Method for measuring micro-deformation of metal damper for inertial platform

Abstract

A method for measuring micro-deformation of a metal damper for an inertial platform belongs to the technical field of inertial measurement, and comprises the following steps: carrying out precision self-measurement and error compensation on a high-precision photoelectric autocollimator under a specific six-degree-of-freedom swing working condition so as to reduce errors of a measurement system; the inertial platform and the high-precision photoelectric auto-collimator are connected and fixed through a (high-rigidity) switching tool, so that the inertial platform and the high-precision photoelectric auto-collimator are located on the same stable installation reference; the installation precision and the installation stability of the external reference hexahedron of the inertial platform are calibrated under a specific six-degree-of-freedom swing working condition, so that the external reference hexahedron can accurately represent a base coordinate system of the inertial platform; and real-time measurement data of the photoelectric autocollimator are obtained and post-processed, and then the tiny deformation of the inertial platform metal damper under the specific six-degree-of-freedom swing working condition is obtained.

Description

Technical Field

[0001] The invention relates to a method for measuring micro-deformation of a metal vibration damper for an inertial platform, and belongs to the technical field of inertial measurement. Background Art

[0002] The fiber optic gyro inertial platform is an inertial navigation measurement device that uses inertial sensitive sensors (fiber optic gyroscopes and quartz accelerometers) to measure the speed and position information of the carrier relative to the inertial space inside the carrier. The fiber optic gyro inertial platform consists of a platform body, a support frame, a shaft end and a base.

[0003] All inertial sensitive sensors are installed on the body of the inertial platform, and the inertial platform is installed on the aircraft carrier through the external base and its metal shock absorber. Therefore, one of the key error sources that causes the carrier coordinate system to not coincide with the inertial platform body coordinate system is the elastic link of the shock absorber, that is, the micro-deformation of the shock absorber during operation.

[0004] The measurement error of the inertial platform caused by the micro-deformation of the shock absorber will directly affect the real-time judgment of the current posture of the carrier. In order to accurately measure the micro-deformation of the shock absorber under specific swing conditions, a high-precision measurement method is particularly important. At present, there is no public information on the micro-deformation measurement method of the metal shock absorber for the inertial platform under specific swing conditions. Summary of the invention

[0005] The technical problem solved by the present invention is: to overcome the shortcomings of the prior art, provide a method for measuring micro-deformation of a metal vibration absorber for an inertial platform, build a metal vibration absorber deformation measurement system under specific swing conditions, and solve the problem of measuring arc-second-level micro-deformation of the metal vibration absorber.

[0006] The technical solution of the present invention is: a method for measuring micro-deformation of a metal shock absorber for an inertial platform, comprising:

[0007] The photoelectric autocollimator is reliably fixed under the preset six-degree-of-freedom swinging working condition, and performs precision self-test and error compensation; the preset six-degree-of-freedom swinging working condition for measuring the micro-deformation of the metal shock absorber for the inertial platform is to use a three-axis six-degree-of-freedom swinging table, and the three axes swing simultaneously. The first condition of the working condition includes: frequency 0.16HZ, amplitude 3°, and the second condition includes: frequency 0.5HZ, amplitude 3°;

[0008] The inertial platform and the photoelectric autocollimator are connected and fixed through the platform bracket, the collimator seat and the adapter fixture respectively, so that the two are in the same stable installation reference;

[0009] Calibrate the installation accuracy and installation stability of the external reference hexahedron of the inertial platform under the preset six-degree-of-freedom swinging working condition to ensure that the external reference hexahedron can represent the inertial platform base coordinate system;

[0010] The photoelectric autocollimator collects and processes the measurement data of the external reference hexahedron to obtain the deformation result of the metal vibration absorber of the inertial platform under the preset six-degree-of-freedom swinging condition.

