Measurement method for multi-specification precision mechanism and single machine component

Abstract

The application provides a kind of measurement method for multi-specification precision mechanism and single machine component, which is by deconstructing transmission efficiency, stiffness and other test principles, and is disassembled into basic physical quantities, and accordingly abstracts general function modules such as loading, driving and testing integration, detection, etc. Through the standardized design of mechanical, electrical and communication interfaces of the modules, the openness and interchangeability are ensured. For extreme environments such as high and low temperature vacuum, optimization is carried out from three aspects of protection design, material selection and thermal error compensation, effectively suppressing environmental errors. By combining standardized modules to build various functional test platforms, and cooperating with the measurement and control system, integrated high-precision measurement of multi-specification and multi-type precision mechanisms is realized. The application solves the problems of strong equipment specificity, non-uniform interface, large environmental error and difficulty in calibration.

Description

Technical Field

[0001] This invention relates to the field of measurement technology, and more specifically, to a measurement method for multi-specification precision mechanisms and single-unit components. Background Technology

[0002] In the development of major aerospace projects in my country, ground-based simulation performance verification tests are required for various types of individual mechanisms and combinations of different mechanisms. The environmental conditions to be simulated include vacuum and extreme temperatures, with a maximum vacuum envelope better than 1.3 x 10⁻⁶. -5 Pa, with a maximum high and low temperature envelope of -100℃ to +100℃. Mechanical transmission performance tests conducted under simulated environments generally include transmission efficiency, force-linear stiffness, torque-angular stiffness, assembly accuracy, and vibration response. Current testing procedures have the following problems:

[0003] Question 1: Currently, the equipment used for these tests is either dedicated testing equipment developed for one type of mechanism or for one type of test content. There is no testing equipment that can simultaneously take into account both single and combined testing of multiple types of mechanisms and multiple test contents.

[0004] Question 2: To ensure the openness and interchangeability of modular construction, it is necessary to standardize the design of interfaces such as mechanisms, electrical systems and communications for various types of functional modules.

[0005] Question 3: Due to the influence of high and low temperature environments, sensors, shaft systems, etc. will be affected to varying degrees, which will introduce test errors. Current experimental equipment does not study and analyze the errors caused by the test environment on the test equipment itself, nor does it provide corresponding guiding principles.

[0006] Question 4: The equipment currently used for these tests is not designed with periodic calibration in mind.

[0007] Therefore, a new measurement method is needed to solve the above problems. Summary of the Invention

[0008] In view of the deficiencies in the prior art, the purpose of this invention is to provide a measurement method for multi-specification precision mechanisms and single-machine components.

[0009] A measurement method for multi-specification precision mechanisms and single-unit components provided by the present invention includes the following steps:

[0010] Step S1: Analyze the test principle and test equipment composition of the mechanical transmission performance test items for precision mechanisms of spacecraft; the test items include transmission efficiency, force-linear stiffness, torque-angular stiffness, assembly accuracy, and vibration response;

[0011] Step S2: Decompose and divide each test item from the perspective of physical quantities;

[0012] Step S3: Based on the composition principles of different test equipment, the test platform hardware is divided into basic platform, drive system, loading system and detection system; the electrical system is divided into drive control, data acquisition, data processing and transmission; and the motion is divided into linear motion system, rotary motion system and compound motion system.

[0013] Based on the above breakdown, the hardware is divided into loading module, driver-test integrated module, detection module, and support module, and further subdivided according to linear and rotational factors to form a functional module tree, and an environmental simulation functional module and a verification module are designed.

[0014] Step S4: Standardize the mechanical, electrical, and communication interfaces for various functional modules;

[0015] Step S5: Optimize the measurement from three aspects: high and low temperature protection device design, material selection, and thermal error compensation design, in response to the impact of high and low temperature and vacuum environments.

[0016] Step S6: Use the above functional modules to form various functional test platforms, and use them with a measurement and control system to measure multiple physical quantities of precision mechanisms and single components.

[0017] Preferably, the test principles and experimental equipment configuration for each test item in step S1 include:

[0018] Transmission efficiency test: The test principle is the percentage of output power to input power when the machine is running stably. Input power and output power are indirectly measured by multiplying the input / output speed by the input / output torque, respectively. The test equipment includes an input end and an output end, with a torque sensor and a high-precision position encoder connected in series in the shaft system of the input end and the output end, respectively.

[0019] Force-Linear Stiffness Test: The test principle is to indirectly measure the linear stiffness by measuring the elastic deformation of the test object under different force loads; the test equipment is driven by a closed-loop controlled linear drive module and equipped with tensile and compressive sensors and linear displacement sensors.

[0020] Torque-Angle Stiffness Test: The test principle is to indirectly measure the torsional stiffness by measuring the torsional elastic deformation of the test object under different torque loads; the test equipment is driven by a closed-loop controlled rotary drive module, and a torque sensor and a rotary displacement sensor are connected in series in the shaft system;

[0021] Vibration performance testing: The testing principle is to apply a specific frequency and displacement excitation to the test object through a vibration table, and at the same time test the response parameters; the test equipment adopts a two-axis vibration test scheme, including a two-axis loading platform, two electric vibration tables, a displacement amplification mechanism, a non-contact direct drive mechanism, a double-layer marble platform, a multi-input multi-output vibration control system, and various measuring devices;

[0022] Assembly accuracy testing includes distance, angle, coaxiality, end runout, and surface detection. The testing principle is based on the calculation of spatial point cloud data of the object under test. The test equipment includes a linear drive module, a rotary drive module, and a precision micro-motion probe.

[0023] Preferably, the test items in step S2 are broken down and divided from the perspective of physical quantities, including:

[0024] The transmission efficiency test is broken down into force parameter measurement, torque parameter measurement, speed parameter measurement, angle parameter measurement, and length parameter measurement.

[0025] Stiffness testing is broken down into force parameter measurement, torque parameter measurement, angle parameter measurement, and length parameter measurement.

[0026] Assembly accuracy measurement is broken down into angle parameter measurement and length parameter measurement;

[0027] Vibration response measurement is broken down into acceleration parameter measurement and displacement parameter measurement.

[0028] Preferably, in step S3:

[0029] The environmental simulation module includes a high and low temperature module, a vacuum module, and a vibration module;

[0030] The calibration module includes a force parameter calibration module, a torque parameter calibration module, an angle parameter calibration module, and a displacement parameter calibration module.

[0031] Preferably, the standardized design of the mechanical interface in step S4 includes:

[0032] Basic platform design: For test modules with high and low temperature testing requirements, a basic support platform is designed, including a basic large platform, a support column structure inside the high and low temperature chamber, and an auxiliary adjustment structure for the coaxiality of the shaft system;

[0033] Interchangeable interface design: Add keyways and key connections to the module contact parts, or connect to the adapter plate and adapter flange. Select appropriate couplings for the measuring shaft system. In the high and low temperature chamber, the test piece is connected to the base platform via a key and keyway through the connecting plate inside the chamber.

[0034] Preferably, the coupling is the Mikipuri SFF model. The external coupling of the high and low temperature chamber is selected with a maximum allowable torque of 1000 N·m, which can achieve a maximum of 1.5 times the allowable torque and ultra-low inertia. The concentricity of the left and right inner diameters is ensured by special fixtures. The connection between the loading module of the torque stiffness test platform and the external support module adopts a wedge fastening method. Other SFF models adopt a clamping method.

[0035] Preferably, the electrical interface standardization design in step S4 includes the standardization and scalability design of internal and external interfaces:

[0036] Internal interface:

[0037] - Power supply system interface: Ripple-free regulated power supply for motor power, with a power margin of 1.5 to 2 times; Low-voltage DC power supply for controller and signal acquisition system uses two 24V standard module power supplies, with adapter terminals and a reserved 220V AC socket.

[0038] -Drive control system interface:The controller is supported by the lower-level controller Compact-RIO device, and the servo motor driver supports 2-3 phase servo motor power connection, multiple position feedback sensor interfaces and multiple I / O interfaces;

[0039] -Signal acquisition interface: It comes with a built-in FPGA high-speed real-time data acquisition interface and 8 pluggable signal acquisition module interfaces;

[0040] - Auxiliary expansion interface: provides terminal blocks for 220V power supply and 24V low voltage power supply;

[0041] External interface:

[0042] - Drive system interface: An aviation plug is selected as the external interface for connecting electrical circuits. The aviation plug is located on the modular terminal block.

[0043] - Signal acquisition interface: It adopts a reserved wiring hole and connects directly to the internal interface through a cable.

[0044] Preferably, the standardized design of the communication interface in step S4 includes:

[0045] Upper and lower computer communication: The Modbus communication architecture based on TCP / IP is adopted. A general user protocol is developed on the basis of the Modbus protocol. The Modbus protocol defines four data storage types and divides the holding register and read / write coil into functional partitions. The general upper and lower computer communication protocol is divided into command transmission part and real-time status refresh part. The lower computer embedded communication program based on LabVIEW is written.

[0046] Internal communication of the lower-level machine: EtherCAT fieldbus is used for communication, and the communication protocol of the internationally standardized DS301 and DS402 drivers is followed. The controller integrates FPGA field programmable gate array, and the signal acquisition module is selected according to the sensor specifications, which has universality and interchangeability.

[0047] Preferably, in step S5:

[0048] High and low temperature protection device design: The design includes a reusable high and low temperature protection device, available in cylindrical and rectangular sizes. It is composed of an aluminum inner cavity, a stainless steel outer shell, a tubular heater, a water-medium copper pipe, polyurethane foam insulation material, a connecting frame, and sealing silicone material. The cooling system uses a plate heat exchanger for cooling, and the heating system uses a direct heating tube heating method. The temperature signal of the protection device is fed back to the high and low temperature module in real time.

