Hemispherical resonator gyroscope initial alignment and navigation method based on dual-mode switching

Abstract

The invention discloses a hemispherical resonator gyroscope initial alignment and navigation method based on dual-mode switching, and belongs to the field of hemispherical resonator gyroscope control. According to the invention, the problem that the single working mode of the hemispherical resonator gyroscope is difficult to meet different requirements in the initial alignment and navigation process is solved. According to the method disclosed by the invention, the precision of the hemispherical resonator gyroscope in an initial alignment stage can be improved compared with a single full-angle mode, and meanwhile, the range of the hemispherical resonator gyroscope in a navigation stage can be improved compared with a single force balance mode. The advantages of the two modes can be combined, different requirements for the precision and the measuring range of the hemispherical resonator gyroscope in different stages can be met by switching the two control modes, and the problem that the single working mode of the hemispherical resonator gyroscope is difficult to meet different requirements in the initial alignment and navigation process is solved. The method can be applied to mode switching of the hemispherical resonator gyroscope.

Description

Technical Field

[0001] The invention belongs to the field of hemispherical resonant gyroscope control, and in particular relates to an initial alignment and navigation method of a hemispherical resonant gyroscope based on dual-mode switching. Background Art

[0002] At present, the hemispherical resonant gyroscope has two working modes: force balance and full angle. The force balance mode uses a negative feedback loop to reduce the gyro output noise. However, in the force balance mode, the hemispherical resonant gyroscope can lock the standing wave azimuth rate range is limited, which limits the measurement range of the hemispherical resonant gyroscope. In the full angle mode, the closed loop is no longer used to generate the control force related to the standing wave precession rate, but the standing wave is allowed to precess freely in the annular direction, and the standing wave azimuth is not fixed. In theory, it has a larger measurement range, but the measurement accuracy is slightly lower than the force balance mode. These two working modes have their own advantages and disadvantages in terms of accuracy and range. The initial posture alignment has higher requirements for the accuracy of the hemispherical resonant gyroscope, and the navigation process has higher requirements for the dynamic range of the hemispherical resonant gyroscope, which makes it difficult for the single working mode of the hemispherical resonant gyroscope to meet the needs of different processes. In order to meet the different requirements of accuracy and range of the posture sensor with the hemispherical resonant gyroscope as the core component in the initial alignment and navigation process, it is necessary to realize the switching of the working mode of the hemispherical resonant gyroscope, but there is no mature method for switching the working mode of the hemispherical resonant gyroscope in the prior art. Summary of the invention

[0003] The purpose of the present invention is to solve the problem that a single working mode of a hemispherical resonant gyroscope is difficult to meet different requirements in the initial alignment and navigation process, and propose an initial alignment and navigation method for a hemispherical resonant gyroscope based on dual-mode switching.

[0004] The technical solution adopted by the present invention to solve the above technical problems is: an initial alignment and navigation method of a hemispherical resonant gyroscope based on dual-mode switching, the specific process of the method is:

[0005] During the initial alignment

[0006] The hemispherical resonant gyro is started in a full-angle mode. After the hemispherical resonant gyro is started, the mode of the hemispherical resonant gyro is switched to a force balance mode until the initial alignment phase is completed and then the navigation phase is entered;

[0007] In the navigation phase

[0008] Design the switching conditions between the force balance mode and the full angle mode, and perform the mode switching of the hemispherical resonant gyroscope according to the standing wave precession angular velocity and the designed switching conditions;

[0009] The switching condition between the force balance mode and the full-angle mode is:

[0010]

[0011] Among them, ω abs is the absolute value of the standing wave precession angular velocity of the current control cycle, is the difference between the absolute value of the standing wave precession angular velocity in the current control period and the absolute value of the standing wave precession angular velocity in the previous control period, h p is the positive switching threshold, h n is the reverse switching threshold, Mode is the control mode selected for the next control cycle, 0 is the force balance mode, and 1 is the full-angle mode.

