Compact Ultra-Precision Coordinate Measuring Instrument Based on Wedge Air-Floatation and Obliquely-Placed Measurement Reference

Abstract

The present invention relates to a compact ultra-precision coordinate measuring instrument based on wedge-shaped air bearings and an inclined measurement reference, belonging to the technical field of precision measurement equipment; wedge-shaped grooves are provided on the upper end surfaces of the front and rear main seats, and a longitudinal air-bearing slider equipped with a first laser reflection surface, a second laser reflection surface, and a longitudinal laser reflection surface can be longitudinally reciprocally moved and assembled. The longitudinal air-bearing slider is installed inside a semi-circular motion frame, and the semi-circular motion frame equipped with a first laser interferometer, a second laser interferometer, a longitudinal laser interferometer, and a probe can move in the vertical and horizontal directions; at the same time, the position of the probe tip is placed at the center of the semi-circular motion frame, and the ranging laser beams of the first laser interferometer, the second laser interferometer, and the longitudinal laser interferometer converge at the position of the probe tip. Through the above solution, the first-order measurement error is eliminated in the structural design, and it can adapt to and meet the micro-nano level precision measurement of the dimensions and shape and position errors of parts with complex shapes.

Description

Technical Field

[0001] The present invention belongs to the technical field of precision measurement equipment, and mainly relates to a geometric error measuring instrument for evaluating the form and position errors of micro-devices with machining precision in the micro-nano scale. Background Art

[0002] In recent years, the progress of microelectronics technology has triggered a miniaturization revolution in many fields. Against this background, micro / nano technologies aiming at micro-machining, nano-structures and systems have emerged, giving rise to various micro / nano-scale micro-devices, such as MEMS products like micro-gears, micro-holes, micro-nozzles, micro-steps, etc.

[0003] When faced with the measurement scenarios of micro-nano devices with geometric dimensions between dozens of micrometers and several millimeters and dimensional uncertainties between dozens of nanometers and hundreds of nanometers, the measurement accuracy and measurement dimensions of traditional coordinate measuring machines 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 nano and picometer scales have small measurement ranges and short probes, and cannot meet the three-dimensional measurement requirements of micro-nano scale devices. Therefore, there is an urgent need in the existing industrial and academic circles for a measurement device that can measure the three-dimensional device dimensions and form and position errors and has a resolution in the micro-nano scale to reliably evaluate the shape-complex micro-nano scale micro-devices.

[0004] The invention patent "Small Micro-Nano Scale 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 scale coordinate measuring machine. This micro-nano coordinate measuring machine has a relatively low cost, but it cannot measure the dimensions and form and position errors of parts with complex shapes. Summary of the Invention

[0005] Aiming at the problems existing in the above-mentioned prior art, the purpose of the present invention is to provide an internal meshing type inclined orthogonal laser measurement reference form and position dimension comprehensive measuring instrument, which can not only adapt to and meet the micro-nano scale precision measurement of the dimensions 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] To achieve the above-mentioned invention purpose, a technical solution provided by the present invention is as follows: A compact ultra-precision coordinate measuring instrument based on wedge air bearings and an inclined measurement reference, the body structure includes a rear main base, a housing, and a front main base; the housing is symmetrically installed on the left and right at the central inner parts of the front main base and the rear main base; wedge-shaped grooves are provided at the middle positions of the front main base and the rear main base;

[0007] An upright lateral driving mechanism is installed inside the lower end of the rear mainframe base. The upright lateral driving mechanism consists of a lateral linear guide rail, a lateral guide rail mounting platform, an upright linear guide rail, and an upright guide rail mounting platform. The lateral guide rail mounting platform is installed inside the lower end face of the rear mainframe base, and the lateral linear guide rail is installed on the lateral guide rail mounting platform. The upright guide rail mounting platform is installed on the lateral linear guide rail so as to be reciprocally movable horizontally. The upright linear guide rail is fixed to the upright guide rail mounting platform. The lower end plane of the probe module frame is installed on the upright linear guide rail so as to be reciprocally movable vertically.

