Method and system for online calibration of control loop phase error of hemispherical resonant gyroscope

Abstract

The present invention discloses a method and system for online calibration of the control loop phase error of a hemispherical resonant gyroscope. The method comprises the following steps: constructing a drive modal transfer function for the hemispherical resonant gyroscope and plotting an amplitude-frequency characteristic curve and a phase-frequency characteristic curve based on the drive modal transfer function; performing frequency domain analysis on the drive modal transfer function of the hemispherical resonant gyroscope based on the amplitude-frequency characteristic curve and the phase-frequency characteristic curve to obtain analysis results; and online calibrating phase error parameters based on the analysis results to compensate for the control loop phase error. The method is simple to operate and requires no external instrumentation. The hemispherical resonant gyroscope only requires normal operation; the remaining calculations are performed by a program. Furthermore, the method is adaptable, as component inconsistencies do not affect the testing process. Therefore, the method is suitable for measuring the phase errors of drive and detection signals in closed-loop control gyroscopes.

Description

Technical Field

[0001] The invention belongs to the technical field of intelligent instruments and meters, and particularly relates to a method and system for online calibration of a control loop phase error of a hemispherical resonator gyroscope. Background Art

[0002] The control loop of a hemispherical resonant gyroscope (HRG) utilizes digital-to-analog converters (DACs), analog-to-digital converters (ADCs), phase-locked loops (PLLs), and filter amplifier circuits for signal transmission and processing. Due to the non-ideal nature of these components, phase errors can occur in the HRG's control loop. This is reflected in phase errors in the gyroscope's drive and detection circuits, significantly impacting the gyroscope's control system stability, bias stability, and scale factor nonlinearity.

[0003] The phase error in the HRG control loop can be measured using a frequency sweep. The measurement results are used by a PLL to track the phase changes, and thus the frequency, of the HRG's vibration signal. However, the frequency sweep method has limitations. It requires specialized instrumentation and can only measure the phase error in the circuit offline. Furthermore, the results do not include phase errors caused by components such as the ADC and DAC. Summary of the Invention

[0004] The present invention aims to solve the problem of difficulty in phase error measurement and calibration in the prior art, and proposes a method for online calibration of the control loop phase error of a hemispherical resonant gyroscope to obtain accurate phase error and automatically calibrate the phase error.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] The method for online calibration of the control loop phase error of a hemispherical resonant gyroscope comprises the following steps:

[0007] Constructing a driving modal transfer function of the hemispherical resonant gyroscope, and drawing an amplitude-frequency characteristic curve and a phase-frequency characteristic curve based on the driving modal transfer function;

[0008] Performing frequency domain analysis on the driving modal transfer function of the hemispherical resonant gyroscope based on the amplitude-frequency characteristic curve and the phase-frequency characteristic curve to obtain an analysis result;

[0009] Based on the analysis results, the phase error parameters are calibrated online to complete the compensation of the control loop phase error.

[0010] Preferably, the method for constructing the driving modal transfer function of the hemispherical resonant gyroscope includes:

[0011] Construct the motion equation of the hemispherical resonator in the open-loop mode of the hemispherical resonator;

[0012] The driving modal transfer function is constructed based on the motion equation.

[0013] Preferably, the motion equation of the hemispherical resonator includes:

[0014]

[0015] Where x and y are the amplitude displacements of the driving mode and the detection mode, respectively, and ω x ,ω y are the resonant frequencies of the driving mode and the detection mode, Q x , Q y are the quality factors of the driving mode and the detection mode, F x is the driving force of the driving mode, m is the mass of the oscillator, ρ xy ,ω xy are the damping coupling coefficient and stiffness coupling coefficient respectively, n is the gyro vibration mode order, γ is the precession factor, and Ω is the external input angular velocity.

[0016] Preferably, the transfer function of the driving mode comprises:

[0017]

[0018] Where m is the mass of the oscillator, F x is the driving force of the driving mode, X(s) is the Laplace transform of x(t), s=jω is the complex frequency domain variable, j is the imaginary unit, ω x is the resonant frequency of the driving mode, Q x is the driving mode quality factor.

