In-situ calibration device and method for six-degree-of-freedom micro-vibration table

Abstract

The application discloses a kind of six-degree-of-freedom microvibration table in-situ calibration device and method, including six-degree-of-freedom microvibration table top, installation platform, line vibration calibration unit and angular vibration calibration unit, coordinate positioning tool, coordinate positioning tool fine adjustment mechanism, data acquisition analysis system host computer, the line vibration calibration unit includes acceleration measurement unit, vibration displacement measurement unit, acceleration measurement unit is used to carry out the in-situ calibration of test system line vibration parameter, and vibration displacement measurement unit is used to carry out the in-situ calibration of test system vibration displacement parameter;The angular vibration calibration unit is used to carry out the in-situ calibration of test system angular vibration parameter.The application realizes the field in-situ calibration of six-degree-of-freedom microvibration table three-axis line vibration and three-axis angular vibration, realizes the calibration in low frequency, small amplitude, multi-axis angular compound vibration state by acceleration sensor and angular vibration sensor, with the advantages of low cost, quick response, high reliability.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of metrological calibration, in particular to a six-degree-of-freedom micro-vibration table in-situ calibration device and method. BACKGROUND

[0002] The in-orbit micro-vibration degree of high-precision spacecraft such as satellites has a great influence on the pointing accuracy and imaging quality of the payload, so six-degree-of-freedom micro-vibration environment simulation tests must be carried out on the satellite and its payload.

[0003] The six-degree-of-freedom micro-vibration test table developed for in-orbit micro-vibration tests has a large frequency bandwidth, small vibration amplitude, and high resolution, which brings great challenges to in-situ calibration.

[0004] Currently, the in-situ calibration of key parameters such as linear vibration parameters and angular vibration parameters of the six-degree-of-freedom micro-vibration table mainly uses accelerometers to calibrate the independent amplitudes in three directions, without testing and calibrating multi-degree-of-freedom test conditions, so it cannot meet the demand for comprehensive parameter system-level in-situ calibration, thus cannot accurately reflect the vibration control precision of the system, cannot achieve the purpose of micro-vibration test, and brings hidden dangers to the performance test and reliability evaluation of the satellite payload. In order to ensure the smooth development of high-precision satellite components and their payloads, it is urgent to carry out research on the in-situ calibration technology of the six-degree-of-freedom test table to solve the problem of traceability of values.

[0005] Patent 201510441726.3 discloses a diffraction grating heterodyne laser vibration meter for angular vibration measurement, which includes a diffraction device, a laser interferometer, a signal processing device, and a phase demodulation device. Although this patent involves calibration of angular vibration based on a standard angular vibration table, it can only perform single-axis angular vibration calibration and cannot be applied to in-situ calibration.

[0006] Patent 201010589368.8 discloses a self-calibration three-axis vibration monitoring and environmental monitoring acquisition system, which is composed of a group of vibration monitoring modules, a temperature compensation module, an environmental monitoring module, and a signal conditioning module. The acceleration module provides acceleration measurement in three directions (three-axis acceleration sensor). However, the acceleration measurement range of this patent is -2g to +2g, and the measurement accuracy is 0.66v / g, so the applicable measurement range is different, and the measurement accuracy is poor. SUMMARY

[0007] To solve the above problems, the purpose of the present application is to provide a six-degree-of-freedom micro-vibration table in-situ calibration device and method to realize in-situ calibration of three-axis six-degree-of-freedom linear vibration and angular vibration parameters of a six-degree-of-freedom micro-vibration table with a wide frequency band and a small range.

[0008] The specific technical solutions of the present application are as follows:

[0009] A six-degree-of-freedom micro-vibration table in-situ calibration device, comprising a six-degree-of-freedom micro-vibration table upper table, a mounting platform, a linear vibration calibration unit and an angular vibration calibration unit, a coordinate positioning tool, a coordinate positioning tool fine adjustment mechanism, a data acquisition and analysis system upper computer, wherein:

[0010] The mounting platform is mounted on the six-degree-of-freedom micro-vibration table upper table, and the center hole of the mounting platform coincides with the center positioning hole of the six-degree-of-freedom micro-vibration table upper table;

[0011] The coordinate positioning tool is used to obtain the corresponding coordinate system origin and the X, Y and Z axis directions of the six-degree-of-freedom micro-vibration table, and ensure accurate coordinate position positioning;

[0012] The linear vibration calibration unit comprises an acceleration measurement unit and a vibration displacement measurement unit, wherein the acceleration measurement unit comprises three-axis acceleration sensors A, B and C, a single-axis acceleration sensor, a sensor mounting seat, a signal conditioning module and a high-precision distance measuring instrument, which are used for in-situ calibration of linear vibration parameters of a test system, wherein the three-axis acceleration sensors A, B and C are respectively mounted on the sensor mounting seat and connected with the signal conditioning module through data cables, and the single-axis acceleration sensor is mounted at the coordinate origin O position for linear vibration signal acquisition;

[0013] The vibration displacement measurement unit comprises a vibration displacement measurement tool, a laser head, a laser head mounting tool and a laser vibration measurement system controller, which are used for in-situ calibration of vibration displacement parameters of a test system, wherein the laser head comprises laser heads A, B and C, which are incident along the X, Y and Z axes of the coordinate system respectively, and the laser heads are fixedly installed on the laser head mounting tool, and the laser head mounting tool is used to ensure that the laser heads do not displace and loosen during in-situ calibration;

[0014] The angular vibration calibration unit comprises three-axis acceleration sensors A, B and C, a sensor mounting seat, an angular vibration sensor, an angular vibration mounting seat and a signal conditioning module, which are used for in-situ calibration of angular vibration parameters of a test system, wherein the angular vibration sensor is mounted on the angular vibration mounting seat, the three-axis acceleration sensors A, B and C are respectively mounted on the sensor mounting seat, and the angular vibration sensor, the three-axis acceleration sensors A, B and C are connected with the signal conditioning module through data cables;

[0015] The three-axis acceleration sensor 1 is installed on the X axis, one sensitive axis is coincidently installed on the X axis, and the other two axes are perpendicular to the coordinate system, the three-axis acceleration sensor 2 is installed on the Y axis, one sensitive axis is coincidently installed on the Y axis, and the other two axes are perpendicular to the coordinate system, and the three-axis acceleration sensor 3 is symmetrically installed with the three-axis acceleration sensor 1 around the Z axis.

[0016] Preferably, the host computer of the data acquisition and analysis system adopts a PXI control system based on PXI bus technology, which is used to collect the voltage signals output by the signal conditioning module and the laser vibration measurement system controller, and obtain vibration parameters through solving algorithms. The system software in the host computer of the data acquisition and analysis system includes a self-checking module, a calibration test module, and a data management module, wherein:

[0017] The self-checking module controls the work of each module of the hardware system, and is used to check the reliability of the work of the system hardware;

[0018] The calibration test module is used to control the hardware system to complete calibration, and realize calibration of three-axis vibration and three-axis angular vibration;

[0019] The data management module displays, saves and arranges the calibration results, and includes a virtual device driver for realizing interruption of sampling data.

