CN116699177A - Accelerometer performance testing device, method and system - Google Patents
Accelerometer performance testing device, method and system Download PDFInfo
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- CN116699177A CN116699177A CN202310669239.7A CN202310669239A CN116699177A CN 116699177 A CN116699177 A CN 116699177A CN 202310669239 A CN202310669239 A CN 202310669239A CN 116699177 A CN116699177 A CN 116699177A
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- G—PHYSICS
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- G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
- G01P21/00—Testing or calibrating of apparatus or devices covered by the preceding groups
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Abstract
The invention discloses an accelerometer performance testing device, method and system, and belongs to the technical field of high-precision inertial sensor testing. The four-wire pendulum-based active vibration isolation system can reduce the influence of ground vibration noise on the residual vibration of the pendulum platform and provide the accelerometer to be tested with the horizontal direction 10 ‑9 m/s 2 A test environment with low level of noise. The invention utilizes a displacement monitoring instrument to record the change of the horizontal displacement of the swinging table, can be used as theoretical input after calibration, performs amplitude spectrum comparison with the actually measured acceleration data of the accelerometer to be measured in the calibration direction, obtains the performance test result of the accelerometer to be measured by changing the amplitude and the frequency of the electromagnetic excitation signal, and realizes the 0.1 Hz-1 Hz frequency band horizontal axis 10 of the high-precision accelerometer ‑9 m/s 2 The magnitude resolution test and sensitivity calibration also have the advantages of providing a low noise environment, realizing acceleration response measurement of different frequencies of the accelerometer and the like。
Description
Technical Field
The invention belongs to the technical field of high-precision inertial sensor testing, and particularly relates to an accelerometer performance testing device, method and system.
Background
High precision spatial electrostatic accelerometer resolution is typically at 10 -9 m/s 2 The high-precision space inertial sensor has been successfully applied for many times as an important load in plans such as satellite gravity measurement at home and abroad, and the research of the high-precision space inertial sensor has become one of important research tasks in the field of space science. The comprehensive test of the functional performance of the high-precision electrostatic accelerometer on the ground is an indispensable step before the on-orbit application, wherein the high-voltage suspension test method adopts electrostatic force to balance the gravity of the accelerometer inspection quality, is an important method in the ground test, and can be used for testing and verifying the performance of the accelerometer such as the resolution, the sensitivity and the like of the horizontal axis.
Conventional accelerometer resolution test and sensitivity calibration method pair 10 -9 m/s 2 Even higher precision accelerometers are no longer suitable, and the performance testing level of high-precision spatial electrostatic accelerometer high-voltage levitation experiments is often limited by factors such as ground vibration. Therefore, in order to further improve the testing and evaluation level of the main performance parameters of the accelerometer, the conventional performance testing method of the accelerometer needs to be improved, a testing platform with low vibration noise is provided, the functional test, the horizontal axis resolution test and the sensitivity coefficient calibration of the accelerometer are completed, and important support is provided for the ground test of the space inertial sensor and the application of the space inertial sensor in the fields of satellite gravity measurement and the like. In addition, the performance tests of the inertial sensors such as MEMS accelerometers, microseisms, gravimeters and the like, such as resolution, sensitivity and the like, also depend on a high-performance vibration isolation device and a calibration test system.
Disclosure of Invention
Aiming at the defects of the prior art, the invention aims to provide an accelerometer performance testing device, an accelerometer performance testing method and an accelerometer performance testing system, which aim to solve the problem that the traditional accelerometer resolution testing and sensitivity calibration method is used for testing the performance of the accelerometer by 10 pairs -9 m/s 2 Even higher precision accelerometers have been proposedAnd is no longer applicable.