[0019] Preferably, the method for drawing the amplitude-frequency characteristic curve and the phase-frequency characteristic curve includes:

[0020] Obtaining a vibration displacement and a first phase of a driving mode in a stable state based on the driving mode transfer function;

[0021] Obtaining the vibration amplitude and the second phase when the driving signal is equal to the driving mode resonant frequency;

[0022] The amplitude-frequency characteristic curve and the phase-frequency characteristic curve are plotted based on the vibration displacement, the first phase, the vibration amplitude, and the second phase.

[0023] Preferably, the vibration displacement and phase of the driving mode in the stable state include:

[0024]

[0025] Where x0 is the vibration amplitude, ω dis the driving signal frequency, t is the time, x represents the vibration displacement of the driving mode in the stable state, represents the phase of the driving mode in the steady state, ω x is the resonant frequency of the driving mode, Q x is the driving mode quality factor.

[0026] Preferably, the method for obtaining the analysis result includes:

[0027] Obtaining a phase difference based on an initial phase angle of the reference signal and an initial phase of the driving signal;

[0028] Modulating the phase difference to collect a control value of the vibration amplitude;

[0029] A phase error is obtained based on the control amount.

[0030] The present invention also provides a system for online calibration of a control loop phase error of a hemispherical resonant gyroscope, comprising:

[0031] mapping unit, analysis unit, and compensation unit;

[0032] The drawing unit is used to construct a driving modal transfer function of the hemispherical resonant gyroscope, and draw an amplitude-frequency characteristic curve and a phase-frequency characteristic curve based on the driving modal transfer function;

[0033] The analyzing unit is configured to perform frequency domain analysis on the driving modal transfer function of the hemispherical resonant gyroscope based on the amplitude-frequency characteristic curve and the phase-frequency characteristic curve to obtain an analysis result;

[0034] The compensation unit is used to calibrate the phase error parameter online based on the analysis result to complete the compensation of the control loop phase error.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] The existing technology measures the phase error generated in the gyroscope control loop through a single frequency sweep, requiring the use of specific instruments and limited to offline use. Consequently, existing phase error compensation methods can only be calibrated offline once, resulting in significant limitations in their application. The present invention, however, has the following advantages: First, it is simple to operate, requiring no external instrumentation; the hemispherical resonant gyroscope only requires normal operation, with the remaining calculations performed by a program. Second, the present invention is adaptable, and component inconsistencies will not affect the testing process. Therefore, the present invention is suitable for measuring the phase error of the drive and detection signals in closed-loop control gyros. Finally, the present invention can calibrate the phase error online, reflecting the gyroscope's real-time phase error with high accuracy, allowing for direct compensation. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solution of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0038] Figure 1 The embodiment of the present invention is to calibrate the PI control of a_PID online to compensate for the phase error of the control loop flow chart;

[0039] Figure 2 Schematic diagram of the amplitude-frequency characteristic curve and phase-frequency characteristic curve of the hemispherical resonant gyroscope according to an embodiment of the present invention;

[0040] Figure 3 The phase error of the control loop in the embodiment of the present invention is Schematic diagram of the amplitude-frequency characteristic curve and phase-frequency characteristic curve when the hemispherical resonant gyroscope has frequency mismatch under the influence;

[0041] Figure 4 Schematic diagram of the amplitude-frequency characteristic curve and phase-frequency characteristic curve of the hemispherical resonant gyroscope when δ is a square wave modulation signal in an embodiment of the present invention;

[0042] Figure 5 In the embodiment of the present invention, δ is a square wave modulation signal and there is a control loop phase error. Schematic diagram of the amplitude-frequency characteristic curve and phase-frequency characteristic curve of the hemispherical resonant gyroscope;

[0043] Figure 6 In the embodiment of the present invention, δ is a square wave modulation signal and there is a control loop phase error. and the output of PI control Schematic diagram of the amplitude-frequency characteristic curve and phase-frequency characteristic curve of the hemispherical resonant gyroscope. DETAILED DESCRIPTION

[0044] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. 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 making creative efforts are within the scope of protection of the present invention.

[0045] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0046] Example 1

[0047] A first embodiment of the present invention provides a method for online calibration of a control loop phase error of a hemispherical resonant gyroscope, comprising the following steps:

[0048] S1. Construct a hemispherical resonant gyroscope drive modal transfer function, and draw an amplitude-frequency characteristic curve and a phase-frequency characteristic curve based on the drive modal transfer function.