[0020] Preferably, the installation platform has a matching assembly interface with the upper surface of the six-degree-of-freedom micro-vibration table, a traceable measurement interface matching the standard device table surface of the upper traceable mechanism, and installation holes uniformly distributed around the center hole, which are matched with coordinate positioning tools and vibration measurement tools, and are used to install the coordinate positioning tools and the vibration measurement tools.

[0021] The installation platform surface can be closely attached to the upper surface, and has rigidity and carrying capacity.

[0022] Preferably, the coordinate positioning tool has three-direction fine adjustment, yaw angle rotation and two-dimensional deflection fine adjustment functions, and can realize coordinate positioning and measurement functions, and is used to determine the coordinate system origin and the X axis, Y axis and Z axis directions of the coordinate system during in-situ calibration.

[0023] Preferably, the signal conditioning module is used to condition, amplify and filter the vibration signals obtained by the three-axis acceleration sensor A, the three-axis acceleration sensor B, the three-axis acceleration sensor C and the angular vibration sensor, and convert them into voltage signals.

[0024] Preferably, the high-precision distance measuring instrument is used to obtain the distances of the three-axis acceleration sensor A, the three-axis acceleration sensor B and the three-axis acceleration sensor C from the coordinate origin.

[0025] Preferably, the vibration displacement measurement tool is connected with the coordinate positioning tool fine adjustment mechanism, is installed at the center hole position of the installation platform through the positioning installation hole, and the measurement plane of the vibration displacement measurement tool is perpendicular to the incident direction of the laser head;

[0026] The vibration displacement measurement tool can provide measurement planes in three directions of the X axis, the Y axis and the Z axis of the coordinate system, and the axis corresponding to the coordinate system is parallel, and the vibration displacement measurement tool does not loosen or deform when the test bench makes linear vibration movement.

[0027] Preferably, the laser vibration measurement system controller controls the laser head to emit laser to the measurement plane of the vibration displacement measurement tool.

[0028] The laser vibration measurement system controller comprises a displacement decoding board and a speed decoding board, which are used for collecting and analyzing analog vibration signals and outputting vibration analog signals to the host computer of the data acquisition system.

[0029] Preferably, the laser head installation tool has a direction adjusting function and a locking function, the direction adjusting function ensures the laser incident direction of the laser probe, and the locking function ensures that the position of the laser probe does not change in the measurement process.

[0030] Preferably, the coordinate positioning tool fine adjustment mechanism is connected with the installation platform and has a locking function with each degree of freedom, which is used for installing and fixing the coordinate positioning tool, the vibration displacement measurement tool and the laser head installation tool, and ensures that the coordinate positioning tool, the vibration displacement measurement tool and the laser head installation tool can coincide with the coordinate system of the six-degree-of-freedom micro-vibration table.

[0031] A six-degree-of-freedom micro-vibration table in-situ calibration method, the in-situ calibration method comprises a linear vibration calibration method, a vibration displacement calibration method and an angular vibration calibration method.

[0032] Preferably, the linear vibration calibration method comprises the following steps:

[0033] S1, installing the installation platform on the upper surface of the six-degree-of-freedom micro-vibration table at a specified position, and making the center hole of the installation platform coincide with the center positioning hole of the upper surface of the six-degree-of-freedom micro-vibration table;

[0034] The three-axis acceleration sensor A, the three-axis acceleration sensor B and the three-axis acceleration sensor C are installed on the sensor mounting seat and are installed at the specified position of the installation platform through the positioning hole on the surface of the installation platform.

[0035] The three-axis acceleration sensor A, the three-axis acceleration sensor B and the three-axis acceleration sensor C are installed on the sensor mounting seat and are installed at the specified position of the installation platform through the positioning hole on the surface of the installation platform.

[0036] The tooling and the sensor are stable for not less than 4 hours at a constant temperature on site;

[0037] S2, a high-precision distance measuring instrument is used to measure the distances of the three-axis acceleration sensor A, the three-axis acceleration sensor B and the three-axis acceleration sensor C from the origin of the coordinate system, 10 measurements are taken for each distance in a short time, and the average of the 10 measurements is taken as the measurement result, and distances l1, l2 and l3 are obtained, wherein the three-axis acceleration sensor 1 and the three-axis acceleration sensor 3 are symmetrically installed around the Z axis, so that the installation distance l1 is equal to the installation distance l3;

[0038] S3, the three-axis acceleration sensor A, the three-axis acceleration sensor B and the three-axis acceleration sensor C are connected with the signal conditioning module through a special data cable, and the output end of the signal conditioning module is connected with the calibration test module of the data acquisition system host computer through a cable;

[0039] The special data cable is attached to the installation platform with a special anti-static adhesive tape to prevent the cable from being pulled and displaced;

[0040] The signal conditioning module is turned on and set to a specified gear, and the data acquisition system host computer is turned on and preheated for 30 minutes;

[0041] S4, the six-degree-of-freedom micro-vibration table is controlled to vibrate at a specified frequency and amplitude, and the amplitude signals ai (i = 1, 2, …, 9) of the three-axis acceleration sensor A, the three-axis acceleration sensor B and the three-axis acceleration sensor C in each axis direction are obtained through the data acquisition system host computer, wherein a1, a2, …a9 represent the numbers of different sensitive axis directions of the sensors.

[0042] The position coordinate matrix l and the sensitive direction coordinate matrix θ of the 9 sensor sensitive axes of the three three-axis sensors relative to the origin of the carrier coordinate system are

[0043]

[0044]

[0045] According to the kinematic equation, the output of any acceleration sensor sensitive axis is obtained

[0046]

[0047] In the formula:

[0048] a - acceleration signal measured on the acceleration sensor

[0049] K - coefficient matrix

[0050] - angular acceleration of the carrier coordinate system

[0051] A - linear acceleration of the carrier coordinate system in three coordinate axis directions

[0052] wherein:

[0053]

[0054] K2 = θ = [θ1 θ2 … θ9], l = [l1 l2 … l9], K1 = [l1 x θ1 l2 x θ2 … l9 x θ9]

[0055] The formula (3) is fully expanded to obtain the angular velocity, angular acceleration and linear acceleration about the carrier coordinate system, and the mutual relationship expression of the related parameters representing the linear vibration in the six degrees of freedom is obtained as formula (4).

[0056]

[0057] The value of the linear vibration parameter of the test system is obtained by formula (4), and the in-situ calibration of the linear vibration parameter of the test system is realized.

