Metal damper micro-deformation measurement method for inertial platform

Abstract

A kind of metal damper micro-deformation measurement method for inertial platform belongs to inertial measurement technical field, including the precision self-test and error compensation of high-precision photoelectric autocollimator under specific six-degree-of-freedom swing working condition, to reduce the measurement system error;Inertial platform and high-precision photoelectric autocollimator are connected and fixed by (high stiffness) adapter tool, so that both are in stable same installation reference;The installation precision and installation stability of inertial platform external reference hexahedron under specific six-degree-of-freedom swing working condition are calibrated, so that external reference hexahedron can accurately represent inertial platform base coordinate system;Real-time measurement data of photoelectric autocollimator are obtained and post-processing is carried out, and then the micro-deformation of inertial platform metal damper under specific six-degree-of-freedom swing working condition is obtained.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of inertial platform metal damper micro deformation measurement method, belong to inertial measurement technical field. BACKGROUND

[0002] Optical fiber gyro inertial platform is a kind of inertial navigation measurement equipment, uses inertial sensitive sensor (optical fiber gyro and quartz accelerometer) to measure the velocity and position information of carrier relative to inertial space inside carrier, and optical fiber gyro inertial platform is composed of platform body, support frame, shaft end and base.

[0003] Inertial sensitive sensor is all installed on the platform body inside inertial platform, and inertial platform is installed on the carrier of aircraft through the base outside and its metal damper.Therefore, one of the key error sources that causes the non-coincidence of carrier coordinate system and inertial platform platform body coordinate system is the damper, i.e.the micro deformation of damper in working process.

[0004] The inertial platform measurement error caused by damper micro deformation will directly affect the real-time judgment of the current attitude of carrier.In order to accurately measure the micro deformation amount of damper under specific swing condition, high-precision measurement method is particularly important.At present, there is no public information to give the micro deformation measurement method of metal damper for inertial platform under specific swing condition. SUMMARY

[0005] The technical problem solved by the present application is to overcome the shortcomings of the prior art, and provide a kind of inertial platform metal damper micro deformation measurement method, and a metal damper deformation measurement system under specific swing condition is built, and the problem of metal damper angular second level micro deformation measurement is solved.

[0006] The technical solution of the present application is: a kind of inertial platform metal damper micro deformation measurement method, comprising:

[0007] Photoelectric autocollimator is reliably fixed under preset six-degree-of-freedom swing condition, and precision self-test and error compensation are carried out;The preset six-degree-of-freedom swing condition for measuring the micro deformation of metal damper for inertial platform is that three-axis six-degree-of-freedom swing table is used, three-axis swing at the same time, and the first condition of working condition includes: frequency 0.16HZ, amplitude 3°, and the second condition includes: frequency 0.5HZ, amplitude 3°;

[0008] Inertial platform and photoelectric autocollimator are connected and fixed by platform support, collimator seat and adapter tooling, so that both are in stable same installation datum;

[0009] The installation precision and installation stability of the external reference hexahedron of the inertial platform under the preset six-degree-of-freedom swing working condition are calibrated, so that the external reference hexahedron can represent the base coordinate system of the inertial platform;

[0010] The measurement data of the external reference hexahedron are collected and processed by the photoelectric autocollimator to obtain the deformation result of the inertial platform metal damper under the preset six-degree-of-freedom swing working condition.

[0011] Further, the precision self-test and error compensation are low-noise measurement error tests of the photoelectric autocollimator under the swing condition, which include:

[0012] Step 1), after the mirror is rigidly connected and fixed with the mirror base, the mirror base is fixed on the six-degree-of-freedom swing table surface through an adapter plate; after installation, the system is stably placed, and the photoelectric autocollimator is preheated;

[0013] Step 2), adjust the light path of the photoelectric autocollimator, so that the light path is perpendicular to the center position of the mirror, so as to reduce the measurement error caused by the light spot out of shadow in the swing process;

[0014] Step 3), control the six-degree-of-freedom swing table to swing according to specific conditions, swing for 5 minutes at each frequency, and record and save the output data of the photoelectric autocollimator at each frequency point, which includes the heading angle and the pitch angle information of the mirror;

[0015] Step 4), repeat steps 2) to 3) to carry out multiple test experiments.