To achieve the above object, in a first aspect, the present invention provides an accelerometer performance testing apparatus, including: the vibration isolator comprises a supporting frame, four equal-length suspension wires, a vibration isolation platform, a plurality of motion sensors, an active vibration isolation controller, a driving controller, a plurality of electromagnetic drivers and a displacement monitoring instrument;
one end of the suspension wire is fixed with a cross beam on the supporting frame, and the other end of the suspension wire is connected with the vibration isolation platform and used for suspending the vibration isolation platform, and the length of the suspension wire can ensure that the four-wire pendulum can move along the horizontal two translational degrees of freedom;
an accelerometer to be measured is fixedly placed at the center of the table top of the vibration isolation platform;
the motion sensors are used for acquiring absolute speed information of the vibration isolation platform and outputting the absolute speed information to the active vibration isolation controller;
the active vibration isolation controller is used for generating an active vibration isolation control signal according to the absolute speed information of the vibration isolation platform, generating corresponding current through the signal conditioning circuit and outputting the current to the electromagnetic driver;
the driving controller is used for generating the frequency f with the amplitude value A and the calibration requirement a The sinusoidal voltage signal of the power supply is generated through a signal conditioning circuit and is output to an electromagnetic driver;
the electromagnetic drivers are used for firstly receiving the current generated by the active vibration isolation controller to form feedback force for reducing the vibration degree of the vibration isolation platform, receiving the current generated by the driving controller after the vibration isolation platform is in an optimal state, and forming the frequency f required by calibration based on the magnetic transmission principle a The electromagnetic driving force of the vibration isolation platform is driven to generate translational displacement change along the calibration direction;
the displacement monitoring instrument is used for monitoring and recording displacement data of the vibration isolation platform in the directions of two horizontal translational degrees of freedom;
the support frame, the four equal-length suspension wires and the vibration isolation platform jointly form a passive vibration isolation structure, and form an active vibration isolation system together with the motion sensor, the active vibration isolation controller and the electromagnetic driver, so that the vibration isolation system has a vibration noise isolation function of the ground in the horizontal direction of the frequency band of 0.1-10 Hz.
Preferably, the electromagnetic driver includes: the permanent magnet is arranged on the table top of the vibration isolation platform, and the electromagnetic coil is arranged on the ground fixedly connected with the base along the direction of the permanent magnet.
Preferably, the plurality of electromagnetic drivers includes:
the first electromagnetic driver is positioned on the east-west axis of the vibration isolation platform and used for controlling the east-west translational degree of freedom motion of the vibration isolation platform;
the second electromagnetic driver and the third electromagnetic driver are symmetrically arranged on two sides of a north-south axis of the vibration isolation platform, and the translational degree of freedom motion and the rotational degree of freedom motion of the vibration isolation platform in the north-south direction are controlled simultaneously.
Preferably, the apparatus further comprises: a magnetic shield;
the magnetic shielding cover covers the electromagnetic driver and is used for shielding magnetic field interference or magnetic leakage generated by the electromagnetic driver to the accelerometer to be tested.
To achieve the above object, in a second aspect, the present invention provides a performance test method for an accelerometer, which is applied to the performance test device for an accelerometer according to the first aspect, and the method includes:
after the vibration isolation platform is in an optimal state and the output data of the accelerometer to be tested are stable, obtaining the output data of the displacement monitoring instrument and the accelerometer to be tested in the same time period;
carrying out differential processing on output data of a displacement monitoring instrument to obtain a translational acceleration signal of the vibration isolation platform, and further carrying out amplitude spectrum calculation on the signal to serve as an acceleration theory output amplitude;
and comparing the amplitude spectrum of the theoretical acceleration with the actual measured acceleration of the accelerometer to be measured in the calibration direction, and judging whether the theoretical acceleration is consistent with the actual measured acceleration of the accelerometer to be measured in the error range, so as to obtain a resolution test result of the accelerometer to be measured.
Preferably, the method further comprises:
and obtaining a sensitivity calibration result of the accelerometer to be measured by performing linear fitting on response acceleration amplitude spectrums of the accelerometer to be measured and the displacement monitoring instrument under electromagnetic excitation signals with different amplitudes.
Preferably, the method further comprises:
by changing the frequency of the injected electromagnetic excitation signal, the transfer function or the low-frequency response characteristic of the accelerometer to be measured is analyzed.
To achieve the above object, in a third aspect, the present invention provides an accelerometer performance test system, comprising: the accelerometer performance testing apparatus, memory and processor of the first aspect;
the memory is used for storing a computer program and executing instructions;
the processor is configured to execute the computer-executable instructions, which when executed on the processor cause the method of the second aspect to be performed.