[0011] Furthermore, the accuracy self-test and error compensation is a low-noise measurement error test of the photoelectric collimator under a swaying condition, including:

[0012] Step 1), after the reflector is rigidly connected and fixed to the reflector base, the reflector base is fixed on the table of the six-degree-of-freedom swing table through an adapter plate; after the installation is completed, the system is left to stand still and stabilize, and the photoelectric autocollimator is preheated at the same time;

[0013] Step 2), adjusting the optical path of the photoelectric autocollimator so that the optical path is perpendicular to the center of the incident reflector, thereby reducing the measurement error caused by the light spot falling out during the swinging process of the optical path;

[0014] Step 3), controlling the six-degree-of-freedom swing platform to swing according to specific conditions, swinging at each frequency for 5 minutes, and recording and saving the output data of the photoelectric collimator at each frequency point, wherein the output data includes the heading angle and pitch angle information of the reflector;

[0015] Step 4), repeat steps 2) to 3) and conduct multiple tests.

[0016] Further, the calibration comprises:

[0017] Step 1), after the inertial platform external reference hexahedron and the platform base are rigidly connected by screws, the inertial platform with the shock absorber simulation component installed is fixed on the six-degree-of-freedom table surface through the platform bracket and the adapter plate. After the installation is completed, the system is static and stable.

[0018] Step 2), adjusting the optical path of the photoelectric collimator so that the optical path is perpendicular to the center of the reference hexahedron to reduce the measurement error caused by the light spot falling out during the swinging process of the optical path;

[0019] Step 3), controlling the six-degree-of-freedom swing platform to swing according to specific conditions, swinging at each frequency for 5 minutes, and recording and saving the output data of the photoelectric collimator at each frequency point; the output data includes the heading angle and pitch angle information of the reference hexahedron;

[0020] Step 4), repeat steps 2) to 3) and conduct multiple tests.

[0021] Furthermore, the step of obtaining the deformation result of the inertial platform metal shock absorber under the preset six-degree-of-freedom swinging condition includes:

[0022] Step 1), performing low-noise measurement amplitude and frequency processing of a photoelectric collimator;

[0023] Step 2), perform platform body measurement frequency and initial phase processing;

[0024] Step 3), calculate the platform body angular deformation based on the processed data.

[0025] Furthermore, the photoelectric collimator low-noise measurement amplitude and frequency processing includes:

[0026] Step a), smoothing the saved heading angle and pitch angle data using the vibration damper simulation component rigid connection;

[0027] Step b), fitting the heading angle data, and obtaining the swing amplitude Ay and the swing frequency fy at each frequency point by fitting;

[0028] Step c), fitting the pitch angle data, and obtaining the swing amplitude Ap and the swing frequency fp at each frequency point through fitting.

[0029] Furthermore, the platform body measures the frequency and initial phase processing including:

[0030] Step a), smoothing the saved heading angle and pitch angle data connected using the real shock absorber;

[0031] Step b), fitting the heading angle data, and obtaining the swing frequency fy and initial phase at each frequency point by fitting

[0032] Step c), fitting the pitch angle data, and obtaining the swing frequency fp and initial phase at each frequency point by fitting

[0033] Furthermore, the computing platform body angle deformation includes:

[0034] The calculation formula of heading angle deformation angle is:

[0035] Y y =Y y减振器 -A y sin(2pf y t+j y )

[0036] The pitch deformation angle calculation formula is:

[0037] Y p =Y p减振器 -Ap sin(2pf p t+j p )

[0038] Among them, Y y减振器 Y is the heading angle data measured in real time using the real shock absorber. p减振器 Y is the pitch angle data measured in real time using a real shock absorber; y is the heading deformation angle, Y p is the pitch deformation angle; A y is the heading swing amplitude, A p is the pitch direction swing amplitude; f y is the heading swing frequency, f p is the pitch direction swing frequency; is the initial heading phase, is the initial phase in the pitch direction; π is the circumference of a circle; t is the sampling time.

[0039] Furthermore, the platform bracket, collimator seat and adapter fixture are designed to increase their rigidity as much as possible to prevent them from deforming during the swinging process and introducing measurement errors.