[0012] Furthermore, in the full-angle mode, the standing wave multi-loop control system of the hemispherical resonant gyroscope includes an amplitude control loop, an orthogonal control loop and a frequency control loop;

[0013] After processing the x-channel detection signal and the y-channel detection signal of the hemispherical resonant gyroscope, the amplitude control loop, the orthogonal control loop and the frequency control loop perform negative feedback control on the hemispherical resonant gyroscope based on the obtained processing results.

[0014] Furthermore, the specific process of processing the x-channel detection signal and the y-channel detection signal of the hemispherical resonant gyroscope is as follows:

[0015] The x-channel detection signal and the y-channel detection signal are expressed as:

[0016]

[0017] Among them, u dx is the x channel detection signal, u dy is the y channel detection signal, a is the main standing wave amplitude, q is the orthogonal wave amplitude, θ is the standing wave azimuth, ω0 is the nominal intrinsic vibration circular frequency of the resonator, is the time phase of the oscillator vibration, t is the time;

[0018] The reference signal at time t is:

[0019]

[0020] Among them, u rc is the x channel reference signal, u rs is the y channel reference signal, is the phase of the reference signal;

[0021] Defining Phase Difference for:

[0022]

[0023] The first demodulation is performed based on the detection signal and the reference signal to obtain the demodulation quantities Cx, Sx, Cy and Sy:

[0024]

[0025] Where LPF{·} is a low-pass filter;

[0026] The first demodulation amount is combined again to obtain the second demodulation amount:

[0027]

[0028] Among them, E, Q, L and M are all secondary demodulation quantities.

[0029] Furthermore, the control process of the amplitude control loop is:

[0030]

[0031] Among them, E0 is the target amplitude, E k is the secondary demodulation value of the kth control cycle, e amp_k is the amplitude control error of the kth control cycle, sat{·} is the saturation function, K ap is the proportional gain of the amplitude controller, K ai is the integral gain of the amplitude controller, ΔT is the controller period, e amp_j is the amplitude control error of the jth control cycle, j = 0, 1, ..., k, u amp_k is the amplitude control value of the kth control cycle;

[0032] Amplitude control u amp_k To make an allocation:

[0033] u amp_x =u amp_k ·cos2θ k ·u rc_k (8)

[0034] u amp_y =u amp_k sin2θ k ·u rc_k (9)

[0035] Among them, u amp_x is the amplitude control value of the x channel, u amp_y is the amplitude control value of the y channel, u rc_k is the x-channel reference signal of the k-th control cycle, θ k is the standing wave azimuth of the kth control cycle.

[0036] Furthermore, the control process of the orthogonal control loop is:

[0037] Design the PI controller as follows:

[0038]

[0039] Among them, Q k is the secondary demodulation value of the kth control cycle, e quad_k is the orthogonal control error of the kth control cycle, K qp is the proportional gain of the orthogonal controller, K qi is the integral gain of the orthogonal controller, e quad_j is the orthogonal control error of the jth control cycle, j = 0, 1, ..., k, u quad_k is the orthogonal amplitude control quantity of the kth control cycle;

[0040] For the orthogonal amplitude control u quad_k To make an allocation:

[0041] u quad_x =-u quad_k sin2θ k ·u rs_k (11)

[0042] u quad_y =u quad_k ·cos2θ k ·u rs_k (12)

[0043] Among them, u quad_x is the orthogonal amplitude control value of the x channel, u quad_y is the orthogonal amplitude control value of the y channel, u rs_k is the y channel reference signal of the kth control cycle.

[0044] Furthermore, the control process of the frequency control loop is:

[0045] According to the secondary demodulation quantity L k and M k Solve

[0046]

[0047] in, is the phase difference between the reference signal and the resonator vibration signal of the kth control cycle;

[0048] Design the PI controller as follows:

[0049]

[0050] Among them, e freq_k is the frequency control error of the kth control cycle, K fp is the proportional gain of the frequency controller, K fi is the integral gain of the frequency controller, efreq_j is the frequency control error of the jth control cycle, j = 0, 1, ..., k, u freq_k is the frequency control value of the kth control cycle;

[0051] Frequency control amount u freq_k A reference signal for controlling the hemispherical resonant gyro is generated by a signal generator.