In general, the above technical solutions conceived by the present invention have the following beneficial effects compared with the prior art:
(1) The invention provides an accelerometer performance testing device, which is based on a four-wire pendulum active vibration isolation system, can reduce the influence of ground vibration noise on the residual vibration of a pendulum platform, and provides a horizontal direction 10 for an accelerometer to be tested -9 m/s 2 A test environment with low level of noise. By adopting a non-contact electromagnetic driver, electromagnetic excitation signals can be provided in the horizontal two translational degrees of freedom directions of the swing table. In addition, compared with the contact type driver, the vibration isolation swing table can prevent the free motion of the vibration isolation swing table so as to influence the system performance, the non-contact type driver has the characteristics of small interference, large output range and no hysteresis, and is more suitable for an active vibration isolation system in the field of precise measurement.
(2) The invention provides a performance test method of an accelerometer, which utilizes a displacement monitoring instrument to record the horizontal displacement change of a swinging table, can be used as theoretical input after calibration, and can be used for comparing amplitude spectrum with measured acceleration data of the accelerometer to be tested in a calibration direction, and finally can be used for testing the performance of the accelerometer to be tested by changing the amplitude and the frequency of an injected excitation signal, thereby realizing the high-precision accelerometer 0.1 Hz-1 Hz frequency band horizontal shaft 10 -9 m/s 2 The magnitude resolution test and the sensitivity calibration also have the advantages of providing a low noise environment, realizing acceleration response measurement of different frequencies of the accelerometer and the like.
Drawings
FIG. 1 is a schematic diagram of a high-precision accelerometer performance testing apparatus according to the present invention.
Fig. 2 is a front view of a high-precision accelerometer performance testing apparatus provided by the invention.
FIG. 3 is a flow chart of a method for testing performance of an accelerometer provided by the invention.
The same reference numbers are used throughout the drawings to reference like elements or structures, wherein:
1-a support frame; 2-hanging wires; 3-vibration isolation platforms; 4-a motion sensor; 5-a controller; 6-an electromagnetic drive; 7-a displacement monitoring instrument; 8-an accelerometer to be measured; 9-a data processing system; 10-magnetic shield; 51-active vibration isolation controller; 52-a drive controller; 53-a signal conditioning circuit; 61-permanent magnets; 62-the ground is fixedly connected with a base; 63-electromagnetic coils; 91-a data processing module; 92-results display module.
Detailed Description
The present invention will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.
As shown in fig. 1 and 2, the present invention provides a high-precision accelerometer performance testing apparatus, comprising: the vibration isolator comprises a supporting frame 1, four equal-length suspension wires 2, a vibration isolation platform 3, a plurality of motion sensors 4, a controller 5, a plurality of electromagnetic drivers 6, a displacement monitoring instrument 7, an accelerometer 8 to be tested, a data processing system 9 and a magnetic shielding cover 10.
The support frame 1 is placed on a flat ground, the upper part of the suspension wire 2 is fixed with a cross beam of the support frame 1 (a screw and a connecting plate), and the lower part of the suspension wire is connected with a connecting plate of the vibration isolation platform 3 (a steel wire rope clamping device) to suspend the vibration isolation platform. The vibration isolation platform is characterized in that a first motion sensor, a second motion sensor and an accelerometer 8 to be measured are respectively placed on the table top of the vibration isolation platform 3, the first motion sensor and the second motion sensor are symmetrically placed on two sides of the accelerometer 8 to be measured, a third motion sensor is placed on the ground near the vibration isolation platform 3, and a signal output end of the third motion sensor is connected with a signal input end of a data processing system 9. The signal output part of the controller 5 is connected with the signal input part of the electromagnetic driver 6, the signal output part of the electromagnetic driver 6 is connected with the signal input part of the vibration isolation platform 3, the signal output part of the displacement monitoring instrument 7 is connected with the signal input part of the data processing system 9, the accelerometer 8 to be measured is fixed at the central position of the table top of the vibration isolation platform 3, and the signal output part of the accelerometer is connected with the signal input part of the data processing system 9. The magnetic shielding covers 10 are located at two sides of the vibration isolation platform and cover the electromagnetic driver 6, and are used for shielding magnetic field interference or magnetic leakage generated by the accelerometer 8 to be tested and the like, but leaving space for a magnetic transmission process, and finally obtaining final resolution test and sensitivity calibration results through calculation and analysis of the data processing system 9.
