Precision measurement calibration method of split type centroid measurement equipment

Abstract

The invention discloses a precision measurement calibration method for split type centroid measurement equipment, which comprises the following steps of: weighing an indication error, determining a centroid indication error, comparing a difference value between a centroid result calculated by a relative position relationship between mass and centroid and a centroid result calculated by the centroid measurement equipment through pressure values of different sensors, and calculating the precision measurement calibration of the split type centroid measurement equipment according to the difference value. And judging whether the equipment mass center measurement precision meets related technical requirements or not. According to the invention, full-scale and full-size precision calibration of the split type centroid measuring equipment is realized by adopting a non-centroid standard.

Description

Technical Field

[0001] The invention belongs to the technical field of metrology and calibration, and relates to a precision metrology and calibration method for a split type centroid measuring device. Background Art

[0002] With the development of economy and the increase of product types, centroid measuring equipment is required to develop from special measuring equipment with fixed size and fixed mass for single product to general measuring equipment with multiple sizes and masses, and split centroid measuring equipment comes into being. Split centroid measuring equipment can meet the centroid measurement requirements of products with different lengths by adjusting the distance between measuring platform 1 and measuring platform 2, and can adapt to the support requirements of products with different diameters by adjusting the relative position of the support frame rollers on the measuring platform.

[0003] At present, the split type centroid measurement equipment uses standard sample columns for centroid accuracy measurement verification. However, the manufacturing technology of standard sample columns is difficult and the manufacturing cost is high, and the centroid accuracy of the centroid measurement equipment can only be verified for a single diameter and length. The standard sample column is a rotating body, and the center of mass passes through the axis of the sample column. This feature makes it impossible to fully reflect the performance of the equipment when calibrating the equipment; in order to meet the full-size and full-range calibration of the equipment, a full set of standard sample columns is required, which has a high manufacturing cost and a single function, which will cause great idleness and waste of property. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a precision metrology calibration method for a split type centroid measuring device.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A precision metrological calibration method for a split type centroid measuring device comprises the following steps:

[0007] S1. Weighing indication error: Select standard weights M of different masses 标 , load at different positions on the measuring platform of the centroid measuring device, and record the device indication M after loading. 测 , compare Δ=M 测 -M 标 Whether the technical requirements for equipment quality and accuracy are met;

[0008] S2, center of mass indication error: select a standard weight as the non-standard body for center of mass measurement, set an observable point on the surface of the weight to record the movement of the weight, flip the weight and place it at different positions on the measuring platform, construct two congruent triangles, and restore the coordinate system K1 defined by the center of mass measurement equipment through their relative position relationship, and then find out the center of mass parameters of the standard weight relative to its own coordinate system and mark them;

[0009] S3. Compare the difference between the displacement of the center of mass calculated by the center of mass measuring device through different data of the pressure sensor when the standard weight moves to different positions and the actual displacement of the center of mass measured by the laser tracker, so as to calibrate the center of mass measurement accuracy of the center of mass measuring device.

[0010] As a preferred embodiment, the split centroid measurement equipment includes two relatively movable measurement platforms 1 and 2, each of which is provided with three pressure sensors distributed in an isosceles triangle. The centroid of the measured mass is obtained by comprehensively calculating the pressure values ​​of the six pressure sensors supporting the two measurement platforms.

[0011] Furthermore, in step S2, a line projector is used to construct a reference straight line between measuring platform 1 and measuring platform 2, so that it is parallel to the line connecting the corresponding elements of the measuring platforms, a laser tracker is set up and connected to the data processing software, and a two-dimensional coordinate system K2 is established in the data processing software along the line connecting the corresponding elements of the measuring platforms and the plane of the measuring platforms as a reference, so that the coordinate system K2 is parallel to the coordinate system K1, but does not overlap.

[0012] Further, in the step S2, a weight is placed at position 1 at any position on the measuring platform 1, and the centroid position p1 (x1, y1) of the standard weight at position 1 under the coordinate system K1 is measured, and an observable point A is set on the surface of the weight, and the laser tracker collects the position information of point A to obtain the centroid position A1 (a1, b1) of the standard weight at position 1 under the coordinate system K2;

[0013] Place the weight at position 2 on the measuring platform 2, flip position 1 180° along the reference line and translate to obtain position 2; measure the center of mass position p2 (x2, y2) of the standard weight at position 2 under the coordinate system K1 by the center of mass measuring equipment; collect the position information of point A with the laser tracker to obtain the corresponding coordinate system A2 (a2, b2) under the K2 coordinate system.