[0016] Further, the calibration includes:

[0017] Step 1), after the external reference hexahedron of the inertial platform is rigidly connected with the platform base through screws, the inertial platform with the damper simulation piece is fixed on the six-degree-of-freedom table surface through the platform support and the adapter plate, and after installation, the system is stably placed.

[0018] Step 2), adjust the light path of the photoelectric autocollimator, so that the light path is perpendicular to the center position of the reference hexahedron, so as to reduce the measurement error caused by the light spot out of shadow in the swing process;

[0019] Step 3), control the six-degree-of-freedom swing table to swing according to specific conditions, swing for 5 minutes at each frequency, and record and save the output data of the photoelectric autocollimator at each frequency point; the output data includes the heading angle and the pitch angle information of the reference hexahedron;

[0020] Step 4), repeat steps 2) to 3) to carry out multiple test experiments.

[0021] Further, the deformation result of the inertial platform metal damper under the preset six-degree-of-freedom swing working condition includes:

[0022] Step 1), low-noise measurement amplitude and frequency processing of the photoelectric collimator is performed;

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

[0024] Step 3), platform body angular deformation is calculated according to the processed data.

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

[0026] Step a), the saved heading angle and pitch angle data rigidly connected with the damper simulation part are smoothed;

[0027] Step b), the heading angle data are fitted to obtain the swing amplitude Ay and the swing frequency fy at each frequency point through fitting;

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

[0029] Further, the platform body measurement frequency and initial phase processing includes:

[0030] Step a), the saved heading angle and pitch angle data connected with the real damper are smoothed;

[0031] Step b), the heading angle data are fitted to obtain the swing frequency fy and the initial phase at each frequency point through fitting;

[0032] Step c), the pitch angle data are fitted to obtain the swing frequency fp and the initial phase at each frequency point through fitting;

[0033] Further, the calculation of the platform body angular deformation includes:

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

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

[0036] The pitch angle deformation angle calculation formula is:

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

[0038] wherein, Y y减振器 is the yaw angle data measured in real time using a real shock absorber, Y p减振器 is the pitch angle data measured in real time using a real shock absorber; Y y is the yaw angle deformation angle, Y p is the pitch angle deformation angle; A y is the yaw swing amplitude, A p is the pitch direction swing amplitude; f y is the yaw swing frequency, f p is the pitch direction swing frequency; is the yaw initial phase, is the pitch direction initial phase; π is the circular constant; t is the sampling time.

[0039] Further, the platform support, collimator seat and adapter tool are designed to improve their rigidity as much as possible to prevent deformation during swinging and introduce measurement errors.

[0040] Further, the photoelectric autocollimator needs to be placed and preheated before testing to reduce the static drift system error and the temperature drift system error caused by temperature instability.

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

[0042] The present application has the following advantages compared with the prior art:

[0043] (1) The present application measures the accuracy of the photoelectric autocollimator under the preset swinging condition and compensates for the error, so that the photoelectric autocollimator can still accurately measure the small angle deformation under the preset swinging condition.

[0044] (2) The present application tests the angle deformation of the external reference hexahedron when using the (rigid) shock absorber simulation piece, so as to further verify the accuracy of the photoelectric autocollimator test result. That is, when using the (rigid) shock absorber simulation piece for testing, the output result of the photoelectric autocollimator should be small, and this result is its own system error, which needs to be deducted in subsequent data processing.

