RU2546983C2 - Method for determining dynamic errors of micromechanical inertial sensors and inertial measurement modules on their basis - Google Patents

Abstract

FIELD: measurement equipment.

SUBSTANCE: invention relates to metrology. A method for determining dynamic errors of micromechanical inertial sensors consists in the fact that determination of a dynamic error is performed by comparison of characteristics set by a stand of oscillations to characteristics reproduced with a micromechanical sensor or a module. With that, oscillations are reproduced with the stand and recorded with the micromechanical sensor or an inertial measurement module in a frequency spectrum covering the whole frequency range of the object operation and corresponding to certain operating conditions with further treatment by the following formula: S_out(ω)=|W(jω)|²·S_in(ω), where S_out(ω) - spectral power density of a signal of the micromechanical sensor or module, S_in(ω) - spectral power density of an input signal from the stand, |W(jω)| - an amplitude-frequency characteristic of the sensor or the module being tested. A calculation of spectral densities of power of input and output signals is performed by transition from a time domain to a frequency domain by Fourier transformation; with that, an experimentally determined amplitude-frequency characteristic |W(jω)| of the sensor or the module characterises dispersion D of error of the object being tested in the specified frequency spectrum, and root-mean-square deviation of dynamic error of the micromechanical sensor is in compliance with the following expression: $$\sigma =\sqrt{D}.$$

EFFECT: higher accuracy.

Description

The invention relates to the field of measurement technology and can be used to determine the dynamic errors of micromechanical inertial sensors (gyroscopes and accelerometers) and inertial measuring modules based on them.

A known method for determining the dynamic errors of micromechanical inertial sensors (gyroscopes and accelerometers) and inertial measuring modules based on setting harmonic vibrations using a test bench. The object under study is installed on the test bench and oscillations with a fixed frequency are set. To assess the dynamic errors in the frequency range of the sensor or module, a series of tests is carried out on various fixed values of the oscillation frequency set by the test bench, and a comparison of the characteristics set by the bench and the characteristics reproduced by an inertial sensor or measuring module [Ivanov V.A. Metrological support of gyro devices. - L .: Shipbuilding, 1983, p. 134].

In addition, there is a method implemented in a test bench for taking the static and dynamic characteristics of linear speed sensors, which simultaneously compares the characteristics of the tested sensor with the reference characteristics of the slide mechanism of the stand [copyright certificate SU 1024856 A1 (Pivovarov L.V.)].

These methods for determining the dynamic errors of sensors or modules require considerable time and do not provide reliable determination of errors in relation to the specific operating conditions of the studied sensors or modules.

где $$S_{вых}(\omega )$$

- спектральная плотность мощности сигнала микромеханического датчика или модуля, $$S_{вх}(\omega )$$

- спектральная плотность мощности входного сигнала со стенда, $$\left|W(j\omega )\right|$$

- амплитудно-частотная характеристика исследуемого датчика или модуля. Указанный способ позволяет экспериментально определить амплитудно-частотную характеристику исследуемого датчика или модуля [Грязин Д.Г. и др. Метрологическое обеспечение испытаний микромеханических датчиков и модулей // Известия Тульского государственного университета. Технические науки, 2012, №7, с. 67-76].A known method for determining the dynamic errors of micromechanical inertial sensors (gyroscopes and accelerometers) and inertial modules based on them. The method consists in the fact that the vibrations are reproduced by the stand and recorded by a micromechanical sensor or an inertial module in the frequency spectrum, covering the entire frequency range of the object under study and corresponding to specific operating conditions. Subsequent processing is performed according to the formula $$S_{\mathrm{at}sx}(\omega )={\left|W(j\omega )\right|}^2\cdot S_{\mathrm{at}x}(\omega ),$$

Where $$S_{\mathrm{at}sx}(\omega )$$

- spectral power density of the signal of the micromechanical sensor or module, $$S_{\mathrm{at}x}(\omega )$$

- spectral power density of the input signal from the stand, $$\left|W(j\omega )\right|$$

- amplitude-frequency characteristic of the studied sensor or module. The specified method allows you to experimentally determine the amplitude-frequency characteristic of the investigated sensor or module [Gryazin DG et al. Metrological support for testing micromechanical sensors and modules // Bulletin of Tula State University. Engineering, 2012, No. 7, p. 67-76].

This method is selected for the prototype of the invention.

The specified method is applicable for determining the frequency characteristics of sensors or modules, but does not allow to determine the dynamic error of the sensor or module in the frequency range of its operation.

The objective of the invention is to determine the dynamic errors of the sensors in real operating conditions.

The problem is solved as follows.

