A Multi-Probe Measurement Method for Spindle Rotation Error Based on a Standard Flat Plate

Abstract

This invention belongs to the field of precision mechanical measurement technology. It proposes a multi-probe measurement method for spindle rotation error based on a standard plate, which solves the technical problems of existing methods being unable to measure angular motion errors or having complex measurement steps. A standard plate and displacement sensor are built on the spindle under test, and the initial displacement signal is continuously and in real time collected and transmitted to the signal acquisition and processing system. The weighted sum is used to construct a weight function. The weight function is then subjected to a Fourier transform and sorted to obtain the Fourier coefficients of the residual surface curve at the radius R of the standard plate and the sum of the residual pure axial motion errors. The inverse Fourier transform is then performed on the above Fourier coefficients to calculate the axial motion errors at the radius R on the X-axis and Y-axis of the spindle under test, as well as the angular motion errors of the spindle under test rotating around the X-axis and Y-axis, respectively. The measurement steps are simple and the cost is low.

Description

Technical Field

[0001] This invention belongs to the field of precision mechanical measurement technology. Background Technology

[0002] In various industrial settings and laboratories, the spindles of rotating components, such as machine tool spindles or rotary table spindles, are crucial forming motion components. Their rotational error significantly affects the machining accuracy of precision machining equipment or the detection accuracy of precision measuring instruments. Generally, this leads to a decrease in the machining accuracy of machine tools and an increase in the measurement uncertainty of instruments such as profilometers. Therefore, during the development process or before being put into use, the spindle rotational error of such rotating components must be measured to evaluate their performance indicators.

[0003] Existing methods for measuring spindle rotation error require high-precision single-ball standard bars with a roundness of less than 50 nanometers. Limited by domestic manufacturing capabilities, these high-precision single-ball standard bars are mostly imported, which are not only expensive but also have long procurement cycles. Even minor scratches during use are difficult to repair, essentially rendering them unusable. Furthermore, single-ball standard bars cannot measure angular motion errors. While double-ball standard bars can measure angular motion errors, the eccentricity adjustment steps are more numerous and the operation more difficult, resulting in longer measurement times. Summary of the Invention

[0004] To address the technical problems of existing measurement methods being unable to measure angular motion errors or having complex measurement steps and low measurement efficiency, this invention proposes a multi-probe measurement method for spindle rotation error based on a standard flat plate.

[0005] A multi-probe method for measuring spindle rotation error based on a standard flat plate includes the following steps:

[0006] Step 1: Set up a standard flat plate and displacement sensor and collect initial displacement signals:

[0007] like Figure 1 As shown, a standard plate 2 is fixedly installed on the spindle 1 being tested;

[0008] Four displacement sensors are non-contactly installed above the end face of the standard plate 2. The axes of the displacement sensors are all perpendicular to the standard plate. The projections of the first displacement sensor probe 31, the second displacement sensor probe 32, and the third displacement sensor probe 33 on the standard plate 2 are located on the same virtual circle with a radius of R. The center of the virtual circle coincides with the rotation center of the measured spindle. The projection of the fourth displacement sensor probe 34 on the standard plate is located at the rotation center of the measured spindle. The X-axis is defined as the line connecting the projection of the first displacement sensor probe 31 and the center of the virtual circle. The angle between the line connecting the projection of the second displacement sensor probe 32 and the center of the virtual circle and the X-axis is φ. The angle between the line connecting the projection of the third displacement sensor probe 33 and the center of the virtual circle and the X-axis is ψ.

[0009] The measured spindle 1 is driven to rotate at a uniform speed. Four displacement sensors continuously and in real time acquire multi-rotation displacement signals and transmit them to the signal acquisition and processing system 4. The multi-rotation displacement signals acquired by the first displacement sensor probe 31, the second displacement sensor probe 32, the third displacement sensor probe 33, and the fourth displacement sensor probe 34 are filtered to remove the first harmonic and DC components and are denoted as follows: m 1 (θ) , m 2 (θ) , m 3 (θ), m 4 (θ) ,

[0010] ,

[0011] ,

[0012] ,

[0013] ,

[0014] in, θ The rotation angle of the spindle being measured. P(θ) This refers to the residual surface profile curve at the virtual circumference radius R on a standard flat plate. z(θ) The residual pure axial motion error of the measured spindle rotation center. x(θ) The axial motion error at radius R on the X-axis of the measured spindle is denoted as denoted as . y(θ) This refers to the axial motion error at radius R on the Y-axis of the measured spindle;

[0015] Step 2, as follows Figure 2 As shown, the data post-processing calculates the gyration error:

[0016] 21. Yes m 1 (θ) , m 2 (θ) , m 3(θ) Construct the weight function by performing weighted summation. M(θ) , For M(θ) Perform a Fourier transform and rearrange to obtain the Fourier coefficients of the sum of the residual surface profile curve and the residual pure axial motion error at the virtual circumference radius R of the standard plate. Then, perform an inverse Fourier transform on these coefficients to obtain the sum of the residual surface profile curve and the residual pure axial motion error at the virtual circumference radius R of the standard plate.