[0058] Preferably, the vibration displacement calibration method comprises the following steps:

[0059] S1, installing the mounting platform on the six-degree-of-freedom micro-vibration table at a specified position on the table top, and making the center hole of the mounting platform coincide with the center positioning hole on the table top of the six-degree-of-freedom micro-vibration table;

[0060] The coordinate positioning tool is installed at the coordinate origin position of the six-degree-of-freedom micro-vibration table, the center of the coordinate positioning tool is made to coincide with the center of the origin of the six-degree-of-freedom micro-vibration table, and the origin of the calibration coordinate system and the X-axis, Y-axis and Z-axis directions of the coordinate system are determined; the coordinate positioning tool is connected with the vibration displacement measurement tool through the installation interface;

[0061] The laser head installation tool is installed along the X-axis, Y-axis and Z-axis directions of the coordinate system, and the laser head is installed on the laser head installation tool, the direction of the incident laser of the laser head being perpendicular to the measurement surfaces of the three directions of the vibration displacement measurement tool; it is ensured that the transmission line of the laser head does not contact the table top of the test table;

[0062] S2, installing and adjusting the fine adjustment mechanism of the coordinate positioning tool, making the coordinate system axis of the coordinate positioning tool coincide with the coordinate system axis of the test table, and using a laser interferometer to perform precision measurement on the measurement surface of the linear vibration measurement tool, so as to ensure that the measurement surfaces of the three directions of the vibration displacement measurement tool are perpendicular to the coordinate system axis;

[0063] S3, connecting the laser vibration measurement system controller with the calibration test module of the data acquisition system host computer through a special data cable;

[0064] Turning on the laser vibration measurement system controller and setting it to a specified gear, and turning on the host computer and preheating for 30 minutes;

[0065] Fine-tune the laser head incident angle installed on the laser head mounting tool, so that the incident laser energy reaches the maximum, and the signal-to-noise ratio of the laser measurement signal is improved;

[0066] S4, control the six-degree-of-freedom micro-vibration table to vibrate at a specified frequency and amplitude, and obtain the amplitude signal of each axis direction through the data acquisition system host computer, and control the motion trajectory curve fitting,

[0067] The sine motion function of each axis is set as

[0068]

[0069] The three axes are measured by the laser vibration measurement system, and the measured signal is represented as Then

[0070]

[0071] The vibration displacement signal of the test bench is Then

[0072]

[0073] The vibration displacement amplitude indication error is calculated by the following formula

[0074]

[0075] Preferably, the angular vibration calibration method comprises the following steps:

[0076] S1, install the installation platform on the six-degree-of-freedom micro-vibration table at a specified position on the table surface, and make the center hole of the installation platform coincide with the center positioning hole on the upper surface of the six-degree-of-freedom micro-vibration table;

[0077] Install three-axis acceleration sensor A, three-axis acceleration sensor B, and three-axis acceleration sensor C on the sensor mounting seat, and install them to the specified position on the installation platform through the positioning hole on the surface of the installation platform;

[0078] Determine the corresponding coordinate information of the six-degree-of-freedom micro-vibration table by using the coordinate positioning tool, determine the origin of the calibration coordinate system and the three-axis directions of the X-axis, Y-axis and Z-axis of the coordinate system, install the angular vibration sensor on the coordinate positioning tool, and ensure that the center of the coordinate positioning tool coincides with the center of the six-degree-of-freedom micro-vibration table;

[0079] Adjust the coordinate positioning tool fine-tuning mechanism to make the coordinate system axis of the coordinate positioning tool coincide with the coordinate system axis of the test bench;

[0080] The tool and the sensor are stable for not less than 4 hours under constant temperature on site;

[0081] S2, the high-precision distance measuring instrument is used to measure the distance of the three-way acceleration sensor A, the three-way acceleration sensor B and the three-way acceleration sensor C from the origin of the coordinate system, and 10 measurements are taken for each distance in a short time, and the average of 10 times is taken as the measurement result, and the distances l1, l2 and l3 are obtained, wherein the three-way acceleration sensor 1 and the three-way acceleration sensor 3 are symmetrically installed around the Z axis, so that the installation distance l1 is equal to the installation distance l3;

[0082] S3, the three-way acceleration sensor A, the three-way acceleration sensor B and the three-way acceleration sensor C are connected with the signal conditioning module through a special data cable, and the output end of the signal conditioning module is connected with the calibration test module of the data acquisition system host computer through a cable;

[0083] The special data cable is attached to the installation platform with a special anti-static adhesive tape to prevent the cable from being pulled and displaced;

[0084] The signal conditioning module is turned on and set to a specified gear, and the data acquisition system host computer is turned on and preheated for 30 minutes;

[0085] S4, the six-degree-of-freedom micro-vibration table is controlled to vibrate at a specified frequency and amplitude, and the amplitude signals ai (i=1, 2, …, 9) of the three-way acceleration sensor A, the three-way acceleration sensor B and the three-way acceleration sensor C in each axis direction are obtained through the data acquisition system host computer, wherein a1, a2, …a9 represent the numbers of different sensitive axis directions of the sensor;

[0086] According to the derivation of formulas (1) and (2), formula (3) is completely expanded, and the related parameters in the six degrees of freedom are solved And

[0087]

[0088] An angular vibration sensor is used, and the data acquisition system is used for acquisition, and the host computer obtains the angular vibration value alpha (x) of the test system around the X axis. The two linear acceleration sensors on the X axis are symmetrically installed around the Z axis, that is, the installation distance l1 is approximately equal to the installation distance l3, and the three-axis angular vibration parameters of the test table are represented as:

[0089]

[0090] Compared with the prior art, the beneficial effects obtained by the present application are as follows:

[0091] (1) The six-degree-of-freedom micro-vibration table in-situ calibration device provided by the present application realizes the in-situ calibration of the three-axis linear vibration and the three-axis angular vibration of the six-degree-of-freedom micro-vibration table;

[0092] (2) The high-precision acceleration sensor and the angular vibration sensor group are adopted in the application, the problem of six-degree-of-freedom parameter test under the condition of low-frequency, small amplitude and multi-axis angular compound vibration is solved, and the application has the advantages of low cost, fast response and high reliability;

[0093] (3) The three-direction acceleration sensor combination is adopted in the application, the installation errors introduced by the traditional mutual orthogonal installation of six or nine single-axis acceleration sensors are avoided, the hidden danger of mutual interference of the installation positions caused by the occupation of a certain volume by each single-axis sensor is also avoided, the space volume of the whole system and the accumulated error of the calculation are small, and the overall measurement precision of the system is improved;

[0094] (4) The installation and positioning tooling developed after accurate measurement and structural design and the vibration displacement measurement tooling based on precision machining and high-precision fine adjustment mechanism are adopted in the application, are applied to the in-situ calibration of the three-axis vibration and three-axis angular vibration of the test table, and the measurement coordinate system of the installation and positioning tooling of the six-degree-of-freedom micro-vibration table motion coordinate system and the measured point position is overlapped in the in-situ calibration. BRIEF DESCRIPTION OF DRAWINGS

[0095] In order to more clearly illustrate the technical solutions disclosed in the application, the following will briefly introduce the drawings needed to be used in some embodiments disclosed by the application. Obviously, the drawings in the following description are only the drawings of some embodiments disclosed by the application, and other drawings can also be obtained by those skilled in the art according to these drawings. In addition, the drawings in the following description can be regarded as schematic diagrams, and are not limited to the actual size, actual process, etc. of the product involved in the embodiments disclosed by the application.

