Multi-degree-of-freedom laser interferometer measurement test evaluation standard device and working method thereof

Abstract

The invention relates to the technical field of measuring instrument metering and testing, in particular to a multi-degree-of-freedom laser interferometer metering and testing evaluation standard device and a working method thereof. A dual-frequency laser and an optical fiber coupling unit are used for providing a light reference and a voltage reference for a measuring unit; the measuring unit is used for measuring a deflection angle, a pitch angle, a roll angle, horizontal displacement and vertical displacement; the displacement / angle generation unit is used for providing a deflection angle, a pitch angle, a roll angle, displacement in the horizontal direction and displacement in the vertical direction; and the upper computer is connected with the output ends of the double-frequency laser and the optical fiber coupling unit, and is used for decoding, analyzing, displaying and storing the measured data. According to the invention, key metrological characteristics such as a three-degree-of-freedom angle measurement precision index, a measurement range index, a two-degree-of-freedom in-plane displacement measurement precision index, a measurement range index and the like of the high-precision integrated multi-degree-of-freedom laser interferometer can be systematically and accurately metered, tested and evaluated.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of measuring instrument metrology testing, and particularly relates to a multi-degree-of-freedom laser interferometer metrology testing evaluation standard device and a working method thereof. BACKGROUND

[0002] With the increasing demand for high-precision manufacturing and scientific research, integrated multi-degree-of-freedom laser interferometer measurement instruments are increasingly widely used in precision manufacturing, large device assembly, and high-end scientific research. The instrument can accurately measure angles and straightness, and can simultaneously perform high-precision angle and displacement measurement, which plays a key role in ensuring and improving the precision of mechanical processing, the precision of large device assembly, and the accuracy of scientific experimental data. As an important precision measuring instrument, the high-precision integrated multi-degree-of-freedom laser interferometer measurement instrument, with its ability to accurately measure angles and straightness, plays an indispensable role in precision manufacturing, large device assembly, and high-end scientific research, and is of great significance to ensuring and improving the precision of mechanical processing, the precision of large device assembly, and the accuracy of scientific experimental data.

[0003] However, in order to ensure the accuracy and reliability of the measurement results of the high-precision integrated multi-degree-of-freedom laser interferometer, it is necessary to accurately test various metrological characteristic parameters of the instrument, such as angle measurement accuracy, straightness measurement accuracy, and measurement range. Only through scientific and rigorous metrological testing can the accuracy and reliability of the instrument's value traceability in actual application be ensured.

[0004] However, there is a lack of standard devices for calibrating such instruments in the prior art. This results in a lack of unified, standardized, and accurate metrological testing methods and standards for the metrological characteristics of integrated multi-degree-of-freedom laser interferometers in actual applications, making it difficult to effectively guarantee the use effect and measurement result reliability of the instrument. SUMMARY

[0005] The present application aims to at least solve one of the technical problems existing in the prior art. To this end, one object of the present application is to provide a multi-degree-of-freedom laser interferometer metrology testing evaluation standard device and a working method thereof. The present application systematically tests and evaluates the key metrological characteristics of the integrated multi-degree-of-freedom laser interferometer measurement instrument, such as angle measurement error and straightness measurement error, to ensure the accuracy and reliability of its value traceability in actual application.

[0006] To achieve the above object and other related objects, the present application provides a multi-degree-of-freedom laser interferometer metrology testing evaluation standard device, comprising:

[0007] The double-frequency laser and the fiber coupling unit are used for providing light reference and voltage reference for the measuring unit, and are in communication connection with the measuring unit and the displacement / angle generating unit.

[0008] The measuring unit is used for measuring the yaw angle, the pitch angle, the roll angle, the horizontal displacement and the vertical displacement.

[0009] The displacement / angle generating unit is used for providing the motion of the yaw angle, the pitch angle, the roll angle, the horizontal displacement and the vertical displacement.

[0010] The double-frequency laser and the fiber coupling unit are also used for receiving and converting the measurement data of the measuring unit.

[0011] The upper computer is connected with the output end of the double-frequency laser and the fiber coupling unit, and is used for decoding, analyzing, displaying and saving the measurement data.

[0012] In an embodiment of the present application, the double-frequency laser and the fiber coupling unit comprise a He-Ne double-frequency laser, a coupling lens C-Lens, a fiber coupling mechanism and a polarization maintaining fiber PMF, the He-Ne double-frequency laser is used for outputting orthogonal linearly polarized light, the orthogonal linearly polarized light sequentially passes through the coupling lens C-Lens, the fiber coupling mechanism and enters the polarization maintaining fiber PMF, and is then output to the measuring unit.