[0045] (3) The present application fits and processes the data measured by the photoelectric autocollimator, so as to accurately measure the small deformation of the inertial platform metal shock absorber under the preset swinging condition. BRIEF DESCRIPTION OF DRAWINGS

[0046] Various other advantages and benefits will become apparent to those of ordinary skill in the art, upon reading the following detailed description of the preferred embodiments with reference made to the accompanying drawings. The drawings are for purposes of illustration only and are not intended to limit the present application thereto, as the present application can have application in environments beyond those shown or described. Like reference numerals are used to denote like parts throughout the various figures. In the drawings:

[0047] Figures 1-6 A curve graph of test results of the present application;

[0048] Figure 7 A data fusion processing block diagram of the present application;

[0049] Figure 8 A schematic diagram of the principle of deformation measurement of the present application. DETAILED DESCRIPTION

[0050] In order to better understand the above technical solutions, the following will be described in detail by the drawings and specific embodiments. It should be understood that the embodiments and specific features in the embodiments are detailed descriptions of the technical solutions of the present application, and are not limitations of the technical solutions of the present application. In the case of no conflict, the technical features in the embodiments and the embodiments can be combined with each other.

[0051] The following will be further described in detail by the drawings and specific embodiments of the present application. As shown in Figure 7 , Figure 8 , the specific implementation can include:

[0052] The high-precision photoelectric autocollimator is reliably fixed in a specific six-degree-of-freedom swing working condition, and precision self-test and error compensation are performed to reduce the measurement system error. Specifically as follows:

[0053] The general applicable scene of the photoelectric autocollimator equipment is to test under static conditions, so the internal structure of the selected photoelectric autocollimator is specially reinforced to obtain high-precision test results under low-frequency and low-amplitude motion conditions. However, during the swing process of the motion platform, low-noise measurement errors from the photoelectric autocollimator may be introduced due to elastic deformation or spot out-of-focus in the swing of the photoelectric autocollimator. In order to ensure the accuracy of the test results, the low-noise measurement error test of the photoelectric autocollimator under the swing condition is first performed, and the process is as follows:

[0054] 1) After the mirror is rigidly connected and fixed with the mirror base, the mirror base is fixed on the six-degree-of-freedom swing table surface. After installation, the system is stably placed, and the photoelectric autocollimator is preheated at the same time. The preheating time is greater than 24 hours, and the laboratory temperature needs to be kept constant during the period, and the central air conditioner needs to be closed;

[0055] 2) Adjust the light path of the photoelectric autocollimator so that the light path is perpendicular to the center of the mirror to reduce measurement errors caused by the light spot out of focus during the swing;

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

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

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

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

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

[0061] 1) After the external reference hexahedron of the inertial platform 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 simulator (rigid body), and the system is left to stabilize after installation.

[0062] 2) Adjust the light path of the photoelectric autocollimator so that the light path is perpendicular to the center of the reference hexahedron to reduce measurement errors caused by the light spot out of focus during the swing.

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

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

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

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

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

[0068] a) Smooth the saved yaw and pitch data with the rigid connection of the damper simulation;

[0069] b) Fit the yaw data, and get the roll amplitude A y and roll frequency f y

[0070] c) Fit the pitch data, and get the roll amplitude A p and roll frequency f p

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

[0072] a) Smooth the saved yaw and pitch data with the real damper connection;

[0073] b) Fit the yaw data, and get the roll frequency f y and initial phase

[0074] c) Fit the pitch data, and get the roll frequency f p and initial phase

[0075] Because of the differences in test objects and test procedures between the two test conditions, the initial phases of the two groups of data are inconsistent. If not handled, abnormal data will appear when the low-noise signal of the photoelectric collimator is deducted. Therefore, the initial phase of the damper working mode is brought into the low-noise fitting formula of the photoelectric collimator in the test to process the data, ensuring that there is no abnormal data when the low-noise data is deducted.

[0076] 3) Platform body angle deformation calculation

[0077] The yaw angle deformation angle calculation formula is:

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

[0079] The pitch angle deformation angle calculation formula is:

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

[0081] wherein Y y减振器 is the yaw angle data measured in real time using a real damper, Y p减振器 is the pitch angle data measured in real time using a real damper, Y y is the yaw angle deformation angle, Y p is the pitch angle deformation angle, A y is the yaw swing amplitude, A p is the pitch swing amplitude, f y is the yaw swing frequency, f p is the pitch swing frequency, is the yaw initial phase, is the pitch initial phase, and π is the circular constant, and t is the sampling time.