[0049] Material selection: The module material placed outside the high and low temperature chamber is 0Cr17Ni4Cu4Nb stainless steel. The test shaft structure inside the high and low temperature chamber, which is greatly affected by temperature, is made of 4J36 Invar steel. The internal support platform and its support columns of the high and low temperature chamber are corrected for errors by software according to temperature changes. The bearing housing inside the high and low temperature chamber is made of stainless steel with a coefficient of thermal expansion similar to that of the bearing material.

[0050] Thermal error compensation design: Conduct thermal error simulation analysis, theoretical analysis, and measurement experiments. Apply the compensation table method and support vector machine regression method to predict and compensate for thermal errors. Place temperature sensors at key points of the heat source and use partial correlation analysis or gray-scale correlation analysis to select the optimal combination of temperature measurement points.

[0051] Preferably, the data storage type and functional partitioning of the Modbus protocol in the communication between the upper and lower computers are as follows:

[0052] Data storage types include read-only coils, read-write coils, read-only registers, and holding registers;

[0053] The holding register function area includes the control status area, instruction area, parameter setting area, process data area, and batch data transfer area;

[0054] The read / write coil functional area includes the system status area, process data area, and batch data transmission area.

[0055] Compared with the prior art, the present invention has the following beneficial effects:

[0056] 1. This invention constructs a measurement framework for multi-specification precision mechanisms and single-unit components. It divides the testing equipment into modules based on two dimensions: the basic components of the testing equipment and the basic elements of the testing content. This forms a variety of serialized functional module sets. Combined with a supporting measurement and control system, various functional testing platforms can be flexibly and quickly assembled to meet the measurement needs of assembly accuracy, force / torque / stiffness, transmission efficiency, vibration, electrical performance, etc. This breaks away from the previous framework of developing specialized testing equipment for different single units and different testing contents, solving the problem of dedicated equipment that cannot handle multiple types of testing.

[0057] 2. This invention solves the problems of modular construction's openness and interchangeability by standardizing the interfaces of various functional modules in terms of structure, electrical and communication.

[0058] 3. This invention addresses the problem that sensors, shaft systems, and other components are affected to varying degrees under high and low temperature environments, leading to testing errors and affecting testing accuracy. This is achieved through three aspects: high and low temperature protection device design, material selection standard design, and thermal error compensation design.

[0059] 4. This invention achieves periodic verification and calibration of equipment by designing a key physical quantity parameter verification module with a standard interface, thus solving the problem that current test equipment designs do not consider periodic calibration functions. Attached Figure Description

[0060] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0061] Figure 1 This is a schematic diagram of a measurement system for precision mechanisms and individual components of various specifications.

[0062] Figure 2 Schematic diagram of the transmission efficiency testing equipment;

[0063] Figure 3 This is a schematic diagram of the structural principle of the force / linear stiffness testing equipment.

[0064] Figure 4 This is a schematic diagram of the torque / rotation stiffness testing platform.

[0065] Figure 5 Schematic diagram of the vibration performance testing platform;

[0066] Figure 6 This is a schematic diagram of the assembly accuracy testing platform.

[0067] Figure 7 A tree-like structure for various types and series of functional modules;

[0068] Figure 8A schematic diagram illustrating measurement methods for various types, physical quantities, and scales of precision mechanisms and single-unit components;

[0069] Figure 9 A schematic diagram of the basic platform;

[0070] Figure 10 A schematic diagram of interchangeable design modules;

[0071] Figure 11 Schematic diagram of the integrated drive and testing adapter;

[0072] Figure 12 This is a schematic diagram of interchangeable connections within the enclosure;

[0073] Figure 13 This is a schematic diagram of the internal interfaces of the electrical control cabinet;

[0074] Figure 14 A schematic diagram of the power supply architecture for the electronic control system;

[0075] Figure 15 This is a schematic diagram of the external interfaces of the electrical control cabinet;

[0076] Figure 16 A schematic diagram of commonly used general-purpose modules;

[0077] Figure 17 Schematic diagram of the power supply aviation plug;

[0078] Figure 18 Define the wiring sequence for a three-phase power supply;

[0079] Figure 19 Schematic diagram of an aviation plug for motor power;

[0080] Figure 20 A diagram defining the wiring sequence for the motor's power lines and brake lines;

[0081] Figure 21 Wiring diagram for motor position feedback;

[0082] Figure 22 Define the motor position feedback wiring sequence diagram;

[0083] Figure 23 Modbus data transfer address partitioning diagram;

[0084] Figure 24 This is a diagram illustrating the execution process of the command transmission protocol.

[0085] Figure 25 A diagram illustrating the execution process of the real-time state refresh protocol;

[0086] Figure 26 This is a diagram of the communication architecture of the electronic control system.

[0087] Figure 27Schematic diagram of a cylindrical high and low temperature protection device;

[0088] Figure 28 This is a schematic diagram of a rectangular high and low temperature protection device;

[0089] Figure 29 This is a simplified diagram of the drive shaft;

[0090] Figure 30 Here is a simplified one-dimensional model of segment b of the drive shaft;

[0091] Figure 31 This is a schematic diagram of the temperature distribution on section b of the drive shaft.

[0092] Explanation of reference numerals in the attached figures:

[0093] 1. Basic large platform; 2. Support column structure inside the high and low temperature chamber; 3. Auxiliary adjustment structure for shaft coaxiality. Detailed Implementation

[0094] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0095] This invention addresses the performance testing needs of multi-specification precision mechanisms and individual components in the aerospace field, proposing a universal measurement method based on modularization and standardization. Its core lies in: first, deconstructing the principles and equipment of various tests (such as transmission efficiency, stiffness, and assembly accuracy) to abstract common hardware functional modules (such as drive, loading, detection, and support); second, thoroughly standardizing the mechanical, electrical, and communication interfaces of these modules to ensure openness and interchangeability between them; simultaneously, systematically optimizing the system from three levels—structural protection, material selection, and error compensation—for extreme testing environments such as high and low temperatures and vacuum, to guarantee measurement accuracy; and finally, rapidly assembling standardized modules in a "building block" manner to construct a functional platform adaptable to different test objects and content, achieving the goal of a complete system capable of handling multiple types of tests.

[0096] This invention, based on the current status of performance testing of precision mechanisms in spacecraft, analyzes the basic testing principles and basic components of testing equipment for items such as transmission efficiency, force-linear stiffness, torque-angular stiffness, assembly accuracy, and vibration response. It categorizes the components in various test benches, abstracting loading modules, integrated drive-test modules, detection modules, and support modules. Based on both linear and rotational factors, each module is further subdivided, ultimately forming a multi-category, serialized functional module tree to adapt to the measurement tasks of various typical test objects and the measurement tasks of new test objects that may emerge in the future.

[0097] To ensure the openness and interchangeability of modular construction, standardized designs were implemented for the mechanical, electrical, and communication interfaces of various functional modules. During implementation, different test modules were planned and combined in a coordinated manner to form various functional test platforms. A system management computer with measurement and control software provided the human-machine interface and performed test task planning, process monitoring, and comprehensive processing and display of test data according to test requirements.

[0098] Each functional test platform is equipped with an embedded data acquisition and control system to perform real-time data acquisition, signal processing, and process control. Each sub-test platform connects to the system management computer via a unified Ethernet interface. It can meet high-precision measurement requirements for assembly accuracy, force / torque / stiffness, transmission efficiency, vibration, and electrical performance. The overall test system is as follows: Figure 1 As shown.

[0099] The present invention will be further described in detail below in light of the current status of performance testing of precision mechanisms in spacecraft.

[0100] Regarding question 1:

[0101] The first step, based on the current testing status, is to analyze the basic testing principles and basic equipment composition of mechanical transmission performance testing items for precision mechanisms of spacecraft, such as transmission efficiency, force-linear stiffness, torque-angular stiffness, assembly accuracy, and vibration response.

[0102] Analysis of the basic testing principle and equipment composition of transmission efficiency:

[0103] Transmission efficiency testing refers to the percentage of output power to input power when the machine is operating stably. The input power and output power are indirectly measured by multiplying the input / output speed by the input / output torque, respectively.

[0104]

[0105] The basic components of transmission efficiency testing equipment are as follows: Figure 2As shown: the left side is the input or drive end, and the right side is the output or load end. The test system drives the test object to operate stably through the input end and applies load through the output end to meet the test requirements under different speeds and loads. A torque sensor and a high-precision position encoder are connected in series in the shaft systems of the input and output ends, respectively, to measure the input and output torque and speed. The speed is measured by differentiating the dynamic position measured by the high-precision position encoder with time.

[0106] Analysis of the basic testing principles and equipment composition of force-linear stiffness:

[0107] Force-linear stiffness testing indirectly measures the linear stiffness of an object by measuring its elastic deformation under different applied force loads.

[0108] The basic components of a force-linear stiffness testing apparatus are as follows: Figure 3 As shown: Driven by a closed-loop controlled linear drive module, one end of the object under test is fixed, while the other end undergoes elastic deformation (displacement) under the tension and compression of the drive module. The tension and compression sensors measure the force applied to the object under test, while the linear displacement sensor measures the elastic displacement at the input end of the object under test. The linear stiffness curve of the object under test under different force conditions can be calculated through the force-elastic displacement curve.

[0109] Analysis of the basic testing principles and equipment composition of torque-angular stiffness:

[0110] Torque-angle stiffness testing indirectly measures the torsional stiffness of an object by measuring its torsional elastic deformation under different torque loads.

