CN102252617A - Morphology registration analysis-based method for detecting precision of precise main shaft rotation - Google Patents

Abstract

The invention provides a precision spindle rotation accuracy detection method based on shape registration analysis. The surface sample is installed on the precision spindle to be tested, and the control system controls the precision spindle to be tested to a position at an angle θ, and the precision spindle to be tested is sequentially collected. The surface topography map of the surface sample at the complete circumferential position; the topography data registration analysis and processing system analyzes the obtained several surface topography maps and evaluates the error. The present invention measures the topography of the surface sample rotating with the precision spindle and performs subsequent topographic registration analysis and processing. The surface sample does not have high precision requirements, and does not require expensive standard outer circular contours or complicated testing systems and testing processes. The two-dimensional shape/image sensor can measure the radial rotation error of the spindle; if the three-dimensional shape measurement sensor is selected, the radial and axial rotation errors of the spindle can be measured at the same time; the high-resolution measurement sensor can realize nanoscale High-precision spindle rotation error detection.

Description

A precision spindle rotation accuracy detection method based on shape registration analysis

technical field

The invention relates to a detection method for the rotation error of a precision main shaft.

Background technique

Precision rotary spindles are key components of precision machining machine tools and testing equipment. With the development of ultra-precision machining and nanotechnology, people have higher and higher requirements for the accuracy of mechanical parts and measuring instruments, especially high-precision rotary parts, such as ultra-precision machine tool spindles, test turntables, laser gyroscope rotors, circular Standards, laser fusion target devices, etc., the manufacturing tolerance is generally between a few nanometers to tens of nanometers, which has reached or exceeded the accuracy level of existing precision roundness instruments (radial rotation error is about 10-50nm) . Improving the rotation accuracy of the spindle to meet the processing requirements of the parts under the limit state and to ensure the accuracy of the measurement results has become a very challenging subject. In addition, since the manufacturing of the components of the precision spindle is also in a state of extreme precision, it is difficult to guarantee it simply by improving the machining accuracy of the spindle components. The error separation and compensation technology is currently recognized as the most effective way to improve the precision spindle rotation accuracy. The rotation error of the precision spindle, especially the static pressure air bearing spindle, is a relatively constant system error under certain working conditions (speed, temperature, etc.), which makes the detection of the precision spindle's rotation error nanometer-level precision a problem to ensure the realization of The key to the separation and compensation of rotation errors and to improve the rotation accuracy of the spindle.

According to the national standard documents, the spindle rotation error refers to the displacement of the instantaneous rotation axis of the spindle relative to the average axis (at the average position of the instantaneous rotation axis). Spindle rotation error can be roughly divided into two basic forms: axial end face runout and radial rotation error (including radial runout and angular swing). The research on precision measurement methods for precision spindle rotation errors can be traced back to the beginning of the 20th century, such as the quantitative test method for machine tool spindles first established by Scheslinger. In the 1950s, Tlustry and Bryan established a complete spindle quantitative testing method and expressed the error results in the polar coordinate system, and became recognized as the founders of modern spindle testing technology. In the 1960s and 1970s, in order to develop ultra-precision machining technology, the Lawrence-Livermore National Laboratory of the United States conducted research on the spindle rotation error, and solved the description and testing of the spindle motion error characteristics, as well as the spindle error motion and workpiece shape. There are three aspects of the relationship between accuracy; Donaldson proposed the error separation theory so that the spindle rotation error is only affected by sensor accuracy, data acquisition and structural design; after several years of work, the International Production Technology Research Association (CIRP) officially established in 1976 Published the document "Unification of Performance Requirements and Error Measurements for Rotary Axes". These documents have become the basis for the establishment of the B89.3.4M international standard in 1985 (the standard was further revised in 2004). After entering the 1990s, a series of high-precision roundness measurement comparisons have been carried out internationally. The participating units include the Italian Metrology Institute (IMGC), Germany (PTB), and British Taylor Hobson, etc. Through these comparisons, the spindle has been further improved. Basic theory of gyration error. In the ISO/FDIS230-7 international standard, the rotary error motion is decomposed into synchronous error motion and asynchronous error motion. In China, the National University Mechanical Engineering Testing Technology Research Association, the Chinese Mechanical Engineering Society, the Mechanical Processing Society and other units have held national academic seminars on high-precision rotary spindle testing since the early 1980s, and the results achieved have greatly promoted my country. The development of the basic theory of spindle rotation error.