[0049] Methods for constructing the transfer function of the HRG drive mode include:

[0050] First, the motion equation of the hemispherical resonator of the hemispherical resonator gyroscope in open-loop mode is constructed.

[0051] In this embodiment, the hemispherical resonator gyroscope operating in the open-loop mode is taken as an example. The motion equation of the hemispherical resonator in the rectangular coordinate system is:

[0052]

[0053] Where x and y are the amplitude displacements of the driving mode and the detection mode, respectively, and ω x ,ω y are the resonant frequencies of the driving mode and the detection mode, Q x , Q y are the quality factors of the driving mode and the detection mode, F x is the driving force of the driving mode, m is the mass of the oscillator, ρ xy ,ω xy are the damping coupling coefficient and stiffness coupling coefficient respectively, n is the gyro vibration mode order, γ is the precession factor, and Ω is the external input angular velocity.

[0054] Then, the transfer function of the driving mode is obtained by performing Laplace transform on both sides of the above motion equation.

[0055] The transfer function in the driving mode is:

[0056]

[0057] Where m is the mass of the oscillator, F x is the driving force of the driving mode, X(s) is the Laplace transform of x(t), s=jω is the complex frequency domain variable, j is the imaginary unit, ω x is the resonant frequency of the driving mode, Q x is the driving mode quality factor.

[0058] The methods for drawing amplitude-frequency characteristic curves and phase-frequency characteristic curves include:

[0059] Firstly, the vibration displacement and the first phase of the driving mode in the steady state are obtained based on the driving mode transfer function;

[0060] Specifically, let the driving force F of the driving mode be x =F0sinω d t, where F0 is the driving force amplitude, ω d is the driving signal frequency, and t is the time. Then the vibration displacement x and phase of the driving mode in the stable state are The expression is:

[0061]

[0062] Where x0 is the vibration amplitude,

[0063] Then, the vibration amplitude and the second phase when the driving signal is equal to the driving mode resonant frequency are obtained;

[0064] Specifically, when the driving signal frequency is equal to the driving mode resonant frequency, that is, ω d =ω x hour,

[0065]

[0066] Finally, according to formula (3) and formula (4), the amplitude-frequency characteristic curve and the phase-frequency characteristic curve are drawn, as shown in Figure 2 As shown, Figure 2 The upper part is the amplitude-frequency characteristic curve, the horizontal axis is the frequency ω, the vertical axis is the gain 20lgX(ω), and the unit is dB. Figure 2 The lower part is the phase-frequency characteristic curve, the horizontal axis is the frequency ω, and the vertical axis is the phase The unit is degree.

[0067] S2. Based on the amplitude-frequency characteristic curve and the phase-frequency characteristic curve, the driving modal transfer function of the hemispherical resonant gyroscope is analyzed in the frequency domain to obtain the analysis results.

[0068] Methods for obtaining analysis results include:

[0069] (1) obtaining a phase difference based on the initial phase angle of the reference signal and the initial phase of the driving signal;

[0070] When d =ω x When , it is assumed that there is a phase error in the control loop The gyro phase will increase each time it is adjusted. After multiple closed-loop runs, the system will be out of control, but in the actual control process, the gyro can still operate. By observing the amplitude-frequency characteristic curve and the phase-frequency characteristic curve, if the phase remains unchanged, then frequency mismatch will inevitably occur, that is, ω d ≠ω x ,like Figure 3This is shown as point P in the figure. This shows that the control system automatically compensates for the phase error at the expense of frequency mismatch, so the control force required to maintain the same amplitude a becomes larger. In FPGA programs, PID control methods are usually used to maintain the stability of the amplitude, which requires a larger control force, that is, the control amount a of the amplitude a_ PID Get bigger.

[0071] During the gyro calculation process, the phase difference δ represents the difference between the initial phase angles of the reference signal and the vibration signal. During operation, it is desirable to maintain a constant phase difference (typically 0) to stabilize the reference signal output by the closed-loop phase-locked loop. In the FPGA program, the parameter δ can be set to change the phase difference value to compensate for the effects of phase error in the control loop.