[0082] In the scheme provided in the embodiments of the present application, firstly, the measurement accuracy of a high-precision photoelectric autocollimator under a specific swing working condition is self-measured and error-compensated to reduce the error of the test system itself. Then, a damper rigid simulation piece is used to replace a real damper, and the installation accuracy and installation stability of an external reference hexahedron of a base are calibrated by using the calibrated photoelectric autocollimator. Finally, a real metal damper is used for testing, real-time data are collected by using the photoelectric autocollimator and are processed and analyzed to obtain the micro-deformation of the metal damper under the specific swing working condition.

[0083] The test results show that the deformation of the metal damper for an inertial platform under the specific swing working condition is better than 4 angular seconds, and the test results have repeatability.

[0084] Specifically, the micro-deformation measurement method of the metal damper for the inertial platform comprises the following steps.

[0085] (1) A high-precision photoelectric autocollimator is reliably fixed under a specific six-degree-of-freedom swing working condition, and the accuracy is self-measured and error-compensated to reduce the measurement system error;

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

[0087] (3) The installation accuracy and installation stability of an external reference hexahedron of the inertial platform under the six-degree-of-freedom swing condition are calibrated to make the external reference hexahedron accurately represent the inertial platform base coordinate system;

[0088] (4) The measurement data of the photoelectric autocollimator are collected and processed to obtain the micro-deformation of the metal damper for the inertial platform under the six-degree-of-freedom swing condition.

[0089] The embodiment carries out six-degree-of-freedom swing test under two working conditions by using the fiber-optic gyroscope inertial platform system, the swing frequency is 0.16 Hz and 0.5 Hz respectively, and the amplitude is 3°. Among them, the attached Figures 1-3 The attached Figures 4-6 The attached

[0090] Through the analysis of the test results, it can be seen that the change of the pitch angle is about 4″, the change of the heading angle is about 1″ under the two swing conditions, and the repeatability and consistency of the measurement results are good. Obviously, those skilled in the art can make various modifications and changes to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and changes of the present application fall within the scope of the claims of the present application and the equivalent technology, the present application also intends to include these modifications and changes.

[0091] The contents not described in detail in the specification of the present application are the known technology of those skilled in the art.

Claims

1. A method of measuring micro-deformation of a metal damper for an inertial platform, characterized by, The application relates to a method for measuring the deformation of a metal shock absorber of an inertial platform under a preset six-degree-of-freedom swing condition. The preset six-degree-of-freedom swing condition for measuring the micro-deformation of the metal shock absorber of the inertial platform is that a three-axis six-degree-of-freedom swing table is used, three axes are swung simultaneously, the first condition of the working condition comprises a frequency of 0.16HZ and an amplitude of 3 DEG, and the second condition comprises a frequency of 0.5HZ and an amplitude of 3 DEG. The inertial platform and the photoelectric autocollimator are connected and fixed through a platform support, a collimator seat and an adapter tool, so that the two are in a stable same installation datum. The installation precision and stability of the external reference hexahedron of the inertial platform under the preset six-degree-of-freedom swing condition are calibrated, so 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, and obtains the deformation result of the metal shock absorber of the inertial platform under the preset six-degree-of-freedom swing condition. The precision self-test and error compensation are low-noise measurement error tests of the photoelectric autocollimator under the swing condition, and the precision self-test and error compensation comprise the following steps.

2. The method of claim 1, wherein the metal damper micro-deformation of the inertial platform is measured by using a laser displacement sensor. In step 1), the mirror is rigidly connected and fixed with the mirror base, the mirror base is fixed on the six-degree-of-freedom swing table table surface through an adapter plate after installation is completed, the system is stably placed, and the photoelectric autocollimator is preheated. In step 2), the light path of the photoelectric autocollimator is adjusted, the light path is vertically incident on the center position of the mirror, and the measurement error caused by light spot out of shadow in the swing process is reduced. In step 3), the six-degree-of-freedom swing table is controlled to swing according to specific conditions, the output data of the photoelectric autocollimator at each frequency point are recorded and saved, and the output data comprises the heading angle and the pitch angle information of the mirror. In step 4), steps 2) to 3) are repeated to carry out multiple test experiments. The calibration comprises the following steps.

