Dual-mode control method of hemispherical resonator gyroscope

Abstract

The invention discloses a dual-mode control method of a hemispherical resonator gyroscope, which comprises the following steps of: firstly calculating an angle theta value of a position where a vibration mode is located, and then calculating a rotation angular velocity omega in a force feedback control mode or a full-angle control mode through theta; therefore, the method can be suitable for calculation of a force feedback control mode, and can also be suitable for calculation of an all-angle control mode. Under different working conditions, the control system can switch two modes for corresponding application, and the complementary effect of the two control modes is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of gyroscopes, and in particular, to a dual-mode control method for a hemispherical resonant gyroscope. Background Art

[0002] The hemispherical resonant gyroscope can be used to measure the rotational angular velocity and rotational angle of an object. Currently, its control modes mainly include the force feedback control mode and the full angle control mode. Each of these two working modes has its own advantages and disadvantages. The advantages of the force feedback mode are: high control accuracy and good tolerance to errors introduced during manufacturing; the disadvantages are: slow response in angular velocity measurement, small output bandwidth, and not suitable for measuring high-maneuver objects. The advantages of the full angle mode are: fast response in angular velocity measurement, high output bandwidth, and a wider range of applicable working conditions; the disadvantages are: when measuring low rotational speeds, the errors introduced during manufacturing have a greater impact on the measurement accuracy. Currently, one of these methods is basically used in hemispherical resonant gyro products. Summary of the Invention

[0003] In view of this, the present invention proposes a dual-mode control method for a hemispherical resonant gyroscope, which is applicable to both the force feedback control mode and the full angle control mode.

[0004] To achieve the above object, the technical solution of the present invention is:

[0005] 2. A dual-mode control method for a hemispherical resonant gyroscope, characterized in that it includes:

[0006] a. Calculate the value of the angle θ at the position where the vibration mode of the resonator is located;

[0007] b. First, switch to the force feedback control mode to calculate the rotational angular velocity Ω: using the current value θ fb of θ as the feedback quantity, and obtaining the value of f fb when θ y = 0 through a preset first PI controller, and substituting f y into the expression in the force feedback control mode to calculate the rotational angular velocity Ω of the gyroscope;

[0008] c. When the rotational angular velocity Ω exceeds the set value, switch to the full angle control mode based on the θ value before switching: using the current amplitude α fb of α as the feedback quantity, the target value as the set target amplitude α ref , the current angle θ fb as the input quantity, and obtaining the value of f a through a preset second PI controller, where f a represents the magnitude of the force required to maintain the amplitude α;

[0009] Substitute f a into the expression in the full angle control mode to calculate and obtain f x , f y ;

[0010] Through θ fb Output the rotational angular velocity Ω of the gyroscope.

[0011] Preferably, calculating the position angle θ value of the vibration mode of the resonator specifically includes:

[0012] Record the current θ value as θ t1 ; record the θ value analyzed in the next calculation period as θ t2 ;

[0013] The θ value is calculated in an incremental manner, that is:

[0014] Δθ = θ t2 - θ t1 ;

[0015] θ = θ ts + Δθ;

[0016] θ ts = θ;

[0017] θ ts is used to store the θ value obtained in the previous calculation period.

[0018] Preferably, within two sampling periods, when Δθ is greater than 90°, -180° is used for equivalence; when Δθ is less than -90°, +180° is used for equivalence.

[0019] Preferably, the first PI controller includes a first adder, a first proportional link, a first differential link, a first integral limiting link, a first adding link, and a first output limiting link; wherein, one input terminal of the first adder inputs the target angle θ = 0 respectively, and the other input terminal inputs the current angle θ fb ; the input terminals of the first proportional link and the first differential link are both connected to the output terminal of the first adder; the input terminal of the first integral limiting link is connected to the output terminal of the first differential link; one input terminal of the first adding link is connected to the output terminal of the first proportional link, and the other input terminal is connected to the output terminal of the first integral limiting link; the input terminal of the first output limiting link is connected to the output terminal of the first adding link.

[0020] Preferably, the second PI controller includes a second adder, a second proportional link, a second differential link, a second integral limiting link, a second adding link, a second output limiting link, and a synthesis calculation link; wherein, one input terminal of the second adder inputs the target amplitude α ref = 0, and the other input terminal inputs the current amplitude α fbThe input ends of the second proportional link and the second differentiating link are both connected to the output end of the second adder; the input end of the second integral limiting link is connected to the output end of the second differentiating link; one input end of the second adding link is connected to the output end of the second proportional link, and the other input end is connected to the output end of the second integral limiting link; the input end of the second output limiting link is connected to the output end of the second adding link; one input end of the synthesis calculation link is connected to the output end of the second output limiting link, and the other input end inputs the current angle θ fb . The calculation formula of the synthesis calculation link is: f x = U a cosθ ref , f y = U a sinθ ref ; where U a is the output value of the second output limiting link.