[0096] Figure 1 A general structure schematic diagram of a six-degree-of-freedom micro-vibration table in-situ calibration device provided by the application is shown in the figure.

[0097] Figure 2 A structure schematic diagram of a linear vibration calibration unit provided by the application is shown in the figure.

[0098] Figure 3 A structure schematic diagram of an angular vibration calibration unit provided by the application is shown in the figure.

[0099] Figure 4 A three-direction sensor installation position schematic diagram provided by the application is shown in the figure.

[0100] Figure 5 An acceleration measurement unit installation position schematic diagram provided by the application is shown in the figure.

[0101] Figure 6 A vibration displacement measurement unit installation position schematic diagram provided by the application is shown in the figure.

[0102] Figure 7 A schematic diagram of an angular vibration calibration unit installation position provided by the present application;

[0103] Figure 8 A schematic diagram of an installation platform provided by the present application;

[0104] Figure 9 A schematic diagram of a coordinate positioning tool provided by the present application;

[0105] Figure 10 A schematic diagram of a vibration displacement measurement tool installed on a coordinate positioning tool provided by the present application. DETAILED DESCRIPTION

[0106] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application. Therefore, the present application is not limited by the specific embodiments disclosed below.

[0107] As shown in Figure 1 , Figure 2 and Figure 3 , a six-degree-of-freedom micro-vibration table in-situ calibration device includes a six-degree-of-freedom micro-vibration table upper surface, an installation platform, a linear vibration calibration unit and an angular vibration calibration unit, a coordinate positioning tool, a coordinate positioning tool fine adjustment mechanism, and a data acquisition and analysis system upper computer, wherein:

[0108] The installation platform is installed on the six-degree-of-freedom micro-vibration table upper surface, and the center hole of the installation platform coincides with the center positioning hole of the six-degree-of-freedom micro-vibration table upper surface;

[0109] The coordinate positioning tool is used to obtain the corresponding coordinate system origin and the X-axis, Y-axis, and Z-axis three-axis directions of the six-degree-of-freedom micro-vibration table, and ensures accurate coordinate position positioning;

[0110] As shown in Figure 2 , the linear vibration calibration unit includes an acceleration measurement unit and a vibration displacement measurement unit, wherein the acceleration measurement unit includes a three-axis acceleration sensor A, a three-axis acceleration sensor B, a three-axis acceleration sensor C, a one-way acceleration sensor, a sensor mounting seat, a signal conditioning module, and a high-precision distance measuring instrument, which are used for in-situ calibration of the linear vibration parameters of the test system, as shown in Figure 5As shown, the three-axis acceleration sensor A, the three-axis acceleration sensor B, and the three-axis acceleration sensor C are respectively installed on the sensor mounting base and connected to the signal conditioning module through a data cable. The unidirectional acceleration sensor is installed at the coordinate origin O position for obtaining the line vibration signal;

[0111] The vibration displacement measurement unit includes a vibration displacement measurement tool, a laser head, a laser head installation tool, and a laser vibration measurement system controller, and is used to perform in-situ calibration of the vibration displacement parameters of the test system, such as Figure 6 As shown, the laser head includes laser head A, laser head B, and laser head B, which are incident along the three directions of the coordinate system X axis, Y axis, and Z axis respectively. The laser head is fixedly mounted on the laser head mounting fixture, and the laser head mounting fixture is used to ensure that the laser head does not move or loosen during in-situ calibration;

[0112] like Figure 3 As shown, the angular vibration calibration unit includes a three-axis acceleration sensor A, a three-axis acceleration sensor B, a three-axis acceleration sensor C, a sensor mounting base, an angular vibration sensor, an angular vibration mounting base, and a signal conditioning module, which is used to perform in-situ calibration of the angular vibration parameters of the test system, such as Figure 7 As shown, the angular vibration sensor is mounted on an angular vibration mounting base; the three-axis acceleration sensor A, the three-axis acceleration sensor B, and the three-axis acceleration sensor C are respectively mounted on the sensor mounting base; the angular vibration sensor, the three-axis acceleration sensor A, the three-axis acceleration sensor B, and the three-axis acceleration sensor C are connected to the signal conditioning module via a data cable;

[0113] like Figure 4 As shown, the three-axis acceleration sensor 1 is installed on the X-axis, with one sensitive axis installed coincidentally with the X-axis, and the other two axes are perpendicular to the coordinate system. The three-axis acceleration sensor B is installed on the Y-axis, with one sensitive axis installed coincidentally with the Y-axis, and the other two axes are perpendicular to the coordinate system. The three-axis acceleration sensor C is installed symmetrically with the three-axis acceleration sensor A around the Z-axis.

[0114] The host computer of the data acquisition and analysis system adopts a PXI control system based on PXI bus technology, which is used to collect the voltage signals output by the signal conditioning module and the laser vibration measurement system controller, and obtain vibration parameters through the solution algorithm. The system software in the host computer of the data acquisition and analysis system includes a self-test module, a calibration test module, and a data management module, among which:

[0115] The self-test module controls the operation of each module of the hardware system and is used to test the reliability of the system hardware operation;

[0116] The calibration test module is used for controlling the hardware system to complete calibration, and realizes calibration of three-axis linear vibration and three-axis angular vibration.

[0117] The data management module displays, saves and arranges the calibration results, and contains a virtual device driver for realizing interruption of sampling data.

[0118] As shown in Figure 8 , the installation platform center has a matching assembly interface with the upper surface of the six-degree-of-freedom micro-vibration table, a traceable measurement interface matching the standard device surface of the upper traceable measurement mechanism, and mounting holes uniformly distributed around the center hole, which are matched with the coordinate positioning tool and the vibration measurement tool and used for mounting the coordinate positioning tool and the vibration measurement tool.

[0119] The installation platform surface can be closely attached to the upper surface and has rigidity and load capacity.

[0120] As shown in Figure 9 , the coordinate positioning tool has fine adjustment functions of three-direction translation, yaw rotation and two-dimensional yaw, and can realize coordinate positioning and measurement functions, and is used for determining the coordinate system origin and the X-axis, Y-axis and Z-axis directions of the coordinate system during in-situ calibration.

[0121] The signal conditioning module is used for conditioning, amplifying and filtering the vibration signals obtained by the three-axis acceleration sensor A, the three-axis acceleration sensor B, the three-axis acceleration sensor C and the angular vibration sensor, and converting them into voltage signals.