где $$S_{вых}(\omega )$$

- спектральная плотность мощности сигнала микромеханического датчика или модуля, $$S_{вх}(\omega )$$

- спектральная плотность мощности входного сигнала со стенда, $$\left|W(j\omega )\right|$$

- амплитудно-частотная характеристика исследуемого датчика или модуля. Экспериментально определенная амплитудно-частотная характеристика $$\left|W(j\omega )\right|$$

датчика или модуля характеризует дисперсию D погрешности исследуемого объекта в заданном спектре частот. Среднеквадратичное отклонение динамической погрешности σ микромеханического датчика или инерциального измерительного модуля находится в соответствии с выражением $$\sigma =\sqrt{D}$$

. Рассчитанное значение характеризует погрешность исследуемого прибора применительно к конкретным условиям эксплуатации, соответствующим задаваемому спектру входного воздействия.Harmonic oscillations reproduced with the help of the test bench are set in the frequency spectrum, covering the entire frequency range of the object under study and corresponding to specific operating conditions. The module under study is installed on an oscillation stand capable of reproducing oscillations with a given frequency spectrum, and the characteristics specified by the stand and the characteristics reproduced by a micromechanical sensor or an inertial measuring module are recorded. Based on the obtained data, the spectral power densities (hereinafter referred to as spectra) of the input and output signals are calculated by switching from the time domain to the frequency domain using the Fourier transform. The resulting spectrum of the output signal of the module is compared with the spectrum of the input signal of the stand corresponding to specific operating conditions, in accordance with the expression $$S_{\mathrm{at}sx}(\omega )={\left|W(j\omega )\right|}^2\cdot S_{\mathrm{at}x}(\omega ),$$

Where $$S_{\mathrm{at}sx}(\omega )$$

- spectral power density of the signal of the micromechanical sensor or module, $$S_{\mathrm{at}x}(\omega )$$

- spectral power density of the input signal from the stand, $$\left|W(j\omega )\right|$$

- amplitude-frequency characteristic of the studied sensor or module. Experimentally determined amplitude-frequency response $$\left|W(j\omega )\right|$$

sensor or module characterizes the variance D of the error of the investigated object in a given frequency spectrum. The standard deviation of the dynamic error σ of the micromechanical sensor or inertial measuring module is in accordance with the expression $$\sigma =\sqrt{D}$$

. The calculated value characterizes the error of the instrument under study in relation to specific operating conditions corresponding to the specified input exposure spectrum.

для экспериментального определения частотной передаточной функции $$\left|W(j\omega )\right|$$

исследуемого объекта, которая определяет динамическую погрешность датчика или модуля во всем частотном диапазоне его работы.The method is implemented as follows. The studied micromechanical inertial sensor or measuring module is mounted on a stand capable of reproducing fluctuations in the frequency spectrum, covering the entire frequency range of the object under study. Vibrations with a spectrum corresponding to specific operating conditions are set. The characteristics set by the stand and the characteristics reproduced by the sensor or module are recorded. The data obtained using the Fourier transform are transferred to the frequency domain to calculate the spectral power density of the signals. The spectra of the input signal of the stand and the output signal of the sensor or module are compared in accordance with the expression $$S_{\mathrm{at}sx}(\omega )={\left|W(j\omega )\right|}^2\cdot S_{\mathrm{at}x}(\omega ),$$

for experimental determination of the frequency transfer function $$\left|W(j\omega )\right|$$

the studied object, which determines the dynamic error of the sensor or module in the entire frequency range of its operation.

The technical result achieved is the determination of dynamic errors of micromechanical inertial sensors and inertial measuring modules based on them in the mode of their operation, increasing the reliability of determining dynamic errors in relation to specific operating conditions, reducing the time for determining dynamic errors in the serial production of micromechanical sensors and modules.

The object under study is mounted on a stand capable of reproducing fluctuations in the frequency spectrum. Oscillations are set with a spectrum corresponding to actual operating conditions. The characteristics set by the stand and the characteristics reproduced by the micromechanical sensor or inertial module are recorded. Subsequent processing of the input and output signals according to the above formulas allows you to determine the dynamic error of the investigated object in the operating mode. Setting oscillations in the frequency spectrum can reduce the time and increase the reliability of determining the dynamic errors of the studied objects in relation to specific operating conditions.

Claims (1)

A method for determining the dynamic errors of micromechanical inertial sensors (gyroscopes and accelerometers) and inertial measuring modules based on them, which consists in determining the dynamic error by comparing the characteristics set by the vibration bench with the characteristics reproduced by the micromechanical sensor or module, while the vibrations are reproduced stand and recorded by a micromechanical sensor or inertial measuring module in the frequency spectrum, covering present the whole frequency range of operation of the object and corresponding to specific operating conditions, followed by treatment of the formula $$S_{\mathrm{at}sx}(\omega )={\left|W(j\omega )\right|}^2\cdot S_{\mathrm{at}x}(\omega ),$$

Where $$S_{\mathrm{at}sx}(\omega )$$

- spectral power density of the signal of the micromechanical sensor or module, $$S_{\mathrm{at}x}(\omega )$$

- spectral power density of the input signal from the stand, $$\left|W(j\omega )\right|$$

- the amplitude-frequency characteristic of the studied sensor or module, characterized in that the calculation of the spectral power densities of the input and output signals is carried out by switching from the time domain to the frequency using the Fourier transform, while the experimentally determined amplitude-frequency characteristic $$\left|W(j\omega )\right|$$

sensor or module characterizes the variance D of the error of the investigated object in a given frequency spectrum, while the standard deviation of the dynamic error σ of the micromechanical sensor or inertial measuring module is in accordance with the expression $$\sigma =\sqrt{D}$$

and determines the error of the instrument under study in relation to specific operating conditions corresponding to a given input exposure spectrum.