High-precision large-stroke precision measuring instrument based on wedge air bearing and orthogonal measurement reference

Abstract

The high-precision large-stroke precision measuring instrument based on wedge-shaped air bearings and orthogonal measurement references belongs to precision measuring instruments. The machine body consists of a main frame base, a vertical support column, and a shaft seat to form a frame. A sample fixing seat with a longitudinal laser mirror, a transverse laser mirror, and a vertical laser mirror is longitudinally movably assembled on the main frame base. The vertical shaft is assembled on the transverse guide rail through a vertical movement seat and a transverse movement seat, and a transverse laser interferometer, a longitudinal laser interferometer, a vertical laser interferometer, and a probe can be moved in the transverse and vertical directions through the vertical shaft. The present invention improves the abundant space at the bottom surface of the longitudinal sliding member through a wedge-shaped air bearing structure, and a vertical laser mirror and a vertical laser interferometer are arranged on the bottom surface of the longitudinal sliding member, so that while the present invention has a micro-nano-level measurement accuracy, it also has a large measurement range and can achieve high-precision measurement of large-size micro-nano-level precision parts.

Description

Technical Field

[0001] The present invention belongs to the technical field of precision measurement equipment, and particularly relates to a high-precision large-stroke precision measuring instrument based on wedge air bearings and orthogonal measurement references. Background Art

[0002] In recent years, the progress of microelectronics technology has triggered a miniaturization revolution in many fields. Micro / nano technologies aimed at micron processing, nanostructures, and systems have emerged accordingly, and various micro / nano-level micro-devices have appeared, such as MEMS products like micro-gears, micro-holes, micro-nozzles, and micro-steps.

[0003] When traditional coordinate measuring machines face the measurement scenarios of micro / nano devices with geometric dimensions between dozens of microns and several millimeters and dimensional uncertainties between dozens of nanometers and hundreds of nanometers, the measurement accuracy and measurement size cannot meet the three-dimensional precision measurement requirements of these devices. At the same time, methods such as scanning probe microscopes (SPMs) and laser heterodyne interferometry techniques with resolutions in the nanometer and picometer ranges have small measurement ranges and short probes, and cannot meet the three-dimensional measurement requirements of micro / nano-level devices. Therefore, there is an urgent need in the existing industrial and academic communities for a measurement device that can measure the three-dimensional device size and form and position errors and has a resolution in the micro / nano range to reliably evaluate micro / nano-level devices with complex shapes.

[0004] The invention patent "Small Micro / Nano Coordinate Measuring Machine" (Publication No.: CN104457563A, Li Zhigang) provides a small micro / nano coordinate measuring machine. This invention uses a nano-positioning workbench, a CCD component, and a probe to design a small micro / nano coordinate measuring machine. This micro / nano coordinate measuring machine has a relatively low cost, but it cannot measure the size and form and position errors of parts with complex shapes, nor can it measure large-size micro / nano-level devices. Summary of the Invention

[0005] The purpose of the present invention is to address the problems existing in the above-mentioned prior art, and in combination with the actual needs of current measurement and evaluation of micro / nano-level micro-devices with complex shapes, research and design a new-structured high-precision large-stroke precision measuring instrument based on wedge air bearings and orthogonal measurement references, so as to not only adapt to and meet the micro / nano-level precision measurement of the size and form and position errors of parts with complex shapes, but also achieve the purposes of high measurement accuracy, good measurement repeatability, fast measurement speed, and high efficiency.

[0006] The object of the present invention is achieved as follows: A high-precision large-stroke precision measuring instrument based on wedge air bearings and orthogonal measurement references. A wedge-shaped installation groove is opened at the upper end of the main frame. A longitudinal sliding member that can reciprocate longitudinally is installed at the inner part of the space of the wedge-shaped installation groove. A vertical laser reflector is installed at the bottom of the longitudinal sliding member. A sample fixing seat is fixedly installed on the upper end surface of the longitudinal sliding member. Air bearing surfaces are provided on the inclined surfaces on both sides of the longitudinal sliding member. A transverse laser reflector and a longitudinal laser reflector are vertically installed on the left side in the transverse direction and the rear side in the longitudinal direction of the sample fixing seat. The vertical laser reflector, the transverse laser reflector, and the longitudinal laser reflector are orthogonally arranged in space. A transverse moving seat and a vertical moving seat are installed on the transverse slide rail. The transverse moving seat is installed on the transverse slide rail and can drive the vertical shaft to reciprocate horizontally. A vertical shaft that can reciprocate vertically is installed in the vertical moving seat. A hanging bracket is fixedly installed at the lower end of the vertical shaft. A probe is installed at the lower end of the hanging bracket. A transverse laser interferometer, a longitudinal laser interferometer, and a vertical laser interferometer are fixedly installed on the hanging bracket. The vertical laser reflector, the transverse laser reflector, the longitudinal laser reflector, and the sample fixing seat are located inside the relative space of the hanging bracket. A vertical laser interferometer installed on the hanging bracket is arranged in the space in the middle of the main frame. The laser beams generated by the transverse laser interferometer, the longitudinal laser interferometer, and the vertical laser interferometer are respectively perpendicular to the transverse laser reflector, the longitudinal laser reflector, and the vertical laser reflector in sequence. And the ranging laser beams in the three laser beams converge at the center of the measuring sphere of the probe. Thus, a high-precision large-stroke precision measuring instrument based on wedge air bearings and orthogonal measurement references is formed.