[0111] The basic components of the torque-angle stiffness testing equipment are as follows: Figure 4 As shown: Driven by a closed-loop controlled rotary drive module, the object under test is also fixed at one end and input at the other. By connecting a torque sensor and a rotary displacement sensor in series in the shaft system, the torsional elastic deformation of the object under test under different torque loads is measured, and finally the torsional stiffness curves under different load conditions are obtained.

[0112] Analysis of the basic testing principles and equipment composition of vibration performance testing:

[0113] Vibration performance testing involves applying a specific frequency and displacement to the object under test using a vibration table, while simultaneously testing the object's response parameters.

[0114] The basic components of vibration performance testing equipment are as follows: Figure 5As shown: A biaxial vibration testing scheme is employed. The test piece is mounted on a biaxial platform. Two electric vibration tables, one on the side and one at the rear, excite the platform, enabling single-axis excitation and biaxial linkage for vibration testing of the test piece. A displacement amplification mechanism amplifies the excitation displacement of the vibration tables to achieve low-frequency, large-displacement excitation; a non-contact direct-drive mechanism achieves high-frequency, low-loss excitation; and a double-layer marble platform isolates low-frequency interference from the ground. A multi-input multi-output vibration control system enables single-axis or biaxial linkage. Measurement methods: Acceleration measurement—using contact accelerometers and non-contact Doppler laser vibrometers to measure the acceleration performance of the test piece and platform in contact or non-contact manner; Displacement measurement—using laser displacement sensors for non-contact measurement; Data acquisition—using a 32-channel data acquisition system to measure multiple physical quantities such as acceleration, voltage, and displacement.

[0115] Analysis of the basic testing principles and basic components of assembly accuracy testing equipment:

[0116] According to the testing requirements of aerospace products, assembly accuracy testing generally includes distance detection, angle detection, coaxiality detection, end runout detection, and surface detection. Plane / surface detection: A circular point layout method can be used. Several concentric circles are selected on the surface to be measured, their spatial positions are measured, and then the least squares method is used to fit the measured element points to a plane / surface. The result is compared with an ideal plane / surface to determine the plane / surface measurement error. Coaxiality detection: A rotation axis method can be used. Multiple cross-sectional circles are measured on the element to be measured and the reference element. The centers of these circles are connected to form a three-dimensional straight line as a common axis. Then, the runout of the reference cylinder and the measured cylinder is calculated separately. End runout detection: Similarly, a rotation axis method can be used. Multiple cross-sectional circles are measured on the element to be measured, and then the runout error between the cross-sectional circles and the reference axis and reference circle surface is calculated. Distance detection: Based on the aforementioned plane detection, a circular point layout method is used to determine the spatial positions of the reference plane and the plane to be measured. The difference between the heights of the two planes is then obtained as the distance between them. Angle Detection: To achieve high-precision angle detection, a photoelectric autocollimator can be used. A reflector is placed on the surface of the part being measured. By measuring the deviation of the reflected light from the original reference cursor of the autocollimator, high-precision measurement of minute rotation angles of the part can be achieved. It can also be used to measure the flatness of part surfaces. Furthermore, combined with a right-angle prism, it can detect the perpendicularity of precision mechanisms. Analysis and summary of the testing principles for each item on the assembly accuracy testing platform revealed that the main test items can be calculated based on the spatial point cloud data of the object being measured. Therefore, referring to the design principle of a two-degree-of-freedom profilometer, a rotational degree of freedom can be added to form high-precision sampling of the spatial points of rotating parts. Based on this, the assembly accuracy testing platform can meet the requirements of static testing items such as length, angle, and surface detection, as well as dynamic measurement items requiring rotation of the object, such as coaxiality and end runout.

[0117] The basic components of assembly accuracy testing equipment are as follows: Figure 6 As shown, it consists of two linear drive modules, one rotary drive module, and a precision micro-motion probe. The micro-motion probe has two degrees of freedom in the X and Z axes, while the measured mechanism, placed on the platform, has one rotational degree of freedom in the Z-axis direction. Firstly, the probe's two degrees of freedom in motion can detect the distance / length between two points on the workpiece or between two parallel end faces. The rotation angle of the measured object can be detected using a rotary displacement sensor configured with the Z-axis rotational degree of freedom. Secondly, in conjunction with the rotation of the measured object, spatial sampling of the end face points of the part and spatial sampling of the cylindrical side surface can be achieved. Then, through planar or cylindrical surface fitting, detection items such as surface curvature, end runout, cylindricity, and coaxiality can be realized.

[0118] The second step, based on the aforementioned analysis of measurement principles, is to break down and divide the transmission efficiency test, force / torque / stiffness test, vibration performance test, and assembly accuracy test into physical quantity dimensions:

[0119] (1) The transmission efficiency test can be broken down into force parameter measurement, torque parameter measurement, speed parameter measurement, angle parameter measurement, and length parameter measurement.

[0120] (2) Stiffness testing techniques and measurement methods can generally be divided into two categories: static stiffness and dynamic stiffness. They can be further broken down into force parameter measurement, torque parameter measurement, angle parameter measurement, and length parameter measurement.

[0121] (3) The measurement of assembly accuracy is mainly transformed into the measurement of assembly gaps, flatness, etc. It can be broken down into the measurement of angular parameters and the measurement of length parameters.

[0122] (4) Vibration response measurement can be broken down into acceleration parameter measurement and displacement parameter measurement.

[0123] The third step, based on the analysis of the structural principles of different testing and experimental equipment, yields the following characteristics:

[0124] (1) The hardware of the test platform can be modularly divided into three parts: basic platform, drive system, loading system, and detection system. The corresponding electrical system includes three aspects: drive control, data acquisition, data processing, and transmission.

[0125] (2) Based on the different physical quantities and their motion forms, the main classifications are: linear motion systems, rotary motion systems, and composite motion systems. Following the above analysis steps, the components in various test benches are classified, abstracting into loading modules, integrated drive-test modules, detection modules, support modules, and drive modules. Based on both linear and rotary factors, each module is further subdivided, ultimately forming a multi-category, serialized functional module tree (e.g., ...). Figure 7 As shown in the figure, it is designed to adapt to the measurement tasks of various typical test objects at present, as well as the measurement tasks of new test objects that may emerge in the future.

[0126] Table 1. Multi-category and serialized functional module table

[0127]

[0128] (3) Considering the testing requirements under extreme environments, it is necessary to design environmental simulation functional modules simultaneously, including high and low temperature modules, vacuum modules and vibration modules.

[0129] (4) Considering the periodic verification and calibration of the equipment, verification modules need to be designed simultaneously, including force parameter verification module, torque parameter verification module, angle parameter verification module, displacement parameter verification module, etc.

[0130] (5) Adopting the modular approach, the main components of various testing and experimental equipment are classified, including the drive part, loading part, measurement part, support and adjustment part. Test parameters are classified for various test contents. Multiple types and series of functional modules are formed from two dimensions. Combined with the supporting measurement and control system, the measurement of various types, multiple physical quantities, and multiple scale precision mechanisms and single-machine components can be realized.

[0131] The core idea of ​​the method is as follows Figure 8 As shown, it mainly consists of various functional modules, a functional testing platform, and a measurement and control system. The functional modules are divided into drive modules, loading modules, measurement modules, support modules, and integrated drive-measurement modules. Considering the changes in measurement range in specific types of measurement tasks, each functional module is also serialized to meet the needs of different measurement ranges. This ultimately forms a variety of serialized test modules, capable of meeting the testing needs of most typical existing test objects. By comprehensively planning and combining different test modules, various functional testing platforms can be formed, which can meet the measurement needs of assembly accuracy, force / torque / stiffness, transmission efficiency, vibration, electrical performance, etc. The functional testing platform is connected to the measurement and control system, which is the brain of the comprehensive performance tester, responsible for controlling the movement of the test platform and collecting and analyzing test data. The hardware of the measurement and control system includes motion control, data acquisition and analysis, bus and communication, temperature control, safety assurance, and power supply systems. The software includes a calculation module, motion control module, communication module, wizard module, configuration module, and expert system module.

[0132] The test content is constructed using the following table:

[0133] Table 2 Examples of Multi-Physical Quantity Testing Platform Construction

[0134]

[0135] Regarding question 2: In order to ensure the openness and interchangeability of modular construction, it is necessary to standardize the mechanical, electrical and communication interfaces of various functional modules.

[0136] (1) Standardized design of mechanical interfaces

[0137] Basic platform design:

[0138] Based on the measurement requirements and functional needs of the testing platforms, the transmission efficiency testing platform, torque stiffness testing platform, and linear stiffness testing platform all require high and low temperature testing environments. The testing modules with high and low temperature testing requirements share a common structural feature: a coaxial shaft system passing through the high and low temperature chamber. Therefore, a basic support platform was designed for the corresponding modules to meet the needs of installation, adjustment, and measurement of the coaxial shaft system under high and low temperature environments.

[0139] Reference Figure 9 As shown, the basic support platform includes the following components: a large basic platform 1; an internal support column structure 2 for the high and low temperature chamber; and a coaxiality auxiliary adjustment structure 3. The large basic platform 1 serves as the basic support base, supporting the high and low temperature chamber and other components and testing modules. The internal support column structure 2 is the internal support structure for the object under test, directly connected to the large basic platform; it is a through-chamber structure. The coaxiality auxiliary adjustment structure 3 is specifically used for measuring the coaxiality of the entire shaft system; after platform assembly, this structure is used to adjust the coaxiality of the shaft system.

[0140] Interchangeable interface design:

[0141] To integrate the various modules, the interfaces between them must be designed for interchangeability. Targeted design and selection of corresponding interchangeable parts were undertaken. Keyways and keys were added to the contact points for precise connection and replacement of each module. For a few modules, adapter plates and flanges were added to ensure system interchangeability. Appropriate couplings were selected for the measuring shaft system to ensure the interoperability of the modules. For example... Figure 10 As shown.