[0052] Furthermore, in the force balance mode, the standing wave multi-loop control system of the hemispherical resonant gyroscope includes an amplitude control loop, an orthogonal control loop, a frequency control loop and an angle control loop;

[0053] After processing the x-channel detection signal and the y-channel detection signal of the hemispherical resonant gyroscope, the amplitude control loop, the orthogonal control loop, the frequency control loop and the angle control loop perform negative feedback control on the hemispherical resonant gyroscope based on the obtained processing results.

[0054] Furthermore, the control process of the angle control loop is:

[0055]

[0056] Among them, θ k is the standing wave azimuth of the kth control cycle, Sx k and Sy k is the demodulation value of the kth control cycle;

[0057] Let the desired standing wave azimuth be θ0 and design the PI controller:

[0058]

[0059] Among them, e ftr_k is the force balance control error of the kth control cycle, e ftr_j is the force balance control error of the jth control cycle, j = 0, 1, ..., k, K ftr_p is the proportional gain of the force balance controller, K ftr_i is the integral gain of the force balance controller, u ftr_k is the force balance control quantity of the kth control cycle;

[0060] Force balance control quantity u ftr_k To make an allocation:

[0061] u f_x =-u ftr_k sin2θ k ·u rc_k (17)

[0062] u f_y =u ftr_k ·cos2θk ·u rc_k (18)

[0063] Among them, u f_x is the force balance control quantity of the x channel, u f_y is the force balance control quantity of the y channel.

[0064] Furthermore, in the full-angle mode, the calculation method of the standing wave precession angular velocity is:

[0065] According to the standing wave azimuth angle θ of the kth control cycle k and the standing wave azimuth θ of the k-1th control cycle k-1 Calculate the standing wave precession angular rate of the kth control cycle:

[0066]

[0067] Among them, ω k is the standing wave precession angular rate of the kth control cycle;

[0068]

[0069] Among them, Sx k and Sy k is the demodulation amount of the kth control cycle.

[0070] Furthermore, in the force balance mode, the calculation method of the standing wave precession angular velocity is:

[0071] ω k =η·u ftr_k (twenty one)

[0072] Where η is the proportional coefficient of the angular velocity of the standing wave precession output in the force balance mode.

[0073] The beneficial effects of the present invention are:

[0074] The method of the present invention can improve the accuracy of the hemispherical resonant gyroscope in the initial alignment stage compared with a single full-angle mode, and can also improve the range of the hemispherical resonant gyroscope in the navigation stage compared with a single force balance mode. The method of the present invention can combine the advantages of the full-angle mode and the force balance mode through automatic switching between the two modes. The switching of the two control modes can meet the different requirements for the accuracy and range of the hemispherical resonant gyroscope in different stages, and solves the problem that the single working mode of the hemispherical resonant gyroscope is difficult to meet the different requirements in the initial alignment and navigation processes. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] Figure 1 is a visualization of the switching conditions;

[0076] Figure 2It is the block diagram of the standing wave multi-loop control of the hemispherical resonator. DETAILED DESCRIPTION

[0077] Specific implementation method 1: This implementation method describes an initial alignment and navigation method for a hemispherical resonant gyroscope based on dual-mode switching. The specific process of the method is as follows:

[0078] During the initial alignment

[0079] Start the hemispherical resonant gyro in full-angle mode. After the hemispherical resonant gyro is started, switch the mode of the hemispherical resonant gyro to the force balance mode (the current mode switching process is controlled manually. Because the force balance mode has high precision and is suitable for initial alignment, it is switched to the force balance mode after the hemispherical resonant gyro is started), and enter the navigation stage after the initial alignment stage is completed;

[0080] In the navigation phase

[0081] Design the switching conditions between the force balance mode and the full angle mode, and perform the mode switching of the hemispherical resonant gyroscope according to the standing wave precession angular velocity and the designed switching conditions;

[0082] like Figure 1 As shown, the switching condition between the force balance mode and the full-angle mode is:

[0083]

[0084] Among them, ω abs is the absolute value of the standing wave precession angular velocity of the current control cycle, is the difference between the absolute value of the standing wave precession angular velocity in the current control period and the absolute value of the standing wave precession angular velocity in the previous control period, h p is the positive switching threshold, h n is the reverse switching threshold, Mode is the control mode selected for the next control cycle (if the control mode selected for the next control cycle is the same as the control mode of the current control cycle, no switching is required, otherwise after the current control cycle ends, it is necessary to switch to the control mode selected for the next control cycle), 0 is the force balance mode, and 1 is the full-angle mode.