[0072] (2) Modulating the phase difference to collect the control value of the vibration amplitude;

[0073] According to the amplitude-frequency characteristic curve and the phase-frequency characteristic curve, The larger the value of d With ω x The greater the difference, the greater the control force required. PID Based on the above, the phase difference δ can be modulated to collect a_ PID The phase error is identified by changing the value.

[0074] (3) Obtain the phase error based on the control quantity.

[0075] For the collected a_ PID After data processing, we can get a_ PID The minimum point represents the minimum control force required, ω d and ω x The difference is the smallest, that is, the phase difference δ value set at this time is the same as the phase error The values cancel each other out.

[0076] S3. Based on the analysis results, the phase error parameters are calibrated online to complete the compensation of the control loop phase error.

[0077] The components selected for the control circuit of each gyroscope are different. The value of is also different. Figure 1 As shown, the phase error of the control loop is compensated based on the online calibration of the PI control of a_PID. Flow chart of the process.

[0078] When the phase error of the control loop is 0, set δ to a square wave modulation signal with an amplitude of A(deg) and a period of T. Under the influence of δ, the frequency of the gyro drive mode will change, ω d ≠ωx When the δ value is A, the driving frequency ω d1 <ω x , the phase is A-90°, such as Figure 4 As shown at point N; when the δ value is -A, the driving frequency ω d2 >ω x , the phase is -A-90°, such as Figure 4 As shown by point M in the middle. At the same time, because the amplitude A remains unchanged, points N and M are in symmetrical positions, and the control force of the two is the same, that is, a_ PID same.

[0079] Considering the control loop phase error is In this case, points N and M become points N' and M', and the corresponding phase becomes Simultaneous driving frequency ω′ d1 and ω′ d2 No longer ω x Symmetrical, such as Figure 5 As shown. At this time, the control force at point N' is less than the control force at point M', and the corresponding a_ PID The same applies to size.

[0080] Real-time acquisition of a_ PID The output of PI control is set as Applying it to the phase control loop, the corresponding phase becomes Due to the effect of PI control, The value will gradually approach Until Points N' and M' will gradually move towards the original points N and M, and eventually return to their original positions. PID The size will also tend to be stable, such as Figure 6 As shown. PID Output of PI control when stable You get it The value of .

[0081] According to the above In the phase control loop, the phase error of the control loop is compensated by adjusting the phase parameters of the digital signal online.

[0082] Example 2

[0083] The present invention also provides a system for online calibration of a control loop phase error of a hemispherical resonant gyroscope, comprising: a drawing unit, an analysis unit, and a compensation unit;

[0084] The drawing unit is used to construct a driving modal transfer function of the hemispherical resonant gyroscope and draw an amplitude-frequency characteristic curve and a phase-frequency characteristic curve based on the driving modal transfer function;

[0085] The method of plotting the transfer function of the unit to construct the hemispherical resonant gyroscope drive mode includes:

[0086] First, the motion equation of the hemispherical resonator of the hemispherical resonator gyroscope in open-loop mode is constructed.

[0087] In this embodiment, the hemispherical resonator gyroscope operating in the open-loop mode is taken as an example. The motion equation of the hemispherical resonator in the rectangular coordinate system is:

[0088]

[0089] Where x and y are the amplitude displacements of the driving mode and the detection mode, respectively, and ω x ,ω y are the resonant frequencies of the driving mode and the detection mode, Q x , Q y are the quality factors of the driving mode and the detection mode, F x is the driving force of the driving mode, m is the mass of the oscillator, ρ xy ,ω xy are the damping coupling coefficient and stiffness coupling coefficient respectively, n is the gyro vibration mode order, γ is the precession factor, and Ω is the external input angular velocity.

[0090] Then, the transfer function of the driving mode is obtained by performing Laplace transform on both sides of the above motion equation.

[0091] The transfer function in the driving mode is:

[0092]

[0093] Where m is the mass of the oscillator, F x is the driving force of the driving mode, X(s) is the Laplace transform of x(t), s=jω is the complex frequency domain variable, j is the imaginary unit, ω x is the resonant frequency of the driving mode, Q x is the driving mode quality factor.