[0142] Keys and keyways were added to the basic platform to facilitate the connection of adjustment modules. The adjustment module and loading module are also connected via keys and keyways to ensure that module replacement does not affect the installation accuracy of the measurement system. Furthermore, an integrated drive-measurement design was chosen for the transmission measurement input and output. Connectors were selected to link the two modules into a single unit, enhancing interchangeability. Taking the input end as an example, the measurement module is interconnected with the drive module via an adapter plate, adapter flange, and adapter flange, such as... Figure 11 As shown in (a) above, it mainly connects the angle encoder to the motor mount of the drive module and ensures the stability of angle measurement. During the design process, a transition fit is made between the outer ring of the flange and the motor mount to ensure the accuracy of angle measurement. Adapter plate Figure 11 As shown in (b), corresponding connection threaded holes have been left in the board to ensure the accuracy of the measurement system can be maintained through adjustments after module replacement.

[0143] Also within the high and low temperature chamber, the test piece is connected to the base platform via a connecting plate inside the chamber to ensure measurement accuracy. A key and keyway connection is used to connect the connecting plate to the base platform, as shown in the schematic diagram below. Figure 12 As shown in (a) above, its adapter plate is as follows: Figure 12 As shown in (b) of the diagram.

[0144] Table 3 shows the couplings used for each module connection. For the external high and low temperature chamber, the Sanmu Puli SFF model coupling is selected, with a maximum allowable torque of 1000 N·m and extremely high torsional stiffness, achieving a maximum torque of 1.5 times the allowable torque and ultra-low inertia. This significantly reduces the number of bolts required during installation, shortens assembly time, and ensures easy interchangeability. During installation, the concentricity of the left and right inner diameters of the coupling is achieved with high precision using a special fixture. The torque and stiffness testing platform loading module is connected to the external support module using a wedge-shaped fastening method; other SFF models use a clamping method.

[0145] Table 3. Module Connection Models and Functions of the Comprehensive Performance Tester

[0146]

[0147] The interchangeable design ensures direct integration and combination of modules, while also providing interfaces for the serial design of the system, making it easier to connect different modules when dealing with different test devices.

[0148] (2) Standardized design of electrical interfaces

[0149] Electrical interfaces can be divided into internal interfaces and external interfaces.

[0150] Internal interface standardization and scalable design

[0151] A schematic diagram of the standardized interface modules inside the electrical control cabinet is shown below. Figure 13 As shown, the internal interfaces are mainly divided into a power supply system section, a servo motor drive section, a sensor signal acquisition section, and auxiliary modules for expansion. To ensure the standardization and scalability of the internal interfaces of the electrical control cabinet, the design focuses on the following four aspects: power supply system interface, motion control and drive system interface, signal acquisition interface, and auxiliary expansion interface.

[0152] Power supply system interface: such as Figure 14The power supply system architecture for the electrical control cabinet is designed for both low-voltage DC and 220V AC power supplies, including those for motor power, controllers, and signal acquisition systems. To ensure the performance of the servo motors and drivers, a ripple-free regulated power supply is used for the motor power. The voltage is selected based on the servo motors and drivers used in the platform, with a power margin of 1.5 to 2 times the peak power required by the platform's power supply to ensure future scalability. The low-voltage DC power supply for the controllers and signal acquisition systems uses two 24V standard modular power supplies, sufficient for most industrial PLC equipment, sensors, and controllers. Adapter terminals are provided for expansion connections beyond the control cabinet's requirements. For some external or special equipment, a 220V AC connection may be needed; therefore, two-prong and three-prong AC sockets are provided inside the control cabinet for direct connection to the 220V input power circuit, expanding the AC connection interface.

[0153] Drive Control System Interface: The drive control system interface includes a controller and a servo motor driver. The controller is supported by a lower-level Compact-RIO device. The servo motor driver selection supports 2-3 phase servo motor power connection; incremental and various absolute position feedback sensor interfaces; multiple digital I / O and analog I / O interfaces; and expandable servo motor position limiting function. Based on the above interfaces, the electrical control cabinet drive system supports the driving of 2 / 3 phase brushless DC motors and brushed DC motors, and supports various absolute and incremental position sensors (specific types are shown in Table 4). Furthermore, to ensure driver scalability, the design allows a single driver to support a minimum maximum power of 1000W, meeting the usage and expansion requirements of different tested mechanisms.

[0154] Table 4 Supported Driver Types for Electrical Control Cabinet Drive Systems

[0155]

[0156] Signal Acquisition Interface: The comprehensive performance tester uses NI's C-RIO series controller, which features a built-in FPGA high-speed real-time data acquisition interface and eight pluggable signal acquisition module interfaces, greatly ensuring the scalability of the test platform. Its signal acquisition module interfaces are all common, standard signal acquisition interfaces, compatible with the vast majority of sensors.

[0157] Currently available C-series modules for custom configuration include, but are not limited to, analog voltage acquisition modules, analog voltage output modules, digital signal acquisition modules, digital signal output modules, Endat protocol encoder / decoder modules, BiSS protocol encoder / decoder modules, and serial communication modules. When selecting C-series modules for a comprehensive performance tester, simply match them according to the sensor signal type of the test platform.

[0158] Auxiliary expansion interfaces: The internal auxiliary expansion interfaces mainly refer to the terminal blocks for 220V power supply and 24V low-voltage power supply, which can provide auxiliary interfaces for power supply, signal level, etc. that are easy to connect and configure for new functional modules.

[0159] External interface standardization and scalable design

[0160] The schematic diagram of the external interface standardization module is as follows: Figure 15 As shown. External interfaces are mainly represented by modular junction boxes mounted on the control cabinet surface, wiring holes reserved for expanding sensor signal lines, and aviation plug modules for motor drive and signal feedback. Meanwhile, the control cabinet also has general-purpose basic modules, specifically power switches, power indicator lights, cooling fans, and emergency stop buttons. The design of the general-purpose basic modules is as follows: Figure 16 and Figure 16 As shown.

[0161] External interfaces are mainly divided into drive system interfaces and signal acquisition interfaces. The drive system interface refers to the physical wiring port used by the servo motor, while the signal acquisition interface refers to the physical wiring port of non-servo drive modules such as sensors and magnetic powder brakes.

[0162] In the design of the external electrical interfaces of the drive system, to ensure circuit reliability and to achieve universality of electrical system connections, aviation connectors are selected as the external interfaces for connecting electrical circuits. Furthermore, the drive system aviation connectors are located on a modular terminal block. The advantage of using a modular terminal block is that the external interfaces of the electrical control cabinet can be customized without replacing the entire control cabinet.

[0163] Aviation connectors offer several advantages: 1. Ease of maintenance: If an electronic component in a circuit fails, an aviation connector allows for quick replacement. 2. Improved production processes: Aviation connectors simplify the assembly process of electronic products and streamline mass production. 3. Facilitated upgrades: As technology advances, aviation connectors allow for the replacement of older components with newer, more advanced ones. 4. Increased design flexibility: Aviation connectors are primarily used as external interfaces for electrical control cabinets. Their connection functions include: introducing 220V AC power into the control cabinet as an extension; connecting the power lines of input / output motors to the control cabinet; connecting the signal lines of input / output encoders to the control cabinet; and connecting the brake signal lines of servo motors to the control cabinet.

[0164] The 220V AC power supply to the control cabinet uses a set of aviation connectors from Weipu Electric, models WS28K3TQ and WS28J3ZG. These aviation connectors are 28mm in diameter and have three terminals. In each sub-test platform, the wiring sequence between the 220V AC three-phase lines and the aviation connectors follows a unified standard. The specific terminal definitions for this aviation connector model and the connection relationships of the three-phase lines in the control cabinet are as follows: Figure 17 and Figure 18 As shown.

[0165] The connection between the motor power line and brake signal line and the electrical control cabinet uses a set of aviation connectors from Weipu Electric, models WS28J7TQ and S28K7ZG. These aviation connectors are 28mm in diameter and have 7 terminals. In each sub-test platform, the connection sequence between the motor power line and the aviation connectors follows a unified standard. The terminal definitions of the aviation connectors and the connection order of the motor power line and brake signal line are as follows: Figure 19 and 20 As shown in the figure, the four power lines of the motor are connected to terminals 1-4 of the connector, and the two brake signal lines of the motor are connected to terminals 6 and 7 of the connector.

[0166] The encoder signal lines of the servo motors are connected to the electrical control cabinet using a complete set of aviation connectors from Weipu Electric, models WS32J12TQ and WS32K12ZG. In each sub-test platform, the connection sequence between the motor encoder and the aviation connector follows a unified standard. The terminal definitions of the aviation connectors and the connection sequence of the motor encoder are as follows: Figure 21 and Figure 22 As shown.

[0167] Signal Acquisition Interface: The signal acquisition interface involves the power supply and signal lines for each sensor, as well as wiring for power components that do not use drivers, such as magnetic particle brakes. Because different instrument combinations use significantly different sensors, aviation connectors are not suitable for the signal acquisition interface. Instead, pre-drilled wiring holes are used, allowing direct cable connection to the internal interface.

[0168] (3) Standardized design of communication interface

[0169] To meet the requirements of system openness and interchangeability, the electrical system of the comprehensive performance tester needs to adopt standardized communication protocols and interfaces. Any device can be connected to the system using the same communication protocol and interface, facilitating system maintenance and expansion. The main communication interfaces of the system are divided into two parts: one is the communication between the system management computer and the lower-level motion control system and data acquisition and processing system, i.e., upper and lower computer communication; the other is the communication between the internal device nodes of the motion control system and the data acquisition and processing system.