[0021] The technical effects of the present invention are mainly reflected in the following aspects:

[0022] It can be applicable to the calculation of the force feedback control mode and also to the calculation of the full angle control mode. It realizes that under different working conditions, the control system can switch between the two modes to deal with them respectively, achieving the complementary effect of the two control modes. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a simplified diagram of the mode shape change in the embodiment (the angle between the mode shape and the axis is not 0°);

[0024] Figure 2 is a schematic diagram of the vibration trajectory of the equivalent mass point of the harmonic oscillator in the embodiment;

[0025] Figure 3 is a simplified diagram of the mode shape change in the embodiment (the angle between the mode shape and the axis is 0°);

[0026] Figure 4 is a schematic diagram of the vibration trajectory of the equivalent mass point of the harmonic oscillator in the embodiment;

[0027] Figure 5 is a schematic diagram of the first PI controller in the embodiment;

[0028] Figure 6 is a schematic diagram of the second PI controller in the embodiment;

[0029] Figure 7 is a schematic diagram of the mode shape azimuth sector in the embodiment Figure 1 ;

[0030] Figure 8 is a schematic diagram of the mode shape azimuth sector in the embodiment Figure 2 .

[0031] Reference signs: 11, first adder; 12, first proportional link; 13, first differentiating link; 14, first integral limiting link; 15, first adding link; 16, first output limiting link; 21, second adder; 22, second proportional link; 23, second differentiating link; 24, second integral limiting link; 25, second adding link; 26, second output limiting link; 27, synthesis calculation link. Detailed implementation mode

[0032] The following further details the specific implementation mode of the present invention in conjunction with the attached drawings, so that the technical solution of the present invention is easier to understand and master.

[0033] This embodiment provides a dual-mode control method for a hemispherical resonant gyroscope, including:

[0034] a. Calculating the position angle θ value of the vibration mode of the resonator;

[0035] b. First switching to the force feedback control mode to calculate the rotational angular velocity Ω;

[0036] c. When the rotational angular velocity Ω exceeds the set value, switching to the full angle control mode based on the θ value before switching.

[0037] Next, this embodiment will detail the principle of the above control method.

[0038] The simple vibration model of the gyroscope used in this embodiment is:

[0039]

[0040] In the formula, x: vibration displacement of the x-axis, y: vibration displacement of the y-axis, k: precession coefficient, τ: vibration attenuation constant, ω n : vibration angular frequency, f x : exciting electric field force on the x-axis, f y : exciting electric field force on the y-axis, m: mass of the hemispherical resonator.

[0041] Force feedback control mode of the gyroscope: By applying a sine excitation signal on the y-axis, making the position angle θ of the vibration mode = 0, and the position of the vibration mode at this time is as Figure 3 and Figure 4 shown. At this time, the vibration displacements of the x-axis and y-axis are:

[0042]

[0043] (where A0 is the target amplitude in the x-axis direction) Substituting into equation (1-1) gives:

[0044]

[0045] In Equation (1-3), Ω is the rotational angular velocity of the gyroscope body. This variable is the quantity to be measured and is unknown. Therefore, a first PI controller is designed. As shown in Figure 5 : Using θ (the angle between the gyroscope mode shape and the x-axis) as the feedback quantity, the target value is θ ref = 0. When θ = 0, the required value is obtained through the first PI controller.

[0046] Specifically as follows:

[0047] Referring to Figure 5 , the first PI controller adopts a positional PI controller, which specifically includes a first adder 11, a first proportional link 12, a first derivative link 13, a first integral limiting link 14, a first summing link 15, and a first output limiting link 16. Among them, one input terminal of the first adder 11 inputs the target angle θ ref = 0, and the other input terminal inputs the current angle θ fb ; the input terminals of the first proportional link 12 and the first derivative link 13 are both connected to the output terminal of the first adder 11; the input terminal of the first integral limiting link 14 is connected to the output terminal of the first derivative link 13; one input terminal of the first summing link 15 is connected to the output terminal of the first proportional link 12, and the other input terminal is connected to the output terminal of the first integral limiting link 14; the input terminal of the first output limiting link 16 is connected to the output terminal of the first summing link 15.

