阅读说明：本技术 一种应用于液浮陀螺仪的高精度信号采集系统及方法 (High-precision signal acquisition system and method applied to liquid floated gyroscope ) 是由 毛佳珍 石慧 赵新宇 于 2021-01-11 设计创作，主要内容包括：本发明涉及一种应用于液浮陀螺仪的高精度信号采集系统及方法,其技术特点是：本发明包括交流信号放大降噪电路、相敏解调器、直流信号放大滤波器、信号校正电路、功率放放大器、力矩器、采样电阻、电流频率转换模块、信号采集电路和上位机,其中交流信号放大器、相敏解调器、直流信号放大器、信号校正电路、功率放放大器、力矩器、采样电阻、电流频率转换模块、信号采集电路和上位机依次连接,电流频率转换模块的接地端接地。本发明能够有效降低方波驱动陀螺电机的谐波对陀螺仪性能的影响,解决陀螺内部可能出现的强电磁耦合现象,避免拍频问题,降低陀螺仪噪声,并且可根据陀螺仪精度要求设置电机电源转速及传感器的工作频率的合理范围。(The invention relates to a high-precision signal acquisition system and a high-precision signal acquisition method applied to a liquid floated gyroscope, which are technically characterized by comprising the following steps of: the device comprises an alternating current signal amplification noise reduction circuit, a phase sensitive demodulator, a direct current signal amplification filter, a signal correction circuit, a power amplifier, a torquer, a sampling resistor, a current frequency conversion module, a signal acquisition circuit and an upper computer, wherein the alternating current signal amplifier, the phase sensitive demodulator, the direct current signal amplifier, the signal correction circuit, the power amplifier, the torquer, the sampling resistor, the current frequency conversion module, the signal acquisition circuit and the upper computer are sequentially connected, and the grounding end of the current frequency conversion module is grounded. The invention can effectively reduce the influence of the harmonic wave of the square wave driving gyro motor on the performance of the gyro, solve the strong electromagnetic coupling phenomenon possibly occurring in the gyro, avoid the beat frequency problem, reduce the noise of the gyro, and set the reasonable ranges of the motor power supply rotating speed and the working frequency of the sensor according to the precision requirement of the gyro.)

1. The utility model provides a be applied to high accuracy signal acquisition system of liquid floating gyroscope which characterized in that: the device comprises an alternating current signal amplification noise reduction circuit, a phase-sensitive demodulator, a direct current signal amplification filter, a signal correction circuit, a power amplifier, a torquer, a sampling resistor, a current frequency conversion module, a signal acquisition circuit and an upper computer, wherein the alternating current signal amplifier, the phase-sensitive demodulator, the direct current signal amplifier, the signal correction circuit, the power amplifier, the torquer, the sampling resistor, the current frequency conversion module, the signal acquisition circuit and the upper computer are sequentially connected, and the grounding end of the current frequency conversion module is grounded.

2. A high-precision signal acquisition system applied to a liquid floated gyroscope according to claim 1, wherein: the signal acquisition circuit includes signal buffer, FPGA and serial ports interface, FPGA includes first counter, the second counter, adder and serial ports communication module, the positive pulse input of signal buffer is connected to current frequency conversion module's positive pulse output, the negative pulse input of signal buffer is connected to current frequency conversion module's negative pulse output, the adder is connected through first counter to signal buffer's first output, the adder is connected through the second counter to signal buffer's second output, the input of serial ports communication is connected to the output of adder, the host computer is connected to the output of serial ports communication.