[0040] Furthermore, the photoelectric autocollimator must be statically stabilized and preheated before testing to reduce its static drift system error and temperature drift system error caused by temperature instability.

[0041] Furthermore, the shock absorber simulation component is made of solid 2A12 aluminum alloy.

[0042] The advantages of the present invention compared with the prior art are:

[0043] (1) The present invention implements the photoelectric autocollimator to accurately measure small angular deformation under preset swing conditions by performing precision self-test and error compensation on the photoelectric autocollimator under preset swing conditions;

[0044] (2) The present invention further verifies the accuracy of the test results of the photoelectric collimator by testing the angular deformation of the external reference hexahedron when using a (rigid) shock absorber simulator. That is, when using a (rigid) shock absorber simulator for testing, the output result of the photoelectric collimator should be very small, and this result is its own systematic error, which needs to be deducted in subsequent data processing;

[0045] (3) The present invention achieves accurate measurement of the tiny deformation of the metal shock absorber of the inertial platform under a preset swing condition by fitting and processing the data measured by the photoelectric collimator. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0047] Figures 1 to 6 It is a curve diagram of the test results of the present invention;

[0048] Figure 7 This is a data fusion processing block diagram of the present invention;

[0049] Figure 8 Schematic diagram of the deformation measurement principle of the present invention. DETAILED DESCRIPTION

[0050] In order to better understand the above technical scheme, the technical scheme of the present invention is described in detail below through the accompanying drawings and specific embodiments. It should be understood that the embodiments of the present invention and the specific features in the embodiments are detailed descriptions of the technical scheme of the present invention, rather than limitations on the technical scheme of the present invention. In the absence of conflict, the embodiments of the present invention and the technical features in the embodiments can be combined with each other.

[0051] The following is a further detailed description of a method for measuring micro-deformation of a metal vibration damper for an inertial platform provided by an embodiment of the present invention in conjunction with the accompanying drawings. Figure 7 , Figure 8 , the specific implementation methods may include:

[0052] The high-precision photoelectric autocollimator is reliably fixed under specific six-degree-of-freedom swing conditions, and performs precision self-test and error compensation to reduce the measurement system error, as follows:

[0053] The general application scenario of photoelectric autocollimator equipment is testing under static conditions, so the internal structure of the selected photoelectric collimator has been specially reinforced to obtain high-precision test results under low-frequency and low-amplitude motion conditions. However, during the swinging of the motion platform, the low-noise measurement error from the photoelectric collimator will be introduced due to elastic deformation or light spot shedding during the swinging of the photoelectric collimator itself. In order to ensure the accuracy of the test results, it is necessary to first conduct a low-noise measurement error test of the photoelectric collimator under swinging conditions. The process is as follows:

[0054] 1) After the reflector and the reflector base are rigidly connected and fixed, the reflector base is fixed on the table top of the six-degree-of-freedom swing table. After the installation is completed, the system is left to stabilize and the photoelectric autocollimator is preheated. The preheating time is more than 24 hours. During this period, the laboratory temperature must be kept constant and the central air conditioner must be turned off;

[0055] 2) Adjust the optical path of the photoelectric autocollimator so that the optical path is perpendicular to the center of the incident reflector, so as to reduce the measurement error caused by the light spot falling out during the swinging process of the optical path;

[0056] 3) Control the six-degree-of-freedom swing platform to swing according to specific conditions, swing at each frequency for 5 minutes, and record and save the output data of the photoelectric collimator at each frequency point (including the heading angle and pitch angle information of the reflector);

[0057] 4) Repeat step 2) and conduct multiple test experiments;

[0058] Through the above process, the accuracy self-test and error compensation of the high-precision photoelectric autocollimator under specific swing conditions can be achieved.