[0170] Communication between upper and lower computers:

[0171] Network communication is the core of maintaining system operation, responsible for receiving various instructions from the host computer, sending status updates from the slave device, and transmitting data. This paper adopts a TCP / IP-based Modbus communication architecture for communication and data transmission with the host computer, and establishes a general user protocol for this method between the host computer and the Modbus protocol.

[0172] I. Introduction to Modbus Transmission Protocol

[0173] Modbus is a serial communication protocol published in 1979 by Modicon (now Schneider Electric) for communication using programmable logic controllers (PLCs). Modbus has become the industry standard for communication protocols in the industrial field and is now a common connection method between industrial electronic devices. The main reasons why Modbus is more widely used than other communication protocols are:

[0174] (1) Publicly published and without copyright requirements

[0175] (2) Easy to deploy and maintain

[0176] (3) For suppliers, there are not many restrictions on modifying the bits or bytes of mobile local data.

[0177] Modbus allows multiple (approximately 240) devices to connect and communicate on the same network. For example, a device might measure temperature and humidity and send the results to a computer. In Supervisory Control and Data Acquisition (SCADA) systems, Modbus is commonly used to connect monitoring computers and remote terminal units (RTUs).

[0178] The Ethernet-based Modbus protocol primarily defines four different data storage types: read-only coils, read-write coils, read-only registers, and holding registers. Coils store Boolean data, while registers store 16-bit unsigned integer data. "Read-only" and "read-write" indicate the read states supported by each storage type. In the communication system of the integrated performance tester, read-write coils and holding registers are mainly used for data and instruction transmission between the upper and lower level machines.

[0179] The holding register and read / write coil will be performed as follows: Figure 23 The functional partitions shown include: Holding registers: control status area, instruction area, parameter setting area, process data area, and batch data transfer area; read / write coils include: system status area, process data area, and batch data transfer area. The functions of each partition are described below:

[0180] 1) Control Status Area: Mainly used for real-time command control during the measurement process of the host computer, such as start-up and stop.

[0181] 2) Instruction area: Used for non-real-time instructions, such as data transmission process control;

[0182] 3) Parameter setting area: This area is used by the host computer to set some system parameters required for the measurement process before the measurement begins, such as measurement range and sampling rate.

[0183] 4) System Status Area: The system status area is divided into two parts. The initial part is used for the handshake protocol during communication: when the host computer completes data reading, it sets the corresponding status bit to 1, notifying the slave computer that it can write subsequent data; simultaneously, after the slave computer completes data writing, it sets the corresponding status bit to 0, notifying the host computer that the data is ready to be read. The subsequent part is mainly used for displaying the system's safety status, facilitating the host computer's online monitoring of hardware system status changes, such as whether there is overspeed or torque overload, and also serves as the area for displaying safety alarm information.

[0184] 5) Process data area: Used for data transmission that needs to be monitored online during the measurement process, ensuring that users can observe the sensor data online through the host computer display interface;

[0185] 6) Batch Data Area: Used to upload measurement data in batches after measurement is completed. The process data area and batch data transmission area coexist with the holding register and read / write coil. The difference is that the holding register is used for numerical data transmission, while the holding register is mainly used for Boolean data transmission, such as digital I / O status data.

[0186] Table 5 shows the four main data storage types supported by the Modbus communication protocol.

[0187]

[0188] II. General Communication Protocol between Upper and Lower Computers

[0189] Based on the Modbus protocol, a general communication protocol for upper and lower computer systems was designed to meet specific functional requirements. The protocol can be divided into a command transmission section and a real-time status update section. The command transmission section refers to the protocol for the upper computer to issue functional instructions and related parameters, while the real-time status update section refers to the protocol for real-time monitoring of program running status and data.

[0190] The execution process of the upper and lower computer command transmission protocol is as follows: Figure 24As shown, by defining a new instruction flag bit coil and an instruction type flag bit register, the function of the host computer issuing instructions to the slave computer is realized. The specific process is as follows: When the host computer generates a new instruction, it sets the new instruction flag bit to 1 and writes the instruction type into the instruction type flag bit register according to the definition. The slave computer cyclically queries the new instruction flag bit. When it detects that the flag bit is set to 1, it reads the instruction type flag bit, looks up the corresponding function according to the instruction table, and executes the corresponding program. After the program execution is completed, the new instruction flag bit is reset.

[0191] The execution process of the real-time status refresh protocol is as follows: Figure 25 As shown, the lower-level machine fills in the status of the lower-level machine into the corresponding address according to the status data address table at regular intervals. The upper-level machine reads the data to detect the real-time dynamics of the instrument, including the real-time trajectory of the motor, the real-time signal data of the sensor, and the process status of certain functions.

[0192] The specific definitions of the communication protocol between the upper and lower computers are divided according to the coil and register for comprehensive performance testing. Boolean quantities related to status are defined using coil addresses, while other numerical quantities are defined using register addresses. Some general basic definitions are shown in Tables 6 and 7 below.

[0193] Table 6. Communication Protocol Read / Write Coil Address Definition Table (Partial)

[0194]

[0195] Table 7. Partial Definition of Holding Register Addresses in Communication Protocols

[0196]

[0197] III. Lower-level machine communication program

[0198] The communication protocol between the host and slave computers is based on the Modbus communication protocol, and a general-purpose, extensible instruction processing and data transmission program has been developed. The main program is a slave embedded communication program developed using LabVIEW. The main functions of this slave communication program are threefold: 1) establishing and maintaining a connection with the host computer; 2) periodically querying and receiving instructions and data from the host computer; 3) responding to communication requests from other program modules on the slave computer and sending status parameters or data to the host computer. First, a TCP / Modbus slave device instance is created as the server, using the default port 502. Then, a while loop is created, and the handle of the created slave device instance is included in the loop. Using the read coil, write coil, read holding register, and write holding register functions provided by LabVIEW, the memory registers on the network are read, thus enabling the transmission of data and instructions.

[0199] Based on the basic Modbus communication program, the system's communication program module is built using the aforementioned state machine structure. Its workflow is as follows: 1) Establish a slave device instance and initialize communication parameters; 2) Listen for connection requests from the host computer. If the host computer completes the connection and communication is successfully established, proceed to the next state; otherwise, loop and wait; 3) Read host computer instructions and initialization parameters from the network; 4) Check if other programs in the system have communication requests. If so, respond; 5) Send some random numbers to the network to confirm a good network connection. If the network is found to be open, reconnect; 6) Cycle through states 3-5 at a specified period; 7) Exit state: If a shutdown command is received from the main program, close the slave device instance and exit the state machine loop.

[0200] Lower-level internal communication

[0201] Internal communication within the lower-level machine mainly refers to the communication between various subsystems within the instrument measurement and control system controlled by the lower-level machine controller. The lower-level machine electrical system consists of three parts: the controller, the motor driver, and the sensor signal acquisition module. Internal communication needs to possess certain standardization characteristics and scalability while ensuring real-time performance.

[0202] I. Overall Internal Communication Architecture

[0203] To ensure the standardization and scalability of each subsystem in the electrical control cabinet, the internal communication interface of the lower-level machine should adopt a common and scalable communication architecture such as fieldbus. Due to the characteristics of the selected controller, the communication between the signal acquisition system and the lower-level controller is connected via an FPGA, encapsulated within the NI-CRIO series controller. For the power drive system, the servo motor driver uses EtherCAT fieldbus for communication, conforming to the internationally standardized DS301 and DS402 driver communication protocols, ensuring the openness, universality, and scalability of the power drive system. The communication architecture of the electrical control cabinet system is as follows: Figure 26 As shown.

[0204] In addition to the EtherCAT bus, the controller itself also has expandable communication interfaces such as USB serial communication, RS232, and RS485, providing support for the subsequent expansion of the motor system.

[0205] II. Fieldbus Communication

[0206] Communication between the motion controller and servo drive, as well as between the controller and data acquisition unit, typically employs a high-speed fieldbus due to its high real-time requirements and to ensure the scalability of functional modules. Common fieldbuses include PROFIBUS, EtherCAT, CANopen, PROFINET, and Modbus. Based on the superior characteristics of EtherCAT, this method utilizes the EtherCAT bus communication method, which shares the same standard, for communication between the motion controller, drive, and acquisition unit.

[0207] The driver enables motion control and braking of the servo motor. The NI motion controller connects to the ELMO driver via an EtherCAT bus, and the ELMO driver communicates with the servo motor via the Biss-C protocol. The servo motor control scheme is universal across all sub-test platforms, and its design adopts a consistent standard.

[0208] The ELMO driver model is Gold-solo-whistle-6 / 200, which can output a maximum continuous power of 960W. The Gold-solo-whistle-10 / 100 driver can output a maximum continuous power of 800W. For different sub-platforms, the selected NI controller models are mainly cRIO-9043 and cRIO-9045.

[0209] III. Data Acquisition Module Communication

[0210] The data acquisition system communication should possess excellent real-time performance and synchronization. The selected controller integrates an FPGA (Field-Programmable Gate Array), supporting programmable high-frequency, high-synchronization multi-signal acquisition. Combined with the selected signal acquisition modules, the controller can be programmed using C-series modules (NIDAQmx) via LabVIEW Real-Time, C-series modules (I / O variables) via LabVIEW Real-Time, and C-series modules via LabVIEW FPGAVI to achieve synchronous signal acquisition. Each slot on the chassis can be individually programmed, allowing for independent program design to implement the functions of each component based on the needs of the controller's extended modules.