[0007] The present invention uses a laser interferometer to measure the relative displacement between the probe and the workpiece to be measured, and can obtain sub-nanometer measurement accuracy in the XYZ three-axis directions. Its accuracy is much higher than that of traditional dimensional and geometric error measuring instruments, and it has the characteristics of unique, reasonable structure, strong applicability, wide application range, high measurement accuracy, fast speed, and good repeatability.

[0008] Specifically, the technical innovation of the present invention and the good effects produced are as follows:

[0009] 1) In the measurement structure proposed by the present invention, the probe displacement measurement and the probe touch point are on the same straight line. This structure eliminates the first-order measurement error and realizes high measurement accuracy.

[0010] 2) The present invention uses a laser interferometer to detect the relative displacement and relative rotation between the probe and the workpiece to be measured in real time, and compensates the displacement error in real time, so as to realize ultra-high-precision measurement of the geometric errors of the surface of the workpiece to be measured.

[0011] In the sample movement mechanism of the present invention, an ample space is given to the bottom surface of the longitudinal sliding member through a wedge-shaped air-floating structure, and a vertical laser reflector and a vertical laser interferometer are provided on the bottom surface of the longitudinal sliding member. As a result, while the present invention has a micro-nano level measurement accuracy, it also has a large measurement range and can achieve high-precision measurement of large-sized parts with micro-nano level accuracy. Description of the Drawings

[0012] Figure 1 It is a schematic diagram of the overall structure of an embodiment of a high-precision large-stroke precision measuring instrument based on a wedge-shaped air-floating and orthogonal measurement reference;

[0013] Figure 2 It is a schematic diagram of the assembly structure of the probe and the first, second, and third laser interferometers;

[0014] Explanation of the part numbers in the figure: 1-1, transverse slide rail; 1-2, vertical support column; 1-3, main base; 1-4, vertical moving seat; 1-5, transverse moving seat; 1-6, vertical shaft; 2-1, hanging frame; 2-2, probe; 2-3, transverse laser interferometer; 2-4, longitudinal laser interferometer; 2-5, vertical laser interferometer; 3-1, longitudinal laser reflector; 3-2, transverse laser reflector; 3-3, sample fixing seat; 3-4, vertical laser reflector; 3-5, longitudinal sliding member; 3-6, rotating shaft; Detailed Embodiment

[0015] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0016] Embodiment

[0017] The present invention provides a high-precision large-stroke precision measuring instrument based on wedge air-floating and orthogonal measurement benchmarks. A wedge-shaped installation groove is opened at the upper end of the main frame 1-3. A longitudinal sliding member 3-5 that can move longitudinally back and forth is assembled inside the space of the wedge-shaped installation groove. A vertical laser reflector 3-4 is assembled at the bottom of the longitudinal sliding member 3-5. A sample fixing seat 3-3 is fixedly installed on the upper end surface of the longitudinal sliding member 3-5. Air-floating surfaces are provided on both inclined surfaces of the longitudinal sliding member 3-5. A transverse laser reflector 3-2 and a longitudinal laser reflector 3-1 are vertically installed on the left side and the rear side of the sample fixing seat 3-3 respectively. The vertical laser reflector 3-4, the transverse laser reflector 3-2, and the longitudinal laser reflector 3-1 are orthogonally arranged in space. A transverse moving seat 1-5 and a vertical moving seat 1-4 are assembled on the transverse slide rail 1-1. The transverse moving seat 1-5 is assembled on the transverse slide rail 1-1 and can drive the vertical shaft 1-6 to move back and forth horizontally. A vertical shaft 1-6 that can move back and forth vertically is assembled in the vertical moving seat 1-4. A hanging frame 2-1 is fixedly installed at the lower end of the vertical shaft 1-6. A probe 2-2 is installed at the lower end of the hanging frame 2-1. A transverse laser interferometer 2-3, a longitudinal laser interferometer 2-4, and a vertical laser interferometer 2-5 are fixedly installed on the hanging frame 2-1. The vertical laser reflector 3-4, the transverse laser reflector 3-2, the longitudinal laser reflector 3-1, and the sample fixing seat 3-3 are located inside the relative space of the hanging frame 2-1. A vertical laser interferometer 2-5 installed on the hanging frame 2-1 is provided in the middle of the main frame 1-3. The laser rays generated by the transverse laser interferometer 2-3, the longitudinal laser interferometer 2-4, and the vertical laser interferometer 2-5 are perpendicular to the transverse laser reflector 3-2, the longitudinal laser reflector 3-1, and the vertical laser reflector 3-4 respectively, and the ranging laser beams in the three laser rays converge at the center of the measuring sphere of the probe 2-2.

