Temperature compensation system and method based on gyroscope driving modal oscillation frequency

Abstract

The invention discloses a temperature compensation system and method based on gyroscope driving modal oscillation frequency, the system comprises a detection module, a demodulation module, a decimation filtering module and a temperature compensation module, the detection module is connected with a gyroscope, a driving signal and a sensing signal are collected and input into the demodulation module, the demodulation module extracts an angular velocity signal in the sensing signal, and the decimation filtering module is connected with the temperature compensation module. The demodulation module outputs an angular velocity signal to the decimation filtering module, the decimation filtering module filters noise outside a target bandwidth and transmits the angular velocity signal to the temperature compensation module, meanwhile, a driving signal is also input to the temperature compensation module, and the temperature compensation module comprises a frequency measurement circuit, a synchronizer, a counter, a calibration unit and a calculation unit; by acquiring the driving signal and the sensing signal of the driving mode, the frequency of the driving mode is acquired, finally, the digital output signal of the gyroscope is obtained through calculation, the processing signal is directly output from the gyroscope, the compensation effect is good, and the zero offset of the gyroscope in a full-temperature environment is effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of gyroscope temperature compensation, and in particular to a temperature compensation system and method based on the oscillation frequency of a gyroscope driving mode. Background Art

[0002] The gyroscope is a precision measuring device whose performance is affected by many factors, among which temperature is an important factor. Temperature changes can cause changes in the physical properties of sensitive components (such as optical fiber materials) inside the gyroscope, which in turn affects its measurement accuracy. In order to reduce this effect and improve measurement accuracy, the gyroscope needs to be temperature compensated. There are many existing temperature compensation methods, including isolating the gyroscope from temperature changes, using temperature sensors to monitor the temperature of the gyroscope and make corresponding compensation, and using neural network models to compensate for fiber optic gyroscope errors. However, the temperature used in the existing temperature compensation circuit comes from the temperature sensor outside the gyroscope, which is different from the actual temperature of the gyroscope, resulting in limited temperature compensation and poor compensation effect. Summary of the invention

[0003] In view of the deficiencies in the prior art, an object of the present invention is to provide a temperature compensation system and method based on the oscillation frequency of a gyroscope driving mode.

[0004] In order to achieve the above object, the present invention provides the following technical solutions: The invention discloses a temperature compensation system based on the oscillation frequency of a gyroscope driving mode, comprising a detection module, a demodulation module, an extraction filter module and a temperature compensation module. The detection module is connected with the gyroscope, collects a driving signal and a sensing signal and inputs them into the demodulation module. The demodulation module extracts an angular velocity signal from the sensing signal, and the demodulation module outputs the angular velocity signal to the extraction filter module. The extraction filter module filters out noise outside the target bandwidth, reduces the data rate and then transmits the processed angular velocity signal to the temperature compensation module. Meanwhile, the driving signal is also input into the temperature compensation module. The temperature compensation module comprises a frequency measurement circuit, a synchronizer, a counter, a calibration unit and a calculation unit.

[0005] In the present invention, preferably, the frequency measuring circuit divides the driving signal by N to increase the frequency difference between the driving signal and the reference clock.

[0006] In the present invention, preferably, the synchronizer synchronizes the output signal of the frequency measuring circuit to the reference clock signal domain.

[0007] In the present invention, preferably, the counter counts rising edges in the signal output by the synchronizer to obtain a first signal, and simultaneously counts rising edges of the reference clock signal to obtain a second signal, wherein the second signal is the frequency of the driving signal.

[0008] In the present invention, preferably, the calibration unit calibrates the second signal to obtain a third signal, and transmits the third signal to the calculation unit.

[0009] In the present invention, preferably, the calculation unit receives the first signal, the third signal and the angular velocity signal and calculates them using a fourth-order polynomial calculation to obtain a compensated gyroscope output angular velocity.

[0010] In the present invention, preferably, the fourth-order polynomial is calculated as: ; ; ; Where Gyro is the angular velocity signal output by the decimation filter module, Gyro comp is the compensated gyro output, ,an,bn,cn,dn, , as, bs, cs, ds are compensation coefficients, which are obtained by fitting a series of measurement data in the early stage. is the third signal, ZR and S are intermediate variables.