[0211] The communication between the data acquisition module and the sensor is customized according to the sensor's specifications and technical parameters. By classifying the modules and the corresponding components in the overall control system, a general-purpose module suitable for the NI controller was selected for the signal acquisition module.

[0212] For a multi-functional module that outputs analog voltage signals, the NI-9215 module is selected.

[0213] For multi-functional modules with internal data processing capabilities that output collected values ​​according to a certain communication protocol, the SEA-9521 and SEA-9510 are selected. The SEA-9521 supports the open BISS-C and SSI standards, while the SEA-9510 module supports the Endat2.2 interface.

[0214] For a multi-functional module with an incremental output signal, the NI-9411 module is selected.

[0215] The above signal acquisition modules are characterized by their versatility and interchangeability, making them easy to use and leaving interfaces for functional expansion.

[0216] Regarding question 3:

[0217] The impact of high and low temperature environments on aerospace mechanisms: First, high and low temperature environments significantly affect the transmission efficiency of aerospace mechanisms. In such environments, mechanical components undergo thermal deformation with temperature changes, altering the internal stress state of the system, particularly affecting the mechanical fit of moving parts such as bearings, thus changing the system's frictional torque and transmission efficiency. Furthermore, high and low temperature environments also affect the lubrication of moving parts, further altering the system's internal frictional torque and transmission efficiency. Second, the elastic modulus and Poisson's ratio of metals change with temperature in high and low temperature environments. Simultaneously, the thermal deformation of metals in these environments may affect the prestress of springs. Therefore, high and low temperature environments influence the loading force, torque, and stiffness of aerospace mechanisms.

[0218] The impact of vacuum environment on aerospace mechanisms: According to existing research, vacuum environment has no significant impact on the mechanical parts of aerospace mechanisms, but mainly affects the viscosity of lubricating grease in moving parts, thus affecting the transmission efficiency of the mechanism. Secondly, since there is no air medium in a vacuum environment, it will affect the discharge characteristics of electrical components, which may affect the electrical performance of the aerospace mechanism's electrical system.

[0219] To address the above impacts, the design is implemented from three aspects: 1. Design of high and low temperature protection devices; 2. Material selection; 3. Thermal error compensation design.

[0220] (1) Design of high and low temperature protection devices

[0221] Design a reusable high / low temperature protection device that encloses functional modules. Through the design of heating and cooling systems, ensure that some module components always operate within a temperature range of -10℃ to 40℃. When the temperature inside the test chamber reaches a high of +100℃, the protection device maintains the temperature within ≤40℃ through cooling; when the temperature inside the test chamber reaches a low of -100℃, the protection device maintains the temperature within ≥-10℃ through cooling. This design method is applicable to all functional modules.

[0222] The model calculation principle is as follows:

[0223] 1) When the temperature is +100℃, the total power of the P refrigeration system is ≥ Qw (total heat load of the module);

[0224] 2) When the temperature is -100℃, the total power of the P heating system is ≥ Qw (total cooling load of the module);

[0225] 3)Qw=F·K·(Inside T-Outside T)

[0226] Where: Qw: heat conducted by the building envelope; F: area of ​​the building envelope; K: heat transfer coefficient of the building envelope;

[0227] Toutside: Calculated temperature outside the protective device; Tinside: Minimum target temperature inside the protective device;

[0228] Cooling system design principles:

[0229] There are currently three main types of refrigeration methods: liquid nitrogen, semiconductor, and physical refrigeration. Semiconductor refrigeration systems are small in size, but their heat dissipation methods and operating environment conditions are quite demanding. This case involves the application inside a high and low temperature test chamber, which makes it difficult to meet the relevant requirements.

[0230] Liquid nitrogen refrigeration has certain advantages in terms of cooling speed, temperature range, and operating environment. However, it has relatively high requirements for pipeline and operational safety, and the temperature control delay is relatively long, which causes large temperature fluctuations and is not conducive to its application in high and low temperature test chambers.

[0231] Physical cooling methods have certain advantages in terms of temperature range, system compatibility, safety, equipment operating environment and size due to their diverse structures. However, since the encoder enclosure needs to be frequently disassembled and reassembled, and the system pressure is high, it has a certain impact on the sealing of the cooling system pipeline. In this case, a plate heat exchanger is used to first cool the medium water, and then the medium water at a constant temperature is sent into the inner cavity of the encoder enclosure through pipeline to achieve the purpose of cooling.

[0232] This refrigeration system consists of an external chiller, an angle encoder enclosure, a length encoder enclosure, an external temperature sensor and control system (integrated into the high and low temperature test chamber system), and related connecting pipelines.

[0233] Working principle of the refrigeration system: When the associated environmental module enters the high-temperature test, the system's control instrument outputs a start signal to activate the chiller. The chiller operates according to the set temperature, and cooling water is sent into the piping within the high and low temperature protection device. Through the copper pipes and aluminum inner liner, heat is evenly conducted, absorbing the temperature within the protection device and thus achieving cooling. The control system adjusts the flow rate of the cooling water entering the high and low temperature protection device based on temperature feedback from sensors.

[0234] Heating system design principles:

[0235] This heating system operates during the low-temperature testing phase of the high and low temperature test chamber, where the internal temperature can reach as low as -100°C. Therefore, the water piping of the shared refrigeration system is abandoned, and a direct heating method using heating elements is adopted. The heating system consists of heating elements, an aluminum inner liner, external sensors, a control system, and solid-state relays. The working principle of the heating system is as follows: When the high and low temperature test chamber is conducting low-temperature tests, the temperature inside the high and low temperature protection device can be set via the control instrument. As the temperature inside the test chamber gradually decreases, when the sensor inside the protection device detects that the temperature is lower than or close to the instrument's set temperature, the instrument controls the solid-state relay to energize the heating elements. To prevent localized high temperatures on the surface of the heating elements from damaging the functional modules, the heating elements are placed inside the aluminum inner liner. The excellent thermal conductivity of aluminum ensures uniform heat distribution, improving the temperature uniformity within the high and low temperature protection device and providing protection. Regardless of how low the external ambient temperature drops, the instrument controls the heating amount of the heating elements to stabilize it at the target set value.

[0236] Based on the defined functional modules, this paper statistically analyzes the external characteristics and outer envelope dimensions of all functional modules, and designs two specifications of high and low temperature protection devices. One is a cylindrical high and low temperature protection device, such as... Figure 27 As shown, one type is a rectangular high and low temperature protection device, such as... Figure 28 As shown, the two types of high and low temperature protection devices can cover the entire functional module set.

[0237] The cylindrical high and low temperature protection device is assembled from an aluminum inner cavity, a stainless steel outer shell, a tubular heater, a water-medium copper pipe, polyurethane foam insulation material, a connecting frame, and sealing silicone material. The rectangular high and low temperature protection device is also assembled from an aluminum inner cavity, a stainless steel outer shell, a tubular heater, a water-medium copper pipe, polyurethane foam insulation material, a connecting frame, and sealing silicone material.

[0238] The high and low temperature protection device designed in this paper is interconnected with the instrument signals of the high and low temperature module and the vacuum environment module. The temperature signal of the high and low temperature protection device is fed back to the high and low temperature module in real time, and the high and low temperature module adjusts the operating parameters of the heating system and the cooling system according to the feedback temperature signal.

[0239] (2) Material selection

[0240] Commonly used materials for structural components of various functional modules under extreme environments include carbon structural steel, stainless steel, aluminum alloy, copper alloy, spring steel (at normal temperature or under conditions where environmental adaptability requirements are not high), and Invar alloy. Through analysis of the deformation of various materials under high and low temperature environments, and taking the principle of minimizing the impact of extreme environments on test accuracy, the design criteria for the materials of each functional module in this method were derived:

[0241] The module material placed outside the high and low temperature chamber is selected as 0Cr17Ni4Cu4Nb stainless steel;

[0242] For the test shaft structural components inside the high and low temperature chamber that are greatly affected by temperature, Invar steel grade 4J36 is selected.

[0243] The internal support platform and its support columns at high and low temperatures exhibit linear height expansion of approximately 13.938 μm and -18.99 μm when the temperature changes from room temperature (20℃) to a high temperature of 100℃ and a low temperature of -100℃. The coefficient of thermal expansion of stainless steel is approximately 10 times that of Invar. If stainless steel is used, the linear height changes of the internal support platform would be approximately 140 μm and -190 μm. The experimental values ​​were corrected using software.

[0244] The bearing housing inside the high and low temperature chamber is made of stainless steel with a coefficient of thermal expansion similar to that of the bearing material. This ensures that when the bearing housing deforms due to temperature changes, its expansion is similar to that of the bearing, preventing excessive changes in bearing clearance and potential seizing.

[0245] (3) Thermal error compensation design

[0246] When temperature changes have a non-negligible impact on the measurement accuracy of functional modules, thermal error compensation should be performed on the modules to improve the measurement accuracy of the test modules and ensure the authenticity and validity of the test data.

[0247] Before thermal error compensation, it is necessary to perform simulation, theoretical analysis, measurement experiments, and algorithm prediction of thermal errors. Thermal error compensation typically includes the following tasks:

[0248] 1) Thermal Error Simulation Analysis. The impact of temperature on the module structure is an unavoidable factor in the structural component design process. Thermal error simulation analysis can provide a reference for the module structure design, and the design process involves the following steps:

[0249] The first step is to set up the physical field. Usually, solid mechanics and solid heat transfer fields are selected, and thermal expansion and temperature coupling are set up. The results of solid heat transfer are then incorporated into solid mechanics.

[0250] The second step is to establish the geometric model. To simplify the model design and improve simulation efficiency, a two-dimensional axisymmetric model should be chosen as the simulation object, while ensuring the simulation effect.