Specifically, as shown in fig. 1 and fig. 2, the support frame 1, the equilong suspension wires 2 and the vibration isolation platform 3 form a two-axis translational four-wire pendulum structure based on a single pendulum model. The vibration isolation platform 3 is an optical platform. The suspension line is long enough to enable the four-line pendulum to move along the directions of two horizontal translational degrees of freedom, and the vibration isolation platform has the function of vibration noise isolation of the ground in the horizontal direction of the frequency band of 0.1-10 Hz, and the vibration isolation performance is determined by the ratio of the residual vibration acceleration noise spectral density on the table top of the vibration isolation platform to the vibration acceleration noise spectral density of the ground near the place where the vibration isolation platform is located in the time period. The horizontal two translational degrees of freedom directions refer to the horizontal y and z directions, which correspond to the east-west and north-south plane directions, respectively.
The number of the motion sensors 4 is three, and the motion sensors comprise micro seismometers symmetrically arranged on two sides of the accelerometer 8 to be measured and on the ground near the vibration isolation platform (the required noise power spectral density reaches 10 -10 m/s 2 /Hz 1/2 Magnitude) can record the residual vibration acceleration noise on the vibration isolation platform and the ground nearby the vibration isolation platform in real timeAnd finally giving out information such as a residual vibration acceleration noise spectrum curve on the vibration isolation platform 3, vibration isolation rate of the residual vibration acceleration noise spectrum curve to ground vibration and the like. By using two symmetrically placed microseismic instruments, the translational degree of freedom read-out data of the accelerometer can be verified through a common mode, and the torsional degree of freedom read-out data of the accelerometer can be verified through a differential mode. The mass center of the balanced vibration isolation platform is overlapped with the geometric center as much as possible, so that the accurate torsion signal can be conveniently obtained.
The controller 5 includes an active vibration isolation controller 51, a drive controller 52, and a signal conditioning circuit 53. The active vibration isolation controller 51 is configured to generate an active vibration isolation control voltage signal according to absolute speed information of the vibration isolation platform. The drive controller 52 provides a single frequency sinusoidal input signal as the drive voltage signal, the amplitude and frequency of which can be varied as required for performance testing. The signal conditioning circuit 53 receives the voltage signal and generates a current.
The electromagnetic driver 6 comprises a permanent magnet 61 arranged on the table top of the four-wire pendulum vibration isolation platform and an electromagnetic coil 63 which is arranged on a ground fixed base 62 along the direction of the permanent magnet 61. The electromagnetic driver 6 mainly works based on the magnetic transmission principle, when the electromagnetic coil 63 is electrified, force is generated between the permanent magnet 61 and the electromagnetic coil 63, the thrust and the attractive force can be switched by changing the direction of the current, so that the vibration isolation platform 3 generates corresponding displacement, and the accelerometer 8 to be measured on the vibration isolation platform also generates displacement in the horizontal direction and outputs an acceleration signal. The electromagnetic driver 6 has the characteristics of wide working frequency band, high precision, high response speed, large output force and large displacement, and is very suitable for precision measurement experiments in a low frequency range. In this example, a cylindrical permanent magnet of smaller size, having a diameter of 10mm and a length of 12mm, was used, thereby increasing the gap between the magnet and the coil to 3.5mm.
The displacement monitoring instrument 7 is used for monitoring the displacement of the vibration isolation platform 3, including but not limited to a laser interferometer, an autocollimator, etc.
The accelerometer 8 to be measured outputs a horizontal axis acceleration signal.
The data processing system 9 comprises a data processing module 91 and a result display module 92. The data processing module 91 is used for performing differential calculation on output data of the displacement monitoring instrument 7 and performing data processing on translational acceleration of the accelerometer 8 to be tested and the vibration isolation platform; the result display module 92 is used for displaying the data processing results of the accelerometer 8 to be tested and the displacement monitoring instrument 7.
The magnetic shielding cover 10 is positioned at two sides of the vibration isolation platform, is connected with the ground fixedly connected base 62, covers the permanent magnet 61, the ground fixedly connected base 62 and the electromagnetic coil 63, and leaves a space for a magnetic transmission process, and the surface of the magnetic shielding cover is covered with a magnetic shielding material for shielding magnetic field interference or magnetic leakage generated by an electromagnetic driver to-be-detected accelerometer and the like.