[0122] The high-precision distance measuring instrument is used for obtaining the distances of the three-axis acceleration sensor A, the three-axis acceleration sensor B and the three-axis acceleration sensor C from the coordinate origin.

[0123] As shown in Figure 10 , the vibration displacement measurement tool is connected with the fine adjustment mechanism of the coordinate positioning tool, is installed at the center hole position of the installation platform through the positioning mounting hole, and the measurement plane of the vibration displacement measurement tool is perpendicular to the incident direction of the laser head.

[0124] The vibration displacement measurement tool can provide measurement planes in three directions of the X-axis, Y-axis and Z-axis of the coordinate system, and the corresponding axis is parallel to the coordinate system, and the vibration displacement measurement tool does not loosen or deform when the test table makes linear vibration motion.

[0125] The laser vibration measurement system controller controls the laser head to emit laser to the measurement plane of the vibration displacement measurement tool.

[0126] The laser vibration measurement system controller includes a displacement decoding board and a speed decoding board, which are used for collecting and analyzing analog vibration signals and outputting vibration analog signals to the host computer of the data acquisition system.

[0127] The laser head mounting tool has a direction adjusting function and a locking function, the direction adjusting function ensures the laser incidence direction of the laser probe, and the locking function ensures that the position of the laser probe does not change during the measurement process.

[0128] The coordinate positioning tool fine adjustment mechanism is connected with the mounting platform and has locking functions of various degrees of freedom, is used for mounting and fixing the coordinate positioning tool, the vibration displacement measurement tool and the laser head mounting tool, and ensures that the coordinate positioning tool, the vibration displacement measurement tool and the laser head mounting tool can coincide with the six-degree-of-freedom micro-vibration table coordinate system.

[0129] A six-degree-of-freedom micro-vibration table in-situ calibration method, the in-situ calibration method includes a six-degree-of-freedom micro-vibration table linear vibration calibration method, a vibration displacement calibration method and an angular vibration calibration method.

[0130] The linear vibration calibration method includes the following steps:

[0131] S1, install the mounting platform on the upper surface of the six-degree-of-freedom micro-vibration table at a specified position, and make the center hole of the mounting platform coincide with the center positioning hole of the upper surface of the six-degree-of-freedom micro-vibration table;

[0132] The coordinate positioning tool is used to determine the corresponding coordinate information of the six-degree-of-freedom micro-vibration table, and the origin of the calibration coordinate system and the X-axis, Y-axis and Z-axis directions of the coordinate system are determined.

[0133] The three-way acceleration sensor A, the three-way acceleration sensor B and the three-way acceleration sensor C are installed on the sensor mounting seat and are installed at a specified position of the mounting platform through the positioning hole on the surface of the mounting platform;

[0134] The tool and the sensor are stable for not less than 4 hours at a constant temperature on site;

[0135] S2, a high-precision distance measuring instrument is used to measure the distances of the three-way acceleration sensor A, the three-way acceleration sensor B and the three-way acceleration sensor C from the origin of the coordinate system, 10 measurements are made for each distance in a short time, and the average of 10 measurements is taken as the measurement result, and distances l1, l2 and l3 are obtained, wherein the three-way acceleration sensor 1 and the three-way acceleration sensor 3 are symmetrically installed around the Z-axis, so that the installation distance l1 is equal to the installation distance l3.

[0136] S3, the three-way acceleration sensor A, the three-way acceleration sensor B and the three-way acceleration sensor C are connected with the signal conditioning module through a special data cable, and the output end of the signal conditioning module is connected with the calibration test module of the upper computer of the data acquisition system through a cable.

[0137] The special data cable is attached to the mounting platform with a special anti-static adhesive tape to prevent the cable from being pulled and displaced;

[0138] The signal conditioning module is turned on and set to a specified gear, the data acquisition system host computer is turned on, and preheating is performed for 30 minutes.

[0139] S4, control the six-degree-of-freedom micro-vibration table to perform vibration with a specified frequency and amplitude, and obtain amplitude signals ai (i = 1, 2,..., 9) of each axis direction of the three-axis acceleration sensor A, the three-axis acceleration sensor B, and the three-axis acceleration sensor C through the data acquisition system host computer, wherein a1, a2,...a9 represent the numbers of different sensitive axis directions of the sensors.

[0140] The position coordinate matrix l and the sensitive direction coordinate matrix θ of the 9 sensor sensitive axes of the 3 three-axis sensors relative to the origin of the carrier coordinate system are

[0141]

[0142] According to the kinematic equation, the output of any acceleration sensor sensitive axis is obtained

[0143]

[0144] In the formula:

[0145] a - the acceleration signal measured on the acceleration sensor

[0146] K - coefficient matrix

[0147] - angular acceleration of the carrier coordinate system

[0148] A - linear acceleration of the carrier coordinate system in the three coordinate axis directions

[0149] Wherein:

[0150]

[0151] K2 = θ = [θ1 θ2 … θ9], r = [r1 r2 … r9], K1 = [r1×θ1 r2×θ2 … r9×θ9]

[0152] The formula (3) is fully expanded to obtain the angular velocity, angular acceleration, and linear acceleration of the carrier coordinate system, and the mutual relationship expression of the related parameters representing the linear vibration in the six-degree-of-freedom is obtained by solving as formula (4).

[0153]

[0154] The value of the linear vibration parameter of the test system is obtained through formula (4), and the in-situ calibration of the linear vibration parameter of the test system is realized.

[0155] The vibration displacement calibration method comprises the following steps:

[0156] S1, install the mounting platform on the six-degree-of-freedom micro-vibration table at a specified position on the table top, with the center hole of the mounting platform coinciding with the center positioning hole on the table top of the six-degree-of-freedom micro-vibration table;

[0157] Install the coordinate positioning tooling at the coordinate origin position of the six-degree-of-freedom micro-vibration table, ensure that the center of the coordinate positioning tooling coincides with the origin center of the six-degree-of-freedom micro-vibration table, and determine the origin of the calibration coordinate system and the X, Y, Z axis directions of the coordinate system; connect the coordinate positioning tooling to the vibration displacement measurement tooling through the installation interface;

[0158] Install the laser head installation tooling along the X, Y, Z axis directions of the coordinate system, and install the laser head on the laser head installation tooling, with the direction of the incident laser of the laser head being perpendicular to the measurement surfaces of the three directions of the vibration displacement measurement tooling; ensure that the transmission line of the laser head does not contact the table top of the test bench;

[0159] S2, install and adjust the fine adjustment mechanism of the coordinate positioning tooling, align the coordinate system axis of the coordinate positioning tooling with the coordinate system axis of the test bench, and use a laser interferometer to perform precision measurement on the measurement surface of the linear vibration measurement tooling, to ensure that the measurement surfaces of the three directions of the vibration displacement measurement tooling are perpendicular to the coordinate system axis;