[0094] The method for the drawing unit to draw the amplitude-frequency characteristic curve and the phase-frequency characteristic curve includes:

[0095] Firstly, the vibration displacement and the first phase of the driving mode in the steady state are obtained based on the driving mode transfer function;

[0096] Specifically, let the driving force F of the driving mode be x =F0sinω d t, where F0 is the driving force amplitude, ω d is the driving signal frequency, and t is the time. Then the vibration displacement x and phase of the driving mode in the stable state are The expression is:

[0097]

[0098] Where x0 is the vibration amplitude,

[0099] Then, the vibration amplitude and the second phase when the driving signal is equal to the driving mode resonant frequency are obtained;

[0100] Specifically, when the driving signal frequency is equal to the driving mode resonant frequency, that is, ω d =ω x hour,

[0101]

[0102] Finally, the amplitude-frequency characteristic curve and the phase-frequency characteristic curve are drawn according to formula (7) and formula (8).

[0103] The analysis unit is used to perform frequency domain analysis on the driving modal transfer function of the hemispherical resonant gyroscope based on the amplitude-frequency characteristic curve and the phase-frequency characteristic curve to obtain analysis results;

[0104] The method for the analysis unit to obtain the analysis result includes:

[0105] (1) obtaining a phase difference based on the initial phase angle of the reference signal and the initial phase of the driving signal;

[0106] When d =ω x When , it is assumed that there is a phase error in the control loop The gyro phase will increase each time it is adjusted. After multiple closed-loop runs, the system will be out of control, but in the actual control process, the gyro can still operate. By observing the amplitude-frequency characteristic curve and the phase-frequency characteristic curve, if the phase remains unchanged, then frequency mismatch will inevitably occur, that is, ω d ≠ω x This means that the control system automatically compensates for the phase error at the expense of frequency mismatch, so the control force required to maintain the same amplitude a becomes larger. In FPGA programs, PID control methods are usually used to maintain the stability of the amplitude, so the required control force becomes larger, that is, the control amount a of the amplitude a_ PID Get bigger.

[0107] During the gyro calculation process, the phase difference δ represents the difference between the initial phase angles of the reference signal and the vibration signal. During operation, it is desirable to maintain a constant phase difference (typically 0) to stabilize the reference signal output by the closed-loop phase-locked loop. In the FPGA program, the parameter δ can be set to change the phase difference value to compensate for the effects of phase error in the control loop.

[0108] (2) Modulating the phase difference to collect the control value of the vibration amplitude;

[0109] According to the amplitude-frequency characteristic curve and the phase-frequency characteristic curve, The larger the value of d With ω x The greater the difference, the greater the control force required. PID Based on the above, the phase difference δ can be modulated to collect a_ PID The phase error is identified by changing the value.

[0110] (3) Obtain the phase error based on the control quantity.

[0111] For the collected a_ PID After data processing, we can get a_ PID The minimum point represents the minimum control force required, ω d and ω x The difference is the smallest, that is, the phase difference δ value set at this time is the same as the phase error The values cancel each other out.

[0112] The compensation unit is used to calibrate the phase error parameters online based on the analysis results to complete the compensation of the control loop phase error.

[0113] The components selected for the control circuit of each gyroscope are different. The value of is also different.

[0114] When the phase error of the control loop is 0, set δ to a square wave modulation signal with an amplitude of A(deg) and a period of T. Under the influence of δ, the frequency of the gyro drive mode will change, ω d ≠ω x When the δ value is A, the driving frequency ω d1 <ω x , the phase is A-90°, such as Figure 4 As shown at point N; when the δ value is -A, the driving frequency ω d2 >ω x , the phase is -A-90°, such as Figure 4 As shown by point M in the middle. At the same time, because the amplitude A remains unchanged, points N and M are in symmetrical positions, and the control force of the two is the same, that is, a_ PID same.

[0115] Considering the control loop phase error is In this case, points N and M become points N' and M', and the corresponding phase becomes Simultaneous driving frequency ω′ d1 and ω′ d2 No longer ω xSymmetrical, such as Figure 5 As shown. At this time, the control force at point N' is less than the control force at point M', and the corresponding a_ PID The same applies to size.

[0116] Real-time acquisition of a_ PID The output of PI control is set as Applying it to the phase control loop, the corresponding phase becomes Due to the effect of PI control, The value will gradually approach Until Points N' and M' will gradually move towards the original points N and M, and eventually return to their original positions. PID The size will also tend to be stable. PID Output of PI control when stable You get it The value of .