3. An acquisition method of a high-precision signal acquisition system applied to a floating gyroscope according to claim 1 or 2, comprising the following steps:

step 1, outputting an electric signal to an alternating current signal amplification noise reduction circuit by a gyroscope, amplifying and reducing noise of the alternating current signal, and simultaneously carrying out Fourier analysis on the signal to determine an interference signal;

step 2, adjusting the working frequency of a sensor in the gyroscope to be positioned at the center positions of two higher harmonics of the interference signal according to the interference signal, and outputting the signal to an alternating current signal amplification noise reduction circuit again;

step 3, inputting the alternating current signals subjected to noise reduction into a phase sensitive demodulator to convert alternating current signals and direct current signals;

step 4, inputting the direct current signal generated by conversion into a direct current signal amplification filter, amplifying the direct current signal, and filtering after signal amplification;

step 5, inputting the filtered direct current signal into a signal correction circuit for signal correction;

step 6, inputting the direct current signal after signal correction into a power amplifier for power amplification;

step 7, inputting the current signal with amplified power to a torquer;

step 8, disconnecting the grounding end of the current frequency conversion module connected with the torquer through the force sampling resistor, connecting the current frequency conversion module into a gyroscope circuit in series, connecting the gyroscope to the analog ground of the current frequency conversion module with reference to the ground, and collecting signals passing through the torquer and converting the signals into excitation frequency signals by the signal collection circuit;

and 9, inputting the excitation frequency signal to an upper computer, and generating a gyroscope signal result by the upper computer.

4. The sampling method of the high-precision signal acquisition circuit applied to the liquid floated gyroscope according to claim 3, wherein the sampling method comprises the following steps: the specific implementation method for determining the interference signal in the step 1 comprises the following steps: and carrying out low-pass or band-pass filtering processing on the output signal to eliminate stray interference, and connecting the processed signal to an oscilloscope to carry out spectrum analysis on the signal.

5. The sampling method of the high-precision signal acquisition circuit applied to the liquid floated gyroscope according to claim 3, wherein the sampling method comprises the following steps: in the step 1, a high-Q band-pass filter is added in the alternating-current signal amplification noise reduction circuit, the parameters of the high-Q band-pass filter are adjusted, a first-order inverse proportion operational amplifier is added on the basis of a second-order BPF structure, a proper amount of positive feedback is introduced, and the Q value is increased to 50.

Technical Field

The invention belongs to the technical field of signal acquisition, and particularly relates to a high-precision signal acquisition system and method applied to a liquid floated gyroscope.

Background

The liquid-floated gyroscope applied to the strapdown system generally adopts a force feedback mode to carry out gyroscope test, and has the advantages that the test mode is consistent with the currently adopted working state, and the performance parameters of the inertial instrument can be more accurately reflected.

The liquid floated gyroscope is provided with a gyro motor, a sensor, a torquer, a magnetic suspension, a heating assembly and other components in a small space, and various elements have corresponding working voltage and working frequency, so that the phenomenon of mutual electromagnetic interference is easy to occur. The gyro motor is driven by square waves or sine waves, and the control mode of the square wave power supply is simple, and the power consumption of the circuit is low, so that the gyro motor is widely applied. Due to the influence of the motor magnetic field, square wave signals of the motor can be distorted, electromagnetic signals superposed on a sensor winding of the gyroscope can be reflected differently, higher harmonics of fundamental frequency signals form interference sources on the output of the sensor, a beat frequency phenomenon can be generated when the sensor is serious, the performance detection of the gyroscope is greatly influenced, and the gyroscope is particularly serious under the working condition of high precision and large bandwidth.

The liquid floated gyroscope in the force feedback test mode obtains the performance index of the gyroscope by measuring and collecting the electric signal of the torquer of the liquid floated gyroscope, and the accuracy of the collection and measurement directly influences the precision of the surface body. In order to meet the test requirements of a high-precision gyroscope, a large-time-constant RC filter and a high-cost high-precision digital multimeter are often adopted to meet the matched test requirements, and in order to meet the data range in the traditional measurement mode, a method of improving the data acquisition digit of an instrument is often adopted, so that the influence of the method is that the sampling rate of the instrument data is reduced, the reduction difference of a high-frequency part of a gyroscope signal is reduced, and a measurement error source is formed.

Disclosure of Invention

The invention aims to overcome the defects of the prior art, provides a high-precision signal acquisition system and method applied to a liquid floated gyroscope, can provide a signal acquisition method for directly acquiring the current of a torquer without using a high-precision voltmeter, and can accurately reflect the performance parameters of an inertial instrument.