[0014] Furthermore, in step S2, the coordinate system K2 is translated, and the translation components in the X and Y directions are m and n respectively, so that K2=K1, recorded as K1', that is, the coordinate system K1 is reproduced in the data processing software; points B1 and B2 are input in the K1' coordinate system in the data processing software, and their coordinate values ​​are (x1, y1) and (x2, y2) respectively, to obtain the coordinate values ​​of the center of mass of the weight in the K1' coordinate system; the center of mass point is found on the surface of the weight through the coordinate value of point B and marked, and the center of mass is recorded as point G.

[0015] Furthermore, in step S3, the positions of the center of mass of the combined non-standard body 1 and non-standard body 2 in the K1' coordinate system are measured by a laser tracker as A3 (a3, b3) and A4 (a4, b4), respectively, and the center of mass G of the combination is calculated according to the moment balance formula; the center of mass p of the combination of non-standard body 1 and non-standard body 2 in the coordinate system K1 is measured by a center of mass measuring device; the combination of non-standard body 1 and non-standard body 2 is arbitrarily moved, and the coordinate values ​​of the center of mass of the combination of 1 and non-standard body 2 at different positions in the K1 coordinate system are calculated through different data of the pressure sensor to obtain the center of mass displacement L1=p i+1 -p i , the laser tracker is used to measure the coordinate values ​​of the center of mass of the non-standard combination at different positions in the K1' coordinate system, and the actual displacement L2 = G of the front and rear positions is obtained. i+1 -G i , compare Δ=L1-L2 to calibrate whether the center of mass measurement accuracy of the equipment meets the technical requirements.

[0016] The metrological calibration of the split-type centroid measuring device requires that the calibration standard (i.e., the standard sample column) be placed as a whole on different measuring platforms of the centroid measuring device. Expanding the concept of the integrity of an object, a single object is a whole with a centroid; multiple objects combined and rigidly connected can also be regarded as a whole with a centroid; multiple objects with relative positional relationships are regarded as a whole, and there is a virtual rigid connection between them, and the whole will still have the concept of centroid. Therefore, when the split-type centroid measuring device is metrologically verified, its centroid standard does not have to be confined to the physical concept of the whole. The two centroid standards are regarded as a whole and placed on different measuring platforms of the split-type centroid measuring device. The mass and relative position relationship of the centroid of the two centroid standards are known, and the centroid position of the whole composed of the two centroid standards is calculated, which can replace the standard sample column to realize the precision calibration of the split-type centroid measuring device. Compare the difference between the centroid result calculated by the mass and relative position relationship of the centroid and the centroid result calculated by the centroid measuring device through different sensor pressure values ​​to determine whether the centroid measurement accuracy of the device meets the relevant technical requirements.

[0017] The present invention has the following advantages:

[0018] The present invention uses multiple single centroid standards to perform metrological verification on the split centroid measuring equipment, and by matching centroid standards of different masses and moving them to different positions on the measuring platform, the full-scale and full-size precision calibration of the split centroid measuring equipment is achieved. A precision metrological calibration method for the centroid measuring equipment using a non-standard body is introduced, and a laser tracker is used to perform comprehensive calculations on the relevant physical quantities before and after the non-standard body is moved in combination with the centroid measuring equipment, and the centroid parameters of the non-standard body in its own defined coordinate system are found, so as to achieve the standardization of the centroid of the non-standard body and achieve the metrological functional replacement of the centroid standard. The non-standard body with different masses of the centroid is matched and moved to different positions on the measuring platform, so as to achieve the full-scale and full-size precision calibration of the split centroid measuring equipment using the non-centroid standard. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the structure of the present invention;

[0020] Figure 2 Construct a schematic diagram for the coordinate system of the centroid measurement device;

[0021] Figure 3 It is a schematic diagram of the relative position relationship between position 1 and position 2;

[0022] Figure 4 Schematic diagram of congruent triangles constructed for the centroid and observation points;

[0023] Figure 5 Schematic diagram of the overall fitting and centroid position of multiple non-standard bodies;

[0024] Figure 6 Schematic diagram of the actual displacement of the center of mass before and after simulating the overall movement.