[0011] The temperature compensation method based on the gyroscope driving modal oscillation frequency comprises the steps of: Collecting driving signals and sensing signals of the gyroscope; Extracting an angular velocity signal from the sensing signal and filtering it; The driving signal is divided in sequence, synchronized to the reference clock domain, and the rising edges are counted to obtain a first signal; At the same time, the reference clock signal is counted and calibrated to obtain a third signal; A fourth-order polynomial calculation is performed on the angular velocity signal and the third signal to obtain a compensated gyroscope output angular velocity signal.

[0012] Compared with the prior art, the present invention has the following beneficial effects: The system of the present invention acquires the driving signal and the sensing signal of the driving mode, acquires the frequency of the driving mode, and finally obtains the digital output signal of the gyroscope by calculation. The processed signal is directly obtained from the gyroscope output, has a good compensation effect, and effectively improves the zero bias of the gyroscope in a full-temperature environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 The schematic diagram of the structure of the temperature compensation system based on the gyroscope driven modal oscillation frequency described in the present system.

[0014] Figure 2 It is a structural schematic diagram of the temperature compensation module described in the system.

[0015] Figure 3 This is a schematic diagram of the connection structure of the demodulation module and the extraction and filtering module described in the system.

[0016] Figure 4 Schematic diagram of the zero-input gyro output G0 and the frequency measurement output F measured at various temperature points in one embodiment.

[0017] Figure 5 The gyro output Gyro after compensation in one embodiment comp And schematic diagram of frequency measurement output F. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0020] Please also see Figure 1 and Figure 2 A preferred embodiment of the present invention provides a temperature compensation system based on the oscillation frequency of the gyroscope driving mode. Based on the linear relationship between the oscillation frequency of the driving mode and the temperature of the gyroscope, the oscillation frequency of the driving mode is obtained by collecting the driving signal of the driving mode and the sensing signal of the sensing mode. The driving signal is a capacitance change signal corresponding to the gyroscope driving mode, which reflects the oscillation of the driving mode, and the sensing signal is a capacitance change signal corresponding to the gyroscope sensing mode, which reflects the change of the input angular velocity. Finally, the digital output signal of the gyroscope is obtained by calculation.

[0021] Specifically, it includes a detection module, a demodulation module, an extraction filter module, and a temperature compensation module. The detection module is connected to the gyroscope. The collected driving signal and sensing signal of the gyroscope are input into the demodulation module. The demodulation module extracts the angular velocity signal in the sensing signal. The demodulation module outputs the angular velocity signal to the extraction filter module. The extraction filter module filters out the noise outside the target bandwidth, and after reducing the data rate, the processed angular velocity signal is transmitted to the temperature compensation module. At the same time, the driving signal is also input into the temperature compensation module. The temperature compensation module includes a frequency measurement circuit, a synchronizer, a counter, a calibration unit and a calculation unit. The driving signal is processed by the frequency measurement circuit, the synchronizer and the counter in the temperature compensation module to obtain a first signal, and the reference clock signal is processed by the counter and the calibration unit to obtain a third signal. Finally, the calculation unit performs a fourth-order polynomial calculation on the first signal, the third signal and the angular velocity signal to obtain the compensated gyroscope output angular velocity signal. The processed signal is directly obtained from the gyroscope output, and the compensation effect is good, which effectively improves the zero bias of the gyroscope in a full temperature environment.

[0022] Specifically, Figure 3 As shown, the demodulation module includes a phase shift unit, a multiplier and a low-pass filter. The sensing signal is first input into the phase shift unit, and the phase of the sensing signal is adjusted by phase shifting to achieve synchronous demodulation. A number of registers are set in the phase shift unit, and each register outputs a signal corresponding to the sensing signal delayed by a different phase. The specific phase of the sensing signal is delayed by the output of the phase shift unit through configuration. The driving signal and the phase-shifted sensing signal are then input into the multiplier, and the multiplier multiplies the two input signals. The multiplied signal is filtered through a low-pass filter and finally output to the extraction filter module. The extraction filter module mainly adopts a CIC filter, which can reduce the sampling rate and achieve efficient filtering. The processed signal of the extraction filter module is input into the temperature compensation module.