[0085] Formula (1) shows that when the absolute value of the standing wave precession angular velocity ω abs When increasing, h p As the switching threshold, when the absolute value of the standing wave precession angular velocity ω abs When decreasing, h nAs the switching threshold. Setting two thresholds is to prevent repeated switching problems caused by noise. For example, if the single threshold is 30, the noise interference rate will fluctuate repeatedly between 29.9 and 30.1, causing the control mode to switch too frequently, resulting in instability. The hysteresis curve with dual thresholds can avoid the problem of too frequent switching of control modes. The specific values ​​of the two thresholds can be set according to actual conditions.

[0086] Specific implementation method 2: This implementation method is different from specific implementation method 1 in that, in the full-angle mode, the standing wave multi-loop control system of the hemispherical resonant gyroscope includes an amplitude control loop, an orthogonal control loop and a frequency control loop;

[0087] After processing the x-channel detection signal and the y-channel detection signal of the hemispherical resonant gyroscope, the amplitude control loop, the orthogonal control loop and the frequency control loop perform negative feedback control on the hemispherical resonant gyroscope based on the obtained processing results.

[0088] The other steps and parameters are the same as those in the first embodiment.

[0089] Specific implementation method three: This implementation method is different from specific implementation method one or two in that the specific process of processing the x-channel detection signal and the y-channel detection signal of the hemispherical resonant gyroscope is as follows:

[0090] The x-channel detection signal and the y-channel detection signal are expressed as:

[0091]

[0092] Among them, u dx is the x channel detection signal, u dy is the y channel detection signal, a is the main standing wave amplitude, q is the orthogonal wave amplitude, θ is the standing wave azimuth, ω0 is the nominal intrinsic vibration circular frequency of the resonator, is the time phase of the oscillator vibration, t is the time;

[0093] The reference signal at time t is:

[0094]

[0095] Among them, u rc is the x channel reference signal, u rs is the y channel reference signal, is the phase of the reference signal;

[0096] Defining Phase Difference for:

[0097]

[0098] The first demodulation is performed based on the detection signal and the reference signal to obtain the demodulation quantities Cx, Sx, Cy and Sy:

[0099]

[0100] Among them, LPF{·} is a low-pass filter, and the cutoff frequency of the low-pass filter is much smaller than ω0;

[0101] The first demodulation amount is combined again to obtain the second demodulation amount:

[0102]

[0103] Among them, E, Q, L and M are all secondary demodulation quantities.

[0104] The other steps and parameters are the same as those in the first or second embodiment.

[0105] The secondary demodulation quantity E indirectly reflects the amplitude of the main standing wave of the resonator, and Q indirectly reflects the amplitude of the orthogonal wave of the resonator. The stability of E and Q is equivalent to the stability of a and q. L and M indirectly reflect the phase difference between the vibration signal and the generated reference signal.

[0106] Specific implementation method 4: This implementation method is different from any one of the specific implementation methods 1 to 3 in that the control process of the amplitude control loop is:

[0107]

[0108] Among them, E0 is the target amplitude, E k is the secondary demodulation value of the kth control cycle, e amp_k is the amplitude control error of the kth control cycle, sat{·} is the saturation function, K ap is the proportional gain of the amplitude controller, K ai is the integral gain of the amplitude controller, ΔT is the controller period, e amp_j is the amplitude control error of the jth control cycle, j = 0, 1, ..., k, u amp_k is the amplitude control value of the kth control cycle;

[0109] Amplitude control u amp_k To make an allocation:

[0110] u amp_x =u amp_k ·cos2θ k ·u rc_k (8)

[0111] u amp_y =u amp_k sin2θ k ·u rc_k (9)

[0112] Among them, u amp_x is the amplitude control value of the x channel, u amp_y is the amplitude control value of the y channel, u rc_k is the x-channel reference signal of the k-th control cycle, θ k is the standing wave azimuth of the kth control cycle.