[0025] In the figure: 1-data processing software equipment, 2-laser tracker, 3-laser line projector, 4-measuring platform 1, 5-measuring platform 2, 6-pressure sensor, 7-center of mass measurement result display, 8-pressure sensor connection, 9-split center of mass measurement equipment coordinate system, 10-reference straight line, 11-position 1, 12-position 2, 13-non-standard body, 14-center of mass point P1, 15 observable point A1, 16-center of mass point P2, 17-observable point A2, 18-straight line The intersection O of A1A2 and P1P2, 19-non-standard body 1, 20-center of mass point G of non-standard body 1, 21-non-standard body 2, 22-center of mass point G of non-standard body 2, 23-combined simulation of non-standard bodies 1 and 2 as a whole A, 24-simulation of the integrated center of mass coordinate value of the whole A before movement, 25-simulation of the whole B, 26-simulation of the integrated center of mass coordinate value of the whole B after movement, 27-displacement L1 measured by the laser tracker, 28-displacement L2 measured by the split center of mass measurement equipment. DETAILED DESCRIPTION

[0026] The present invention will be described in detail below in conjunction with the accompanying drawings.

[0027] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0028] Example:

[0029] The split centroid measuring equipment is composed of two relatively movable independent measuring platforms. Three pressure sensors are distributed in an isosceles triangle under a single measuring platform. The centroid of the measured mass is obtained by comprehensively calculating the pressure values ​​of the six pressure sensors supporting the two measuring platforms.

[0030] Set up a laser tracker and connect it to the SA data processing software to measure the coordinate values ​​of the non-standard body at different spatial positions before and after the movement, and use a laser line projector to build a non-standard body flip movement benchmark, such as Figure 2 shown.

[0031] The metrological characteristics of the split centroid measuring equipment include the weighing indication error and the centroid indication error. The measuring platform needs to be measured before metrological calibration, and its levelness is required to be maintained at ≤0.35mm / m.

[0032] Weighing indication error: Select standard weights M of different masses to load at different positions on the measuring platform of the centroid measuring equipment, and record the equipment indication M after loading. 测 , compare Δ=M 测 -M 标 Whether the technical requirements for equipment quality and accuracy are met;

[0033] Center of mass indication error: In order to facilitate the measurement and calibration of the equipment, standard weights are selected as non-standard objects for center of mass measurement.

[0034] Part 1: Standardization of non-standard body center of mass

[0035] Step 1: Define the centroid measurement device coordinate system K1.

[0036] The split type centroid measuring device adds pressure sensors and weighing platforms to the traditional equipment, but its working principle remains unchanged, that is, by measuring the force change of the sensor "before and after loading the object to be measured", the mass and two-dimensional centroid position of the object to be measured are calculated according to the moment balance formula. To simplify the calculation, the coordinate system K1 defined by the device will be established along the sensor connection line corresponding to each weighing platform, so as to facilitate the calculation of the centroid of the object to be measured by using the value of each pressure sensor through the moment balance formula, such as Figure 2 shown.

[0037] Step 2: Establish the non-standard body flip movement baseline.

[0038] In order to reduce the measurement error caused by the twisting of the non-standard body before and after flipping, the principle of establishing the flipping movement baseline is to make it as parallel as possible to the coordinate system K1 defined by the split-type centroid measurement equipment.

[0039] Use the line projection instrument to construct a reference straight line between measuring platform 1 and measuring platform 2, making it parallel to the connecting line of the corresponding elements of the split measuring platform, such as Figure 3 Shown by the dashed line.

[0040] Step 3: Establish the laser tracker measurement coordinate system K2.

[0041] Set up a laser tracker and connect it to the SA data processing software. In the SA software, a two-dimensional coordinate system K2 is established along the connecting line of the corresponding elements of the split measurement platform and the plane of the measurement platform as a reference, so that K2 is parallel to K1 but does not overlap.

[0042] Step 4: Non-standard body flip movement measurement.