3. The method of claim 1, wherein the metal damper micro-deformation is measured by using a laser displacement sensor. In step 1), the external reference hexahedron of the inertial platform is rigidly connected with the platform base through screws, the inertial platform with a shock absorber simulation piece is fixed on the six-degree-of-freedom table table surface through a platform support and an adapter plate after installation is completed, and the system is stably placed. In step 2), the light path of the photoelectric autocollimator is adjusted, the light path is vertically incident on the center position of the reference hexahedron, and the measurement error caused by light spot out of shadow in the swing process is reduced. In step 3), the six-degree-of-freedom swing table is controlled to swing according to specific conditions, the output data of the photoelectric autocollimator at each frequency point are recorded and saved, and the output data comprises the heading angle and the pitch angle information of the reference hexahedron. In step 4), steps 2) to 3) are repeated to carry out multiple test experiments. The deformation result of the metal shock absorber of the inertial platform under the preset six-degree-of-freedom swing condition comprises the following steps.

4. The method for measuring the micro-deformation of a metal vibration damper for an inertial platform according to claim 3, characterized in that, In step 1), the low-noise measurement amplitude and frequency of the photoelectric autocollimator are processed. In step 2), the platform body measurement frequency and initial phase are processed. In step 3), the platform body angle deformation is calculated according to the processed data. The low-noise measurement amplitude and frequency of the photoelectric autocollimator comprise the following steps.

5. The method for measuring the micro-deformation of a metal vibration damper for an inertial platform according to claim 4, characterized in that, ​ Step a), smoothing the saved yaw angle and pitch angle data connected with the rigid simulator of shock absorber; Step b) fitting the heading angle data to obtain the yaw amplitude at each frequency point by the fitting Ay and the yaw frequency fy ; Step c) fitting the pitch angle data to obtain the roll amplitude at each frequency point by the fitting Ap and the roll frequency fp .

6. The method of claim 4, wherein the micro-deformation of the metal damper is measured by using a laser displacement sensor. The platform body measurement frequency and initial phase processing includes: Step a), smoothing the saved yaw angle and pitch angle data connected with the real shock absorber; Step b) fitting the heading angle data to obtain the yaw frequency at each frequency point by fitting fy and initial phase φy ; Step c) fitting the pitch angle data to obtain the roll frequency at each frequency point by fitting fp and the initial phase φp .

7. The method of claim 4, wherein the micro-deformation of the metal damper is measured by using a laser displacement sensor. The calculation platform body angle deformation includes: The yaw angle deformation angle calculation formula is: The pitch angle deformation angle calculation formula is: wherein, is the yaw angle data measured in real time using a real damper, is the pitch angle data measured in real time using a real damper; is the yaw angle deformation angle, is the pitch angle deformation angle; is the yaw angle swing amplitude, is the pitch angle swing amplitude; is the yaw angle swing frequency, is the pitch angle swing frequency; is the yaw angle initial phase, is the pitch angle initial phase; π is the circular constant; t is the sampling time.

8. The method of claim 1, wherein the metal damper micro-deformation of the inertial platform is measured. The platform support, collimator seat and adapter tool are designed to improve their rigidity as much as possible to prevent deformation in the swing process and introduce measurement errors.

9. The method of claim 1, wherein the metal damper micro-deformation of the inertial platform is measured by using a laser displacement sensor. The photoelectric autocollimator must be stationary and preheated before testing to reduce the static drift system error and the temperature drift system error caused by temperature instability.

10. The method of claim 3, wherein the metal damper micro-deformation of the inertial platform is measured. The shock absorber simulator is made of solid 2A12 aluminum alloy.

Images