[0059] The inertial platform and the high-precision photoelectric autocollimator are connected and fixed through a high-rigidity adapter plate so that the two are on the same installation basis;

[0060] The installation accuracy and installation stability of the inertial platform external reference hexahedron under the condition of six-degree-of-freedom swing are calibrated to ensure that the external reference hexahedron can accurately represent the inertial platform base coordinate system, as follows:

[0061] 1) After the inertial platform external reference hexahedron is rigidly connected to the platform base through screws, the platform is fixed on the six-degree-of-freedom table surface using a shock absorber simulation component (rigid body). After installation, the system is static and stable.

[0062] 2) Adjust the optical path of the photoelectric collimator so that the optical path is perpendicular to the center of the reference hexahedron to reduce the measurement error caused by the light spot being removed during the swinging of the optical path.

[0063] 3) Control the six-degree-of-freedom swing table to swing according to specific conditions, swing at each frequency for 5 minutes, and record and save the output data of the photoelectric collimator at each frequency point (including the heading angle and pitch angle information of the reference hexahedron);

[0064] 4) Repeat step 2) and conduct multiple test experiments;

[0065] Through the above process, the installation accuracy and installation stability calibration of the inertial platform external reference hexahedron under six-degree-of-freedom swing conditions can be completed.

[0066] By collecting and processing the measurement data of the photoelectric autocollimator, the micro deformation of the metal shock absorber of the inertial platform under the six-degree-of-freedom swing condition is obtained, as follows:

[0067] 1) Low-noise measurement amplitude and frequency processing method of photoelectric collimator

[0068] a) Smoothing the saved heading and pitch angle data using the rigid connection of the shock absorber simulation parts;

[0069] b) Fit the heading angle data and obtain the swing amplitude A at each frequency point through fitting y and the swing frequency f y

[0070] c) Fit the pitch angle data and obtain the swing amplitude A at each frequency point through fitting p and the swing frequency f p

[0071] 2) Platform body measurement frequency and initial phase processing method

[0072] a) Smoothing of the saved heading and pitch angle data using real damper connections;

[0073] b) Fit the heading angle data and obtain the swing frequency f at each frequency point through fitting y and initial phase

[0074] c) Fit the pitch angle data and obtain the swing frequency f at each frequency point through fitting p and initial phase

[0075] Due to the differences in the test objects and test processes of the two test conditions, the two sets of data will have inconsistent initial phases. If not processed, data anomalies will occur when the low-noise signal of the photoelectric collimator is subtracted. Therefore, in the test, the initial phase under the shock absorber working mode is brought into the photoelectric collimator low-noise fitting formula for data processing to ensure that there is no abnormal data when the low-noise data is subtracted.

[0076] 3) Calculation of platform body angle deformation

[0077] The calculation formula of heading angle deformation angle is:

[0078] Y y =Y y减振器 -A y sin(2pf y t+j y )

[0079] The pitch deformation angle calculation formula is:

[0080] Y p =Y p减振器 -A p sin(2pf p t+j p )

[0081] Among them, Y y减振器 Y is the heading angle data measured in real time using the real shock absorber. p减振器 is the pitch angle data measured in real time using the real shock absorber, Y y is the heading deformation angle, Y p is the pitch deformation angle, A y is the heading swing amplitude, A p is the pitch direction swing amplitude, f y is the heading swing frequency, f p is the pitch direction swing frequency, is the initial heading phase, is the initial phase in the pitch direction, π is the circumference of a circle, and t is the sampling time.

[0082] In the solution provided in the embodiment of the present invention, the measurement accuracy of the high-precision photoelectric autocollimator under specific swing conditions is firstly self-tested and error compensation is performed to reduce the error of the test system itself. Then, the real vibration damper is replaced by a vibration damper rigid simulation part, and the installation accuracy and installation stability of the external reference hexahedron of the base are calibrated by the calibrated photoelectric autocollimator. Finally, the real metal vibration damper is used for testing, and the photoelectric autocollimator is used to collect data in real time and process and analyze it to obtain the micro-deformation of the metal vibration damper under specific swing conditions.