[0117] According to the above In the phase control loop, the phase error of the control loop is compensated by adjusting the phase parameters of the digital signal online.

[0118] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A method for online calibration of a control loop phase error of a hemispherical resonant gyroscope, characterized in that: The following steps are involved: Constructing a driving modal transfer function of the hemispherical resonant gyroscope, and drawing an amplitude-frequency characteristic curve and a phase-frequency characteristic curve based on the driving modal transfer function; Performing frequency domain analysis on the driving modal transfer function of the hemispherical resonant gyroscope based on the amplitude-frequency characteristic curve and the phase-frequency characteristic curve to obtain an analysis result; Based on the analysis results, the phase error parameters are calibrated online to complete the compensation of the control loop phase error.

2. The method for online calibration of the control loop phase error of a hemispherical resonant gyroscope according to claim 1, characterized in that: The method for constructing the driving modal transfer function of the hemispherical resonant gyroscope includes: Construct the motion equation of the hemispherical resonator in the open-loop mode of the hemispherical resonator; The driving modal transfer function is constructed based on the motion equation.

3. The method for online calibration of the control loop phase error of a hemispherical resonant gyroscope according to claim 2, characterized in that: The equations of motion for the hemispherical resonator include: Where x and y are the amplitude displacements of the driving mode and the detection mode, respectively, and ω x ,ω y are the resonant frequencies of the driving mode and the detection mode, Q x , Q y are the quality factors of the driving mode and the detection mode, F x is the driving force of the driving mode, m is the mass of the oscillator, ρ xy ,ω xy are the damping coupling coefficient and stiffness coupling coefficient respectively, n is the gyro vibration mode order, γ is the precession factor, and Ω is the external input angular velocity.

4. The method for online calibration of the control loop phase error of a hemispherical resonant gyroscope according to claim 2, characterized in that: The transfer function of the driving mode includes: Where m is the mass of the oscillator, F x is the driving force of the driving mode, X(s) is the Laplace transform of x(t), s=jω is the complex frequency domain variable, j is the imaginary unit, ω x is the resonant frequency of the driving mode, Q x is the driving mode quality factor.

5. The method for online calibration of the control loop phase error of a hemispherical resonant gyroscope according to claim 1, characterized in that: The method for drawing the amplitude-frequency characteristic curve and the phase-frequency characteristic curve includes: Obtaining a vibration displacement and a first phase of a driving mode in a stable state based on the driving mode transfer function; Obtaining the vibration amplitude and the second phase when the driving signal is equal to the driving mode resonant frequency; The amplitude-frequency characteristic curve and the phase-frequency characteristic curve are plotted based on the vibration displacement, the first phase, the vibration amplitude, and the second phase.

6. The method for online calibration of the control loop phase error of a hemispherical resonant gyroscope according to claim 1, characterized in that: The vibration displacement and phase of the driving mode in the steady state include: Where x0 is the vibration amplitude, ω d is the driving signal frequency, t is the time, x represents the vibration displacement of the driving mode in the stable state, represents the phase of the driving mode in the steady state, ω x is the resonant frequency of the driving mode, Q x is the driving mode quality factor.

7. The method for online calibration of the control loop phase error of a hemispherical resonant gyroscope according to claim 1, characterized in that: The method for obtaining the analysis result includes: Obtaining a phase difference based on an initial phase angle of the reference signal and an initial phase of the driving signal; Modulating the phase difference to collect a control value of the vibration amplitude; A phase error is obtained based on the control amount.

8. A system for online calibration of the phase error of the control loop of a hemispherical resonant gyroscope, characterized in that: include: mapping unit, analysis unit, and compensation unit; The drawing unit is used to construct a driving modal transfer function of the hemispherical resonant gyroscope, and draw an amplitude-frequency characteristic curve and a phase-frequency characteristic curve based on the driving modal transfer function; The analyzing unit is configured to perform frequency domain analysis on the driving modal transfer function of the hemispherical resonant gyroscope based on the amplitude-frequency characteristic curve and the phase-frequency characteristic curve to obtain an analysis result; The compensation unit is used to calibrate the phase error parameter online based on the analysis result to complete the compensation of the control loop phase error.

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