[0113] The other steps and parameters are the same as those in Specific Embodiments 1 to 3.

[0114] Specific implementation mode 5: This implementation mode is different from any one of the specific implementation modes 1 to 4 in that the control process of the orthogonal control loop is:

[0115] The expected orthogonal wave amplitude is 0. The control loop applies a reverse orthogonal signal based on the detected orthogonal wave to cancel out the original signal.

[0116] Design the PI controller as follows:

[0117]

[0118] Among them, Q k is the secondary demodulation value of the kth control cycle, e quad_k is the orthogonal control error of the kth control cycle, K qp is the proportional gain of the orthogonal controller, K qi is the integral gain of the orthogonal controller, e quad_j is the orthogonal control error of the jth control cycle, j = 0, 1, ..., k, u quad_k is the orthogonal amplitude control quantity of the kth control cycle;

[0119] For the orthogonal amplitude control u quad_k To make an allocation:

[0120] u quad_x =-u quad_k sin2θ k ·u rs_k (11)

[0121] u quad_y =u quad_k ·cos2θ k ·u rs_k (12)

[0122] Among them, u quad_x is the orthogonal amplitude control value of the x channel, u quad_y is the orthogonal amplitude control value of the y channel, u rs_k is the y channel reference signal of the kth control cycle.

[0123] The other steps and parameters are the same as those in Specific Embodiments 1 to 4.

[0124] Specific implementation method 6: This implementation method is different from any one of the specific implementation methods 1 to 5 in that the control process of the frequency control loop is:

[0125] According to the secondary demodulation quantity L k and M k Solve

[0126]

[0127] in, is the phase difference between the reference signal and the resonator vibration signal of the kth control cycle;

[0128] Design the PI controller as follows:

[0129]

[0130] Among them, e freq_k is the frequency control error of the kth control cycle, K fp is the proportional gain of the frequency controller, K fi is the integral gain of the frequency controller, e freq_j is the frequency control error of the jth control cycle, j = 0, 1, ..., k, u freq_k is the frequency control value of the kth control cycle;

[0131] Frequency control amount u freq_k A reference signal for controlling the hemispherical resonant gyro is generated by a signal generator.

[0132] The other steps and parameters are the same as those in Specific Implementation Methods 1 to 5.

[0133] Specific implementation example 7: This implementation example is different from any one of specific implementation examples 1 to 6 in that, in the force balance mode, the standing wave multi-loop control system of the hemispherical resonant gyroscope includes an amplitude control loop, an orthogonal control loop, a frequency control loop and an angle control loop;

[0134] After processing the x-channel detection signal and the y-channel detection signal of the hemispherical resonant gyroscope, the amplitude control loop, the orthogonal control loop, the frequency control loop and the angle control loop perform negative feedback control on the hemispherical resonant gyroscope based on the obtained processing results.

[0135] The other steps and parameters are the same as those in Specific Embodiments 1 to 6.

[0136] Specific implementation eight: This implementation differs from any one of specific implementations one to seven in that the control process of the angle control loop is:

[0137]

[0138] Among them, θ k is the standing wave azimuth of the kth control cycle, Sx k and Sy k is the demodulation value of the kth control cycle;

[0139] Let the desired standing wave azimuth be θ0 and design the PI controller:

[0140]

[0141] Among them, e ftr_k is the force balance control error of the kth control cycle, e ftr_j is the force balance control error of the jth control cycle, j = 0, 1, ..., k, K ftr_p is the proportional gain of the force balance controller, K ftr_i is the integral gain of the force balance controller, u ftr_k is the force balance control quantity of the kth control cycle;

[0142] Force balance control quantity u ftr_k To make an allocation:

[0143] u f_x =-u ftr_k sin2θ k ·u rc_k (17)

[0144] u f_y =u ftr_k ·cos2θ k ·u rc_k (18)

[0145] Among them, u f_x is the force balance control quantity of the x channel, u f_y is the force balance control quantity of the y channel.