The working process of the whole performance testing device is specifically as follows: firstly, a low-noise test environment is provided based on an active vibration isolation system, then a single-frequency sine input signal is provided as a drive voltage signal by a drive controller 52 in a controller 5, a signal conditioning circuit 53 generates current after receiving the signal, when an electromagnetic coil 63 is electrified, a force is generated between a permanent magnet 61 and the electromagnetic coil 63, and the thrust and attractive force of the permanent magnet and the electromagnetic coil 63 can be switched by changing the direction of the current, so that a vibration isolation platform can generate displacement change in the directions of two horizontal translational degrees of freedom. On one hand, displacement data of the vibration isolation platform 3 are monitored by using a displacement monitoring instrument 7, and can be calculated as theoretical input through position calibration; on the other hand, the accelerometer 8 to be measured outputs a horizontal axis acceleration signal, and finally the output data of the displacement monitoring instrument 7 is subjected to differential processing through the data processing system 9, and amplitude spectrum analysis, error calculation and linear fitting are performed on the translational acceleration of the accelerometer 8 to be measured and the vibration isolation platform, and the resolution test and sensitivity calibration results of the accelerometer 8 to be measured and the displacement monitoring instrument 7 are displayed on the basis of the result display module 92.
As shown in fig. 3, the invention provides a performance test method for an accelerometer, comprising the following steps:
s1, calibrating an execution force sensitivity coefficient of the electromagnetic driver by using a current excitation method before an experiment.
The permanent magnet is fixed at the lower end of the dynamometer, the electromagnetic coil is fixed on the base of the spiral side shaking machine, and the dynamometer can be moved up and down by adjusting the machine knob, so that the distance between the permanent magnet and the coil is changed. The DC stabilized power supply is used for providing current for the coil, the indication of the dynamometer when the power supply is turned off and turned on is recorded respectively, and the execution force sensitivity coefficient of the electromagnetic driver formed by the magnet and the coil under a specific distance can be obtained according to the indication difference.
S2, starting an experiment, placing the accelerometer to be tested at the central position of the vibration isolation platform, and performing ground active vibration isolation by using the vibration isolation platform to provide a test environment with low vibration noise.
Firstly, a power switch of an accelerometer to be measured is turned on, accelerometer output data received by a data processing system is observed, then an active vibration isolation control switch is turned on, and the vibration isolation platform is waited to further improve vibration isolation performance and stabilize for about 8-12 hours (according to the ground vibration condition at the time).
S3, injecting sinusoidal driving voltage (with amplitude of A mV and frequency of f) through a driving controller after the vibration isolation platform is in an optimal state and the output data of the accelerometer to be tested is stable a Hz) and a permanent magnet fixedly connected with the table top of the four-wire pendulum vibration isolation platform and an electromagnetic coil outside the table top are utilized to generate the frequency f required by calibration a The electromagnetic driving force of the vibration isolation platform generates translational displacement change in the calibration direction.
Firstly, according to the acceleration input a required by the accelerometer to be tested, multiplying the acceleration input a by the total mass M of the vibration isolation platform and the object placed on the table top to obtain the electromagnetic driving force F=Mxa required by calibration, and then according to the electromagnetic driving force F=kx (H vccs X V) to obtain the magnitude of the electromagnetic drive voltage required for calibration, where H vccs I=h as transfer function of voltage-controlled current source unit vccs The x V is the current generated after the signal conditioning circuit passes through, the execution force sensitivity coefficient of the electromagnetic driver is k N/A, and the V is the electromagnetic driving voltage required by calibration. In addition, different frequency points (such as f b 、f c Hz, etc.).
And S4, simultaneously recording output data of the displacement monitoring instrument and the accelerometer to be measured.
The specific steps of S4 include:
s41, monitoring displacement change of the vibration isolation platform by using a displacement monitoring instrument, and performing differential processing on the displacement data to obtain a translational acceleration signal of the vibration isolation platform as theoretical input.
S42, simultaneously recording output acceleration data of the horizontal axis of the accelerometer to be measured.