[0160] S3, connect the laser vibration measurement system controller to the calibration test module of the data acquisition system host computer through a special data cable;

[0161] Turn on the laser vibration measurement system controller and set it to the specified gear, and turn on the host computer and preheat for 30 minutes;

[0162] Fine-tune the incident angle of the laser head installed on the laser head installation tooling, so that the incident laser energy reaches the maximum, and the signal-to-noise ratio of the laser measurement signal is improved;

[0163] S4, control the six-degree-of-freedom micro-vibration table to vibrate at a specified frequency and amplitude, acquire the amplitude signals of each axis direction through the host computer of the data acquisition system, and perform control motion trajectory curve fitting,

[0164] Set the sinusoidal motion function of each axis direction as

[0165]

[0166] Measure the three axis directions through the laser vibration measurement system, and the measured signal is represented as Then

[0167]

[0168] The vibration displacement signal of the test bench is Then

[0169]

[0170] The amplitude error of the vibration displacement is calculated by the following formula

[0171]

[0172] The angular vibration calibration method comprises the following steps:

[0173] S1, install the mounting platform on the six-degree-of-freedom micro-vibration table at a specified position on the table top, and make the center hole of the mounting platform coincide with the center positioning hole on the table top of the six-degree-of-freedom micro-vibration table;

[0174] Install the three-axis acceleration sensor A, the three-axis acceleration sensor B and the three-axis acceleration sensor C on the sensor mounting seat and through the positioning hole on the surface of the mounting platform to the specified position on the mounting platform;

[0175] Determine the corresponding coordinate information of the six-degree-of-freedom micro-vibration table by using the coordinate positioning tool, determine the origin of the calibration coordinate system and the X, Y and Z axes of the coordinate system, install the angular vibration sensor on the coordinate positioning tool, and ensure that the center of the coordinate positioning tool coincides with the center of the six-degree-of-freedom micro-vibration table;

[0176] Adjust the coordinate positioning tool fine adjustment mechanism to make the coordinate system axis of the coordinate positioning tool coincide with the coordinate system axis of the test table;

[0177] The tool and the sensor are stable for not less than 4 hours at a constant temperature on site;

[0178] S2, measure the distances of the three-axis acceleration sensor A, the three-axis acceleration sensor B and the three-axis acceleration sensor C from the origin of the coordinate system by using a high-precision distance measuring instrument, measure each distance for 10 times in a short time, take the average of the 10 times as the measurement result, and obtain distances l1, l2 and l3, wherein the three-axis acceleration sensor 1 and the three-axis acceleration sensor 3 are symmetrically installed around the Z axis, so that the installation distance l1 is equal to the installation distance l3;

[0179] S3, connect the three-axis acceleration sensor A, the three-axis acceleration sensor B and the three-axis acceleration sensor C with the signal conditioning module through a special data cable, and connect the output end of the signal conditioning module with the calibration test module of the host computer of the data acquisition system through a cable;

[0180] The special data cable is attached to the mounting platform with a special anti-static tape to prevent the cable from being pulled and displaced;

[0181] Turn on the signal conditioning module and set it to the specified gear, and turn on the host computer of the data acquisition system host computer and preheat for 30 minutes;

[0182] S4. Control the six-degree-of-freedom micro-vibration table to vibrate at a specified frequency and amplitude, and obtain the amplitude signals ai (i = 1, 2, ..., 9) of the three-axis acceleration sensor A, the three-axis acceleration sensor B, and the three-axis acceleration sensor C in each axis direction through the data acquisition system host computer, where a1, a2, ..., a9 represent the numbers of the different sensitive axis directions of the sensors;

[0183] According to the derivation of formula (1) and (2), formula (3) is fully expanded to solve the relevant parameters in the six degrees of freedom and

[0184]

[0185] The angular vibration sensor is used to collect data through the data acquisition system, and the host computer obtains the angular vibration of the test system around the X axis. The two linear acceleration sensors on the X-axis are installed symmetrically around the Z-axis, that is, the installation distance l1≈l3, and the three-axis angular vibration parameters of the test bench are expressed as:

[0186]

[0187] Although the present invention has been disclosed above in terms of preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art may use the above-disclosed contents to make possible changes and modifications to the technical solutions of the present invention without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the contents of the technical solutions of the present invention shall fall within the scope of protection of the technical solutions of the present invention.

Claims

1. An in-situ calibration device for a six-degree-of-freedom micro-vibration table, characterized by: The calibration device includes a six-degree-of-freedom micro-vibration table top, a mounting platform, a linear vibration calibration unit and an angular vibration calibration unit, a coordinate positioning tool, a coordinate positioning tool fine-tuning mechanism, and a data acquisition and analysis system host computer, wherein: The table top of the six-degree-of-freedom micro-vibration table is provided with a central positioning hole and a mounting hole that matches the shape and size of the test product; The mounting platform is mounted on the tabletop of the six-degree-of-freedom micro-vibration table, and the mounting platform is provided with a center hole that coincides with the center positioning hole on the tabletop of the six-degree-of-freedom micro-vibration table; The coordinate positioning tool is used to obtain the coordinate system origin and the three-axis directions of the coordinate system X-axis, Y-axis and Z-axis corresponding to the six-degree-of-freedom micro-vibration table to ensure accurate coordinate positioning; The linear vibration calibration unit includes an acceleration measurement unit and a vibration displacement measurement unit, wherein: the acceleration measurement unit includes a three-axis acceleration sensor A, a three-axis acceleration sensor B, a three-axis acceleration sensor C, a unidirectional acceleration sensor, a sensor mounting seat, a signal conditioning module, and a high-precision distance measuring instrument, and is used to perform in-situ calibration of the linear vibration parameters of the test system, wherein the three-axis acceleration sensor A, the three-axis acceleration sensor B, and the three-axis acceleration sensor C are respectively mounted on the sensor mounting seat and connected to the signal conditioning module via a data cable, and the unidirectional acceleration sensor is mounted at the coordinate origin O position for acquiring the linear vibration signal; The vibration displacement measurement unit includes a vibration displacement measurement tool, a laser head, a laser head mounting tool, and a laser vibrometer system controller, and is used to perform in-situ calibration of the vibration displacement parameters of the test system. The laser heads include laser head A, laser head B, and laser head C, which are incident along the X-axis, Y-axis, and Z-axis of the coordinate system, respectively. The laser heads are fixedly mounted on the laser head mounting tool, and the laser head mounting tool is used to ensure that the laser heads do not move or become loose during in-situ calibration. The angular vibration calibration unit includes a three-axis acceleration sensor A, a three-axis acceleration sensor B, a three-axis acceleration sensor C, a sensor mounting base, an angular vibration sensor, an angular vibration mounting base, and a signal conditioning module, and is used to perform in-situ calibration of the angular vibration parameters of the test system, wherein the angular vibration sensor is mounted on the angular vibration mounting base; the three-axis acceleration sensor A, the three-axis acceleration sensor B, and the three-axis acceleration sensor C are respectively mounted on the sensor mounting base; the angular vibration sensor, the three-axis acceleration sensor A, the three-axis acceleration sensor B, and the three-axis acceleration sensor C are connected to the signal conditioning module via a data cable; The three-axis acceleration sensor 1 is installed on the X-axis, with one sensitive axis installed coincident with the X-axis, and the other two axes are perpendicular to the coordinate system. The three-axis acceleration sensor B is installed on the Y-axis, with one sensitive axis installed coincident with the Y-axis, and the other two axes are perpendicular to the coordinate system. The three-axis acceleration sensor C is installed symmetrically with the three-axis acceleration sensor A around the Z-axis.