[0083] The test results show that the deformation of the metal shock absorber for the inertial platform under specific rocking conditions is better than 4 arc seconds, and the test results are repeatable.

[0084] Specifically, the present invention provides a method for measuring micro-deformation of a metal vibration damper for an inertial platform, comprising:

[0085] (1) The high-precision photoelectric autocollimator is reliably fixed under specific six-degree-of-freedom swing conditions, and performs precision self-test and error compensation to reduce measurement system errors;

[0086] (2) The inertial platform and the high-precision photoelectric autocollimator are connected and fixed through a high-rigidity adapter plate so that the two are on the same installation reference;

[0087] (3) Calibrate the installation accuracy and installation stability of the inertial platform external reference hexahedron under six-degree-of-freedom swing conditions to ensure that the external reference hexahedron can accurately represent the inertial platform base coordinate system;

[0088] (4) By collecting and processing the measurement data of the photoelectric autocollimator, the tiny deformation of the metal shock absorber of the inertial platform under the six-degree-of-freedom swing condition is obtained.

[0089] This embodiment uses a fiber optic gyro inertial platform system to carry out six-degree-of-freedom swing tests under two working conditions, with swing frequencies of 0.16 Hz and 0.5 Hz, respectively, and amplitudes of 3°. Figure 1-3 It shows the measurement results of three repeated tests under the swing condition of frequency 0.16HZ and amplitude 3°. Figure 4-6 It shows the measurement results of three repeated tests under the swing condition of frequency 0.5HZ and amplitude 3°.

[0090] By analyzing the test results, it can be seen that the pitch angle changes by about 4" and the heading angle changes by about 1" under the two swing conditions, and the measurement results have good repeatability and consistency. Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

[0091] The contents not described in detail in the specification of the present invention belong to the common knowledge of those skilled in the art.

Claims

1. A method for measuring micro-deformation of a metal shock absorber for an inertial platform, characterized in that: include: The photoelectric autocollimator is reliably fixed under the preset six-degree-of-freedom swinging condition, and performs accuracy self-test and error compensation; The preset six-degree-of-freedom swing condition for measuring the micro-deformation of the metal shock absorber for the inertial platform is to use a three-axis six-degree-of-freedom swing table, and the three axes are swung simultaneously. The first condition of the condition includes: frequency 0.16HZ, amplitude 3°, and the second condition includes: frequency 0.5HZ, amplitude 3°; The inertial platform and the photoelectric autocollimator are connected and fixed through the platform bracket, the collimator seat and the adapter fixture respectively, so that the two are in the same stable installation reference; Calibrate the installation accuracy and installation stability of the external reference hexahedron of the inertial platform under the preset six-degree-of-freedom swinging working condition to ensure that the external reference hexahedron can represent the inertial platform base coordinate system; The photoelectric autocollimator collects and processes the measurement data of the external reference hexahedron to obtain the deformation result of the metal vibration absorber of the inertial platform under the preset six-degree-of-freedom swinging condition.

2. The method for measuring micro-deformation of a metal vibration damper for an inertial platform according to claim 1, characterized in that: The accuracy self-test and error compensation is a low-noise measurement error test of the photoelectric collimator under swaying conditions, including: Step 1), after the reflector is rigidly connected and fixed to the reflector base, the reflector base is fixed on the table of the six-degree-of-freedom swing table through an adapter plate; after the installation is completed, the system is left to stand still and stabilize, and the photoelectric autocollimator is preheated at the same time; Step 2), adjusting the optical path of the photoelectric autocollimator so that the optical path is perpendicular to the center of the incident reflector, thereby reducing the measurement error caused by the light spot falling out during the swinging process of the optical path; Step 3), controlling the six-degree-of-freedom swing platform to swing according to specific conditions, swinging at each frequency for 5 minutes, and recording and saving the output data of the photoelectric collimator at each frequency point, wherein the output data includes the heading angle and pitch angle information of the reflector; Step 4), repeat steps 2) to 3) and conduct multiple tests.