[0043] Place the weight at position 1 (position 1 is an arbitrary position) on the measuring platform 1 of the centroid measuring device, and measure the centroid position p1 (x1, y1) of the standard weight at position 1 under the device definition coordinate system K1;

[0044] An observable point A is set on the surface of the weight, and the laser tracker collects the position information of point A to obtain the centroid position A1 (a1, b1) of the standard weight at position 1 under the laser tracker measurement coordinate system K2;

[0045] Place the weight at position 2 on the measuring platform 2 of the centroid measuring device. Position 1 is flipped 180° along the reference line and translated to position 2, as shown in Figure 3 As shown;

[0046] The center of mass position p2 (x2, y2) of the standard weight at position 2 under the device definition coordinate system K1 is measured by a center of mass measuring device;

[0047] The laser tracker collects the position information of point A and obtains the corresponding coordinate system A2 (a2, b2) in the K2 coordinate system in the SA software;

[0048] Lines A1A2 and P1P2 intersect at point O. Points P1, P2, A1, A2 and O form two congruent triangles. Figure 4 shown.

[0049] Step 5: Calculate the translation coordinate system so that K2 = K1

[0050] Purpose of constructing congruent triangles: (x1+x2) / 2=(a1+a2) / 2+m, (y1+y2) / 2=(b1+b2) / 2+n, where m and n are the translation coefficients of the two-dimensional coordinate systems K1 and K2;

[0051] The coordinate system K2 is translated, and the translation components in the X and Y directions are m and n respectively, so that K2 = K1, which is recorded as K1', that is, the coordinate system K1 defined by the split centroid measurement device is reproduced in the SA software;

[0052] In the SA software, input points B1 and B2 in the K1' coordinate system, whose coordinate values ​​are (x1, y1) and (x2, y2) respectively, and the coordinate values ​​of the center of mass of the weight in the K1' coordinate system are obtained;

[0053] The center of mass is found and marked on the surface of the weight by the coordinate value of point B, and the center of mass is recorded as point G to make the center of mass observable.

[0054] Part 2: Combined non-standard bodies for metrological calibration of split-type centroid measuring equipment.

[0055] Step 1: Calculate the combined centroid

[0056] Consider the combination of non-standard bodies 1 and 2 as a whole, such as Figure 5 In the equation, the masses of non-standard bodies 1 and 2 are known to be G1 and G2 respectively, and the positions of their centers of mass in the K1' coordinate system are measured by a laser tracker to be A3 (a3, b3) and A4 (a4, b4) respectively. According to the moment balance formula, the combined center of mass point G is pi (xi, yi), and we have

[0057] G1*a3+G2*a4=(G1+G2)*xi

[0058] G1*b3+G2*b4=(G1+G2)*yi

[0059] Calculate the center of mass G of the combination;

[0060] Step 2: Weigh and measure the centroid of the combination

[0061] The center of mass p of the combination of non-standard body 1 and non-standard body 2 in the device definition coordinate system K1 is measured by a center of mass measuring device;

[0062] Step 3: Compare the difference between the calculated center of mass and the weighed center of mass

[0063] By moving the weights arbitrarily, the coordinate values ​​p of the center of mass of the non-standard combination at different positions in the K1 coordinate system are calculated through different data from the pressure sensor, and the displacement of the center of mass L1 = p is obtained. i+1 -p i, the laser tracker is used to measure the coordinate values ​​G of the center of mass of the non-standard combination at different positions in the K1' coordinate system, and the actual displacement L2 = G of the front and rear positions is obtained. i+1 -G i , compare Δ = L1-L2 to calibrate whether the center of mass measurement accuracy of the equipment meets the technical requirements, such as Figure 6 shown.

[0064] The combination of non-standard bodies 1 and 2 can be extended to any number of monomers. The center of mass of the non-standard body can be standardized by combining the flip method, and its center of mass position information can be unified in the same coordinate system to calculate the center of mass coordinate value of the entire combination. Any combination of multiple monomers can achieve full range coverage of the center of mass measurement equipment from small to large. Multiple monomers are not restricted by physical distance from each other, and the full range and full size range of the split center of mass measurement equipment can be calibrated.

[0065] The present invention is not limited to the aforementioned specific embodiments. The present invention extends to any new features or any new combination disclosed in this specification, and any new method or process steps or any new combination disclosed.