[0008] On the inner side of the semi-circular inner surface at the upper end of the probe module frame, a first laser interferometer and a second laser interferometer are fixedly installed. The probe is installed on the upper end face of the probe module frame. A hanging bracket is installed at the rear side of the probe module frame, and the longitudinal laser interferometer is fixed by the hanging bracket.

[0009] The longitudinal movement module includes a first laser reflection surface, a second laser reflection surface, a longitudinal laser reflection surface, an air-floating surface, a rotating shaft, a sample fixing surface, and a baffle. The longitudinal movement module is installed inside the wedge-shaped grooves of the front mainframe base and the rear mainframe base so as to be reciprocally movable longitudinally. In the longitudinal movement module, the first laser reflection surface, the second laser reflection surface, and the longitudinal laser reflection surface are perpendicular to each other. Air-floating surfaces are symmetrically arranged on the front side and the rear side of the first laser reflection surface and the second laser reflection surface longitudinally. The middle sections of the first laser reflection surface and the second laser reflection surface without air-floating surfaces are used for reflecting laser light rays.

[0010] The longitudinal movement module is arranged inside the relative space of the probe module frame.

[0011] A longitudinal driving module is arranged at the rear side of the longitudinal movement module. The longitudinal driving module consists of a driving rod and a driving motor. The longitudinal movement module is driven by the longitudinal driving module to move longitudinally along the wedge-shaped grooves of the front mainframe base and the rear mainframe base.

[0012] The laser light rays generated by the first laser interferometer, the second laser interferometer, and the longitudinal laser interferometer are successively distributed perpendicular to the first laser reflection surface, the second laser reflection surface, and the longitudinal laser reflection surface. And the ranging laser beams in the laser light rays converge at the center of the probe tip. The center of the probe tip is located at the center of the semi-circular structure of the probe module frame.

[0013] Preferably, the first laser reflection surface, the second laser reflection surface, and the longitudinal laser reflection surface are made of microcrystalline glass.

[0014] Preferably, the laser light rays generated by the first laser interferometer, the second laser interferometer, and the longitudinal laser interferometer contain multiple laser beams.

[0015] Preferably, a rotating shaft is installed at the middle part of the sample fixing surface and at the inner side part of the relative space of the first laser reflection surface, the second laser reflection surface, and the longitudinal laser reflection surface.

[0016] Preferably, the probe can be in contact with and measure a sample placed on the sample fixation surface of the longitudinal motion module.

[0017] Preferably, the vertical and horizontal driving mechanism drives the probe, the first laser interferometer, the second laser interferometer and the longitudinal laser interferometer to move vertically and horizontally, and the longitudinal driving module controls the longitudinal motion module to move longitudinally;

[0018] The longitudinal laser interferometer obtains a displacement of x″ and a yaw angle of r y , and obtains a pitch angle of r z ;

[0019] The first laser interferometer obtains a displacement of y″ and a rotation angle of r x ;

[0020] The second laser interferometer obtains a vertical axis displacement of z″;

[0021] Calculate the compensated lateral axis displacement x′, longitudinal axis displacement y′, and vertical axis displacement z′ of the measured sample according to the compensation formula;

[0022] The compensation formula is:

[0023]

[0024] Preferably, in the coordinate system of the workpiece to be measured, when measuring the workpiece to be measured, the vertical and horizontal driving mechanism drives the probe, the first laser interferometer, the second laser interferometer and the longitudinal laser interferometer to move vertically and horizontally, and the longitudinal driving module controls the longitudinal motion module to move longitudinally, and the coordinates (a i ′, b i ’, c i ′) of the i-th position point to be detected are obtained, where i = 1,..., N;

[0025] The coordinates (a i ′, b i ′, c i ′) of the i-th position point to be detected, where i = 1,..., N need to be converted to the standard coordinate system through the conversion formula to obtain the coordinates (a i , b i , c i ), where i = 1,..., N,

[0026] The conversion formula is:

[0027] where: θ = -45°

[0028] The rotating shaft drives the workpiece to be measured to rotate by an angle Rotation angle After that, the vertical and horizontal driving mechanism drives the probe, the first laser interferometer, the second laser interferometer and the longitudinal laser interferometer to move in the vertical and horizontal directions, and the longitudinal driving module controls the longitudinal movement module to move longitudinally, and the coordinates (a2 j , b2 j , c2 j ) of the j-th position point to be detected are obtained in the instrument coordinate system, where j = N + 1,..., N + K, and N and K are integers;

[0029] The surface coordinates (a2 j , b2 j , c2 j ) are converted to the standard coordinate system through the conversion formula to obtain the coordinates (a j , b j , c j ); among them, the conversion formula is:

[0030]

[0031] The coordinates (a j , b j , c j ) of a number of position points to be detected and the coordinate values (a i , b i , c i ) of a number of position points to be detected are combined to obtain a set of surface coordinate sets (a i , b i , c i ) of the workpiece to be measured, where i = 1,..., N + K.

[0032] The present invention provides a compact ultra-precision coordinate measuring instrument based on wedge-shaped air bearings and inclined measurement references. Through the structural design that combines the Abbe principle, the Abbe errors in the three-axis directions are eliminated, and a laser interferometer is used to measure the relative displacement and relative rotation between the probe and the workpiece to be measured, and the measurement errors caused by rotation are eliminated in real time. The precision of the present invention 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 precision, fast speed and good repeatability.

[0033] Specifically, the technical innovation and good effects of the present invention are as follows:

[0034] 1) The present invention proposes a design of a triangular pyramid-shaped moving block, and the air-bearing surface is a conical structure, which is simple in processing and assembly and is easy to ensure the movement and assembly precision;

[0035] 2) The probe module framework of the present invention adopts a semi-circular structure design. The probe tip is arranged at the circular part of the semi-circular frame structure, which is simple for debugging and installation, and ensures the assembly accuracy through the structural design;

[0036] 3) The triangular pyramid-shaped moving block and the probe frame of the present invention cooperate to realize that 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.

[0037] 4) 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, which can realize the ultra-high-precision measurement of the shape and position error of the surface of the workpiece to be measured. The present invention proposes a

[0038] In the present invention, the Abbe error in the measurement is eliminated through the structural design, and the measurement accuracy is improved. The relative movement between the probe and the workpiece to be measured is realized through the vertical and horizontal drive mechanism and the longitudinal nano drive motor, and the high-precision measurement of complex parts with a precision in the micro-nano level can be realized. Description of the Drawings

[0039] Figure 1 is a front structural schematic diagram of the compact ultra-precision coordinate measuring instrument based on wedge-shaped air bearings and inclined measurement reference of the present invention

[0040] Figure 2 is a rear structural schematic diagram of the compact ultra-precision coordinate measuring instrument based on wedge-shaped air bearings and inclined measurement reference of the present invention

[0041] Figure 3 is a detailed structural schematic diagram of the protruding inner side of the compact ultra-precision coordinate measuring instrument based on wedge-shaped air bearings and inclined measurement reference of the present invention

[0042] Figure 4 is a detailed structural schematic diagram of the vertical and horizontal drive mechanism of the compact ultra-precision coordinate measuring instrument based on wedge-shaped air bearings and inclined measurement reference of the present invention

[0043] Figure 5 is a detailed structural schematic diagram of the longitudinal motion module of the compact ultra-precision coordinate measuring instrument based on wedge-shaped air bearings and inclined measurement reference of the present invention

[0044] Reference numerals in the drawings:

[0045] 100, Body structure; 110, Rear main base; 120, Outer shell; 130, Front main base; 200, Vertical and horizontal drive mechanism; 210, Horizontal linear guide; 220, Horizontal guide installation platform; 230, Vertical linear guide; 240, Vertical guide installation platform; 300, Longitudinal motion module; 310, First laser reflection surface; 320, Second laser reflection surface; 330, Longitudinal laser reflection surface; 340, Aerostatic surface; 350, Rotating shaft; 360, Sample fixing surface; 370, Baffle; 400, Probe; 410, First laser interferometer; 420, Second laser interferometer; 430, Longitudinal laser interferometer; 440, Probe module frame; 450, Hanging bracket; 500, Longitudinal drive module; 510, Drive rod; 520, Drive motor; Detailed implementation mode