The technical problem to be solved by the invention is realized by adopting the following technical scheme:

the utility model provides a be applied to high accuracy signal acquisition system of liquid floated gyroscope, including the circuit of making an uproar of alternating current signal amplification, the phase sensitive demodulator, direct current signal amplification filter, signal correction circuit, power amplifier, the torquer, sampling resistor, current frequency conversion module, signal acquisition circuit and host computer, wherein alternating current signal amplifier, the phase sensitive demodulator, direct current signal amplifier, signal correction circuit, power amplifier, the torquer, sampling resistor, current frequency conversion module, signal acquisition circuit and host computer connect gradually, current frequency conversion module's earthing terminal ground connection.

And, the signal acquisition circuit includes signal buffer, FPGA and serial port interface, FPGA includes first counter, the second counter, adder and serial port communication module, the positive pulse input of signal buffer is connected to the positive pulse output of current frequency conversion module, the negative pulse input of signal buffer is connected to the negative pulse output of current frequency conversion module, the adder is connected through first counter to the first output of signal buffer, the adder is connected through the second counter to the second output of signal buffer, the input of serial port communication is connected to the output of adder, the host computer is connected to the output of serial port communication.

A collection method of a high-precision signal collection system applied to a liquid floated gyroscope comprises the following steps:

step 1, outputting an electric signal to an alternating current signal amplification noise reduction circuit by a gyroscope, amplifying and reducing noise of the alternating current signal, and simultaneously carrying out Fourier analysis on the signal to determine an interference signal;

step 2, adjusting the working frequency of a sensor in the gyroscope to be positioned at the center positions of two higher harmonics of the interference signal according to the interference signal, and outputting the signal to an alternating current signal amplification noise reduction circuit again;

step 3, inputting the alternating current signals subjected to noise reduction into a phase sensitive demodulator to convert alternating current signals and direct current signals;

step 4, inputting the direct current signal generated by conversion into a direct current signal amplification filter, amplifying the direct current signal, and filtering after signal amplification;

step 5, inputting the filtered direct current signal into a signal correction circuit for signal correction;

step 6, inputting the direct current signal after signal correction into a power amplifier for power amplification;

step 7, inputting the current signal with amplified power to a torquer;

step 8, disconnecting the grounding end of the current frequency conversion module connected with the torquer through the force sampling resistor, connecting the current frequency conversion module into a gyroscope circuit in series, connecting the gyroscope to the analog ground of the current frequency conversion module with reference to the ground, and collecting signals passing through the torquer and converting the signals into excitation frequency signals by the signal collection circuit;

and 9, inputting the excitation frequency signal to an upper computer, and generating a gyroscope signal result by the upper computer.

Moreover, the specific implementation method for determining the interference signal in step 1 is as follows: and carrying out low-pass or band-pass filtering processing on the output signal to eliminate stray interference, and connecting the processed signal to an oscilloscope to carry out spectrum analysis on the signal.

And in the step 1, a high-Q band-pass filter is added in the alternating current signal amplification noise reduction circuit, the parameters of the high-Q band-pass filter are adjusted, a first-stage inverse proportion operational amplifier is added on the basis of a second-order BPF structure, a proper amount of positive feedback is introduced, and the Q value is increased to 50.

The invention has the advantages and positive effects that:

1. the device comprises an alternating current signal amplification noise reduction circuit, a phase sensitive demodulator, a direct current signal amplification filter, a signal correction circuit, a power amplifier, a torquer, a sampling resistor, a current frequency conversion module, a signal acquisition circuit and an upper computer, wherein the alternating current signal amplifier, the phase sensitive demodulator, the direct current signal amplifier, the signal correction circuit, the power amplifier, the torquer, the sampling resistor, the current frequency conversion module, the signal acquisition circuit and the upper computer are sequentially connected, and the grounding end of the current frequency conversion module is grounded. The invention can effectively reduce the influence of the harmonic wave of the square wave driving gyro motor on the performance of the gyro, solve the strong electromagnetic coupling phenomenon possibly occurring in the gyro, avoid the beat frequency problem, reduce the noise of the gyro, and set the reasonable ranges of the motor power supply rotating speed and the working frequency of the sensor according to the precision requirement of the gyro.