[0017] ,

[0018] in, m To calculate the highest Fourier order, j For imaginary part operators, k For Fourier order, P(jk) , z(jk) These are the Fourier coefficients of the residual surface shape and the residual pure axial motion error of the standard flat plate, respectively.

[0019] 22. The displacement signal from the fourth displacement sensor probe 34, after filtering out the first harmonic and DC components, is numerically equivalent to the residual pure axial motion error at the rotation center of the measured spindle. Subtracting this from the above calculation results yields the residual surface profile curve at the radius R of the standard flat plate.

[0020] ,

[0021] Residual pure axial motion error of the measured spindle rotation center for:

[0022] ,

[0023] 23. Calculate the axial motion error at radius R on the X and Y axes of the measured spindle:

[0024] ,

[0025] or ;

[0026] 24. Calculate the angular motion errors of the measured spindle rotating around the X-axis and Y-axis respectively:

[0027] ,

[0028] ,

[0029] 25. Calculate the average value of the multi-rotation measurement results to obtain the pure axial motion synchronization error. for:

[0030] ,

[0031] Synchronization error of the angular motion of the measured spindle rotating around the X-axis and Y-axis respectively , for:

[0032] ,

[0033] ,

[0034] in, n To measure the total number of revolutions, i Indicates the first i Transfer to measurement, subscript s Indicates synchronization error;

[0035] 26. Subtract the synchronization error from the measurement result of any revolution to obtain the asynchronous error of pure axial motion for any revolution. for:

[0036] ,

[0037] Asynchronous motion error of the measured spindle rotating around the X-axis and Y-axis respectively , for:

[0038] ,

[0039] ,

[0040] in, n To measure the total number of revolutions, i Indicates the first i Transfer to measurement, subscript a This indicates asynchronous error.

[0041] Technical effects:

[0042] This invention proposes a multi-probe measurement method for spindle rotation error based on a standard plate. This method uses a standard plate and a displacement sensor for measurement, and performs post-processing on the acquired displacement signals to calculate the spindle rotation error. Compared with existing spindle error measurement methods:

[0043] 1. Simple operation: The position of the standard plate remains unchanged during a continuous measurement process. The initial installation position only needs to be within the measurement area of ​​the displacement sensor. There is no need to adjust the eccentricity of the installation position of the standard plate. The measurement process is fast and efficient.

[0044] 2. The measurement method eliminates the reliance on imported high-precision single-ball standard rods and double-ball standard rods, resulting in low cost. Measurement can be completed using only a standard plate machined by a single-point diamond lathe or optical milling machine, paired with a high-precision displacement sensor. Occasional scratches on the standard plate can also be quickly repaired using a single-point diamond lathe or optical milling machine.

[0045] 3. It can simultaneously measure axial motion error and angular motion error. With just one continuous measurement, the surface shape of the standard plate can be separated and the components of the spindle error can be calculated. Attached Figure Description

[0046] Figure 1 This is a schematic diagram of the measurement principle in step 1 of the present invention.

[0047] Figure 2 This is a flowchart of the overall process for step 2 of the present invention. Detailed Implementation

[0048] To make the technical solution of the present invention clearer, the technical solution of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0049] The specific calculation process for step 21 is as follows:

[0050] right m 1 (θ) , m 2 (θ) , m 3 (θ) Perform weighted summation and construct the weight function. M(θ) :

[0051] ,

[0052] In the formula, a and b These are the weighting coefficients;

[0053] For weight function M(θ) Perform a Fourier transform and rearrange the results to obtain the following:

[0054] ,

[0055] In the formula, j For imaginary part operators, k For Fourier order, P(jk) , z(jk) These are the Fourier coefficients of the residual surface shape and the residual pure axial motion error of the standard flat plate, respectively.

[0056] Performing an inverse Fourier transform on the above Fourier coefficients yields the sum of the residual surface shape of the standard plate and the residual pure axial motion error.

[0057] In the formula, m This represents the highest Fourier order calculated.

[0058] The standard plate 2 is made of aluminum alloy and is machined by a single-point diamond lathe with a machining surface accuracy of less than 50 nanometers; the displacement sensor is a capacitive displacement sensor with a measurement accuracy of nanometer level.

[0059] Furthermore, the standard flat plate 2 can also be made of microcrystalline glass, processed by an optical milling machine, with a surface accuracy of less than 50 nanometers; the displacement sensor adopts a laser displacement sensor, with a measurement accuracy of nanometer level.