[0013] In an embodiment of the present application, the measuring unit comprises:

[0014] The first laser collimator is used for receiving the orthogonal linearly polarized light output by the polarization maintaining fiber PMF, and collimates the orthogonal linearly polarized light into measuring collimated light;

[0015] The light splitting prism is used for receiving the measuring collimated light output by the first laser collimator, and splits the measuring collimated light into two beams, one beam of light passes through a polarizer and is received by a first photoelectric detector to generate an interference signal as a reference signal of angle measurement; the other beam of light passes through the polarizing beam splitter and is split into transmitted light and reflected light;

[0016] The right-angle prism is used for receiving the reflected light, the reflected light is reflected after passing through the right-angle prism, enters the double-angle pyramid prism together with the transmitted light of the polarizing beam splitter, and returns to the measuring unit, the two beams of returned light converge in the polarizing beam splitter, pass through the polarizer and are received by a second detector to generate an interference signal as an angle measurement signal; the reference signal and the angle measurement signal are used for calculating angle information;

[0017] A second laser collimator is used for receiving the orthogonal linearly polarized light output by the PMF, and the first laser collimator collimates the orthogonal linearly polarized light into measurement collimated light rays, which are reflected back onto a four-quadrant detector after being incident on a corner cube prism in the displacement / angle generating unit;

[0018] The corner cube prism is used for generating a displacement of the light spots on the four-quadrant detector simultaneously when a relative displacement is generated between the measurement collimated light rays, and the amount of displacement is calculated according to the amount of displacement.

[0019] In an embodiment of the present application, the displacement / angle generating unit comprises:

[0020] A roll angle sensing component is arranged on a platform on which the measurement unit is arranged, and the roll angle sensing component is arranged along a first direction;

[0021] A pitch angle sensing component is arranged on the platform on which the measurement unit is arranged, and the pitch angle sensing component is arranged along a second direction, and the first direction is perpendicular to the second direction;

[0022] A horizontal and vertical direction straightness offset sensing component is arranged on the platform on which the measurement unit is arranged, and the horizontal and vertical direction straightness offset sensing component is arranged along the second direction;

[0023] A yaw angle sensing component is arranged on the platform on which the measurement unit is arranged, and the yaw angle sensing component is arranged along the second direction;

[0024] A corner cube prism is arranged on the roll angle sensing component, the pitch angle sensing component, the horizontal and vertical direction straightness offset sensing component, and the yaw angle sensing component, respectively, and the corner cube prism is used for returning the measurement collimated light rays emitted by the measurement unit to the measurement unit to identify the yaw angle, the pitch angle, the roll angle, the horizontal direction displacement, and the vertical direction displacement.

[0025] In an embodiment of the present application, the host computer is further used for connecting a serial port module.

[0026] In an embodiment of the present application, the host computer is further used for connecting a USB module.

[0027] In an embodiment of the present application, the displacement / angle generating unit is a five-degree-of-freedom laser interferometer mounting platform.

[0028] The present application further provides a working method of a multi-degree-of-freedom laser interferometer metrological test evaluation standard device, comprising:

[0029] S1, providing light reference and voltage reference for the measurement unit by a dual-frequency laser and a fiber coupling unit;

[0030] S2. The yaw angle, pitch angle, roll angle, horizontal displacement, and vertical displacement are measured using the measurement unit.

[0031] S3. Provides yaw angle, pitch angle, roll angle, horizontal displacement, and vertical displacement motion through displacement / angle generation unit;

[0032] S4. Receive and convert the measurement data from the measurement unit through a dual-frequency laser and an optical fiber coupling unit;

[0033] S5. The measurement data is decoded, analyzed, displayed, and saved by the host computer.

[0034] In one embodiment of the present invention, step S2, which involves measuring the yaw angle, pitch angle, roll angle, horizontal displacement, and vertical displacement using a measuring unit, includes:

[0035] S21. The orthogonally linearly polarized light output from the polarization-maintaining fiber PMF is received through the first laser collimator, and the first laser collimator collimates the orthogonally linearly polarized light into a measurement collimated light.

[0036] S22. The measurement collimated light output from the first laser collimator is received by a beam splitter, and the measurement collimated light is split into two beams. One beam is received by the first photodetector after passing through a polarizer, generating an interference signal, which serves as a reference signal for angle measurement. The other beam is split into transmitted light and reflected light after passing through a polarizing beam splitter.

[0037] S23. The reflected light is received by a right-angle prism. After being reflected by the right-angle prism, the reflected light, together with the transmitted light from the polarizing beam splitter, enters the bicornuate prism and returns to the measurement unit. The two returning beams converge in the polarizing beam splitter, pass through a polarizer, and are received by the second detector, generating an interference signal, which serves as the angle measurement signal. The reference signal and the angle measurement signal are used to calculate the angle information.

[0038] S24. The first laser collimator receives the orthogonally linearly polarized light output from the polarization-maintaining fiber PMF through the second laser collimator. The first laser collimator collimates the orthogonally linearly polarized light into a measurement collimated light ray. The measurement collimated light ray is incident on the corner prism in the displacement / angle generating unit and then reflected back to the four-quadrant detector.

[0039] S25. When a relative displacement occurs between the corner prism and the collimating light beam, the light spot on the four-quadrant detector will also be displaced synchronously. The change in relative position is calculated based on the displacement, which is used to measure the yaw angle, pitch angle, roll angle, horizontal displacement, and vertical displacement.

