A method and device for suppressing periodic pulse error of micrometer sensor

Abstract

A method and device for suppressing periodic pulse errors of a micrometer sensor include a set of ultra-high frequency acquisition equipment and a corresponding frequency domain compensation filter. The ultra-high frequency acquisition equipment is used to collect the step wave driving signal and the sensor output signal of the micrometer sensor in real time. The step wave driving signal is used as the input signal of the IIR filter, and the sensor output signal is used as the output signal of the IIR filter to obtain the transfer function of the IIR filter. The inverse function of the obtained transfer function is obtained to obtain the frequency domain compensation filter. The step wave driving signal is processed by the frequency domain compensation filter and then drives the waveguide, which can compensate for the non-ideal frequency domain response caused by insufficient waveguide bandwidth and realize effective suppression of periodic pulse errors. The method is simple and has good error suppression effect.

Description

Technical Field

[0001] The invention relates to a method and a device for suppressing periodic pulse errors of a micrometer sensor, which can suppress periodic pulse errors of a micrometer sensor and belong to the technical field of optical fiber gyroscopes. Background Art

[0002] Fiber optic gyroscopes are now widely used in space systems due to their all-solid-state, high reliability, and high precision. The basic principle diagram of fiber optic gyroscopes is shown in the figure below. Figure 2 As shown. Traditional fiber optic gyroscopes are mostly used in low-frequency scenarios with a detection bandwidth below 10Hz. Due to the low detection bandwidth, high-frequency interference outside the detection bandwidth has no effect on the gyroscope performance. With the improvement of remote sensing satellite imaging accuracy, the demand for satellite micro-vibration measurement has increased. The microsensor is a new type of fiber optic gyroscope with a detection bandwidth greater than 1KHz, which can realize accurate measurement of satellite high-frequency micro-vibrations. As the detection bandwidth increases, high-frequency interference outside the original fiber optic gyroscope detection bandwidth will have a greater impact on the accuracy of the microsensor. Figure 1 The figure shows the high-frequency output data of the micrometer sensor. From the data, we can see that there is a periodic pulse error in the high-frequency output of the micrometer sensor. The reason for the periodic pulse error is that the waveguide modulation bandwidth is insufficient, and the modulation signal cannot be responded to in time at the step wave reset point, which causes the gyro output to have a long transition process at the step wave reset point. It is reflected in the time domain as Figure 1 The pulse error shown in . In traditional fiber optic gyroscopes, due to the low signal bandwidth, this pulse error will be filtered out and will have no effect on it. However, the detection bandwidth of the micrometer sensor is wide and cannot be filtered out. This pulse error will have a greater impact on the accuracy of the micrometer sensor. The most direct way to solve the problem of insufficient waveguide bandwidth is to increase the bandwidth of the waveguide by optimizing the waveguide solution and manufacturing process. However, in practice, due to the limitations of domestic technology and process level, the bandwidth of the waveguide cannot be further improved. The pulse error can also be filtered out by directly filtering the output of the micrometer sensor. However, since the pulse error frequency is the same as the step wave reset frequency, this frequency changes with different angular velocity inputs and can cover the full frequency range of 0.1Hz to 10KHz. On the one hand, the variable error frequency cannot be filtered out by a fixed filter. On the other hand, the use of a filter will also filter out the useful information to be measured at the filter filter frequency, affecting the use of the product. Summary of the invention

[0003] The technical problem solved by the present invention is to overcome the deficiency that the prior art cannot suppress the periodic pulse error in the micrometer sensor, and propose a suppression method and device based on frequency domain compensation.

[0004] The technical solution of the present invention is: a method for suppressing periodic pulse errors of a micrometer sensor, comprising:

[0005] Step 1: Collect the step wave driving signal and sensor output signal in each closed-loop cycle of the micrometer sensor;

[0006] Step 2: Take the step wave driving signal of each closed-loop cycle collected in step 1 as input, the sensor output signal as output, and the IIR filter as waveform to obtain the transfer function;

[0007] Step 3: Inverse the IIR filter transfer function obtained in step 2 to obtain a frequency domain compensation filter;

[0008] Step 4: The step wave driving signal is processed by the frequency domain compensation filter and then driven to drive the Y waveguide to suppress the periodic pulse error.