[0018] Further, a rotary shaft 3-6 is installed at the relative inner side of the upper end surface of the longitudinal sliding member 3-5, the transverse laser reflector 3-2, and the longitudinal laser reflector 3-1.

[0019] Further, the vertical laser reflector 3-4, the transverse laser reflector 3-2, and the longitudinal laser reflector 3-1 are made of microcrystalline glass.

[0020] Further, the laser rays emitted by the transverse laser interferometer 2-3, the longitudinal laser interferometer 2-4, and the vertical laser interferometer 2-5 include a ranging function laser beam and an angle measuring function laser beam.

[0021] When the longitudinal sliding member moves longitudinally, or the vertical shaft moves horizontally or vertically, three angular errors will be generated, namely the pitch angle, the yaw angle, and the rotation angle. The pitch angle refers to the angular value r generated by the moving part around the Y axis y , and the rotation angle refers to the angular value r generated by the moving part around the X axis x, the yaw angle refers to the angular value r generated by the moving part around the Z-axis z , during the measurement process of the instrument, it is necessary to compensate for the measurement errors of the three-axis displacement caused by the pitch angle, yaw angle, and rotation angle.

[0022] The compensation process is as follows. During measurement, first, the sample to be measured is fixedly installed on the rotary shaft 3-6. The external input power drives the transverse laser interferometer 2-3, longitudinal laser interferometer 2-4, vertical laser interferometer 2-5, and probe 2-2 to move vertically on the axis seat through the vertical shaft 1-6. Another external input power drives the vertical movement seat 1-4, vertical shaft 1-6, transverse laser interferometer 2-3, longitudinal laser interferometer 2-4, vertical laser interferometer 2-5, and probe 2-2 to move horizontally on the horizontal guide rail through the horizontal movement seat. Another external input power drives the sample fixing seat 3-3, longitudinal laser mirror 3-1, transverse laser mirror 3-2, and vertical laser mirror 3-4 to move longitudinally along the wedge surface of the main frame 1-3 through the longitudinal sliding part 3-5.

[0023] The transverse laser interferometer 2-3 obtains the transverse axis displacement as x″, the pitch angle as ry, and the yaw angle as r z ; the longitudinal laser interferometer 2-4 obtains the longitudinal axis displacement as y″ and the rotation angle r x ; the vertical laser interferometer 2-5 obtains the vertical axis displacement as z″. The measured pitch angle r y , yaw angle r z , rotation angle r x After that, based on the pitch angle, yaw angle, and rotation angle, the supplementary formula is used to compensate the transverse axis displacement x″, longitudinal axis displacement y″, and vertical axis displacement z″, and the compensated transverse axis displacement x′, longitudinal axis displacement y′, and vertical axis displacement z′ are obtained. The supplementary formula is:

[0024]

[0025] When measuring the workpiece to be measured, in the instrument coordinate system, the external input power drives the transverse laser interferometer 2-3, longitudinal laser interferometer 2-4, vertical laser interferometer 2-5, and probe 2-2 to move vertically on the axis seat through the vertical shaft 1-6. Another external input power drives the vertical movement seat 1-4, vertical shaft 1-6, transverse laser interferometer 2-3, longitudinal laser interferometer 2-4, vertical laser interferometer 2-5, and probe 2-2 to move horizontally on the horizontal guide rail through the horizontal movement seat. Another external input power drives the sample fixing seat 3-3, longitudinal laser mirror 3-1, transverse laser mirror 3-2, and vertical laser mirror 3-4 to move longitudinally along the wedge surface of the main frame 1-3 through the longitudinal sliding part 3-5. The probe 2-2 is used to measure the workpiece to be measured. When the probe 2-2 contacts the sample to be measured and the feedback of the probe 2-2 reaches the set threshold, this contact position is the position point to be detected.