[0060] All content not described in detail in this specification belongs to the prior art known to those skilled in the art. Furthermore, for those skilled in the art, there will be changes in specific implementation methods and application scope based on the ideas of this invention. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A multi-probe method for measuring spindle rotation error based on a standard flat plate, characterized in that, Includes the following steps: Step 1: Set up a standard flat plate and displacement sensor and collect initial displacement signals: A standard plate (2) is fixedly installed on the spindle (1) to be tested; Four displacement sensors are non-contactly installed above the end face of a standard plate (2). The axes of the displacement sensors are all perpendicular to the standard plate. The projections of the first displacement sensor probe (31), the second displacement sensor probe (32), and the third displacement sensor probe (33) on the standard plate (2) are located on the same virtual circle with a radius of R. The center of the virtual circle coincides with the rotation center of the measured spindle. The projection of the fourth displacement sensor probe (34) on the standard plate is located at the rotation center of the measured spindle. The line connecting the projection of the first displacement sensor probe (31) and the center of the virtual circle is defined as the X-axis. The angle between the line connecting the projection of the second displacement sensor probe (32) and the center of the virtual circle and the X-axis is φ. The angle between the line connecting the projection of the third displacement sensor probe (33) and the center of the virtual circle and the X-axis is ψ. The spindle under test (1) is driven to rotate at a constant speed. Four displacement sensors continuously and in real time collect multi-rotation displacement signals and transmit them to the signal acquisition and processing system (4). The multi-rotation displacement signals collected by the first displacement sensor probe (31), the second displacement sensor probe (32), the third displacement sensor probe (33), and the fourth displacement sensor probe (34) are filtered to remove the first harmonic and DC components and are respectively denoted as follows: m 1 (θ) , m 2 (θ) , m 3 (θ), m 4 (θ) , ， ， ， ， in, θ The rotation angle of the spindle being measured. P(θ) This refers to the residual surface profile curve at the virtual circumference radius R on a standard flat plate. z(θ) The residual pure axial motion error of the measured spindle rotation center. x(θ) The axial motion error at radius R on the X-axis of the measured spindle is denoted as denoted as . y(θ) This refers to the axial motion error at radius R on the Y-axis of the measured spindle; Step 2: Post-processing data to calculate gyration error: Step 21, for m 1 (θ) , m 2 (θ) , m 3 (θ) Construct the weight function by performing weighted summation. M(θ) , For M(θ) Perform a Fourier transform and rearrange to obtain the Fourier coefficients of the sum of the residual surface profile curve and the residual pure axial motion error at the virtual circumference radius R of the standard plate. Then, perform an inverse Fourier transform on these coefficients to obtain the sum of the residual surface profile curve and the residual pure axial motion error at the virtual circumference radius R of the standard plate. ， in, m To calculate the highest Fourier order, j For imaginary part operators, k For Fourier order, P(jk) , z(jk) These are the Fourier coefficients of the residual surface shape and the residual pure axial motion error of the standard flat plate, respectively. Step 22: The displacement signal of the fourth displacement sensor probe (34) after filtering out the first harmonic and DC components is numerically equivalent to the residual pure axial motion error of the rotation center of the measured spindle. Subtract it from the above calculation results to obtain the residual surface profile curve at the radius R of the standard plate. ， Residual pure axial motion error of the measured spindle rotation center for: ， Step 23: Calculate the axial motion error at radius R on the X and Y axes of the measured spindle: ， or ； Step 24: Calculate the angular motion errors of the measured spindle rotating around the X-axis and Y-axis respectively: ， ， Step 25: Calculate the average value of the multi-rotation measurement results to obtain the pure axial motion synchronization error. for: ， Synchronization error of the angular motion of the measured spindle rotating around the X-axis and Y-axis respectively , for: ， ， in, n To measure the total number of revolutions, i Indicates the first i Transfer to measurement, subscript s Indicates synchronization error; Step 26: Subtract the synchronization error from the measurement result of any revolution to obtain the asynchronous error of pure axial motion for any revolution. for: ， Asynchronous motion error of the measured spindle rotating around the X-axis and Y-axis respectively , for: ， ， in, n To measure the total number of revolutions, i Indicates the first i Transfer to measurement, subscript a This indicates asynchronous error.

2. The multi-probe measurement method for spindle rotation error based on a standard flat plate according to claim 1, characterized in that, The specific calculation process for step 21 is as follows: right m 1 (θ) , m 2 (θ) , m 3 (θ) Perform weighted summation and construct the weight function. M(θ) : ， In the formula, a and b These are the weighting coefficients; For weight function M(θ) Perform a Fourier transform and rearrange the results to obtain the following: ， In the formula, j For imaginary part operators, k For Fourier order, P(jk) , z(jk) These are the Fourier coefficients of the residual surface shape and the residual pure axial motion error of the standard flat plate, respectively. Performing an inverse Fourier transform on the above Fourier coefficients yields the sum of the residual surface shape of the standard plate and the residual pure axial motion error. In the formula, m This represents the highest Fourier order calculated.

3. The multi-probe measurement method for spindle rotation error based on a standard flat plate according to claim 1, characterized in that, The standard plate (2) is made of aluminum alloy and is machined by a single-point diamond lathe. Its machining surface accuracy is below 50 nanometers. The displacement sensor is a capacitive displacement sensor with a measurement accuracy of nanometer level.

4. The multi-probe measurement method for spindle rotation error based on a standard flat plate according to claim 1, characterized in that, The standard flat plate (2) is made of microcrystalline glass and is processed by an optical milling machine. Its surface accuracy is below 50 nanometers. The displacement sensor is a laser displacement sensor with a measurement accuracy of nanometer level.

Images