[0009] Preferably, the frequency measured in step 1 is greater than 1 / T, where T is the closed loop period of the micrometer sensor.

[0010] Preferably, the input data for obtaining the IIR filter transfer function in step 2 is obtained by intercepting the data collected in step 1, and the intercepted data segment starts at the reset point of the step wave drive signal and ends when the sensor output signal recovers to be equal to the mean value before the reset.

[0011] Preferably, the step wave driving signal and the sensor output signal need to be time-adjusted according to the delay characteristics of the sensor closed-loop detection algorithm to ensure that the collected sensor output signal corresponds to the step wave driving signal at the same time.

[0012] Preferably, steps 1-4 are repeated for different Y waveguides to obtain corresponding frequency domain compensation filters to achieve periodic pulse error suppression.

[0013] A device for suppressing periodic pulse errors of a micrometer sensor, comprising a measuring device and a frequency domain compensation filter;

[0014] The measuring device is used to measure the step wave driving signal and the sensor output signal in each closed loop cycle of the micrometer sensor;

[0015] The transfer function of the frequency domain compensation filter is the inverse function of the IIR filter transfer function. The transfer function of the IIR filter is obtained by taking the step wave driving signal of each closed-loop cycle as input, the sensor output signal as output, and the IIR filter as waveform. It is used to drive the Y waveguide after processing the step wave driving signal to achieve suppression of periodic pulse errors.

[0016] Preferably, the measuring device is an ultra-high frequency measuring device, and its measuring frequency is greater than 1 / T, where T is the closed-loop period of the micrometer sensor.

[0017] A micrometer sensor comprises an ASE light source, a photodetector, a coupler, a photoelectric modulator, a preamplifier, an FPGA for closed-loop detection, and a waveguide driver, and also comprises the frequency domain compensation filter described in claim 4, wherein the frequency domain compensation filter processes the step wave driving signal after the closed-loop detection process and then drives the Y waveguide to suppress the periodic pulse error.

[0018] Preferably, the frequency domain compensation filter is arranged in the FPGA, the input of which is the output of the closed-loop detection, and the output enters the waveguide drive.

[0019] Preferably, the FPGA includes three working modes, namely, a high-speed acquisition mode for extracting periodic pulse error characteristics; a frequency compensation filter parameter injection mode for injecting the corresponding parameters of the calculated frequency compensation filter transfer function; and a closed-loop detection working mode containing a frequency compensation filter, which realizes a micrometer sensor output without periodic pulse error after adding the frequency compensation filter.

[0020] The advantages of the present invention compared with the prior art are:

[0021] Existing waveguide manufacturing technology cannot achieve a higher signal bandwidth for waveguides. Existing filtering technology can only filter the high-frequency output of the micrometer sensor, but the pulse error frequency is variable, and filtering will also filter out useful information. This paper proposes a method and device for suppressing periodic pulse errors of micrometer sensors based on frequency domain compensation. First, the step wave driving signal and sensor output signal in each closed-loop cycle are collected by an ultra-high frequency acquisition system to obtain the filter parameters corresponding to the frequency response. At the same time, the inverse function of the filter parameters is obtained to obtain the frequency domain compensation filter parameters. After the step wave driving signal of the micrometer sensor is processed by the filter, the periodic pulse error can be effectively suppressed without affecting the normal measurement of the micrometer sensor. This method adjusts the corresponding filter parameters for different waveguides, suppresses the periodic pulse error, and does not affect the normal measurement of the micrometer sensor, and has good engineering application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The micrometer gyro collects output data at high speed;

[0023] Figure 2 Fiber optic gyroscope basic principle block diagram;

[0024] Figure 3 Fiber optic gyroscope principle block diagram including frequency domain compensation filtering;

[0025] Figure 4 Periodic pulse error suppression flow chart;

[0026] Figure 5 Schematic diagram of waveguide drive signal;

[0027] Figure 6 Schematic diagram of high-speed demodulation signal;

[0028] Figure 7 Data comparison before and after periodic pulse error suppression. DETAILED DESCRIPTION