[0146] The other steps and parameters are the same as those in Specific Embodiments 1 to 7.

[0147] The standing wave of the hemispherical resonant gyroscope is locked in a fixed position under the action of the force balance loop, and the initial alignment is performed by utilizing the high precision and good stability of the force balance mode. The control process of the amplitude control loop, orthogonal control loop, and frequency control loop in the force balance mode is the same as that of the amplitude control loop, orthogonal control loop, and frequency control loop in the full-angle mode.

[0148] Specific implementation method 9: This implementation method is different from any one of specific implementation methods 1 to 8 in that, in the full-angle mode, the calculation method of the standing wave precession angular velocity is:

[0149] The HRG in full-angle mode is a rate-integrating gyro, and the standing wave of the HRG is not locked at a fixed azimuth angle but precesses freely.

[0150] According to the standing wave azimuth angle θ of the kth control cycle k and the standing wave azimuth θ of the k-1th control cycle k-1 Calculate the standing wave precession angular rate of the kth control cycle:

[0151]

[0152] Among them, ω k is the standing wave precession angular rate of the kth control cycle;

[0153]

[0154] Among them, Sx k and Sy k is the demodulation amount of the kth control cycle.

[0155] The other steps and parameters are the same as those in Specific Embodiments 1 to 8.

[0156] Specific implementation method 10: This implementation method is different from any one of specific implementation methods 1 to 9 in that, in the force balance mode, the calculation method of the standing wave precession angular velocity is:

[0157] ω k =η·u ftr_k (twenty one)

[0158] Where η is the proportional coefficient of the angular velocity of the standing wave precession output in the force balance mode.

[0159] The other steps and parameters are the same as those in Specific Embodiments 1 to 9.

[0160] The following further explains the hemispherical resonant gyro standing wave multi-loop control system composed of various loops. Figure 2 As shown in the figure, the hemispherical resonant gyro standing wave multi-loop control system can be divided into signal detection and excitation circuit, signal demodulation circuit, frequency control loop, amplitude control loop, orthogonal control loop, and force feedback control loop (i.e., angle control loop) according to specific functions. The signal detection and excitation circuit completes the excitation and detection of the signal through the capacitor-voltage model, and demodulates the detected voltage signal to obtain information such as amplitude and angular velocity. In order to ensure that the resonator standing wave can move with the gyro sensitive axis, the frequency, amplitude, and orthogonal control loops are used to maintain the stable standing wave vibration state of the resonator, and the force feedback control loop is used to lock the standing wave in a fixed position.

[0161] Switching from force balance mode to full-angle mode: disconnecting the force feedback control loop in the standing wave multi-loop control system of the hemispherical resonant gyroscope switches the hemispherical resonant gyroscope to full-angle mode. At the same time, the integral value of the force balance loop controller is cleared, and the angular rate output is changed from direct output of the force feedback loop to differential output of the azimuth angle under full-angle mode.

[0162] Switching from full-angle mode to force balance mode: enabling the force feedback control loop in the standing wave multi-loop control system of the hemispherical resonant gyroscope, setting the target value θ0 of the force balance controller to the standing wave azimuth during switching, and changing the angular rate output from the differential output of the azimuth in full-angle mode to the direct output of the force feedback loop.

[0163] The output data of the posture sensor include azimuth, angular velocity, and angular acceleration. The standing wave precession angular velocity ω and the actual gyro shell precession angular velocity Ω have the following relationship:

[0164] ω=λΩ (21)

[0165] Where, λ is the precession coefficient;

[0166] The external azimuth θ at time t can be calculated based on the actual gyro shell precession angular velocity Ω, that is, it can be obtained by integrating the gyro shell precession angular velocity Ω:

[0167]

[0168] Among them, Θ0 is the initial orientation.