In the step S4, the vibration isolation platform is driven by electromagnetic force to generate tiny translational displacement, and the accelerometer to be tested positioned on the vibration isolation platform outputs dynamic response acceleration data; meanwhile, displacement data of the vibration isolation platform are recorded by a displacement detection instrument, and a translational acceleration signal of the vibration isolation platform is obtained by carrying out differential processing on the displacement, wherein the specific formula is as follows:
s5, respectively loading the horizontal axis output data of the accelerometer to be tested and the time domain data of the translational acceleration of the vibration isolation platform, which are recorded in the experimental process, wherein each time domain data is obtained in the same time period of not less than 1000S, and FFT is carried out on the time domain data by using a data processing system, and the calculation formula is as follows:
where N represents the length of the data point calculated by the FFT in the data processing.
The corresponding modulus of each data point after FFT (taking the first half of the data length, N/2) is then divided by N/2 to obtain the actual amplitude of the signal, according to Δf=F s and/N, obtaining the frequency spectrum resolution of the corresponding amplitude.
S6, respectively drawing the displacement monitoring instrument and the accelerometer to be measured at the calibration frequency f a Judging the calibration frequency f according to the amplitude spectrum curve of the response acceleration signal a Whether there is peak value or not, and obtain amplitude of signalSize of the product.
S7, performing error calculation according to the accuracy of 1% of the frequency stability, and taking the frequency range of f in the amplitude spectrum a X (1.+ -. 1%) Hz (f is subtracted a The corresponding signal amplitude) is used as an error of an amplitude spectrum to obtain an amplitude spectrum error result of translational acceleration of the accelerometer to be measured and the vibration isolation platform.
And S5 to S7 are all completed in the data processing system.
S8, changing the injected sinusoidal driving voltage (the amplitude is B, C, D and E mV in sequence, and the corresponding frequency is f a Hz), electromagnetic driving force corresponding to the excitation signals of different magnitudes is generated, and steps S5 to S7 are repeated.
In S8, the amplitude of the excitation signal is changed by the driving controller (the injection amplitude can be B, C, D, E mV, and the frequency is f respectively a Hz), the response of the accelerometer to be measured in the horizontal direction is detected.
S9, comparing the acceleration responded by the accelerometer to be measured with the amplitude spectrum of translational acceleration of the vibration isolation platform obtained by monitoring of the displacement monitoring instrument in an error range according to the measurement specification of the resolution test, and performing linear fitting on response results under different excitation signal amplitudes to finally obtain the resolution test and sensitivity calibration results of the accelerometer to be measured.
In the step S9, the error range of the accelerometer means that the ratio of the measured output amplitude value to the theoretical output amplitude value of the accelerometer to be measured is 50% -150%.
In the method, a displacement monitoring instrument monitors displacement change of the vibration isolation platform, a translational acceleration signal of the vibration isolation platform can be obtained through differential processing, and further amplitude spectrum calculation is carried out on the signal to serve as a theoretical output amplitude of acceleration. Comparing the response acceleration of the accelerometer to be measured with the amplitude spectrum of the translational acceleration of the vibration isolation platform obtained by monitoring of the displacement monitoring instrument in an error range to obtain the resolution test level of the accelerometer to be measured; and obtaining a sensitivity calibration result of the accelerometer to be measured by performing linear fitting on response acceleration amplitude spectrums of the accelerometer to be measured and the displacement monitoring instrument under electromagnetic excitation signals with different amplitudes.
It will be readily appreciated by those skilled in the art that the foregoing description is merely a preferred embodiment of the invention and is not intended to limit the invention, but any modifications, equivalents, improvements or alternatives falling within the spirit and principles of the invention are intended to be included within the scope of the invention.