[0029] The block diagram of the periodic pulse error suppression method of the present invention is as follows: Figure 3 As shown in FIG. 1 , based on the principle of the traditional fiber optic gyroscope, a frequency domain compensation filter is added inside the FPGA to perform frequency domain compensation filtering on the step wave driving signal to achieve the suppression of the periodic pulse error. The flowchart of the suppression method is shown in FIG. Figure 4 As shown, the transfer function calculation method of the frequency domain compensation filter is as follows:

[0030] (1) Use ultra-high frequency acquisition equipment to collect the step wave drive signal and sensor output signal of each feedback cycle of the micrometer sensor. The typical output signal is as follows: Figure 5 and Figure 6 As shown;

[0031] (2) For the collected Figure 5 and Figure 6 The data shown is intercepted, the starting point of the intercepted data is the reset point of the step wave, and the end point of the intercepted data is the point where the sensor output returns to the state before the step wave reset.

[0032] (3) Due to the time delay characteristics of the closed-loop detection algorithm and optical path of the micrometer sensor, the step wave driving signal will be reflected in the output of the micrometer sensor after a certain delay after being applied to the waveguide. In order to ensure the accuracy of the model, it is necessary to calculate the system delay based on the closed-loop detection algorithm and the optical path, and adjust the timing of the intercepted signal to ensure that the step wave driving signal and the sensor output signal caused by the signal application are at the same time;

[0033] (4) Taking the intercepted and time-adjusted step wave drive signal as the filter input signal and the sensor output signal as the filter output signal, the IIR filter with the transfer function shown in equation (2) is used as the model to obtain the periodic pulse error transfer function H(z):

[0034]

[0035] (5) Obtain the inverse function H of the transfer function H(z) in step (4): -1 (z);

[0036] (6) In the actual gyro closed-loop detection program, the original closed-loop feedback signal digital quantity to be output is converted into the digital quantity through the transfer function H -1 The output after filter processing of (z) can achieve periodic pulse error suppression;

[0037] (7) For different Y-waveguide parameters, steps (1) to (6) are repeated to obtain the corresponding frequency domain compensation filter to achieve periodic pulse error suppression.

[0038] The periodic pulse error suppression method proposed in the present invention is used to filter the digital quantity of the original closed-loop feedback signal of the gyroscope. The data before and after filtering are compared. Figure 7 As shown in the figure, it can be seen that the algorithm proposed in the present invention can effectively suppress the periodic pulse error of the micrometer sensor.

[0039] Based on the above introduction, a device for suppressing periodic pulse errors of micrometer sensors is provided, including a measuring device and a frequency domain compensation filter;

[0040] The measuring device is used to measure the step wave driving signal and the sensor output signal in each closed loop period of the micrometer sensor; the measuring device is an ultra-high frequency measuring device, and its measuring frequency is greater than 1 / T, where T is the closed loop period of the micrometer sensor.

[0041] The transfer function of the frequency domain compensation filter is the inverse function of the IIR filter transfer function. The transfer function of the IIR filter is obtained by taking the step wave driving signal of each closed-loop cycle as input, the sensor output signal as output, and the IIR filter as waveform. It is used to drive the Y waveguide after processing the step wave driving signal to achieve suppression of periodic pulse errors.

[0042] A micrometer sensor includes an ASE light source, a photodetector, a coupler, a photoelectric modulator, a preamplifier, an FPGA for closed-loop detection, and a waveguide driver. The frequency domain compensation filter processes the step wave drive signal after the closed-loop detection and then drives the Y waveguide to suppress the periodic pulse error. The frequency domain compensation filter is arranged in the FPGA, and its input is the output of the closed-loop detection, and the output enters the waveguide driver.

[0043] Parts of the present invention that are not described in detail belong to common knowledge among those skilled in the art.