[0251] The third step is to set up the analysis conditions. This includes basic simulation data such as the selection of simulation materials, the setting of the simulation region, and the setting of boundary conditions.

[0252] The fourth step is mesh generation. Mesh density affects not only the accuracy and speed of the simulation, but also the simulation speed. A high mesh density results in high simulation accuracy but a decrease in simulation speed, while a low mesh density results in high simulation speed but low accuracy. Therefore, mesh generation requires a trade-off between simulation efficiency and accuracy when choosing the appropriate mesh density.

[0253] The fifth step is model solving. After setting all simulation parameters, the computer automatically runs the simulation and plots the simulation parameters of interest. Combined with the graphical structural analysis, this provides guidance for the module structure design (including material selection, structural dimensions, and other parameters) and provides guidance for structural optimization.

[0254] 2) Thermal Error Theoretical Analysis. A thermal error model is constructed from the perspective of thermodynamic principles to theoretically analyze the impact of temperature on functional modules. The general steps of thermal error theoretical analysis are: selection of the analysis object → model simplification → theoretical data analysis.

[0255] This paper presents a thermal error analysis of the influence of temperature on the shaft system.

[0256] a) Selection of analysis objects

[0257] The object of analysis is the drive shaft of a high and low temperature measuring device. Part of the drive shaft is located inside a high and low temperature chamber (temperature range -100℃ to 100℃), and part is located at room temperature (23℃±2℃). Based on material selection criteria, Invar 4J36 steel was selected, whose coefficient of thermal expansion remains at 1.5ppm / ℃ over a considerable temperature range. A simplified diagram of the drive shaft is shown below. Figure 31 As shown.

[0258] b) Model simplification

[0259] Assume the initial length of the entire drive shaft at room temperature (T0) is l, the initial length of the drive shaft portion inside the high / low temperature chamber is l1, defined as segment a; and the length of the drive shaft portion at room temperature is l2, defined as segment b. When the temperature inside the high / low temperature chamber changes by ΔT1, segment a of the drive shaft experiences axial deformation due to heat. l1; Furthermore, due to heat conduction, some of the heat from section a of the drive shaft is transferred to section b of the drive shaft, causing axial deformation in that section. l2. Figure 29 This is a simplified one-dimensional model of segment b of the drive shaft.

[0260] c) Theoretical Data Analysis

[0261] The thermal deformation of section b of the drive shaft will be analyzed first.

[0262] The drive shaft section b has only one heat source from the left end of the high and low temperature chamber. Heat enters from the left end of section b and dissipates through convection and radiation heat exchange with the surrounding environment. The axial thermal deformation caused by the increased temperature of the drive shaft is as follows:

[0263] (1)

[0264] In the formula —The coefficient of thermal expansion of the drive shaft material;

[0265] —Length of section b of the drive shaft;

[0266] —Position on the drive shaft;

[0267] —Temperature field distribution on the drive shaft;

[0268] —Actual temperature in a normal environment.

[0269] Applying the Mean Value Theorem to equation (1), we have:

[0270] (2)

[0271] In the formula —At the median temperature, we have:

[0272] (3)

[0273] In the formula, Let l be a point on segment b of the drive shaft between [0, l2], such as Figure 30 As shown.

[0274] From equation (3), we can draw the following conclusion:

[0275] There is at least one point on segment b of the drive shaft ( ) temperature Capable of expressing the amount of thermal deformation of section b of the drive shaft. ,and Temperature of point Thermal deformation of section b of the drive shaft They are in a linear proportional relationship.

[0276] For example Figure 31 Heat is transferred from the left end of drive shaft segment b (heat transferred from the high and low temperature chamber) and then discharged from drive shaft segment b. Let the cross-sectional area of ​​the drive shaft be A, the circumference be C, the radius be r, the surface thermal conductivity be λ, the convective heat transfer coefficient be h, the ambient temperature be T0, and the temperature at each point on drive shaft segment b be T.

[0277] When section b of the drive shaft is conducting heat in a steady state, for each differential unit, the heat input and heat output are equal, i.e., the energy equation is:

[0278] (4)

[0279] In the formula —Differential unit in The heat introduced into the area;

[0280] —Differential unit in The heat introduced into the area;

[0281] —Convection heat between the periphery of drive shaft section b and the surrounding environment;

[0282] By converting equation (4), we can obtain:

[0283] (5)

[0284] In the formula Let be the combined parameters of the drive shaft. It is not difficult to see that the heat conduction differential equation (5) for segment b of the drive shaft is a second-order non-homogeneous linear differential equation with constant coefficients, and its general solution is:

[0285] (6)

[0286] In the formula, c1 and c2 are two integration constants of the equation, and solving them requires two boundary conditions. For the steady-state heat conduction of section b of the drive shaft, the boundary conditions are: ① When x=0, T=T(0); ② When x=l2, the total heat conduction at the right end of section b of the drive shaft is equal to the total convective heat transfer. Substituting the above two boundary conditions into formula (6), we get:

[0287] (7)

[0288] Analyzing the temperature and temperature gradient of the right end face of segment b of the transmission shaft, we can obtain equation (8):

[0289] (8)

[0290] Solving the system of equations (7) and (8) simultaneously, we get:

[0291] (9)

[0292] Additionally, for the midpoint of the integral Substituting formula (6) into formula (2), we get:

[0293] (10)

[0294] Substituting equation (9) into equation (10), we can obtain:

[0295] (11)

[0296] In the formula, , , Taking the convective heat transfer coefficient h = 20 W / m²K, the surface thermal conductivity λ = 60 W / mK, the length of section b of the drive shaft l² = 0.7 m, and the radius of the drive shaft r = 0.02 m, substituting these values ​​into equation (11), we can calculate:

[0297] (12)

[0298] Substituting different values ​​for h, λ, l2, and r yields minimal changes, remaining approximately 1 / 3 of the length l2 of segment b of the drive shaft. This indicates that the key point for the temperature sensor is approximately 1 / 3 of the way down from the left end of segment b. Therefore, the thermal deformation model of segment b can be described by a first-order linear function. These results demonstrate that, with proper placement of the temperature sensors, a linear model can be used to predict the thermal deformation of segment b of the drive shaft. Similarly, the thermal deformation of segment a of the drive shaft can also be predicted using one or more key temperature points.

[0299] In practical applications, since the actual measured thermal deformation of the drive shaft is the sum of the thermal deformations of segments a and b, it is insufficient to predict the thermal deformation of segment b using only two temperature measurement points. Therefore, it is proposed to place a temperature sensor at each of the key heat source points (inside the high and low temperature chamber, at the left end of segment a of the drive shaft, at the right end of segment a, at one-third of the distance from the left end of segment b of the drive shaft, and at room temperature) as temperature measurement points. Partial correlation analysis or grayscale correlation analysis will be used to assess the influence of these temperature measurement points on the thermal error of the drive shaft, and the optimal combination of temperature measurement points will be selected.

[0300] 3) Thermal error measurement experiment: The project conducted experiments on the relationship between workpiece temperature and time in high and low temperature chambers and at room temperature. When the high and low temperature chamber was set from 40℃ to 80℃, the curves were basically consistent, and the workpiece temperature usually took 2 hours to stabilize. Different initial room temperatures would have some impact on the stable temperature of the workpiece at room temperature, but the curves were basically parallel, that is, the temperature difference remained basically consistent.

[0301] Based on the above experimental results, this invention further investigated the influence of the high and low temperature chamber setting temperature and room temperature on thermal errors. The following conclusions were drawn: When the high and low temperature chamber is set to 80 degrees Celsius, the thermal expansion can reach 98.3 μm to 107.1 μm due to the coupling of multiple factors. This result includes errors introduced by the thermal expansion of the shaft system, the thermal expansion of internal mounting components, and the thermal expansion of the desktop. The thermal expansion of the shaft system changes with the room temperature; in the short term, for every 0.11°C change in room temperature, the thermal expansion of the shaft system changes by 1.5 μm.

[0302] 4) Apply the compensation table algorithm to predict thermal errors and achieve thermal error compensation. The ultimate goal of the above work is to compensate for the temperature of the module structure to eliminate or reduce the impact of temperature on the module's measurement accuracy. Support vector machine regression can be used not only for classification but also for regression prediction analysis. For the training sample set (xi,yi) (where i=1,2,…,n;xi∈Rn, which are input variables; yi∈R, which are the corresponding output values), the basic idea of ​​support vector machine regression theory is to find a nonlinear mapping φ from the input space to the output space. Through this nonlinear mapping, the data x is mapped to a high-dimensional feature space F, and linear regression is performed in the feature space using the following estimation function:

[0303]

[0304] (13)

[0305] in, The threshold is used. The function approximation problem is equivalent to the following function:

[0306] (14)

[0307] In the formula The objective function is...

[0308] : Sample size;

[0309] Error penalty factor;

[0310] : Adjustment constant;

[0311] :reflect fFlat complexity in high-dimensional space.

[0312] Considering linearity ε The insensitive loss function has good sparsity and can be obtained as follows:

[0313] (15)

[0314] The empirical risk function is:

[0315] (16)

[0316] According to statistical theory, the support vector machine minimizes the following objective function to determine the regression function:

[0317] (17)

[0318] In the formula, C —Weight parameters used to balance the model complexity term and the training error term;

[0319] , — Relaxation factor;

[0320] ε — Insensitive loss function.

[0321] This problem can be transformed into the following dual problem:

[0322] (18)

[0323] Solving the above problem yields the support vector machine regression function:

[0324] (19)

[0325] Based on the regression theory of support vector machines, a suitable support vector machine toolbox is selected to analyze and predict the measurement data obtained from the thermal error measurement experiment.