Claims

1. A precision metrological calibration method for a split type centroid measuring device, characterized in that: The steps include: S1. Weighing indication error: Select standard weights M of different masses 标 , load at different positions on the measuring platform of the centroid measuring device, and record the device indication M after loading. 测 , compare Δ=M 测 -M 标 Whether the technical requirements for equipment quality and accuracy are met; S2, center of mass indication error: select a standard weight as the non-standard body for center of mass measurement, set an observable point on the surface of the weight to record the movement of the weight, flip the weight and place it at different positions on the measuring platform, construct two congruent triangles, and restore the coordinate system K1 defined by the center of mass measurement equipment through their relative position relationship, and then find out the center of mass parameters of the standard weight relative to its own coordinate system and mark them; S3. Compare the difference between the displacement of the center of mass calculated by the center of mass measuring device through different data of the pressure sensor when the standard weight moves to different positions and the actual displacement of the center of mass measured by the laser tracker, so as to calibrate the center of mass measurement accuracy of the center of mass measuring device.

2. The precision measurement and calibration method of a split type centroid measuring device according to claim 1 is characterized in that: The split type centroid measuring device comprises two relatively movable measuring platforms 1 and 2, each of which is provided with three pressure sensors distributed in an isosceles triangle. The centroid of the mass being measured is obtained by comprehensively calculating the pressure values ​​of six pressure sensors supporting the two measuring platforms.

3. The precision measurement and calibration method of a split type centroid measuring device according to claim 2 is characterized in that: In step S2, a line projector is used to construct a reference straight line between the measuring platform 1 and the measuring platform 2, so that it is parallel to the line connecting the corresponding elements of the measuring platform, a laser tracker is set up and connected to the data processing software, and a two-dimensional coordinate system K2 is established in the data processing software along the line connecting the corresponding elements of the measuring platform and the plane of the measuring platform as a reference, so that the coordinate system K2 is parallel to the coordinate system K1, but does not overlap.

4. The precision measurement and calibration method of a split type centroid measuring device according to claim 2, characterized in that: In the step S2, a weight is placed at position 1 at any position on the measuring platform 1, and the centroid position p1 (x1, y1) of the standard weight at position 1 under the coordinate system K1 is measured, and an observable point A is set on the surface of the weight. The laser tracker collects the position information of point A to obtain the centroid position A1 (a1, b1) of the standard weight at position 1 under the coordinate system K2; Place the weight at position 2 on the measuring platform 2, flip position 1 180° along the reference line and translate to obtain position 2; measure the center of mass position p2 (x2, y2) of the standard weight at position 2 under the coordinate system K1 by the center of mass measuring equipment; collect the position information of point A with the laser tracker to obtain the corresponding coordinate system A2 (a2, b2) under the K2 coordinate system.

5. The precision measurement and calibration method of a split type centroid measuring device according to claim 4 is characterized in that: In the step S2, the coordinate system K2 is translated, and the translation components in the X and Y directions are m and n respectively, so that K2=K1, recorded as K1', that is, the coordinate system K1 is reproduced in the data processing software; points B1 and B2 are input in the K1' coordinate system in the data processing software, and their coordinate values ​​are (x1, y1) and (x2, y2) respectively, to obtain the coordinate values ​​of the center of mass of the weight in the K1' coordinate system; the center of mass point is found on the surface of the weight through the coordinate value of point B and marked, and the center of mass is recorded as point G.

6. The precision measurement and calibration method of a split type centroid measuring device according to claim 5, characterized in that: In step S3, the positions of the mass centers of the combined non-standard body 1 and the non-standard body 2 in the K1' coordinate system are measured by a laser tracker as A3 (a3, b3) and A4 (a4, b4), respectively, and the mass center G of the combination is calculated according to the moment balance formula; The center of mass p of the combination of non-standard body 1 and non-standard body 2 under the coordinate system K1 is measured by a center of mass measuring device; Arbitrarily move the combination of non-standard body 1 and non-standard body 2, and calculate the coordinate values ​​of the center of mass of the combination of 1 and non-standard body 2 at different positions in the K1 coordinate system through different data of the pressure sensor, and obtain the center of mass displacement L1=p i+1 -p i , the laser tracker is used to measure the coordinate values ​​of the center of mass of the non-standard combination at different positions in the K1' coordinate system, and the actual displacement L2 = G of the front and rear positions is obtained. i+1 -G i , compare Δ=L1-L2 to calibrate whether the center of mass measurement accuracy of the equipment meets the technical requirements.

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