[0023] Specifically, in the temperature compensation module, the specific steps are as follows: the frequency measuring circuit divides the driving signal by N to increase the frequency difference between the driving signal and the reference clock to reduce the measurement error. The synchronizer synchronizes the output signal of the frequency measuring circuit to the reference clock signal domain, and then transmits it to the counter. The counter counts the rising edges in the signal output by the synchronizer to obtain the first signal, and obtains the number of cycles of the synchronizer output signal by counting the rising edges, such as Figure 2 As shown, the cycle number is the time period from the rising edge count increasing from 0 to NUM, that is, the time required for a frequency measurement, and the rising edge of the reference clock signal within the cycle number is counted to obtain a second signal, wherein the second signal is the frequency of the driving signal. The calibration unit calibrates the second signal to obtain a third signal, which is transmitted to the calculation unit. The calibration specifically reduces the second signal by 2 ntimes, where n can be any value from 0 to 12, which can be selected according to actual needs. After each count is completed, the counter is cleared to proceed to the next count.

[0024] Specifically, the calculation unit receives the first signal, the third signal and the angular velocity signal, and calculates the third signal using a fourth-order polynomial calculation to obtain a compensated gyroscope output angular velocity. The fourth-order polynomial calculation is: ; ; ; Where Gyro is the angular velocity signal output by the decimation filter module, Gyro comp is the compensated gyro output, ,an,bn,cn,dn, , as, bs, cs, ds are compensation coefficients, which are obtained by fitting a series of measurement data in the early stage. is the third signal, and ZR and S are intermediate variables. The specific fitting process is: N points are uniformly selected between the lowest and highest temperatures of the expected gyroscope operation, and N is greater than or equal to 5. At each temperature point, each gyroscope output G and frequency measurement output F (third signal) of the gyroscope are recorded at zero input, maximum input, and minimum input (the maximum input and minimum input depend on the expected gyroscope working range), and N groups of gyroscope outputs G corresponding to zero input, maximum input, and minimum input are obtained at N temperature points, as well as frequency measurement outputs F corresponding to N temperature points. N zero inputs and N frequency measurement outputs F are fitted into a fourth-order polynomial to obtain compensation coefficients V0, an, bn, cn, dn; the absolute value average of the maximum input and minimum input at N temperature points (the default maximum input / minimum input absolute value is equal) and N frequency measurement outputs F are fitted into a fourth-order polynomial to obtain compensation coefficients S0, as, bs, cs, ds.

[0025] Specifically, in the present embodiment, the operating temperature of the gyroscope is -40°C to 80°C, and -40°C, -20°C, 0°C, 20°C, 40°C, 60°C, and 80°C are selected as simulated temperature points in the range of -40°C to 80°C. The operating temperature of the gyroscope is gradually increased from -40°C, and maintained at each simulated temperature point for a period of time to collect a number of data, and the zero-input gyroscope output G0 and the frequency measurement output F corresponding to the several data points at each temperature point are measured, and the number of collected data points is used as the horizontal coordinate, and the zero-input gyroscope output G0 and the frequency measurement output F are respectively used as the vertical coordinates, such as Figure 4 shown.

[0026] The frequency measurement output F is used as the independent variable, and the gyro output G0 is used as the variable to perform fourth-order polynomial fitting to obtain the temperature compensation coefficients V0, an, bn, cn, and dn, as shown in Table 1 below: Table 1

[0027] Measure the gyro output G at the maximum / minimum input (taking ±500° / s as an example) at each simulated temperature point max / G min And the frequency measurement output F (all are the average values ​​of multiple measurements). It is proposed that the gyro output under the maximum input after compensation corresponds to 7500000LSB, and the calculation is performed at each temperature point Denoted as SF, as shown in Table 2 below: Table 2

[0028] The frequency measurement output F is used as the independent variable and SF is used as the variable to perform fourth-order polynomial fitting to obtain the temperature compensation coefficients S0, as, bs, cs, and ds, as shown in Table 3 below: Table 3

[0029] For the zero input gyro output at each temperature point, use the previously calculated temperature compensation coefficient and calculate ZR, S, and the compensated gyro output Gyro comp ,as follows Figure 5 As shown. Compare the zero bias stability before and after temperature compensation. The standard deviation of the zero input gyro output before compensation is about 1977LSB, corresponding to 1977 / 7500000*500° / s=474.5° / h; the standard deviation of the zero input gyro output after compensation is about 303LSB, corresponding to 303 / 7500000*500° / s=72.7° / h, which is 84.5% less than before compensation.

