that the receiving target and the laser are always aligned with the laser throughout the entire range.

[0057] S2: As Figure 3 As shown, m measurement positions are selected on the X-axis guide rail to measure the motion trajectory of the laser spot, with the target mounting position as the origin of the coordinate system. i Establish a coordinate system o parallel to the coordinate system o0x0y0z0. i x i y i z i Origin of coordinate system i The distance from the origin o0 of the coordinate system is L i (i = 1, 2, 3L m).

[0058] S3: When the distance between the receiving target and the laser is L i At that time, the laser rotates in a full circle with the turntable at angular intervals of 2π / n, and the receiving target collects the laser spot at a fixed distance L in real time. i plane o i y i z i Position coordinates P on ij (y ij ,z ij (j = 1, 2, 3L n).

[0059] S4: Let the general equation for the circular trajectory of the laser spot be...

[0060]

[0061] P ij (y ij ,z ij Substituting into equation (1) and establishing an overdetermined system of equations, the sum of squares of the residual errors δ i 2 for

[0062]

[0063] When δ i 2 When the value is minimized, the partial derivative of equation (2) is 0, and the center of the circle is o. i (y i ,z i There exists a least-squares solution, that is, we have

[0064]

[0065] United achievable

[0066]

[0067] United achievable

[0068]

[0069] By combining equations (3) and (4), we can obtain

[0070]

[0071] In the formula

[0072]

[0073] The solution is obtained when the distance between the receiving target and the laser is L. i When, the parameter a of the general equation for the circular trajectory of the laser spot i b i and c i They are respectively

[0074]

[0075] The center o can be found by using the transformation relationship between the general equation and the standard equation of a circle. i (y i ,z i ) and radius R i for

[0076]

[0077] S5: Combine the center o i (y i ,z i Position L on the guide rail i The laser axis is obtained at a distance L i coordinate point p on the time axis i (x i ,y i ,z i ), where x i =L i Let the equation of the laser axis be...

[0078]

[0079] Rewrite equation (10) as follows:

[0080]

[0081] p i (x i ,y i ,z i Substituting into equation (11), an overdetermined system of equations is established, and the sum of squares of the residual errors is... and for

[0082]

[0083] make Right now

[0084]

[0085] Sum of squares of residual errors and When it is at its minimum, the partial derivative is 0, that is...

[0086]

[0087] make K1 = [AB] T K2 = [CD] T X = [x1x2x3Lx] n ] T Y = [y1y2y3Ly] n ] T That is,

[0088]

[0089] The parameters K1 and K2 are obtained as follows:

[0090]

[0091] S6: After solving the axis equation of the laser collimation measurement system, when using the laser collimation measurement system to measure coaxiality on site, it is only necessary to obtain the actual distance between the laser and the receiving target, and the coaxiality error of the laser itself at the current position can be calculated according to equation (10), thereby realizing the separation of coaxiality error from the object being measured.

[0092] The coaxiality error calibration device and calibration method based on laser collimation measurement described above have the following advantages:

[0093] 1. High measurement efficiency, easy to realize dynamic and continuous measurement of coaxiality error of laser collimation measurement system;

[0094] 2. The coaxiality error calibration device can measure the two-dimensional displacement indication error of the receiving target while simultaneously measuring the coaxiality error.

[0095] 3. Simple to operate and applicable to a variety of scenarios, suitable for online testing during the assembly, debugging, and daily use of laser collimation measurement systems.

[0096] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these specific embodiments are merely illustrative. Those skilled in the art can omit, substitute, and modify the details of the above methods and systems in various ways without departing from the principles and essence of the present invention. For example, combining the above method steps to perform substantially the same function and achieve substantially the same result according to substantially the same method falls within the scope of the present invention. Therefore, the scope of the present invention is defined only by the appended claims.

Claims

1. A coaxiality error calibration device based on laser collimation measurement method, comprising a base, a horizontal rotary table, an X-axis long guide rail, an X-axis moving platform, a Y-axis displacement table, an adapter and a Z-axis displacement table, characterized in that, the horizontal rotary table is installed at one end of the base, and the rotary shaft working surface is used for coaxially installing a laser of a laser collimation measurement system, the X-axis long guide rail is installed on the base to provide displacement in the X-axis direction, the X-axis moving platform is installed on the X-axis long guide rail, the Y-axis displacement table is directly fixed on the X-axis moving platform to provide displacement in the Y-axis direction, the Z-axis displacement table is fixed on the Y-axis displacement table through the adapter to provide displacement in the Z-axis direction, and the Z-axis displacement table working surface is used for installing a receiving target of the laser collimation measurement system; The X-axis long guide rail is used for selecting m A measuring position is selected to measure the laser spot trajectory of the emitted laser. The receiving target is arranged at a fixed distance from the laser m The receiving target is arranged at a fixed distance from the laser The receiving target is arranged at a fixed distance from the laser The receiving target is arranged at a fixed distance from the laser The device is also used to utilize the collected position coordinates to obtain the track circle center of the laser spot by least square fitting, and utilize the track circle center and the distance to obtain the coordinate points of the laser rotation axis at different distances for spatial straight line fitting, so as to realize the calibration of the rotation axis equation of the laser collimation measurement system. The device is also used to utilize the collected position coordinates to obtain the track circle center of the laser spot by least square fitting, and utilize the track circle center and the distance to obtain the coordinate points of the laser rotation axis at different distances for spatial straight line fitting, so as to realize the calibration of the rotation axis equation of the laser collimation measurement system.

2. A method for calibrating coaxiality error of a laser collimation measurement method according to claim 1, characterized in that, the steps include: S1: install the laser coaxially with the working surface of the rotation axis of the horizontal rotary table, taking the laser installation position as the coordinate system origin o 0, establish the coordinate system o 0 x 0 y 0 z 0; install the receiving target on the working surface of the Z-axis displacement table, and always align the receiving target and the laser in the full range by moving the Y-axis displacement table and the Z-axis displacement table; S2: Select on the X-axis long guide rail m The measurement positions are used to measure the trajectory of the laser spot emitted by the laser, with the target mounting position as the origin of the coordinate system. o i Establish coordinate system o 0 x 0 y 0 z 0 parallel coordinate system o i x i y i z i ; S3: when the distance between the receiving target and the laser is , drive the laser to rotate with the horizontal turntable whole circumference, and make the receiving target collect the position coordinates of the laser spot on the plane with fixed distance o i x i y i z i ​ S4: fitting the distances using least squares to get the center of the trajectory circle of the laser spot the center of the trajectory circle of the laser spot at the time S5: using the trajectory center and distance The coordinate points of the laser rotation axis at different distances are obtained, and the coordinate points are subjected to spatial straight line fitting, so as to realize calibration of the rotation axis equation of the laser collimation measurement system.

3. The coaxiality error calibration method of claim 2, wherein, the step S6 of calculating the coaxiality error of the laser collimation measurement system at any distance according to the calibration result of the rotary axis equation.

4. The coaxiality error calibration method of claim 3, wherein, the actual distance between the laser and the receiving target is obtained when the laser collimation measurement system is used to measure the coaxiality on site, and the coaxiality error of the laser itself at the current position is calculated according to the calibrated rotary axis equation, so as to realize the separation of the coaxiality error of the measured object.

5. The coaxiality error calibration method of claim 4, wherein, In step S4, let the general equation of the circular trajectory of the laser spot be By substituting the collected position coordinates into the equation, an over-determined equation set is established to solve the least square solution at the minimum square sum of residual errors, so as to determine the center of the trajectory circle.

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