Claims

1. A method for suppressing periodic pulse errors of microsensors, characterized in that include: Step 1: Measure the step wave driving signal and sensor output signal in each closed loop cycle of the micrometer sensor; Step 2: Take the step wave driving signal of each closed-loop cycle measured in step 1 as input, the sensor output signal as output, and the IIR filter as waveform to obtain the transfer function; Step 3: Obtain an inverse function of the IIR filter transfer function obtained in step 2 to obtain a frequency domain compensation filter; the frequency domain compensation filter is set in the FPGA, the input of which is the output of the closed-loop detection, and the output enters the waveguide drive; Step 4: The step wave driving signal is processed by the frequency domain compensation filter and then driven to drive the Y waveguide to suppress the periodic pulse error; The reason for the periodic pulse error is that the waveguide modulation bandwidth is insufficient, and the modulation signal cannot be responded to in time at the step wave reset point, which causes a long transition process of the gyroscope output at the step wave reset point, which is reflected in the time domain as a pulse error.

2. The method according to claim 1, characterized in that: The frequency measured in step 1 is greater than 1 / T, where T is the closed-loop period of the micrometer sensor.

3. The method according to claim 1, characterized in that: The input data for obtaining the IIR filter transfer function in step 2 is obtained by intercepting the data collected in step 1. The intercepted data segment starts at the reset point of the step wave drive signal and ends when the sensor output signal recovers to be equal to the mean value before the reset.

4. The method according to claim 1, characterized in that: It is necessary to adjust the timing of the step wave drive signal and the sensor output signal according to the delay characteristics of the sensor closed-loop detection algorithm to ensure that the collected sensor output signal corresponds to the step wave drive signal at the same time.

5. The method according to claim 1, characterized in that: For different Y-waveguides, steps 1-4 are repeated to obtain corresponding frequency domain compensation filters to achieve periodic pulse error suppression.

6. A device for suppressing periodic pulse errors of a micrometer sensor, characterized in that: It includes a measuring device and a frequency domain compensation filter; The measuring device is used to measure the step wave driving signal and the sensor output signal in each closed loop cycle of the micrometer sensor; The transfer function of the frequency domain compensation filter is an inverse function of the IIR filter transfer function, and the transfer function of the IIR filter is obtained by taking the step wave driving signal of each closed-loop cycle as input, the sensor output signal as output, and the IIR filter as waveform; and is used to drive the Y waveguide after processing the step wave driving signal to achieve suppression of periodic pulse errors; The frequency domain compensation filter is arranged in the FPGA, the input of which is the output of the closed-loop detection, and the output enters the waveguide drive; The reason for the periodic pulse error is that the waveguide modulation bandwidth is insufficient, and the modulation signal cannot be responded to in time at the step wave reset point, which causes a long transition process of the gyroscope output at the step wave reset point, which is reflected in the time domain as a pulse error.

7. The device according to claim 6, characterized in that: The measuring device is an ultra-high frequency measuring device, and its measuring frequency is greater than 1 / T, where T is the closed-loop period of the micrometer sensor.

8. A microsensor comprising an ASE light source, a photodetector, a coupler, a photoelectric modulator, a preamplifier, an FPGA for closed-loop detection, and a waveguide driver, characterized in that: It also includes the frequency domain compensation filter as described in claim 6, which processes the step wave driving signal after the closed-loop detection process and then drives the Y waveguide to achieve the suppression of periodic pulse errors; The frequency domain compensation filter is arranged in the FPGA, the input of which is the output of the closed-loop detection, and the output enters the waveguide drive; The reason for the periodic pulse error is that the waveguide modulation bandwidth is insufficient, and the modulation signal cannot be responded to in time at the step wave reset point, which causes a long transition process of the gyroscope output at the step wave reset point, which is reflected in the time domain as a pulse error.

9. The micrometer sensor according to claim 8, characterized in that: The frequency domain compensation filter is arranged in the FPGA, the input of which is the output of the closed-loop detection, and the output enters the waveguide drive.

10. The micrometer sensor according to claim 8, characterized in that: The FPGA includes three working modes, namely, a high-speed acquisition mode for extracting periodic pulse error characteristics; a frequency compensation filter parameter injection mode for injecting the corresponding parameters of the calculated frequency compensation filter transfer function; and a closed-loop detection working mode including a frequency compensation filter, which realizes the output of a micrometer sensor without periodic pulse error after adding a frequency compensation filter.

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