[0026] In the coordinate system of the device under test, when the probe 2-2 and the device under test move relative to each other, the compensated lateral axis displacement x′, longitudinal axis displacement y′, and vertical axis displacement z′ can be obtained. Continuously move the probe 2-2 to contact the device under test. When the probe 2-2 contacts the sample to be measured, this contact position is set as the i-th position point to be detected. According to the axial displacements in the lateral, longitudinal, and vertical directions, in the instrument coordinate system, the coordinate values (a i , b i , c i ) of the i-th position point to be detected can be obtained, where i = 1,..., N.

[0027] If the rotary shaft 3-6 is used for cooperative measurement, after the rotary shaft 3-6 drives the device under test to rotate by an angle , move the probe 2-2 again to measure the device under test. According to the axial displacements in the lateral, longitudinal, and vertical directions, the coordinate values (a2 j , b2 j , c2 j ) of the j-th position point to be detected are measured in the instrument coordinate system, where j = N + 1,…, N + K, and N and K are integers.

[0028] Since the rotary shaft 3-6 drives the device under test to rotate, when the probe 2-2 contacts the sample to be measured before rotation, this contact position is set as the i-th position point to be detected, and a set of coordinate values (a i , b i , c i ) are obtained, where i = 1,..., N; after rotation, when the probe 2-2 contacts the sample to be measured, this contact position is set as the j-th position point to be detected, and a new set of coordinate values (a2 j , b2 j , c2 j ) are obtained. The coordinate system where j = N + 1,…, N + K has also changed. The new set of coordinate values (a2 j , b2 j , c2 j ) obtained after rotation, where j = N + 1,…, N + K, need to be processed through the conversion formula to map the two to the same coordinate system, that is, to convert them to the coordinate system of the device under test. The processed coordinate values are (a j , b j , c j ). Among them, the conversion formula is:

[0029]

[0030] The coordinates of several position points to be detected (a j , b j , c j ) and the coordinate values of several position points to be detected (ai , b i , c i ) are combined to finally obtain a set of surface coordinate sets of the workpiece to be measured (a i , b i , c i ), i = 1,..., N + K. In the above, a set of surface coordinates of the workpiece to be measured includes the coordinates of several positions to be detected.

[0031] Based on this set of surface coordinate sets (a i , b i , c i ), i = 1,..., N + K, the dimensions and geometric tolerances of the workpiece to be measured can be quickly evaluated.

[0032] When the rotary shaft 3-6 is not installed, the displacements of each axis, x', y', and z', can be measured by the transverse laser interferometer 2-3, the longitudinal laser interferometer 2-4, and the vertical laser interferometer 2-5. After one qualified contact is determined by the probe, based on the displacements of each axis x', y', and z', through error compensation and data processing, a measurement point coordinate (x, y, z) on the surface of the workpiece to be measured can be obtained. By measuring several measurement points on the surface of the workpiece to be measured, high-precision measurement of the geometric tolerances of the workpiece to be measured with a complex shape can be achieved.

[0033] Among them, the above external driving force is a prior art, which can be the linear motor in the paper "A Biped-Driven Piezoelectric Linear Motor", or other driving motors that can achieve linear movement, and is not limited here.

[0034] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", "front", "rear", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0035] In the description of the present invention, it should be noted that, unless otherwise clearly specified and defined, the terms "installed", "connected", and "coupled" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection, an electrical connection; it may be a direct connection, or an indirect connection through an intermediate medium, and it may be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations. Without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other.

[0036] The above embodiments only represent the implementation manners of the present invention, and the description thereof is relatively specific and detailed, but it should not be construed as a limitation to the scope of the patent of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the appended claims.