[0046] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described below in conjunction with 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. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0047] Embodiment

[0048] A compact ultra-precision coordinate measuring instrument based on wedge-shaped aerostatic and obliquely arranged measurement reference, the body structure 100 includes a rear main base 110, an outer shell 120, and a front main base 130; the outer shell 120 is symmetrically installed on the left and right at the central inner parts of the front main base 130 and the rear main base 110; wedge-shaped grooves are provided at the middle positions of the front main base 130 and the rear main base 110;

[0049] A vertical and horizontal drive mechanism 200 is installed inside the lower end of the rear main base 110. The vertical and horizontal drive mechanism 200 is composed of a horizontal linear guide 210, a horizontal guide installation platform 220, a vertical linear guide 230, and a vertical guide installation platform 240. The horizontal guide installation platform 220 is installed inside the lower end surface of the rear main base 110, the horizontal linear guide 210 is installed on the horizontal guide installation platform 220, the vertical guide installation platform 240 is installed on the horizontal linear guide 210 so as to reciprocate horizontally, the vertical linear guide 230 is fixed on the vertical guide installation platform 240, and the lower end plane of the probe module frame 440 is installed on the vertical linear guide 230 so as to reciprocate vertically;

[0050] On the inner side of the semi-circular upper end of the probe module frame 440, a first laser interferometer 410 and a second laser interferometer 420 are fixedly installed. The probe 400 is installed on the upper end surface of the probe module frame 440. A hanging bracket 450 is installed at the rear side of the probe module frame 440, and the longitudinal laser interferometer 430 is fixed by the hanging bracket 450;

[0051] The longitudinal movement module 300 includes a first laser reflection surface 310, a second laser reflection surface 320, a longitudinal laser reflection surface 330, an air-floating surface 340, a rotary shaft 350, a sample fixing surface 360, and a baffle 370. The longitudinal movement module 300 is installed in the wedge-shaped grooves of the front main base 130 and the rear main base 110 in a longitudinally reciprocating manner. In the longitudinal movement module 300, the first laser reflection surface 310, the second laser reflection surface 320, and the longitudinal laser reflection surface 330 are perpendicular to each other. Air-floating surfaces 340 are symmetrically arranged on the front and rear sides of the first laser reflection surface 310 and the second laser reflection surface 320 in the longitudinal direction. The middle sections of the first laser reflection surface 310 and the second laser reflection surface 320 without air-floating surfaces are used to reflect laser light rays;

[0052] The longitudinal movement module 300 is arranged inside the relative space of the probe module frame 440;

[0053] A longitudinal drive module 500 is arranged at the rear side of the longitudinal movement module 300. The longitudinal drive module is composed of a drive rod 510 and a drive motor 520. The longitudinal movement module 300 is driven by the longitudinal drive module 500 and moves longitudinally along the wedge-shaped grooves of the front main base 130 and the rear main base 110;

[0054] The laser light rays generated by the first laser interferometer 410, the second laser interferometer 420, and the longitudinal laser interferometer 430 are successively perpendicular to the first laser reflection surface 310, the second laser reflection surface 320, and the longitudinal laser reflection surface 330, and the ranging laser beam in the laser light rays converges at the center of the probe tip of the probe 400. The center of the probe tip of the probe 400 is located at the center of the semi-circular structure of the probe module frame 440;

[0055] Furthermore, the first laser reflection surface 310, the second laser reflection surface 320, and the longitudinal laser reflection surface 330 are made of microcrystalline glass.

[0056] Furthermore, the laser light rays generated by the first laser interferometer 410, the second laser interferometer 420, and the longitudinal laser interferometer 430 include a ranging laser beam and an angle-measuring laser beam.

[0057] Furthermore, a rotary shaft 350 is installed at the middle part of the sample fixing surface 360 and at the inner side of the relative space of the first laser reflection surface 310, the second laser reflection surface 320, and the longitudinal laser reflection surface 330.