In terms of the measurement and analysis methods of the spindle rotation error, the introduction of each new technology has made a great leap forward in the rotation error test work. For example, the digital processing technology and rotary encoders adopted by Vanherck and Peters not only promoted the development of rotary error testing technology, but also were widely used in the manufacture of precision machine tool spindles; Arora and Murthy respectively used resolvers and digital notch filters to process Rotation eccentricity problem; Chapman used capacitive displacement sensor to realize radial, axial and tilt motion error measurement with 5nm resolution; British Professor Whitehouse made a systematic summary of error separation technology in theory, making "multi-step method", "reverse Chetwynd conducted error separation experiments based on the above method, and obtained nanoscale separation repeatability errors; Estler and Donaldson adopted the inversion method measurement technology, which effectively eliminated the rotation error of the spindle, and further explored Relevant theory of multi-probe method and multi-inversion method, separation and compensation of rotation error.

In China, in recent years, research on various measurement methods of gyration errors has also been carried out. For example, the National Defense Science and Technology University Huang Longzheng adopted the two-point method to establish a lathe spindle rotation error test system based on double probes. The two sensors are symmetrically installed and fixed at a distance of 180° in the circumferential direction. When the lathe spindle rotates, the sensor does not move and picks up the signal. Eccentric measures and error separation technology can obtain the rotational error motion of the main shaft, and can obtain the roundness error of the test shaft; Harbin Institute of Technology Tan Jiubin et al. use multiple multi-step methods to identify and separate the circular contour error of the standard instrument and the rotational motion error of the main shaft , which mainly solves the problem of harmonic suppression to eliminate the principle error, and at the same time solves the simplification problem of the error separation process to reduce or eliminate the influence of mechanical, electrical drift and external interference; Shanghai Jiaotong University Li Zijun et al. The online method detects the rotary motion error of the main shaft, uses three sensor probes with different intervals to obtain the measurement data, and reorganizes the data according to the principle of quadratic phase shift, so as to separate the rotary error; Wang Weidong of the University of Science and Technology of China uses digital image processing technology, A set of CCD measurement system for the rotation accuracy of the main shaft is established, and the optical CCD is used to detect the position of the light source installed on the main shaft, and then the motion error amount during the main shaft rotation is obtained, and the data processing and error evaluation are discussed.

In a nutshell, the current measurement methods of spindle rotation error mainly include static measurement method, dynamic multi-probe method, multiple positioning method and optical measurement method. Among them, the static measurement method is a relatively primitive measurement method, which uses a sensor to measure the standard circle profile under the manual slow rotation of the spindle, so the measurement accuracy cannot be further improved. The dynamic multi-probe method uses two or more precision probes to simultaneously measure the same circular profile, which has high measurement efficiency and is suitable for on-line measurement; The application occasions are not as widely used as the multiple positioning method. There are many ways to achieve dynamic multiple positioning, such as two-step method, inversion method, multi-step method, etc. This method is easy to implement and can achieve high separation accuracy of rotation error. There are similar problems in the head method) there is a method error caused by the harmonic suppression problem, which requires further analysis, processing and reconstruction of the measurement data; the optical measurement method can realize a non-contact measurement method without the aid of a standard (ball), using The CCD detects the position of the light source installed on the spindle, and then obtains the runout information when the spindle rotates. However, due to the influence of optical diffraction, this method cannot achieve nanometer-level lateral measurement resolution, so it cannot meet the detection of rotation errors with nanometer-level precision. question. It can be seen that there are still some important theoretical and key technical problems in the precision spindle rotation accuracy level to reach the nanometer level detection.

Contents of the invention

The purpose of the present invention is to solve the problem that the traditional precision spindle rotation error measurement method needs expensive standard outer circle profile or complex test system and testing process, and further provide a precision spindle rotation accuracy detection method based on shape registration analysis.

The purpose of the present invention is achieved through the following technical solutions:

Firstly, install the surface sample on the precision spindle to be tested, and adjust the position of the surface sample so that it is near the center of rotation of the precision spindle to be tested; The measurement range of the shape measurement sensor covers the position of the center of rotation when the surface sample rotates with the precision spindle to be measured; 3. The control system controls the precision spindle to be measured to a certain angular position, and the surface microscopic shape measurement sensor measures a piece of surface shape. Appearance diagram; the control system controls the precision spindle to be measured to a position at an angle θ, and measures a surface topography diagram again; according to the above process, sequentially collect the surface topography diagram of the surface sample of the precision spindle to be measured at a complete circumferential position; 4. The topography data registration analysis and processing system analyzes the obtained surface topography images to obtain the rotation error data of the precision spindle to be tested and perform error evaluation.