2. The in-situ calibration device for a six-degree-of-freedom micro-vibration table according to claim 1, characterized in that: The host computer of the data acquisition and analysis system adopts a PXI control system based on PXI bus technology, which is used to collect the voltage signals output by the signal conditioning module and the laser vibration measurement system controller, and obtain vibration parameters through the solution algorithm. The system software in the host computer of the data acquisition and analysis system includes a self-test module, a calibration test module, and a data management module, among which: The self-test module controls the operation of each module of the hardware system and is used to test the reliability of the system hardware operation; The calibration test module is used to control the hardware system to complete the calibration, realizing the calibration of three-axis vibration and three-axis angular vibration; The data management module displays, saves, and organizes the calibration results, and includes a virtual device driver for implementing interruption of sampling data.

3. The in-situ calibration device for a six-degree-of-freedom micro-vibration table according to claim 1, characterized in that: The center of the mounting platform has an assembly interface that matches the table top of the six-degree-of-freedom micro-vibration table, a traceability measurement interface that matches the table top of the superior traceability mechanism standard device, and mounting holes that are evenly distributed around the center hole. The mounting holes match the coordinate positioning tooling and the vibration measurement tooling and are used to install the coordinate positioning tooling and the vibration measurement tooling; The mounting platform table top can be tightly fitted on the upper table top and has rigidity and load-bearing capacity.

4. The in-situ calibration device for a six-degree-of-freedom micro-vibration table according to claim 1, characterized in that: The coordinate positioning fixture is used to determine the origin of the coordinate system and the three-axis directions of the coordinate system X-axis, Y-axis and Z-axis during in-situ calibration.

5. The in-situ calibration device for a six-degree-of-freedom micro-vibration table according to claim 1, characterized in that: The signal conditioning module is used to condition, amplify and filter the vibration signals obtained by the three-axis acceleration sensor A, the three-axis acceleration sensor B, the three-axis acceleration sensor C and the angular vibration sensor, and convert them into voltage signals.

6. The six-degree-of-freedom micro-vibration table in-situ calibration device according to claim 1, characterized in that: The high-precision distance measuring instrument is used to obtain the distances between the three-axis acceleration sensor A, the three-axis acceleration sensor B, and the three-axis acceleration sensor C and the coordinate origin.

7. The in-situ calibration device for a six-degree-of-freedom micro-vibration table according to claim 1, characterized in that: The vibration displacement measuring fixture is connected to the fine-tuning mechanism of the coordinate positioning fixture and is installed at the center hole position of the mounting platform through the positioning mounting hole. The measuring plane of the vibration displacement measuring fixture is perpendicular to the incident direction of the laser head. The vibration displacement measurement fixture can provide measurement planes in the three directions of the coordinate system X axis, Y axis and Z axis, and is parallel to the axis corresponding to the coordinate system. At the same time, the vibration displacement measurement fixture does not loosen or deform when the test bench performs linear vibration motion.

8. The in-situ calibration device for a six-degree-of-freedom micro-vibration table according to claim 1, characterized in that: The laser vibration measurement system controller controls the laser head to emit laser light onto the measuring surface of the vibration displacement measurement fixture; The laser vibration measurement system controller includes a displacement decoding board and a speed decoding board, which are used to collect and analyze analog vibration signals and output vibration simulation signals to the data acquisition system host computer.

9. The in-situ calibration device for a six-degree-of-freedom micro-vibration table according to claim 1, characterized in that: The laser head installation tooling has a direction adjustment function and a locking function. The direction adjustment function ensures the laser incident direction of the laser probe, and the locking function ensures that the position of the laser probe does not change during the measurement process.

10. The in-situ calibration device for a six-degree-of-freedom micro-vibration table according to claim 1, characterized in that: The coordinate positioning tooling fine-tuning mechanism is connected to the installation platform and has a degree of freedom locking function. It is used to install the fixed coordinate positioning tooling, vibration displacement measurement tooling, and laser head installation tooling to ensure that the fixed coordinate positioning tooling, vibration displacement measurement tooling, and laser head installation tooling can coincide with the six-degree-of-freedom micro-vibration table coordinate system.

11. A six-degree-of-freedom micro-vibration table in-situ calibration method, characterized in that: An in-situ calibration device for a six-degree-of-freedom micro-vibration table according to any one of claims 1 to 9 is used, wherein the in-situ calibration method includes a linear vibration calibration method, a vibration displacement calibration method, and an angular vibration calibration method.

12. The in-situ calibration method of a six-degree-of-freedom micro-vibration table according to claim 11, characterized in that: The linear vibration calibration method comprises the following steps: S1. Install the mounting platform at the designated position on the tabletop of the six-degree-of-freedom micro-vibration table, so that the center hole of the mounting platform coincides with the center positioning hole on the tabletop of the six-degree-of-freedom micro-vibration table; Use coordinate positioning tooling to determine the coordinate information corresponding to the six-degree-of-freedom micro-vibration table, and determine the origin of the calibration coordinate system and the directions of the X-axis, Y-axis, and Z-axis of the coordinate system; Install three-axis acceleration sensor A, three-axis acceleration sensor B, and three-axis acceleration sensor C on the sensor mounting base and install them to the designated position of the mounting platform through the positioning holes on the surface of the mounting platform; The tooling and sensor are kept stable at a constant temperature on site for more than or equal to 4 hours; S2. Use a high-precision distance measuring instrument to measure the distances between three-axis accelerometer A, three-axis accelerometer B, and three-axis accelerometer C and the origin of the coordinate system. Measure each distance 10 times in a short period of time, and take the average of the 10 measurements as the measurement result to obtain distances Q, W, and E, respectively. Three-axis accelerometer A and three-axis accelerometer C are installed symmetrically around the Z axis, so that the installation distance Q is equal to the installation distance E. S3. Connect three-axis acceleration sensor A, three-axis acceleration sensor B, and three-axis acceleration sensor C to the signal conditioning module through dedicated data cables, and connect the output end of the signal conditioning module to the calibration test module of the data acquisition system host computer through cables; Special data cables are attached to the installation platform with special anti-static tape to prevent the cables from being pulled and displaced; Turn on the signal conditioning module and set it to the specified gear, turn on the data acquisition system host computer, and preheat for 30 minutes; S4. Control the six-degree-of-freedom micro-vibration table to vibrate at a specified frequency and amplitude, and obtain the amplitude signals ai (i = 1, 2, ..., 9) of the three-axis acceleration sensor A, the three-axis acceleration sensor B, and the three-axis acceleration sensor C in each axis direction through the data acquisition system host computer, where a1, a2, ..., a9 represent the numbers of the different sensitive axis directions of the sensors; The position coordinate matrix l and the sensitive direction coordinate matrix θ of the nine sensor sensitive axes of the three three-directional sensors relative to the origin of the carrier coordinate system are: Obtain the output of any acceleration sensor's sensitive axis according to the kinematic equation Where: a——Acceleration signal measured on the accelerometer K——Coefficient Matrix ——Angular acceleration of the carrier coordinate system A——Linear acceleration in the three coordinate axes of the carrier coordinate system in: K2=θ=[θ1θ2…θ9], l=[l1 l2…l9], K1=[l1×θ1l2×θ2…l9×θ9] Expanding Equation (3) completely, we can obtain the angular velocity, angular acceleration, and linear acceleration of the carrier coordinate system. The relationship between the relevant parameters characterizing the six-degree-of-freedom midline vibration is obtained as Equation (4). The values ​​of the test system line vibration parameters are obtained by formula (4), and the on-site in-situ calibration of the test system line vibration parameters is achieved.