[0040] As described above, the multi-degree-of-freedom laser interferometer metrological test evaluation standard device and the working method thereof have the following beneficial effects:

[0041] (1) The multi-degree-of-freedom laser interferometer metrological test evaluation standard device adopts the technical route combining the laser heterodyne interferometry principle and the laser collimation measurement principle, can perform systematic and accurate metrological test evaluation on key metrological characteristics such as the three-degree-of-freedom angle measurement precision index, the measurement range index, and the two-degree-of-freedom in-plane displacement measurement precision index, and the measurement range index of the high-precision integrated multi-degree-of-freedom laser interferometer. This makes the accuracy and reliability of the measurement results of the instrument in practical application be strongly guaranteed, provides solid and reliable measurement data support for the fields of precision manufacturing, large device assembly, and high-end scientific research, and greatly reduces the risk of production accidents and experimental deviation caused by measurement errors.

[0042] (2) The multi-degree-of-freedom laser interferometer metrological test evaluation standard device provides accurate and standardized standards for the value traceability of the integrated multi-degree-of-freedom laser interferometer in actual use. The measurement value of the instrument can be traced back to the standard system established by the standard device, avoiding the problem of inaccurate and unreliable value caused by the lack of standard devices, ensuring that the measurement results have good consistency and comparability between different times, different places, and different instruments, and improving the credibility and effectiveness of the measurement data of the entire industry.

[0043] (3) The multi-degree-of-freedom laser interferometer metrological test evaluation standard device establishes a scientific and reasonable metrological test evaluation method and standard, provides unified specifications and guidance for the design, production, use, and maintenance of the integrated multi-degree-of-freedom laser interferometer. Promotes relevant enterprises to follow standardized requirements in the product research and development and production process, improves product quality and technical level, promotes the standardization and standardization development of the entire industry, and is conducive to forming a healthy and orderly market competition environment. BRIEF DESCRIPTION OF DRAWINGS

[0044] Figure 1 A structural block diagram of a multi-degree-of-freedom laser interferometer metrological test evaluation standard device provided for the embodiments of the present application.

[0045] Figure 2 A calibration process schematic diagram of a multi-degree-of-freedom laser interferometer metrological test evaluation standard device provided for the embodiments of the present application.

[0046] Figure 3 A dual-frequency laser interference angle measurement principle of a multi-degree-of-freedom laser interferometer metrological test evaluation standard device provided for the embodiments of the present application.

[0047] Figure 4 A two-degree-of-freedom displacement simultaneous measurement method schematic diagram of a multi-degree-of-freedom laser interferometer metrology test evaluation standard device provided for an embodiment of the present application.

[0048] Figure 5 A general measurement principle diagram of a multi-degree-of-freedom laser interferometer metrology test evaluation standard device provided for an embodiment of the present application.

[0049] Figure 6 A QD and tilt angle sensor light spot position real-time display effect diagram of a multi-degree-of-freedom laser interferometer metrology test evaluation standard device provided for an embodiment of the present application.

[0050] Figure 7 A structure schematic diagram of a multi-degree-of-freedom laser interferometer metrology test evaluation standard device provided for an embodiment of the present application.

[0051] Figure 8 A roll angle sensing component schematic diagram of a multi-degree-of-freedom laser interferometer metrology test evaluation standard device provided for an embodiment of the present application.

[0052] Figure 9 A pitch angle sensing component schematic diagram of a multi-degree-of-freedom laser interferometer metrology test evaluation standard device provided for an embodiment of the present application.

[0053] Figure 10 A horizontal and vertical direction straightness offset amount sensing component schematic diagram of a multi-degree-of-freedom laser interferometer metrology test evaluation standard device provided for an embodiment of the present application.

[0054] Figure 11 A yaw angle sensing component schematic diagram of a multi-degree-of-freedom laser interferometer metrology test evaluation standard device provided for an embodiment of the present application. DETAILED DESCRIPTION

[0055] The present application is described and explained more fully with reference to the following detailed description. Other advantages of the present application will be more fully understood in view of the detailed description and drawings.

[0056] It should be noted that the drawings provided in the following embodiments only schematically illustrate the basic concept of the present application, and only show the components related to the present application in the drawings, not the number, shape and size of the components when actually implemented. The actual implementation of each component may be arbitrarily changed in type, number and proportion, and the component layout pattern may be more complex.

[0057] Terms such as first or second can be used to describe various components, but the components are not limited by the above terms. The above terms are used to distinguish one component from another component, for example, a first component can be referred to as a second component, and likewise, a second component can be referred to as a first component, without departing from the scope of the concept according to the present disclosure.

[0058] In addition, "connected / coupled" means that one component is electrically coupled directly to another component or indirectly through another component. The singular form can include the plural form as long as the context does not clearly indicate otherwise. In addition, "comprise / comprising" or "include / including" used in the specification means that one or more components, steps, operations, and elements exist or have been added. The specific structure or function description of the example of the embodiment disclosed in the specification is merely exemplified to describe the example of the embodiment according to the concept, and the example of the embodiment according to the concept can be implemented in various forms, but the description is not limited to the example of the embodiment described in the specification.

[0059] According to the concept, various modifications and changes can be applied to the example of the embodiment, so that the example of the embodiment will be illustrated in the drawings and described in the specification. However, the example of the embodiment according to the concept is not limited to the specific embodiment, but includes all changes, equivalents, or substitutions included in the spirit and technical scope of the disclosure.