[0326] Regarding question 4: Considering the periodic verification and calibration of the equipment, force parameter verification modules, torque parameter verification modules, angle parameter verification modules, and displacement parameter verification modules were designed simultaneously to calibrate the accuracy of the multi-functional module. Each verification module adopts the same standardized design as the multi-functional module, including mechanical interfaces, electrical interfaces, and communication interfaces.

[0327] The technical specifications of the torque parameter verification module must meet the following requirements:

[0328] 1) The measurement range is (0~500) Nm;

[0329] 2) The uncertainty is 0.15%FS (k=2) (0.8Nm);

[0330] 3) The operating temperature range is -100℃ to 100℃.

[0331] The technical specifications of the angle parameter calibration module must meet the following requirements:

[0332] 1) Measurement range: 0~360°;

[0333] 2) Expanded uncertainty: 12'' (k=2);

[0334] 3) Operating temperature range: -100℃~100℃.

[0335] The technical specifications of the length parameter verification module must meet the following requirements:

[0336] 1) Measuring range: 0~70mm;

[0337] 2) Expanded uncertainty: 1.5 μm (k=2);

[0338] 3) Temperature range of high and low temperature chamber: -100~100℃.

[0339] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0340] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A measurement method for multi-specification precision mechanisms and single machine components, characterized in that, Includes the following steps: Step S1: Analyze the test principle and test equipment composition of the mechanical transmission performance test items for precision mechanisms of spacecraft; the test items include transmission efficiency, force-linear stiffness, torque-angular stiffness, assembly accuracy, and vibration response; Step S2: Decompose and divide each test item from the perspective of physical quantities; Step S3: Based on the composition principles of different test equipment, the test platform hardware is divided into basic platform, drive system, loading system and detection system; the electrical system is divided into drive control, data acquisition, data processing and transmission; and the motion is divided into linear motion system, rotary motion system and compound motion system. Based on the above breakdown, the hardware is divided into loading module, driver-test integrated module, detection module, and support module, and further subdivided according to linear and rotational factors to form a functional module tree, and an environmental simulation functional module and a verification module are designed. Step S4: Standardize the mechanical, electrical, and communication interfaces for various functional modules; Step S5: Optimize the measurement from three aspects: high and low temperature protection device design, material selection, and thermal error compensation design, in response to the impact of high and low temperature and vacuum environments. Step S6: Use the above functional modules to form various functional test platforms, and use them with a measurement and control system to measure multiple physical quantities of precision mechanisms and single components.

2. The measurement method for multi-specification precision mechanisms and single machine components according to claim 1, characterized in that, The testing principles and experimental equipment composition for each test item in step S1 include: Transmission efficiency test: The test principle is the percentage of output power to input power when the machine is running stably. Input power and output power are indirectly measured by multiplying the input / output speed by the input / output torque, respectively. The test equipment includes an input end and an output end, with a torque sensor and a high-precision position encoder connected in series in the shaft system of the input end and the output end, respectively. Force-Linear Stiffness Test: The test principle is to indirectly measure the linear stiffness by measuring the elastic deformation of the test object under different force loads; the test equipment is driven by a closed-loop controlled linear drive module and equipped with tensile and compressive sensors and linear displacement sensors. Torque-Angle Stiffness Test: The test principle is to indirectly measure the torsional stiffness by measuring the torsional elastic deformation of the test object under different torque loads; the test equipment is driven by a closed-loop controlled rotary drive module, and a torque sensor and a rotary displacement sensor are connected in series in the shaft system; Vibration performance testing: The testing principle is to apply a specific frequency and displacement excitation to the test object through a vibration table, and at the same time test the response parameters; the test equipment adopts a two-axis vibration test scheme, including a two-axis loading platform, two electric vibration tables, a displacement amplification mechanism, a non-contact direct drive mechanism, a double-layer marble platform, a multi-input multi-output vibration control system, and various measuring devices; Assembly accuracy testing includes distance, angle, coaxiality, end runout, and surface detection. The testing principle is based on the calculation of spatial point cloud data of the object under test. The test equipment includes a linear drive module, a rotary drive module, and a precision micro-motion probe.

3. The measurement method for multi-specification precision mechanisms and single machine components according to claim 1, characterized in that, Step S2 involves breaking down each test item into its physical quantity components, including: The transmission efficiency test is broken down into force parameter measurement, torque parameter measurement, speed parameter measurement, angle parameter measurement, and length parameter measurement. Stiffness testing is broken down into force parameter measurement, torque parameter measurement, angle parameter measurement, and length parameter measurement. Assembly accuracy measurement is broken down into angle parameter measurement and length parameter measurement; Vibration response measurement is broken down into acceleration parameter measurement and displacement parameter measurement.

4. The measurement method for multi-specification precision mechanisms and single machine components according to claim 1, characterized in that, In step S3: The environmental simulation module includes a high and low temperature module, a vacuum module, and a vibration module; The calibration module includes a force parameter calibration module, a torque parameter calibration module, an angle parameter calibration module, and a displacement parameter calibration module.

5. The measurement method for multi-specification precision mechanisms and single machine components according to claim 1, characterized in that, The standardized design of mechanical interfaces in step S4 includes: Basic platform design: For test modules with high and low temperature testing requirements, a basic support platform is designed, including a basic large platform, a support column structure inside the high and low temperature chamber, and an auxiliary adjustment structure for the coaxiality of the shaft system; Interchangeable interface design: Add keyways and key connections to the module contact parts, or connect to the adapter plate and adapter flange. Select appropriate couplings for the measuring shaft system. In the high and low temperature chamber, the test piece is connected to the base platform via a key and keyway through the connecting plate inside the chamber.

6. The measurement method for multi-specification precision mechanisms and single-machine components according to claim 5, characterized in that, The coupling selected is the Mikipuri SFF model. The external coupling of the high and low temperature chamber has a maximum allowable torque of 1000 N.m, which can achieve a maximum of 1.5 times the allowable torque and ultra-low inertia. The concentricity of the left and right inner diameters is ensured by special fixtures. The connection between the loading module and the external support module of the torque stiffness test platform adopts a wedge fastening method. Other SFF models adopt a clamping method.

7. The measurement method for multi-specification precision mechanisms and single machine components according to claim 1, characterized in that, Step S4, the electrical interface standardization design, includes the standardization and scalability design of internal and external interfaces: Internal interface: - Power supply system interface: Ripple-free regulated power supply for motor power, with a power margin of 1.5 to 2 times; Low-voltage DC power supply for controller and signal acquisition system uses two 24V standard module power supplies with adapter terminals and a reserved 220V AC socket. -Drive control system interface:The controller is supported by the lower-level controller Compact-RIO device, and the servo motor driver supports 2-3 phase servo motor power connection, multiple position feedback sensor interfaces and multiple I / O interfaces; -Signal acquisition interface: It comes with a built-in FPGA high-speed real-time data acquisition interface and 8 pluggable signal acquisition module interfaces; - Auxiliary expansion interface: provides terminal blocks for 220V power supply and 24V low voltage power supply; External interface: - Drive system interface: An aviation plug is selected as the external interface for connecting electrical circuits. The aviation plug is located on the modular terminal block. - Signal acquisition interface: It adopts a reserved wiring hole and connects directly to the internal interface through a cable.

8. The method of claim 1, wherein, The standardized design of the communication interface in step S4 includes: Upper and lower computer communication: The Modbus communication architecture based on TCP / IP is adopted. A general user protocol is developed on the basis of the Modbus protocol. The Modbus protocol defines four data storage types and divides the holding register and read / write coil into functional partitions. The general upper and lower computer communication protocol is divided into command transmission part and real-time status refresh part. The lower computer embedded communication program based on LabVIEW is written. Internal communication of the lower-level machine: EtherCAT fieldbus is used for communication, and the communication protocol of the internationally standardized DS301 and DS402 drivers is followed. The controller integrates FPGA field programmable gate array, and the signal acquisition module is selected according to the sensor specifications, which has universality and interchangeability.

9. The measurement method for multi-specification precision mechanisms and single-unit components according to claim 1, characterized in that, In step S5: High and low temperature protection device design: The design includes a reusable high and low temperature protection device, available in cylindrical and rectangular sizes. It is composed of an aluminum inner cavity, a stainless steel outer shell, a tubular heater, a water-medium copper pipe, polyurethane foam insulation material, a connecting frame, and sealing silicone material. The cooling system uses a plate heat exchanger for cooling, and the heating system uses a direct heating tube heating method. The temperature signal of the protection device is fed back to the high and low temperature module in real time. Material selection: The module material placed outside the high and low temperature chamber is 0Cr17Ni4Cu4Nb stainless steel. The test shaft structure inside the high and low temperature chamber, which is greatly affected by temperature, is made of 4J36 Invar steel. The internal support platform and its support columns of the high and low temperature chamber are corrected for errors by software according to temperature changes. The bearing housing inside the high and low temperature chamber is made of stainless steel with a coefficient of thermal expansion similar to that of the bearing material. Thermal error compensation design: Conduct thermal error simulation analysis, theoretical analysis, and measurement experiments. Apply the compensation table method and support vector machine regression method to predict and compensate for thermal errors. Place temperature sensors at key points of the heat source and use partial correlation analysis or gray-scale correlation analysis to select the optimal combination of temperature measurement points.

10. The measurement method for multi-specification precision mechanisms and single-unit components according to claim 8, characterized in that, The data storage types and functional partitions of the Modbus protocol in upper and lower computer communication are as follows: Data storage types include read-only coils, read-write coils, read-only registers, and holding registers; The holding register function area includes the control status area, instruction area, parameter setting area, process data area, and batch data transfer area; The read / write coil functional area includes the system status area, process data area, and batch data transmission area.

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