[0058] Further, the probe 400 can be brought into contact with a sample placed on the sample fixing surface 360 of the longitudinal movement module 300 for measurement.

[0059] The vertical linear guide 230 and the horizontal linear guide mentioned above are prior arts, which can be "Japanese IKO linear motor workbench", or other workbenches that can achieve the same function, and are not limited herein.

[0060] The longitudinal drive module 500 mentioned above is a prior art, which can be a voice coil motor or other drive modules that can achieve the same function, and are not limited herein.

[0061] When the component under test mounted on the rotary shaft 560 moves horizontally or longitudinally, or when the vertical shaft moves vertically, three angular errors will be generated, namely pitch angle, yaw angle, and rotation angle. The pitch angle refers to the angular value r generated by the probe assembly around the axis perpendicular to the first laser reflector. y The rotation angle refers to the angular value r generated by the probe assembly around the axis perpendicular to the longitudinal laser reflector. x The yaw angle refers to the angular value r generated by the probe assembly around the axis perpendicular to the second laser reflector. 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.

[0062] The compensation process is as follows. The vertical and horizontal drive mechanism 200 drives the probe 400, the first laser interferometer 410, the second laser interferometer 420, and the longitudinal laser interferometer 430 to move vertically and horizontally, and the longitudinal drive module 500 controls the longitudinal movement module 300 to move longitudinally; the longitudinal laser interferometer 430 obtains a displacement of x″ and a yaw angle of r y and obtains a pitch angle of r z ; the first laser interferometer 410 obtains a displacement of y″ and a rotation angle r x ; the second laser interferometer 420 obtains a displacement of z″ by; calculates the compensated lateral axis displacement x′, longitudinal axis displacement y′, and vertical axis displacement z′ of the measured sample according to the compensation formula; the compensation formula is:

[0063]

[0064] Further, when measuring the workpiece to be measured in the coordinate system of the workpiece to be measured, the vertical and horizontal driving mechanism 200 drives the probe 400, the first laser interferometer 410, the second laser interferometer 420 and the longitudinal laser interferometer 430 to move vertically and horizontally, and the longitudinal driving module 500 controls the longitudinal movement module 300 to move longitudinally. Displacements are obtained based on the first laser interferometer 410, the second laser interferometer 420 and the longitudinal laser interferometer 430, and the coordinates (a i ′, b i ′, c i ′) of the i-th position point to be detected in the coordinate system of the workpiece to be measured are obtained, where i = 1,..., N;

[0065] The coordinates (a i ′, b i ′, c i ′) of the i-th position point to be detected, where i = 1,..., N, need to be converted to the standard coordinate system through conversion formula 1 to obtain the coordinates (a i , b i , c i ), where i = 1,..., N.

[0066] The conversion formula 1 is:

[0067] where: θ = -45°

[0068] If the rotary shaft 430 is used for cooperative measurement, the rotary shaft 350 drives the workpiece to be measured to rotate by an angle Rotation angle After that, the vertical and horizontal driving mechanism 200 drives the probe 400, the first laser interferometer 410, the second laser interferometer 420 and the longitudinal laser interferometer 430 to move vertically and horizontally, and the longitudinal driving module 500 controls the longitudinal movement module 300 to move longitudinally. The coordinates (a2 j , b2 j , c2 j ) of the j-th position point to be detected are obtained in the coordinate system of the workpiece to be measured, where j = N + 1,..., N + K, and N and K are integers;

[0069] Since the rotary shaft 430 drives the workpiece to be measured to rotate, when the probe 400 contacts the workpiece to be measured before rotation, the 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 400 contacts the workpiece to be measured, the contact position is set as the j-th position point to be detected, and this set of new coordinate values (a2 j , b2 j , c2j ) When \(j = N + 1,\cdots,N + K\), the coordinate system also changes. It is necessary to process this set of new coordinate values \((a_2\) j , \(b_2\) j , \(c_2\) j ) obtained after rotation, where \(j = N + 1,\cdots,N + K\), through the conversion formula, and convert the surface coordinates \((a_2\) j , \(b_2\) j , \(c_2\) j ) to the standard coordinate system to obtain the coordinates \((a\) j , \(b\) j , \(c\) j ). Among them, the conversion formula 2 is:

[0070]

[0071] Combine the coordinates \((a\) j , \(b\) j , \(c\) j ) of several position points to be detected and the coordinate values \((a\) i , \(b\) i , \(c\) i ) of several position points to be detected to obtain a set of surface coordinate sets \((a\) i , \(b\) i , \(c\) i ) of the workpiece to be measured, where \(i = 1,\cdots,N + K\).

[0072] If the rotation axis 430 is not used, according to the first laser interferometer 410, the second laser interferometer 420 and the longitudinal laser interferometer 430, the displacements of each axis can be measured as \(x'\), \(y'\), \(z'\). After the probe determines a qualified contact once, based on the displacements \(x'\), \(y'\), \(z'\) of each axis, 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 shape and position errors of the workpiece to be measured with a complex shape can be realized.

[0073] 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 the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It 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, so it cannot be understood as a limitation of the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0074] 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 can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can 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.

[0075] The above-described embodiments only express the implementation manners of the present invention, and the description thereof is relatively specific and detailed, but it cannot be construed as a limitation to the scope of the patent of the present invention. It should be noted 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 should be subject to the appended claims.

Claims

1. A compact ultra-precision coordinate measuring instrument based on wedge-shaped air bearings and an inclined measurement reference, characterized in that: The body structure (100) includes a rear main base (110), a housing (120), and a front main base (130); the housing (120) is symmetrically installed on the left and right at the central inner part of the front main base (130) and the rear main base (110); wedge-shaped grooves are provided at the middle positions of the front main base (130) and the rear main base (110). A vertical and horizontal driving mechanism (200) is installed inside the lower end of the rear main base (110). The vertical and horizontal driving mechanism (200) is composed of a horizontal linear guide (210), a horizontal guide installation platform (220), a vertical linear guide (230), and a vertical guide installation platform (240). The horizontal guide installation platform (220) is installed inside the lower end face of the rear main base (110), and the horizontal linear guide (210) is installed on the horizontal guide installation platform (220). The vertical guide installation platform (240) is installed on the horizontal linear guide (210) to be reciprocally movable horizontally. The vertical linear guide (230) is fixed on the vertical guide installation platform (240). The lower end plane of the probe module frame (440) is installed on the vertical linear guide (230) to be reciprocally movable vertically. A first laser interferometer (410) and a second laser interferometer (420) are fixedly installed on the inner side of the upper semi-circular surface of the upper end of the probe module frame (440). The probe (400) is installed on the upper end face of the probe module frame (440). A hanging bracket (450) is installed at the rear side of the probe module frame (440), and the longitudinal laser interferometer (430) is fixed by the hanging bracket (450). The longitudinal motion module (300) includes a first laser reflection surface (310), a second laser reflection surface (320), a longitudinal laser reflection surface (330), an air floating surface (340), a rotating shaft (350), a sample fixing surface (360), and a baffle (370). The longitudinal motion module (300) is installed inside the wedge-shaped grooves of the front main base (130) and the rear main base (110) to be reciprocally movable longitudinally. The first laser reflection surface (310), the second laser reflection surface (320), and the longitudinal laser reflection surface (330) in the longitudinal motion module (300) are perpendicular to each other. Air floating surfaces (340) are symmetrically provided on the front and rear sides of the first laser reflection surface (310) and the second laser reflection surface (320) longitudinally. The middle sections of the first laser reflection surface (310) and the second laser reflection surface (320) without air floating surfaces are used to reflect laser light rays. The longitudinal motion module (300) is arranged inside the relative space of the probe module frame (440). A longitudinal driving module (500) is provided at the rear side of the longitudinal motion module (300). The longitudinal driving module is composed of a driving rod (510) and a driving motor (520). The longitudinal motion module (300) is driven by the longitudinal driving module (500) to move longitudinally along the wedge-shaped grooves of the front main base (130) and the rear main base (110). The first laser interferometer (410), the second laser interferometer (420), and the longitudinal laser interferometer (430) generate laser beams that are successively perpendicular to the first laser reflection surface (310), the second laser reflection surface (320), and the longitudinal laser reflection surface (330), and the ranging laser beams in the laser beams converge at the center of the probe head of the probe (400). The center of the probe head of the probe (400) is located at the center of the semicircular structure of the probe module frame (440).