[0060] It should be understood that when an element is described as "coupled" or "connected" to another element, it can be directly coupled or connected to the other element, or can be coupled or connected to the other element through a third element. Conversely, it should be understood that when an element is referred to as "directly connected to" or "directly coupled to" another element, no other element is interposed therebetween. Other expressions describing the relationship between components, i.e., "between" and "directly between" or "adjacent to" and "directly adjacent to", need to be interpreted in the same way.

[0061] The terms used in the specification are used only to describe the specific example of the embodiment, and are not intended to limit the disclosure. If there is no explicit opposite meaning in the context, the singular form can include the plural form. In the specification, it should be understood that the term "include" or "have" indicates the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, but cannot preclude the possibility of existence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0062] If there is no contrary definition, all terms (including technical terms or scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art. If terms defined in a commonly used dictionary are not clearly defined in the specification, they should be interpreted as having the same meaning as in the context of the relevant technology, not as an ideal or overly formal meaning.

[0063] Descriptions of well-known components and processing techniques can be omitted so as not to unnecessarily obscure the embodiments of the present disclosure.

[0064] Throughout the specification, the same reference numerals refer to the same elements throughout the specification. Therefore, even if the reference numerals are not mentioned or described with reference to one drawing, the reference numerals can be mentioned or described with reference to another drawing. In addition, even if the reference numerals are not shown in one drawing, the reference numerals can be mentioned or described with reference to another drawing.

[0065] In addition, the logic level of a signal can be different or opposite from the described logic level. For example, a signal described as having a logic 'high' level can alternatively have a logic 'low' level, and a signal described as having a logic 'low' level can alternatively have a logic 'high' level.

[0066] The embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. However, those of ordinary skill in the art can understand that in the embodiments of the present disclosure, many technical details are presented in order to enable the reader to better understand the present disclosure. However, the technical solutions claimed by the present disclosure can be implemented even without these technical details and various changes and modifications based on the following embodiments.

[0067] Please refer to Figure 1 , Figure 2 , Figure 1 A structural block diagram of a multi-degree-of-freedom laser interferometer metrology test evaluation standard device provided by an embodiment of the present application. Figure 2The application provides a calibration process schematic diagram of a multi-degree-of-freedom laser interferometer measurement test evaluation standard device. The application provides a multi-degree-of-freedom laser interferometer measurement test evaluation standard device, which comprises a double-frequency laser and a fiber coupling unit, a measurement unit, a displacement / angle generating unit and an upper computer, the double-frequency laser and the fiber coupling unit are used for providing light reference and voltage reference for the measurement unit, the double-frequency laser and the fiber coupling unit are in communication connection with the measurement unit, and the double-frequency laser and the fiber coupling unit are in communication connection with the displacement / angle generating unit; the measurement unit is used for measuring yaw angle, pitch angle, roll angle, horizontal direction displacement and vertical direction displacement; the displacement / angle generating unit is used for providing yaw angle, pitch angle, roll angle, horizontal direction displacement and vertical direction displacement movement; the double-frequency laser and the fiber coupling unit are also used for receiving and converting measurement data of the measurement unit; the upper computer is connected with an output end of the double-frequency laser and the fiber coupling unit, and the upper computer is used for decoding, analyzing, displaying and saving the measurement data. Specifically, the signal transmitted by the measurement unit is the protocol of the measurement data, which is RS485, and is transmitted to the double-frequency laser and the fiber coupling unit, the double-frequency laser and the fiber coupling unit convert the 485 signal into a USB signal, and the upper computer decodes, analyzes, displays and saves the USB signal. The displacement / angle generating unit comprises two piezoelectric displacement tables and three piezoelectric angle displacement tables, and a drive controller of the displacement table is integrated in the double-frequency laser and the fiber coupling unit.

[0068] Specifically, the double-frequency laser and the fiber coupling unit comprise a He-Ne double-frequency laser, a coupling lens C-Lens, a fiber coupling mechanism and a polarization maintaining optical fiber PMF, the He-Ne double-frequency laser is used for outputting orthogonal linearly polarized light, the orthogonal linearly polarized light sequentially passes through the coupling lens C-Lens, the fiber coupling mechanism and enters the polarization maintaining optical fiber PMF, and is then output to the measurement unit.

[0069] Please refer to Figure 3 , Figure 3The two-frequency laser interference angle measurement principle of a multi-degree-of-freedom laser interferometer metrology test evaluation standard device provided by the embodiment of the application is as follows. The orthogonal linearly polarized light output by a two-frequency laser enters a single-mode polarization maintaining optical fiber through an optical coupler. After transmission through the optical fiber, the light enters an optical collimator in a measurement unit. The optical collimator collimates the divergent light into measurement collimated light with a divergence angle at the level of angle seconds. After passing through a beam splitter prism, the measurement light is split into two beams. One beam of light is received by a photodetector 1 through a polarizer, generating an interference signal as a reference for angle measurement. The other beam of light is split into transmitted light and reflected light after passing through a polarization beam splitter prism. The reflected light is reflected by a right-angle prism and, together with the transmitted light of the polarization beam splitter prism, enters a double-angle pyramid prism and returns to the measurement unit. The two returning beams of light converge in the polarization beam splitter prism and, after passing through a polarizer, are received by a detector 2, generating an interference signal as an angle measurement signal. Finally, the reference signal and the measurement signal jointly calculate the angle information.