Beneficial effects of the present invention: the present invention uses a measurement sensor to measure the topography of the surface sample that rotates with the precision spindle and to perform subsequent topography registration analysis and processing to realize the comprehensive measurement of the precision spindle rotation error data. The measurement method is simple and the surface The sample does not have high precision requirements, and does not require expensive standard outer circular contours or complex testing systems and testing processes. If a two-dimensional shape/image sensor is used, the radial rotation error of the spindle can be measured; if a three-dimensional shape measurement is used The sensor can measure the radial and axial rotation errors of the spindle at the same time; the use of high-resolution (including longitudinal and lateral) measurement sensors can realize the detection of the spindle rotation error with nanometer precision.

Description of drawings

Fig. 1 is a schematic diagram of the measurement principle of the method of the present invention, and Fig. 2 is a schematic diagram of the topography registration analysis of the method of the present invention.

Detailed ways

A preferred embodiment of the present invention is shown in Fig. 1 and Fig. 2, at first, the surface sample 2 is installed on the precision spindle 3 to be measured, and the position of the surface sample 2 is adjusted so that it is near the center of rotation of the precision spindle 3 to be measured; , adjust the position of the surface micro-topography measurement sensor 1 relative to the surface sample 2, so that the measurement range of the surface micro-topography measurement sensor 1 covers the position of the center of rotation when the surface sample 2 rotates with the precision spindle 3 to be measured; 3. Control system 4 Control the precision spindle 3 to be measured to a certain angular position (for example, to the 0° position or the origin position), and measure a surface topography map by the surface microscopic topography measurement sensor 1; the control system 4 controls the precision spindle 3 to be measured to a Angle θ position (a number of positions can be evenly distributed on the circumference according to the equal interval angle), measure a surface topography map again; according to the above process, sequentially collect the surface topography map of the surface sample 2 on the complete circumferential position of the precision spindle 3 to be measured , then these topography maps are actually the same area on the surface sample 2, but with the rotation of the precision spindle 3 to be measured, these topography maps are different in spatial position, but they all include the precision spindle 3 to be measured Slewing error information. 4. Topography data registration analysis and processing system 5 analyzes the obtained surface topography images to obtain the rotation error data of the precision spindle 3 to be measured and perform error evaluation.

The measurement accuracy and measurement error items of the rotation error in the method of the present invention mainly depend on the measurement accuracy and capability of the surface microtopography measurement sensor 1 . If the surface microscopic topography measurement sensor 1 is a two-dimensional topography/image sensor (such as an optical microscope and a CCD system), the present invention can be used to measure the radial rotation error of the precision spindle 3 to be measured; if the surface microscopic topography measurement sensor 1 If it is a three-dimensional shape sensor (such as white light interference microscope and or atomic force microscope system), then the present invention can be used to simultaneously measure the radial and axial rotation errors of the precision spindle 3 to be measured. The measurement accuracy and resolution of the rotation error of the precision spindle 3 to be measured are mainly affected by the accuracy and resolution of the surface microtopography measurement sensor 1 .

The rotation error calculation method based on the topographical data registration analysis is also one of the keys to ensure the acquisition of high-precision precision spindle rotation error data. The specific implementation of the topography data registration analysis and processing system 5 of the method of the present invention is based on three-dimensional (or two-dimensional, for data obtained by two-dimensional sensors) rigid body motion homogeneous coordinate transformation matrix theory for calculation. If the precision spindle is at a certain position, a topography map of the surface sample 2 is obtained, and there is a characteristic point (x ₁ , y ₁ , z ₁ ) on it, after the spindle is rotated by a known angle θ, This feature point is changed to (x ₂ , y ₂ , z ₂ ) on another topography map, and the center of rotation is set at (x _c , y _c , z _c ), then the geometric change relationship of the rigid body rotating around the Z axis ,have