3. The method for measuring micro-deformation of a metal vibration damper for an inertial platform according to claim 1, characterized in that: The calibration comprises: Step 1), after the inertial platform external reference hexahedron is rigidly connected to the platform base through screws, the inertial platform with the shock absorber simulation component installed is fixed on the six-degree-of-freedom platform surface through the platform bracket and the adapter plate. After the installation is completed, the system is static and stable; Step 2), adjusting the optical path of the photoelectric collimator so that the optical path is perpendicular to the center of the reference hexahedron to reduce the measurement error caused by the light spot falling out during the swinging process of the optical path; Step 3), controlling the six-degree-of-freedom swing platform to swing according to specific conditions, swinging at each frequency for 5 minutes, and recording and saving the output data of the photoelectric collimator at each frequency point; the output data includes the heading angle and pitch angle information of the reference hexahedron; Step 4), repeat steps 2) to 3) and conduct multiple tests.

4. The method for measuring micro-deformation of a metal vibration damper for an inertial platform according to claim 1, characterized in that: The step of obtaining the deformation result of the metal shock absorber of the inertial platform under the preset six-degree-of-freedom swinging condition includes: Step 1), performing low-noise measurement amplitude and frequency processing of a photoelectric collimator; Step 2), perform platform body measurement frequency and initial phase processing; Step 3), calculate the platform body angular deformation based on the processed data.

5. The method for measuring micro-deformation of a metal vibration damper for an inertial platform according to claim 4, characterized in that: The photoelectric collimator low-noise measurement amplitude and frequency processing includes: Step a), smoothing the saved heading angle and pitch angle data using the vibration damper simulation component rigid connection; Step b), fitting the heading angle data, and obtaining the swing amplitude Ay and the swing frequency fy at each frequency point by fitting; Step c), fitting the pitch angle data, and obtaining the swing amplitude Ap and the swing frequency fp at each frequency point through fitting.

6. The method for measuring micro-deformation of a metal vibration damper for an inertial platform according to claim 4, characterized in that: The platform body measurement frequency and initial phase processing includes: Step a), smoothing the saved heading angle and pitch angle data connected using the real shock absorber; Step b), fitting the heading angle data, and obtaining the swing frequency fy and initial phase at each frequency point by fitting Step c), fitting the pitch angle data, and obtaining the swing frequency fp and initial phase at each frequency point by fitting 7. The method for measuring micro-deformation of a metal vibration damper for an inertial platform according to claim 4, characterized in that: The computing platform body angle deformation includes: The calculation formula of heading angle deformation angle is: Y y =Y y减振器 -A y sin(2pf y t+j y ) The pitch deformation angle calculation formula is: Y p =Y p减振器 -A p sin(2pf p t+j p ) Among them, Y y减振器 Y is the heading angle data measured in real time using the real shock absorber. p减振器 Y is the pitch angle data measured in real time using a real shock absorber; y is the heading deformation angle, Y p is the pitch deformation angle; A y is the heading swing amplitude, A p is the pitch direction swing amplitude; f y is the heading swing frequency, f p is the pitch direction swing frequency; is the initial heading phase, is the initial phase in the pitch direction; π is the circumference of a circle; t is the sampling time.

8. The method for measuring micro-deformation of a metal vibration damper for an inertial platform according to claim 1, characterized in that: The platform bracket, collimator seat and adapter fixture are designed to increase their rigidity as much as possible to prevent them from deforming during the swinging process and introducing measurement errors.

9. The method for measuring micro-deformation of a metal vibration damper for an inertial platform according to claim 1, characterized in that: The photoelectric autocollimator must be left to stand and be preheated before testing to reduce its static drift system error and temperature drift system error caused by temperature instability.

10. The method for measuring micro-deformation of a metal vibration damper for an inertial platform according to claim 1, characterized in that: The shock absorber simulation part is made of solid 2A12 aluminum alloy.

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