[0070] Please refer to Figure 4 , Figure 4 The two-degree-of-freedom displacement simultaneous measurement method schematic diagram of a multi-degree-of-freedom laser interferometer metrology test evaluation standard device provided by the embodiment of the application is as follows. The orthogonal linearly polarized light output by a two-frequency laser enters a single-mode polarization maintaining optical fiber through an optical coupler. After transmission through the optical fiber, the light enters an optical collimator in a measurement unit. The optical collimator collimates the divergent light into measurement collimated light with a divergence angle at the level of angle seconds. The light is reflected back onto a four-quadrant detector in the measurement unit after being incident on an angle pyramid prism. When a relative displacement occurs between the angle pyramid prism and the measurement light, the light spot on the four-quadrant detector will also produce a synchronous displacement, and the relative position change amount can be calculated according to the displacement amount.

[0071] Please refer to Figure 5 , Figure 5The overall measurement principle diagram of a multi-degree-of-freedom laser interferometer measurement test evaluation standard device provided by the embodiment of the application is shown. The measurement unit comprises: a first laser collimator for receiving orthogonal linearly polarized light output by the polarization maintaining optical fiber PMF, the first laser collimator collimating the orthogonal linearly polarized light into measurement collimated light; a beam splitter prism for receiving the measurement collimated light output by the first laser collimator and splitting the measurement collimated light into two beams, one beam of light passing through a polarizer and being received by a first photodetector to generate an interference signal as a reference signal for angle measurement; the other beam of light passing through a polarization beam splitter prism and being split into transmitted light and reflected light; a right-angle prism for receiving the reflected light, the reflected light being reflected by the right-angle prism and entering a double-angle pyramid prism together with the transmitted light of the polarization beam splitter prism, and returning to the measurement unit, the two beams of returned light converging in the polarization beam splitter prism and passing through a polarizer and being received by a second photodetector to generate an interference signal as an angle measurement signal; the reference signal and the angle measurement signal are used to calculate angle information; a second laser collimator for receiving orthogonal linearly polarized light output by the polarization maintaining optical fiber PMF, the first laser collimator collimating the orthogonal linearly polarized light into measurement collimated light, the measurement collimated light being reflected by an angle pyramid prism in the displacement / angle generating unit and returning to a four-quadrant photodetector; the angle pyramid prism is used to generate a relative displacement between the measurement collimated light, and the light spot on the four-quadrant photodetector is simultaneously displaced when the relative displacement occurs, and the relative position change amount is calculated according to the displacement amount.

[0072] In an embodiment of the application, the orthogonal linearly polarized light output by the dual-frequency laser enters a single-mode polarization maintaining optical fiber through an optical coupler. After transmission through the optical fiber, the light enters an optical collimator in the measurement unit. The optical collimator collimates the divergent light into measurement collimated light with a divergence angle at the level of angle seconds. After passing through a beam splitter prism, the measurement light is split into two beams. One beam of light passes through a polarizer and is received by a photodetector 1 to generate an interference signal as a reference for angle measurement. The other beam of light passes through a polarization beam splitter prism and is split into transmitted light and reflected light. The reflected light is reflected by a right-angle prism and enters a double-angle pyramid prism together with the transmitted light of the polarization beam splitter prism, and returns to the measurement unit. The two beams of returned light converge in the polarization beam splitter prism and pass through a polarizer and are received by a photodetector 2 to generate an interference signal as an angle measurement signal. Finally, the reference signal and the measurement signal jointly calculate angle information. The orthogonal linearly polarized light output by the dual-frequency laser enters a single-mode polarization maintaining optical fiber through an optical coupler. After transmission through the optical fiber, the light enters an optical collimator in the measurement unit. The optical collimator collimates the divergent light into measurement collimated light with a divergence angle at the level of angle seconds. The light is reflected by an angle pyramid prism and returns to a four-quadrant photodetector in the measurement unit. When the angle pyramid prism produces a relative displacement between the measurement light, the light spot on the four-quadrant photodetector will simultaneously produce a displacement, and the relative position change amount can be calculated according to the displacement amount.

[0073] In one embodiment of the present application, the dual-frequency laser and the fiber coupling unit provide a high-quality light reference with frequency stability, power stability and polarization direction stability for the entire measurement system. It also provides a stable voltage reference for the photodetector driving circuit and data processing transmission circuit in the measurement unit. It is composed of a He-Ne dual-frequency laser, a polarization maintaining fiber PMF, a coupling lens C-Lens and a fiber coupling mechanism. The He-Ne dual-frequency laser, as the light source of the measurement system, has the characteristics of frequency stability, polarization direction stability and output power stability, providing a good reference for error measurement. A specially designed high-resolution, high-stability and compact 4DOF fiber coupling mechanism is used to couple the orthogonal linearly polarized light output by the dual-frequency laser into a single-mode polarization maintaining fiber through the coupling lens group C_Lens.