Claims (8)
1. An accelerometer performance testing apparatus, comprising: the vibration isolator comprises a supporting frame, four equal-length suspension wires, a vibration isolation platform, a plurality of motion sensors, an active vibration isolation controller, a driving controller, a plurality of electromagnetic drivers and a displacement monitoring instrument;
one end of the suspension wire is fixed with a cross beam on the supporting frame, and the other end of the suspension wire is connected with the vibration isolation platform and used for suspending the vibration isolation platform, and the length of the suspension wire can ensure that the four-wire pendulum can move along the horizontal two translational degrees of freedom;
an accelerometer to be measured is fixedly placed at the center of the table top of the vibration isolation platform;
the motion sensors are used for acquiring absolute speed information of the vibration isolation platform and outputting the absolute speed information to the active vibration isolation controller;
the active vibration isolation controller is used for generating an active vibration isolation control signal according to the absolute speed information of the vibration isolation platform, generating corresponding current through the signal conditioning circuit and outputting the current to the electromagnetic driver;
the driving controller is used for generating the frequency f with the amplitude value A and the calibration requirement a The sinusoidal voltage signal of the power supply is generated through a signal conditioning circuit and is output to an electromagnetic driver;
the electromagnetic drivers are used for firstly receiving the current generated by the active vibration isolation controller to form feedback force for reducing the vibration degree of the vibration isolation platform, receiving the current generated by the driving controller after the vibration isolation platform is in an optimal state, and forming the frequency f required by calibration based on the magnetic transmission principle a The electromagnetic driving force of the vibration isolation platform is driven to generate translational displacement change along the calibration direction;
the displacement monitoring instrument is used for monitoring and recording displacement data of the vibration isolation platform in the directions of two horizontal translational degrees of freedom;
the support frame, the four equal-length suspension wires and the vibration isolation platform jointly form a passive vibration isolation structure, and form an active vibration isolation system together with the motion sensor, the active vibration isolation controller and the electromagnetic driver, so that the vibration isolation system has a vibration noise isolation function of the ground in the horizontal direction of the frequency band of 0.1-10 Hz.
2. The apparatus of claim 1, wherein the electromagnetic drive comprises: the permanent magnet is arranged on the table top of the vibration isolation platform, and the electromagnetic coil is arranged on the ground fixedly connected with the base along the direction of the permanent magnet.
3. The apparatus of claim 1, wherein the number of electromagnetic drives comprises:
the first electromagnetic driver is positioned on the east-west axis of the vibration isolation platform and used for controlling the east-west translational degree of freedom motion of the vibration isolation platform;
the second electromagnetic driver and the third electromagnetic driver are symmetrically arranged on two sides of a north-south axis of the vibration isolation platform, and the translational degree of freedom motion and the rotational degree of freedom motion of the vibration isolation platform in the north-south direction are controlled simultaneously.
4. A device according to any one of claims 1 to 3, wherein the device further comprises: a magnetic shield;
the magnetic shielding cover covers the electromagnetic driver and is used for shielding magnetic field interference or magnetic leakage generated by the electromagnetic driver to the accelerometer to be tested.
5. A method of testing performance of an accelerometer, applied to the device of any one of claims 1 to 4, the method comprising:
after the vibration isolation platform is in an optimal state and the output data of the accelerometer to be tested are stable, obtaining the output data of the displacement monitoring instrument and the accelerometer to be tested in the same time period;
carrying out differential processing on output data of a displacement monitoring instrument to obtain a translational acceleration signal of the vibration isolation platform, and further carrying out amplitude spectrum calculation on the signal to serve as an acceleration theory output amplitude;
and comparing the amplitude spectrum of the theoretical acceleration with the actual measured acceleration of the accelerometer to be measured in the calibration direction, and judging whether the theoretical acceleration is consistent with the actual measured acceleration of the accelerometer to be measured in the error range, so as to obtain a resolution test result of the accelerometer to be measured.
6. The method of claim 5, wherein the method further comprises:
and obtaining a sensitivity calibration result of the accelerometer to be measured by performing linear fitting on response acceleration amplitude spectrums of the accelerometer to be measured and the displacement monitoring instrument under electromagnetic excitation signals with different amplitudes.
7. The method of claim 5, wherein the method further comprises:
by changing the frequency of the injected electromagnetic excitation signal, the transfer function or the low-frequency response characteristic of the accelerometer to be measured is analyzed.
8. An accelerometer performance testing system, comprising: an accelerometer performance testing apparatus, memory and processor according to any one of claims 1 to 4;
the memory is used for storing a computer program and executing instructions;
the processor being configured to execute the computer-executable instructions, which when executed on the processor cause the method of any of claims 5 to 7 to be performed.
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