$\left[\begin{array}{c}{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}}\\ {\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}}\\ {\mathrm{<span\; class="notranslate">\; z</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="z\; c"\; filenames="HSA00000466769000011.png"\; state="\{\{state\}\}">z</figure-callout></span><figure-callout\; id="1"\; label="z\; c"\; filenames="HSA00000466769000011.png"\; state="\{\{state\}\}">\; </figure-callout>}}_{\mathrm{<span\; class="notranslate">\; </span>}}\\ \mathrm{<span\; class="notranslate">\; 1</span>}\end{array}\right]<span\; class="notranslate">\; =</span>\left[\begin{array}{cccc}\mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&theta;</span>}& <span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&theta;</span>}& \mathrm{<span\; class="notranslate">\; 0</span>}& \mathrm{<span\; class="notranslate">\; 0</span>}\\ \mathrm{<span\; class="notranslate">\; sin</span>}\mathrm{<span\; class="notranslate">\; \&theta;</span>}& \mathrm{<span\; class="notranslate">\; cos</span>}\mathrm{<span\; class="notranslate">\; \&theta;</span>}& \mathrm{<span\; class="notranslate">\; 0</span>}& \mathrm{<span\; class="notranslate">\; 0</span>}\\ \mathrm{<span\; class="notranslate">\; 0</span>}& \mathrm{<span\; class="notranslate">\; 0</span>}& \mathrm{<span\; class="notranslate">\; 1</span>}& \mathrm{<span\; class="notranslate">\; 0</span>}\\ \mathrm{<span\; class="notranslate">\; 0</span>}& \mathrm{<span\; class="notranslate">\; 0</span>}& \mathrm{<span\; class="notranslate">\; 0</span>}& \mathrm{<span\; class="notranslate">\; 1</span>}\end{array}\right]\left[\begin{array}{c}{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; x</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}}\\ {\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; the\; y</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}}\\ {\mathrm{<span\; class="notranslate">\; z</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="z\; c"\; filenames="HSA00000466769000011.png"\; state="\{\{state\}\}">z</figure-callout></span><figure-callout\; id="1"\; label="z\; c"\; filenames="HSA00000466769000011.png"\; state="\{\{state\}\}">\; </figure-callout>}}_{\mathrm{<span\; class="notranslate">\; </span>}}\\ \mathrm{<span\; class="notranslate">\; 1</span>}\end{array}\right]$

In the above formula, the coordinates and rotation angles of the two corresponding feature points are known, so the coordinates of the rotation center can be calculated. Since only the spatial position of the surface sample 2 changes during the rotation process, the points on the surface topography should revolve around a certain instantaneous center point, so the registration analysis and calculation of multiple feature points on the surface topography can be done. Accurate instantaneous center position of rotation is obtained. The rotation error data of the measured precision spindle 3 at each angular position can be obtained by calculating the change of the instantaneous center of rotation of all the topography diagrams.

The topography data registration analysis processing system 5 of the present invention uses the homogeneous coordinate transformation matrix theory of three-dimensional (or two-dimensional, for data obtained by two-dimensional sensors) rigid body motion to calculate the rotation error data of the precision spindle 3 to be measured. Since only the spatial position of the surface sample 2 changes during the rotation process, the points on the surface topography should rotate around a common point. Therefore, by performing registration analysis and calculation on multiple feature points on the surface topography, accurate The instantaneous center position of the rotation. The rotation error data of the measured spindle can be obtained by calculating the change of the instantaneous center of rotation of the precision spindle at each angular position.

Claims (4)

1. A precision spindle rotation accuracy detection method based on shape registration analysis, characterized in that, at first, the surface sample is installed on the precision spindle to be measured, and the position of the surface sample is adjusted so that it rotates on the precision spindle to be measured Near the center; 2. Adjust the position of the surface micro-topography measurement sensor relative to the surface sample, so that the measurement range of the surface micro-topography measurement sensor covers the position of the center of rotation when the surface sample rotates with the precision spindle to be measured; 3. Control system control When the precision spindle to be measured reaches a certain angle position, a surface topography map is measured by the surface microscopic topography measurement sensor; the control system controls the precision spindle to be measured to a position at an angle θ, and a surface topography map is measured again; according to the above process , sequentially collect the surface topography of the surface sample of the precision spindle to be tested at the complete circumferential position; 4. The topography data registration analysis processing system analyzes the obtained surface topography to obtain the surface topography of the precision spindle to be tested Rotate error data and perform error evaluation. 2. The method according to claim 1, wherein the surface microscopic topography measurement sensor is a two-dimensional topography/image sensor. 3. The method according to claim 2, wherein the surface microscopic topography measuring sensor is a three-dimensional topography sensor. 4. The method according to claim 1, 2 or 3, wherein the topography data registration analysis and processing system uses the homogeneous coordinate transformation matrix theory of three-dimensional rigid body motion to calculate the rotational error data of the precision spindle to be measured.

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