[0074] In one embodiment of the present application, the measurement unit is the core functional unit of the high-precision integrated multi-degree-of-freedom laser interferometer metrology test evaluation standard device, and is the identification unit of the yaw angle, pitch angle, horizontal straightness, vertical straightness and roll angle. Based on the yaw angle / pitch angle measurement principle and method, the straightness measurement principle and method, and the roll angle measurement principle and method, the functions and volume of the measurement unit are considered comprehensively, and the optical system, circuit system and mechanical structure in the measurement unit are designed as a whole.

[0075] In one embodiment of the present application, the main function of the displacement / angle generating unit is to simulate the generation of each geometric quantity measured by the interferometer. It includes yaw angle, pitch angle, roll angle, horizontal straightness and vertical straightness. When the multi-parameter laser interferometer metrology test is performed, the error sensitive unit of the interferometer is placed on the displacement / angle generating unit. In order to ensure that the displacement and angle generating have sub-micron and sub-arcsecond level resolution, a piezoelectric ceramic driving table is selected to complete the displacement and angle generating function. In addition, the displacement / angle generating unit also includes a light receiving module matched with the measurement unit. The light receiving module includes five high-precision corner cubes. The corner cube is used to return the measurement light emitted by the measurement unit to the measurement unit, so as to identify the yaw angle, pitch angle, roll angle, horizontal straightness and vertical straightness.

[0076] In an embodiment of the present application, the multi-degree-of-freedom laser interferometer metrology test evaluation standard device is based on Python to develop the host computer software, which mainly realizes functions such as data receiving, decoding, analysis, display and saving. The driving development of the serial port and the USB module is performed to realize the function of measurement data transmission. The measurement data of the four-quadrant detector from the multi-channel data synchronous acquisition circuit, the measurement data of the tilt sensor and the measurement data transmitted by the high-precision multi-channel digital phase meter are decoded and displayed in the fixed area of the software. In order to better show the position of the light spot on the detector, the function of simulating the change and display of the light spot position is developed. The real-time display effect of the light spot position is as shown in Figure 6 .

[0077] The dual-frequency laser and the fiber coupling unit provide a high-quality light reference with stable frequency, stable power and stable polarization direction for the entire measurement system. It also provides a stable voltage reference for the photodetector driving circuit and the data processing and transmission circuit in the measurement unit. It also contains a precision piezoelectric displacement and angle platform driver, which is responsible for driving two displacement tables and three angle control tables.

[0078] The measurement unit is used for measuring the yaw angle, pitch angle, roll angle, horizontal direction displacement and vertical direction displacement. It is the core functional unit of the device.

[0079] Please refer to Figure 7 , Figure 8 , Figure 9 , Figure 10 , Figure 11 , Figure 7 for the structure diagram of a multi-degree-of-freedom laser interferometer metrology test evaluation standard device provided in an embodiment of the present application. Figure 8 for the roll angle sensitive component diagram of a multi-degree-of-freedom laser interferometer metrology test evaluation standard device provided in an embodiment of the present application. Figure 9 for the pitch angle sensitive component diagram of a multi-degree-of-freedom laser interferometer metrology test evaluation standard device provided in an embodiment of the present application. Figure 10 for the horizontal and vertical direction straightness offset sensitive component diagram of a multi-degree-of-freedom laser interferometer metrology test evaluation standard device provided in an embodiment of the present application. Figure 11 for the yaw angle sensitive component diagram of a multi-degree-of-freedom laser interferometer metrology test evaluation standard device provided in an embodiment of the present application.

[0080] Specifically, the displacement / angle generating unit comprises: a roll angle sensitive component 1 arranged on a platform where the measuring unit is located, and the roll angle sensitive component 1 is arranged along a first direction; a pitch angle sensitive component 2 arranged on the platform where the measuring unit is located, and the pitch angle sensitive component 2 is arranged along a second direction, the first direction being perpendicular to the second direction; a horizontal and vertical direction straightness offset sensitive component 3 arranged on the platform where the measuring unit is located, and the horizontal and vertical direction straightness offset sensitive component 3 is arranged along the second direction; and a yaw angle sensitive component 4 arranged on the platform where the measuring unit is located, and the yaw angle sensitive component 4 is arranged along the second direction.

[0081] Specifically, a corner cube prism is arranged on the roll angle sensitive component 1, the pitch angle sensitive component 2, the horizontal and vertical direction straightness offset sensitive component 3 and the yaw angle sensitive component 4 respectively, and the corner cube prism is used for returning the measuring collimated light emitted by the measuring unit to the measuring unit, so as to identify the yaw angle, the pitch angle, the roll angle, the horizontal direction displacement and the vertical direction displacement.

[0082] In an embodiment of the present application, the displacement / angle generating unit is a 5-degree-of-freedom high-precision workbench, which can provide the motion of the yaw angle, the pitch angle, the roll angle, the horizontal direction displacement and the vertical direction displacement. In the process of measuring the corresponding parameters of the integrated multi-degree-of-freedom laser interferometer, the multi-beam receiver of the interferometer and the receiver of the calibration device are simultaneously installed on the workbench, and the motion change of the workbench is measured together, and the software can display, record and save the metrological calibration data in real time.