2. The invention adopts the current frequency conversion module to carry out information conversion, has the characteristics of strong anti-interference capability and small temperature coefficient, adopts the current balance type principle design for the conversion mode of the current signal of the gyroscope of the liquid floating gyroscope, continuously acquires and converts the input signal, can overcome the phenomenon of number loss, simultaneously adopts the high-speed processing design of the current frequency conversion module and the data acquisition circuit for the current signal of the liquid floating gyroscope, improves the sampling rate of data, and effectively solves the problem of signal aliasing of the existing test mode.

3. The invention combines the analog feedback loop used in the gyroscope test with the high-precision digital signal conversion process, and is beneficial to the miniaturization of the detection device.

Drawings

FIG. 1 is a block diagram of the system of the present invention;

FIG. 2 is a block diagram of a high Q bandpass filter of the present invention;

fig. 3 is a schematic structural diagram of a current frequency conversion signal acquisition device according to the present invention.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

A high-precision signal acquisition system and method applied to a liquid floated gyroscope comprise the following steps:

a high-precision signal acquisition system applied to a liquid floated gyroscope comprises an alternating current signal amplification noise reduction circuit, a phase-sensitive demodulator, a direct current signal amplification filter, a signal correction circuit, a power amplifier, a torquer, a sampling resistor, a current frequency conversion module, a signal acquisition circuit and an upper computer, wherein the alternating current signal amplifier, the phase-sensitive demodulator, the direct current signal amplifier, the signal correction circuit, the power amplifier, the torquer, the sampling resistor, the current frequency conversion module, the signal acquisition circuit and the upper computer are sequentially connected, and a grounding end of the current frequency conversion module is grounded.

As shown in fig. 3, the signal acquisition circuit includes a signal buffer, FPGA and serial port interface, FPGA includes a first counter, a second counter, adder and serial port communication module, the positive pulse output end of current frequency conversion module connects the positive pulse input end of signal buffer, the negative pulse output end of current frequency conversion module connects the negative pulse input end of signal buffer, the first output end of signal buffer connects adder through first counter, the second output end of signal buffer connects adder through second counter, the input of serial port communication is connected to the output of adder, the output of serial port communication connects the host computer.

A collection method of a high-precision signal collection system applied to a liquid floated gyroscope comprises the following steps:

step 1, outputting an electric signal to an alternating current signal amplification noise reduction circuit by a gyroscope, amplifying the alternating current signal, reducing noise, and simultaneously carrying out Fourier analysis on the signal to determine an interference signal.

The method for determining the interference signal in the step is to perform Fourier analysis on the sensor output signal subjected to noise reduction processing, and perform frequency domain analysis on the electric signal of the sensor output winding by using the spectrum analysis function of the oscilloscope. The specific implementation method comprises the steps of carrying out low-pass or band-pass filtering processing on the alternating current signal of the output winding of the gyroscope sensor, eliminating stray interference, connecting the processed signal to an oscilloscope, and carrying out spectrum analysis on the signal.

Taking a certain type of permanent magnet motor gyroscope as an example, when the driving power frequency of the gyroscope is fm, the electromagnetic interference generated by the motor to the gyroscope sensor is mainly an integral multiple of fm spectrum signals, and at this time, the working frequency fc of the sensor can be located at the center position of two higher harmonics of the motor interference signals by using the display wave energy, that is, fc ═ 1/2) fm, and at this time, the maximum noise reduction effect can be obtained. And when necessary, comprehensively considering the feasible parameter schemes of the sensor excitation power supply and the motor power supply in the design process.

Meanwhile, in order to enhance the suppression of noise components in the signal of the gyroscope sensor, as shown in fig. 2, a band-pass filter with a higher Q value is used, a first-order inverse proportion operational amplifier is added on the basis of a second-order BPF structure, and a proper amount of positive feedback is introduced to increase the Q value to about 50.