Claims

1. A high-precision large-stroke precision measuring instrument based on wedge air bearings and orthogonal measurement references, characterized in that: A wedge-shaped installation groove is opened at the upper end of the main frame (1-3). A longitudinal sliding member (3-5) that can reciprocate longitudinally is assembled inside the space of the wedge-shaped installation groove. A vertical laser reflector (3-4) is assembled at the bottom of the longitudinal sliding member (3-5). A sample fixing seat (3-3) is fixedly installed on the upper end surface of the longitudinal sliding member (3-5). Air-floating surfaces are provided on both inclined surfaces of the longitudinal sliding member (3-5). A transverse laser reflector (3-2) and a longitudinal laser reflector (3-1) are vertically installed on the left side in the transverse direction and the rear side in the longitudinal direction of the sample fixing seat (3-3). The vertical laser reflector (3-4), the transverse laser reflector (3-2), and the longitudinal laser reflector (3-1) are orthogonally arranged in space. A transverse motion seat (1-5) and a vertical motion seat (1-4) are assembled on the transverse slide rail (1-1). The transverse motion seat (1-5) is assembled on the transverse slide rail (1-1) and can drive the vertical shaft (1-6) to reciprocate horizontally. A vertical shaft (1-6) that can reciprocate vertically is assembled in the vertical motion seat (1-4). A hanging bracket (2-1) is fixedly installed at the lower end of the vertical shaft (1-6). A probe (2-2) is installed at the lower end of the hanging bracket (2-1). A transverse laser interferometer (2-3), a longitudinal laser interferometer (2-4), and a vertical laser interferometer (2-5) are fixedly installed on the hanging bracket (2-1). The vertical laser reflector (3-4), the transverse laser reflector (3-2), the longitudinal laser reflector (3-1), and the sample fixing seat (3-3) are located inside the relative space of the hanging bracket (2-1). A vertical laser interferometer (2-5) installed on the hanging bracket (2-1) is arranged in the space in the middle of the main frame (1-3). The laser rays generated by the transverse laser interferometer (2-3), the longitudinal laser interferometer (2-4), and the vertical laser interferometer (2-5) are respectively perpendicular to the transverse laser reflector (3-2), the longitudinal laser reflector (3-1), and the vertical laser reflector (3-4) in sequence. And the ranging laser beams in the three laser rays converge at the measuring ball center of the probe (2-2). The probe (2-2) moves vertically and horizontally, and the sample fixing seat (3-3) moves longitudinally. The lateral laser interferometer (2-3) obtains the lateral axis displacement as x″ and the yaw angle as r y , get the pitch angle as r z ; The longitudinal laser interferometer (2-4) obtains a longitudinal axis displacement of y″ and obtains a rotation angle r x ; The vertical axis displacement z″ is obtained through the vertical laser interferometer (2-5). According to the supplementary formula, the compensated transverse axis displacement x′, longitudinal axis displacement y′, and vertical axis displacement z′ of the measured sample are calculated. The supplementary formula is:

2. The high-precision large-stroke precision measuring instrument based on wedge-shaped air floating and orthogonal measurement reference according to claim 1, characterized in that: A rotating shaft (3-6) is installed at the upper end surface of the longitudinal sliding member (3-5), the relative space inside the transverse laser reflector (3-2), and the longitudinal laser reflector (3-1).

3. The high-precision large-stroke precision measuring instrument based on wedge air bearing and orthogonal measurement reference according to claim 1, characterized in that: The vertical laser reflector (3-4), the transverse laser reflector (3-2), and the longitudinal laser reflector (3-1) are made of microcrystalline glass.

4. The high-precision large-stroke precision measuring instrument based on wedge-shaped air bearings and orthogonal measurement references according to claim 1, wherein: The laser rays emitted by the transverse laser interferometer (2-3), the longitudinal laser interferometer (2-4), and the vertical laser interferometer (2-5) contain multiple laser beams.

5. The high-precision large-stroke precision measuring instrument based on wedge-shaped air-floating and orthogonal measurement reference according to claim 1, characterized in that: The probe (2-2) moves vertically and horizontally, and the sample fixing base (3-3) drives the component to be measured to move longitudinally; the coordinates (a i , b i , c i ) of the i-th position point to be detected are obtained, where i = 1,..., N; The rotating shaft (3-6) drives the sample to be measured to rotate by an angle Rotation angle After that, the probe (2-2) moves vertically and horizontally, and the sample fixing seat (3-3) drives the component to be measured to move longitudinally. The coordinates (a2 j , b2 j , c2 j ) of the j-th position to be detected are obtained in the instrument coordinate system, where j = N+1,...,N+K, and N and K are integers; Convert the surface coordinates (a2 j , b2 j , c2 j ) to the coordinate system of the device under test through the conversion formula, obtaining the coordinates (a j , b j , c j ); where the conversion formula is: Coordinates of several positions to be detected (a j , b j , c j ) and coordinate values of several positions to be detected (a i , b i , c i ) are combined to obtain a set of surface coordinate sets of the workpiece to be measured (a i , b i , c i ), i = 1, ..., N + K.

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