[0083] Table 1: Multi-degree-of-freedom laser interferometer metrological test evaluation standard device

[0084] Name Measurement range Maximum permissible error Yaw / pitch standard module ±300″ ±0.05″ Roll standard module ±500″ ±0.2″ Straightness deviation standard module ± 250 pm ± 0.3 pm

[0085] The present application also provides a working method of a multi-degree-of-freedom laser interferometer metrological test evaluation standard device, comprising:

[0086] S1, providing light reference and voltage reference for the measuring unit by the dual-frequency laser and the optical fiber coupling unit;

[0087] S2, measuring the yaw angle, the pitch angle, the roll angle, the horizontal direction displacement and the vertical direction displacement by the measuring unit;

[0088] S3, providing the motion of the yaw angle, the pitch angle, the roll angle, the horizontal direction displacement and the vertical direction displacement by the displacement / angle generating unit;

[0089] S4, receiving and converting the measurement data of the measuring unit by the dual-frequency laser and the optical fiber coupling unit;

[0090] S5, decoding, analyzing, displaying and saving the measurement data by the host computer.

[0091] The measurement of the yaw angle, the pitch angle, the roll angle, the horizontal direction displacement and the vertical direction displacement by the measurement unit in step S2 comprises:

[0092] S21, receiving the orthogonal linearly polarized light output by the polarization maintaining optical fiber PMF by a first laser collimator, which collimates the orthogonal linearly polarized light into measurement collimated light rays;

[0093] S22, receiving the measurement collimated light rays output by the first laser collimator by a light splitting prism, and splitting the measurement collimated light rays into two beams, one beam of light passing through a polarizer is received by a first photodetector to generate an interference signal as a reference signal for angle measurement; the other beam of light passes through the polarizing light splitting prism and is split into transmitted light and reflected light;

[0094] S23, receiving the reflected light by a right-angle prism, which, after being reflected by the right-angle prism, enters the double-angle pyramid prism together with the transmitted light of the polarizing light splitting prism, and returns to the measurement unit, the two returned light beams converge in the polarizing light splitting prism and pass through the polarizer to be received by a second detector to generate an interference signal as an angle measurement signal; the reference signal and the angle measurement signal are used to calculate the angle information;

[0095] S24, receiving the orthogonal linearly polarized light output by the polarization maintaining optical fiber PMF by a second laser collimator, which collimates the orthogonal linearly polarized light into measurement collimated light rays, which are reflected back onto a four-quadrant detector after being incident on the angle pyramid prism in the displacement / angle generating unit;

[0096] S25, when a relative displacement is generated between the angle pyramid prism and the measurement collimated light rays, the light spots on the four-quadrant detector will synchronously generate displacement, and the relative position change amount is calculated according to the displacement amount, i.e. the measurement of the yaw angle, the pitch angle, the roll angle, the horizontal direction displacement and the vertical direction displacement.

[0097] In summary, the multi-degree-of-freedom laser interferometer metrological test evaluation standard device adopts the technical route combining the laser heterodyne interferometry principle and the laser collimation measurement principle, can perform systematic and accurate metrological test evaluation on the three-degree-of-freedom angle measurement precision index, measurement range index and two-degree-of-freedom in-plane displacement measurement precision index, measurement range index and other key metrological characteristics of the high-precision integrated multi-degree-of-freedom laser interferometer. This makes the instrument in actual application, the accuracy and reliability of the measurement results are effectively guaranteed, provides solid and reliable measurement data support for the fields of precision manufacturing, large device assembly and high-end scientific research, greatly reduces the risk of production accidents and experimental deviation caused by measurement errors.

[0098] The above embodiments only exemplarily illustrate the principles and effects of the present application, and are not used to limit the present application. Any person skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the present application. Therefore, all equivalent modifications or changes completed by those skilled in the art without departing from the spirit and technical thought disclosed by the present application should be covered by the claims of the present application.

Claims

1. A multi-degree-of-freedom laser interferometer metrology test evaluation criteria device, characterized by, The application relates to a double-frequency laser and fiber coupling unit, a measurement unit, a displacement / angle generating unit and an upper computer. The double-frequency laser and fiber coupling unit is used for providing light and voltage references for the measurement unit, and is connected with the measurement unit and the displacement / angle generating unit. The measurement unit is used for measuring the yaw angle, the pitch angle, the roll angle, the horizontal displacement and the vertical displacement. The displacement / angle generating unit is used for providing the yaw angle, the pitch angle, the roll angle, the horizontal displacement and the vertical displacement. The double-frequency laser and fiber coupling unit is also used for receiving and converting the measurement data of the measurement unit. The upper computer is connected with the output end of the double-frequency laser and fiber coupling unit, and is used for decoding, analyzing, displaying and saving the measurement data.

2. The multi-degree of freedom laser interferometer metrology test evaluation criteria device of claim 1, wherein, The double-frequency laser and fiber coupling unit comprises a He-Ne double-frequency laser, a coupling lens C-Lens, a fiber coupling mechanism and a polarization maintaining fiber PMF.