[0169] Assuming the control period is ΔT, the angular acceleration α is obtained by the difference of the angular velocity Ω:

[0170]

[0171] Among them, Ω k+1 and Ω k is the angular velocity between two adjacent moments.

[0172] The above calculation examples of the present invention are only used to explain the calculation model and calculation process of the present invention in detail, and are not intended to limit the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are still within the scope of protection of the present invention.

Claims

1. A method for initial alignment and navigation of a hemispherical resonant gyroscope based on dual-mode switching, characterized in that: The specific process of the method is: During the initial alignment The hemispherical resonant gyro is started in a full-angle mode. After the hemispherical resonant gyro is started, the mode of the hemispherical resonant gyro is switched to a force balance mode until the initial alignment phase is completed and then the navigation phase is entered; In the navigation phase Design the switching conditions between the force balance mode and the full angle mode, and perform the mode switching of the hemispherical resonant gyroscope according to the standing wave precession angular velocity and the designed switching conditions; The switching condition between the force balance mode and the full-angle mode is: Among them, ω abs is the absolute value of the standing wave precession angular velocity of the current control cycle, is the difference between the absolute value of the standing wave precession angular velocity in the current control period and the absolute value of the standing wave precession angular velocity in the previous control period, h p is the positive switching threshold, h n is the reverse switching threshold, Mode is the control mode selected for the next control cycle, 0 is the force balance mode, and 1 is the full-angle mode.

2. The method for initial alignment and navigation of a hemispherical resonant gyroscope based on dual-mode switching according to claim 1, characterized in that: In the full-angle mode, the standing wave multi-loop control system of the hemispherical resonant gyroscope includes an amplitude control loop, an orthogonal control loop and a frequency control loop; After processing the x-channel detection signal and the y-channel detection signal of the hemispherical resonant gyroscope, the amplitude control loop, the orthogonal control loop and the frequency control loop perform negative feedback control on the hemispherical resonant gyroscope based on the obtained processing results.

3. The method for initial alignment and navigation of a hemispherical resonant gyroscope based on dual-mode switching according to claim 2, characterized in that: The specific process of processing the x-channel detection signal and the y-channel detection signal of the hemispherical resonant gyroscope is as follows: The x-channel detection signal and the y-channel detection signal are expressed as: Among them, u dx is the x channel detection signal, u dy is the y channel detection signal, a is the main standing wave amplitude, q is the orthogonal wave amplitude, θ is the standing wave azimuth, ω0 is the nominal intrinsic vibration circular frequency of the resonator, is the time phase of the oscillator vibration, t is the time; The reference signal at time t is: Among them, u rc is the x channel reference signal, u rs is the y channel reference signal, is the phase of the reference signal; Defining Phase Difference for: The first demodulation is performed based on the detection signal and the reference signal to obtain the demodulation quantities Cx, Sx, Cy and Sy: Where LPF{·} is a low-pass filter; The first demodulation amount is combined again to obtain the second demodulation amount: Among them, E, Q, L and M are all secondary demodulation quantities.

4. The method for initial alignment and navigation of a hemispherical resonant gyroscope based on dual-mode switching according to claim 2, characterized in that: The control process of the amplitude control loop is: Among them, E0 is the target amplitude, E k is the secondary demodulation value of the kth control cycle, e amp_k is the amplitude control error of the kth control cycle, sat{·} is the saturation function, K ap is the proportional gain of the amplitude controller, K ai is the integral gain of the amplitude controller, ΔT is the controller period, e amp_j is the amplitude control error of the jth control cycle, j = 0, 1, ..., k, u amp_k is the amplitude control value of the kth control cycle; Amplitude control u amp_k To make an allocation: u amp_x =u amp_k ·cos2θ k ·u rc_k (8) and amp_y =and amp_k ·sin2θ k ·and rc_k (9) Among them, u amp_x is the amplitude control value of the x channel, u amp_y is the amplitude control value of the y channel, u rc_k is the x-channel reference signal of the k-th control cycle, θ k is the standing wave azimuth of the kth control cycle.