[0030] Another preferred embodiment of the present invention provides a temperature compensation method based on the oscillation frequency of the gyroscope driving mode, comprising the steps of: Collecting driving signals and sensing signals of the gyroscope; Extracting an angular velocity signal from the sensing signal and filtering it; The driving signal is divided in sequence, synchronized to the reference clock domain, and the rising edges are counted to obtain a first signal; At the same time, the reference clock signal is counted and calibrated to obtain a third signal; A fourth-order polynomial calculation is performed on the angular velocity signal and the third signal to obtain a compensated gyroscope output angular velocity signal.

[0031] In some other preferred embodiments of the present invention, a computer-readable storage medium is provided, storing a computer program. When the computer program is executed by a processor, the processor executes the steps of the method described in the above embodiment.

[0032] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc., which can store program codes.

[0033] The above description is a detailed description of the preferred feasible embodiments of the present invention, but the embodiments are not intended to limit the scope of the patent application of the present invention. All equivalent changes or modified changes completed under the technical spirit suggested by the present invention should fall within the patent scope covered by the present invention.

Claims

1. A temperature compensation system based on gyroscope driven modal oscillation frequency, characterized in that: It includes a detection module, a demodulation module, an extraction filter module, and a temperature compensation module. The detection module is connected to the gyroscope, collects the driving signal and the sensing signal and inputs them into the demodulation module. The demodulation module extracts the angular velocity signal from the sensing signal, and the demodulation module outputs the angular velocity signal to the extraction filter module. The extraction filter module filters out the noise outside the target bandwidth, reduces the data rate, and then transmits the processed angular velocity signal to the temperature compensation module. At the same time, the driving signal is also input into the temperature compensation module. The temperature compensation module comprises a frequency measuring circuit, a synchronizer, a counter, a calibration unit and a calculation unit which are connected in sequence.

2. The temperature compensation system based on gyroscope drive modal oscillation frequency according to claim 1, characterized in that: The frequency measuring circuit divides the driving signal by N to increase the frequency difference between the driving signal and a reference clock.

3. The temperature compensation system based on gyroscope drive modal oscillation frequency according to claim 2, characterized in that: The synchronizer synchronizes the output signal of the frequency measuring circuit to the reference clock signal domain.

4. The temperature compensation system based on gyroscope drive modal oscillation frequency according to claim 3, characterized in that: The counter counts the rising edges of the signal output by the synchronizer to obtain a first signal, and simultaneously counts the rising edges of the reference clock signal to obtain a second signal, wherein the second signal is the frequency of the driving signal.

5. The temperature compensation system based on gyroscope driving modal oscillation frequency according to claim 4, characterized in that: The calibration unit calibrates the second signal to obtain a third signal, and transmits the third signal to the calculation unit.

6. The temperature compensation system based on gyroscope driving modal oscillation frequency according to claim 5, characterized in that: The calculation unit receives the first signal, the third signal and the angular velocity signal, and calculates the third signal using a fourth-order polynomial calculation to obtain a compensated gyroscope output angular velocity signal.

7. The temperature compensation system based on gyroscope driving modal oscillation frequency according to claim 6, characterized in that: The fourth-order polynomial is calculated as: ； ； ； Where Gyro is the angular velocity signal output by the decimation filter module, Gyro comp is the compensated gyro output, ,an,bn,cn,dn, , as, bs, cs, ds are compensation coefficients, is the third signal, ie, the frequency signal, and ZR and S are intermediate variables.

8. A method for temperature compensation system based on gyro drive modal oscillation frequency according to any one of claims 1 to 7, characterized in that: Includes steps: Collecting driving signals and sensing signals of the gyroscope; Extracting an angular velocity signal from the sensing signal and filtering it; The driving signal is divided in sequence, synchronized to the reference clock domain, and the rising edges are counted to obtain a first signal; At the same time, the reference clock signal is counted and calibrated to obtain a third signal; A fourth-order polynomial calculation is performed on the angular velocity signal and the third signal to obtain a compensated gyroscope output angular velocity signal.

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