2. The compact ultra-precision coordinate measuring instrument based on wedge air floatation and inclined measurement reference according to claim 1, characterized in that: The first laser reflection surface (310), the second laser reflection surface (320), and the longitudinal laser reflection surface (330) are made of glass ceramics.

3. The compact ultra-precision coordinate measuring instrument based on wedge-shaped air bearings and an inclined measurement reference according to claim 1, wherein: The laser beams generated by the first laser interferometer (410), the second laser interferometer (420), and the longitudinal laser interferometer (430) include multiple laser beams.

4. The compact ultra-precision coordinate measuring instrument based on wedge-shaped air bearings and an inclined measurement reference according to claim 1, characterized in that: A rotary shaft (350) is installed at the middle part of the sample fixing surface (360), and at the inner side of the relative space of the first laser reflection surface (310), the second laser reflection surface (320), and the longitudinal laser reflection surface (330).

5. The compact ultra-precision coordinate measuring instrument based on wedge-shaped air bearings and an inclined measurement reference according to claim 1, wherein: The probe (400) can be brought into contact with the sample placed on the sample fixing surface (360) of the longitudinal motion module (300) for measurement.

6. The compact ultra-precision coordinate measuring instrument based on wedge air bearings and inclined measurement reference according to claim 1, characterized in that: The vertical and horizontal drive mechanism (200) drives the probe (400), the first laser interferometer (410), the second laser interferometer (420), and the longitudinal laser interferometer (430) to move vertically and horizontally, and the longitudinal drive module (500) controls the longitudinal motion module (300) to move longitudinally; The longitudinal laser interferometer (430) obtains a displacement of x″ and obtains a yaw angle of r y , and obtains a pitch angle of r z ; The first laser interferometer (410) obtains a displacement of y″ and obtains a rotation angle r x ; The second laser interferometer (420) obtains the displacement of the vertical axis as z″; Calculate the compensated lateral axis displacement x′, longitudinal axis displacement y′, and vertical axis displacement z′ of the measured sample according to the compensation formula; The compensation formula is:

7. The compact ultra-precision coordinate measuring instrument based on wedge air bearings and inclined measurement reference according to claim 1, characterized in that: When measuring the device under test in the coordinate system of the device under test, the vertical and horizontal drive mechanism (200) drives the probe (400), the first laser interferometer (410), the second laser interferometer (420), and the longitudinal laser interferometer (430) to move vertically and horizontally, and the longitudinal drive module (500) controls the longitudinal movement module (300) to move longitudinally to obtain the coordinates (a i ′, b i ′, c i ′) of the i-th position point to be detected, where i = 1,..., N; The coordinates (a i ′, b i ′, c i ′) of the i-th position point to be detected, where i = 1,..., N, need to be transformed into the standard coordinate system through the transformation formula (1) to obtain the coordinates (a i , b i , c i ), i = 1,..., N. The conversion formula (1) is as follows: Where: θ = -45° The rotating shaft (350) drives the sample to be measured to rotate by an angle Rotation angle After that, the vertical and horizontal driving mechanism (200) drives the probe (400), the first laser interferometer (410), the second laser interferometer (420) and the longitudinal laser interferometer (430) to move vertically and horizontally. The longitudinal driving module (500) controls the longitudinal movement module (300) to move longitudinally, and the coordinates (a2 j , b2 j , c2 j ) of the j-th position point 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 standard coordinate system through the conversion formula to obtain the coordinates (a j , b j , c j ); where the conversion formula (2) 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 coordinates of the workpiece to be measured (a i , b i , c i ) i = 1,..., N + K.

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