5. The method for initial alignment and navigation of a hemispherical resonant gyroscope based on dual-mode switching according to claim 2, characterized in that: The control process of the orthogonal control loop is: Design the PI controller as follows: Among them, Q k is the secondary demodulation value of the kth control cycle, e quad_k is the orthogonal control error of the kth control cycle, K qp is the proportional gain of the orthogonal controller, K qi is the integral gain of the orthogonal controller, e quad_j is the orthogonal control error of the jth control cycle, j = 0, 1, ..., k, u quad_k is the orthogonal amplitude control quantity of the kth control cycle; For the orthogonal amplitude control u quad_k To make an allocation: and quad_x =-and quad_k ·sin2θ k ·and rs_k (11) u quad_y =u quad_k ·cos2θ k ·u rs_k (12) Among them, u quad_x is the orthogonal amplitude control value of the x channel, u quad_y is the orthogonal amplitude control value of the y channel, u rs_k is the y channel reference signal of the kth control cycle.

6. The method for initial alignment and navigation of a hemispherical resonant gyroscope based on dual-mode switching according to claim 2, characterized in that: The control process of the frequency control loop is: According to the secondary demodulation quantity L k and M k Solve in, is the phase difference between the reference signal and the resonator vibration signal of the kth control cycle; Design the PI controller as follows: Among them, e freq_k is the frequency control error of the kth control cycle, K fp is the proportional gain of the frequency controller, K fi is the integral gain of the frequency controller, e freq_j is the frequency control error of the jth control cycle, j = 0, 1, ..., k, u freq_k is the frequency control value of the kth control cycle; Frequency control amount u freq_k A reference signal for controlling the hemispherical resonant gyro is generated by a signal generator.

7. The method for initial alignment and navigation of a hemispherical resonant gyroscope based on dual-mode switching according to claim 1, characterized in that: In the force balance mode, the standing wave multi-loop control system of the hemispherical resonant gyroscope includes an amplitude control loop, an orthogonal control loop, a frequency control loop and an angle control loop; After processing the x-channel detection signal and the y-channel detection signal of the hemispherical resonant gyroscope, the amplitude control loop, the orthogonal control loop, the frequency control loop and the angle control loop perform negative feedback control on the hemispherical resonant gyroscope based on the obtained processing results.

8. The method for initial alignment and navigation of a hemispherical resonant gyroscope based on dual-mode switching according to claim 7, characterized in that: The control process of the angle control loop is: Among them, θ k is the standing wave azimuth of the kth control cycle, Sx k and Sy k is the demodulation value of the kth control cycle; Let the desired standing wave azimuth be θ0 and design the PI controller: Among them, e ftr_k is the force balance control error of the kth control cycle, e ftr_j is the force balance control error of the jth control cycle, j = 0, 1, ..., k, K ftr_p is the proportional gain of the force balance controller, K ftr_i is the integral gain of the force balance controller, u ftr_k is the force balance control quantity of the kth control cycle; Force balance control quantity u ftr_k To make an allocation: and f_x =-and ftr_k ·sin2θ k ·and rc_k (17) u f_y =u ftr_k ·cos2θ k ·u rc_k (18) Among them, u f_x is the force balance control quantity of the x channel, u f_y is the force balance control quantity of the y channel.

9. The method for initial alignment and navigation of a hemispherical resonant gyroscope based on dual-mode switching according to claim 2, characterized in that: In the full-angle mode, the calculation method of the standing wave precession angular rate is: According to the standing wave azimuth angle θ of the kth control cycle k and the standing wave azimuth θ of the k-1th control cycle k-1 Calculate the standing wave precession angular rate of the kth control cycle: Among them, ω k is the standing wave precession angular rate of the kth control cycle; Among them, Sx k and Sy k is the demodulation amount of the kth control cycle.

10. The method for initial alignment and navigation of a hemispherical resonant gyroscope based on dual-mode switching according to claim 7, characterized in that: In the force balance mode, the calculation method of the standing wave precession angular velocity is: oh k =η·u ftr_k (21) Where η is the proportional coefficient of the angular velocity of the standing wave precession output in the force balance mode.

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