The specific parameters are obtained by the following formula:

at determining the amplification K of the filter_FCentral angular frequency omega₀And Q value, the parameter value of each element can be determined by the following formula.

The capacitors in the circuit have the same value, the second-stage operational amplifier realizes 10 times of inverted amplification of signals and applies the inverted amplification to the input end of the first-stage operational amplifier to form certain positive feedback, and the Q value of the circuit can be correspondingly improved. The three resistors, designated R1, all take the same value and are at a predetermined magnification K_FCentral angular frequency omega₀And Q value and capacitor value, and obtaining the values of the resistors R1, R2 and R3 by using the calculation formula.

In this embodiment, the sensor is composed of two high-precision low-noise low-drift operational amplifiers OP27 and a resistor capacitor, the center frequency of the filter is set as the excitation frequency of the sensor, the Q value is set to 50, and the amplification factor KF is set to 10. The input signal of the circuit is an alternating voltage signal output by a gyroscope sensor, and the output signal is connected to a post-stage phase-sensitive demodulation circuit.

And 2, adjusting the working frequency of a sensor in the gyroscope to be positioned at the center positions of two higher harmonics of the interference signal according to the interference signal, and outputting the signal to the alternating current signal amplification noise reduction circuit again.

And 3, inputting the noise-reduced alternating current signal into a phase-sensitive demodulator to convert an alternating current signal into a direct current signal.

And 4, inputting the direct current signal generated by conversion into a direct current signal amplification filter, amplifying the direct current signal, and filtering after signal amplification.

And 5, inputting the filtered direct current signal into a signal correction circuit for signal correction.

And 6, inputting the direct current signal after signal correction into a power amplifier for power amplification.

And 7, inputting the power amplified current signal to a torquer.

And 8, disconnecting the grounding end of the current frequency conversion module connected with the moment device through the force sampling resistor, connecting the current frequency conversion module into a gyroscope circuit in series, connecting the gyroscope to the analog ground of the current frequency conversion module with reference to the ground, acquiring signals passing through the moment device by a signal acquisition circuit, converting the signals into positive and negative pulses F + and F-, outputting the pulses by TTL (transistor-transistor logic), wherein the low level is effective, and the duration time of the high level depends on the magnitude of input current.

In the step, a high-precision current frequency conversion module IFC is adopted to collect the gyro moment applying current passing through the liquid floating gyroscope torquer. The current frequency conversion module is a mature module produced by Hongzhou Hongda electronic corporation, the model is HMIFC541ST35, the range of the current frequency conversion module is +/-35 mA (full temperature), the scale factor is 7000 +/-300 pulses/mA, the maximum output frequency is 256KHz, and the current frequency conversion module has the characteristics of full temperature of 1pulse quantization noise and temperature coefficient superior to 0.5 ppm/DEG C. The original product is mainly used in the conversion acquisition of the output current signal of the accelerometer serving as a measuring element of the inertial navigation and guidance product. The high-precision current frequency conversion module is applied to the acquisition process of the output signal of the detection circuit of the liquid floating gyroscope.

The current-frequency conversion module is adopted for high-speed acquisition, the sampling frequency is improved, the obtained data can better restore high-frequency electromagnetic interference signals brought by a gyro motor in output signals of the gyroscope, targeted filtering processing is carried out on the signals in subsequent gyroscope data analysis work, and test data are more concentrated in a frequency range reflecting the motion characteristics of a carrier. In the implementation, through analysis and balance, 100s smooth filtering processing of data is selected, and noise and jitter influence is eliminated.

And 9, inputting the excitation frequency signal to an upper computer, and generating a gyroscope signal result by the upper computer.

It should be emphasized that the embodiments described herein are illustrative rather than restrictive, and thus the present invention is not limited to the embodiments described in the detailed description, but also includes other embodiments that can be derived from the technical solutions of the present invention by those skilled in the art.