13. The in-situ calibration method of a six-degree-of-freedom micro-vibration table according to claim 11, characterized in that: The vibration displacement calibration method comprises the following steps: S1. Install the mounting platform at the designated position on the tabletop of the six-degree-of-freedom micro-vibration table, so that the center hole of the mounting platform coincides with the center positioning hole on the tabletop of the six-degree-of-freedom micro-vibration table; Install the coordinate positioning fixture at the coordinate origin of the six-degree-of-freedom micro-vibration table, ensure that the center of the coordinate positioning fixture coincides with the center of the six-degree-of-freedom micro-vibration table origin, determine the origin of the calibration coordinate system and the directions of the X-axis, Y-axis, and Z-axis of the coordinate system; connect the coordinate positioning fixture to the vibration displacement measurement fixture through the installation interface; The laser head mounting fixture is installed along the X-axis, Y-axis, and Z-axis directions of the coordinate system, and the laser head is mounted on the laser head mounting fixture. The direction of the incident laser from the laser head is perpendicular to the measuring surfaces of the three directions of the vibration displacement measurement fixture; ensure that the transmission line of the laser head does not touch the test bench surface; S2. Install and adjust the fine-tuning mechanism of the coordinate positioning fixture to align the coordinate axis of the coordinate positioning fixture with the coordinate axis of the test bench. Use a laser interferometer to precisely measure the measuring surface of the linear vibration measurement fixture to ensure that the three-directional measuring surfaces of the vibration displacement measurement fixture are perpendicular to the coordinate axis. S3, connecting the laser vibrometer system controller to the calibration test module of the data acquisition system host computer through a dedicated data cable; Turn on the laser vibrometer system controller and set it to the specified gear, turn on the host computer, and preheat for 30 minutes; Fine-tune the incident angle of the laser head mounted on the laser head mounting fixture to maximize the incident laser energy and improve the signal-to-noise ratio of the laser measurement signal; S4, control the six-degree-of-freedom micro-vibration table to vibrate at the specified frequency and amplitude, obtain the amplitude signal of each axis direction through the data acquisition system host computer, and perform control motion trajectory curve fitting. Set the sinusoidal motion function of each axis to The three axes are measured separately by the laser vibrometer system, and the measured signals are expressed as but The vibration displacement signal of the test bench is but The vibration displacement amplitude indication error is calculated by the following formula 。 14. The in-situ calibration method of a six-degree-of-freedom micro-vibration table according to claim 11, characterized in that: The angular vibration calibration method comprises the following steps: S1. Install the mounting platform at the designated position on the tabletop of the six-degree-of-freedom micro-vibration table, so that the center hole of the mounting platform coincides with the center positioning hole on the tabletop of the six-degree-of-freedom micro-vibration table; Install three-axis acceleration sensor A, three-axis acceleration sensor B, and three-axis acceleration sensor C on the sensor mounting base and install them to the designated position of the mounting platform through the positioning holes on the surface of the mounting platform; Use the coordinate positioning fixture to determine the coordinate information corresponding to the six-degree-of-freedom micro-vibration table, determine the origin of the calibration coordinate system and the directions of the X-axis, Y-axis, and Z-axis of the coordinate system; install the angular vibration sensor on the coordinate positioning fixture to ensure that the center of the coordinate positioning fixture coincides with the center of the six-degree-of-freedom micro-vibration table; By adjusting the fine-tuning mechanism of the coordinate positioning fixture, the coordinate axis of the coordinate positioning fixture is made to coincide with the coordinate axis of the test bench; The tooling and sensor are kept stable at a constant temperature on site for more than or equal to 4 hours; S2. Use a high-precision distance measuring instrument to measure the distances between three-axis accelerometer A, three-axis accelerometer B, and three-axis accelerometer C and the origin of the coordinate system. Measure each distance 10 times in a short period of time, and take the average of the 10 measurements as the measurement result to obtain distances Q, W, and E, respectively. Three-axis accelerometer A and three-axis accelerometer C are installed symmetrically around the Z axis, so that the installation distance Q is equal to the installation distance E. S3. Connect three-axis acceleration sensor A, three-axis acceleration sensor B, and three-axis acceleration sensor C to the signal conditioning module through dedicated data cables, and connect the output end of the signal conditioning module to the calibration test module of the data acquisition system host computer through cables; Special data cables are attached to the installation platform with special anti-static tape to prevent the cables from being pulled and displaced; Turn on the signal conditioning module and set it to the specified gear, turn on the data acquisition system host computer, and preheat for 30 minutes; S4. Control the six-degree-of-freedom micro-vibration table to vibrate at a specified frequency and amplitude, and obtain the amplitude signals ai (i = 1, 2, ..., 9) of the three-axis acceleration sensor A, the three-axis acceleration sensor B, and the three-axis acceleration sensor C in each axis direction through the data acquisition system host computer, where a1, a2, ..., a9 represent the numbers of the different sensitive axis directions of the sensors; According to the derivation of formula (1) and (2), formula (3) is fully expanded to solve the relevant parameters in the six degrees of freedom and The angular vibration sensor is used to collect data through the data acquisition system, and the host computer obtains the angular vibration of the test system around the X axis. The two linear acceleration sensors on the X-axis are installed symmetrically around the Z-axis, that is, the installation distance l1≈l3, and the three-axis angular vibration parameters of the test bench are expressed as follows:

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