3. The multi-degree of freedom laser interferometer metrology test evaluation criteria device of claim 1, wherein, The measurement unit comprises a first laser collimator, a light splitting prism, a right-angle prism and a second laser collimator. The first laser collimator is used for receiving the orthogonal linearly polarized light output by the polarization maintaining fiber PMF and collimating the orthogonal linearly polarized light into measurement collimated light. The light splitting prism is used for receiving the measurement collimated light output by the first laser collimator and splitting the measurement collimated light into two beams. The right-angle prism is used for receiving the reflected light, and the reflected light is reflected by the right-angle prism and enters the double-angle pyramid prism together with the transmitted light of the light splitting prism, and returns to the measurement unit. The second laser collimator is used for receiving the orthogonal linearly polarized light output by the polarization maintaining fiber PMF, and collimating the orthogonal linearly polarized light into measurement collimated light. The angle pyramid prism is used for generating a relative displacement between the measurement collimated light, and the light spot on the four-quadrant detector is synchronously displaced.

4. The multi-degree of freedom laser interferometer metrology test evaluation criteria device of claim 3, wherein, The displacement / angle generating unit comprises a roll angle sensitive component (1) arranged on a platform of the measurement unit and arranged along a first direction. ​ A pitch angle sensitive component (2) is arranged on the platform where the measuring unit is located, and the pitch angle sensitive component (2) is arranged along a second direction, the first direction is perpendicular to the second direction; A horizontal and vertical direction straightness offset sensitive component (3) is arranged on the platform where the measuring unit is located, and the horizontal and vertical direction straightness offset sensitive component (3) is arranged along a second direction; A yaw angle sensitive component (4) is arranged on the platform where the measuring unit is located, and the yaw angle sensitive component (4) is arranged along a second direction; A corner cube prism is arranged on the roll angle sensitive component (1), the pitch angle sensitive component (2), the horizontal and vertical direction straightness offset sensitive component (3), and the yaw angle sensitive component (4) respectively, and the corner cube prism is used to return the measuring collimated light emitted by the measuring unit to the measuring unit to identify the yaw angle, the pitch angle, the roll angle, the horizontal direction displacement, and the vertical direction displacement.

5. The multi-degree of freedom laser interferometer metrology test evaluation criteria device of claim 1, wherein: The host computer is further connected with a serial port module.

6. The multi-degree of freedom laser interferometer metrology test evaluation criteria device of claim 1, wherein: The host computer is further connected with a USB module.

7. The multi-degree of freedom laser interferometer metrology test evaluation criteria device of claim 1, wherein: The displacement / angle generating unit is a five-degree-of-freedom laser interferometer installation platform.

8. A method for operating a metrological testing and evaluation standard device for a multi-degree-of-freedom laser interferometer, characterized in that, Comprise: S1, providing light reference and voltage reference for the measuring unit by a dual-frequency laser and a fiber coupling unit; S2, measuring the yaw angle, the pitch angle, the roll angle, the horizontal direction displacement, and the vertical direction displacement by the measuring unit; S3, providing the motion of the yaw angle, the pitch angle, the roll angle, the horizontal direction displacement, and the vertical direction displacement by the displacement / angle generating unit; S4, receiving and converting the measurement data of the measuring unit by the dual-frequency laser and the fiber coupling unit; S5, decoding, analyzing, displaying, and saving the measurement data by the host computer.

9. The method of operation of a multi-degree-of-freedom laser interferometer metrology test and evaluation standards apparatus according to claim 8, wherein: The measurement of the yaw angle, the pitch angle, the roll angle, the horizontal direction displacement, and the vertical direction displacement by the measuring unit in step S2 comprises: S21, receiving the orthogonal linearly polarized light output by the polarization maintaining optical fiber PMF by a first laser collimator, and collimating the orthogonal linearly polarized light into measuring collimated light; S22, receiving the measuring collimated light output by the first laser collimator by a beam splitting prism, and splitting the measuring collimated light into two beams, one beam of light is received by a first photodetector through a polarizer to generate an interference signal as a reference signal for angle measurement; the other beam of light is split into transmitted light and reflected light after passing through the polarization beam splitting prism; S23, receiving the reflected light by a right-angle prism, the reflected light is reflected by the right-angle prism and enters the dual corner cube prism together with the transmitted light of the polarization beam splitting prism, and returns to the measuring unit, the two returning lights converge in the polarization beam splitting prism and are received by a second detector through a polarizer to generate an interference signal as an angle measurement signal; the reference signal and the angle measurement signal are used to calculate the angle information; S24, receiving the orthogonal linearly polarized light output by the polarization maintaining optical fiber PMF through a second laser collimator, the first laser collimator collimates the orthogonal linearly polarized light into measurement collimated light rays, which are reflected back onto a four-quadrant detector after being incident on an angle prism in the displacement / angle generating unit; S25, when a relative displacement is generated between the angle prism and the measurement collimated light rays, the light spots on the four-quadrant detector will be displaced synchronously, and the relative position change amount is calculated according to the displacement amount, that is, the measurement of the yaw angle, the pitch angle, the roll angle, the horizontal direction displacement and the vertical direction displacement.

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