[0048] The output of the above first PI controller at the nth beat after discretization: The difference between the target value and the current value: Δθ = θ ref - θ fb ; k p is the proportional coefficient, and k i is the integral coefficient. To ensure the stability of the control system, a first integral limiting link and a first output limiting link are set. Finally

[0049] Returning to the above force feedback calculation formula (1-3), where f y is obtained by the first PI controller, the mass m and the precession coefficient k are known quantities, the amplitude A0 of the mode shape is maintained at a set value by the amplitude loop control, and the vibration frequency ω n is obtained by the frequency loop. Therefore, the magnitude of the rotational angular velocity Ω can be finally calculated through this first PI controller.

[0050] Full-angle control mode: According to the value of the angle θ at which the mode shape is located, sinusoidal excitation voltages with different amplitudes are applied to the x-axis and y-axis excitation electrodes to maintain the magnitude of the mode shape amplitude a. For example:

[0051]

[0052] In formula (1-4), f a represents the magnitude of the force required to maintain the amplitude a of the vibration mode. f a The value of can be obtained through the second PI controller: taking a (the angle between the gyroscopic vibration mode and the x-axis) as the feedback quantity and the set target amplitude as the target value, f a is obtained through the second PI controller.

[0053] As Figure 6 shown, the second PI controller includes a second adder 21, a second proportional link 22, a second differential link 23, a second integral limiting link 24, a second summing link 25, a second output limiting link 26, and a synthesis calculation link 27; among them, one input terminal of the second adder 21 inputs the target amplitude α ref = 10um, and the other input terminal inputs the current amplitude α fb ; the input terminals of the second proportional link 22 and the second differential link 23 are both connected to the output terminal of the second adder 21; the input terminal of the second integral limiting link 24 is connected to the output terminal of the second differential link 23; one input terminal of the second summing link 25 is connected to the output terminal of the second proportional link 22, and the other input terminal is connected to the output terminal of the second integral limiting link 24; the input terminal of the second output limiting link 26 is connected to the output terminal of the second summing link 25; one input terminal of the synthesis calculation link 27 is connected to the output terminal of the second output limiting link 26, and the other input terminal inputs the current angle θ fb .

[0054] The output of the second PI controller at the nth beat after discretization: The difference between the target value and the current value: Δα = α ref -α fb ; k p is the proportional coefficient, and k i is the integral coefficient.

[0055] For the stability of the control system, the second integral limiting link 24 and the second output limiting link 26 are set, and finally the amplitude U of the excitation voltage a=u(n). In the full-angle control mode, the vibration mode position is not fixed on the x-axis, but rotates within the entire angular period (360°) according to the input external angular velocity. The excitation voltage to maintain the vibration of the gyroscope must be applied according to the position of the vibration mode, and the excitation cannot be applied only in the fixed x-axis direction as in the force feedback mode. Therefore, after the amplitude of the applied excitation voltage is obtained by the second PI controller, the excitation voltage on the x-axis and y-axis must be distributed according to the vibration mode position θ, so that the direction of the synthesized excitation voltage coincides with the antinode axis of the vibration mode, thereby achieving effective amplitude maintenance. Therefore, a synthesis calculation link 27 is set in the second output limiting link 26 to synthesize the excitation voltage vector, and the calculation method involved in the synthesis calculation link is:

[0056] f x =U a cosθ fb

[0057] f y =U a sinθ fb

[0058] From the above, it can be seen that the angular velocity measurement value of the full-angle mode is directly obtained by the change in the vibration mode position angle θ per unit time.

[0059] Based on the above content, it can be seen that both control modes require the use of the vibration mode position angle θ as a variable. The force feedback control mode requires θ as the feedback quantity of the corresponding PI controller; the full-angle control mode combines the θ value to control f x and f y The value of the gyroscope is output through θ, which is the rotation angle and rotation angular velocity of the gyroscope.

[0060] The following is a detailed description of how to calculate the θ value in this embodiment.

[0061] By collecting the x-axis displacement detection electrodes and the y-axis displacement detection electrodes, we can simply analyze the tanθ=M value, and take the inverse tangent to get θ=atanM. At this time, the range of θ can only represent the range of -90° to +90°, that is, it can only represent Figure 7 The position of sectors I and IV in the graph cannot be distinguished, and it is impossible to tell which sector θ is in between I and III, or which sector II and IV. That is, the θ value obtained by simply analyzing the x-axis vibration displacement and the y-axis vibration displacement cannot be distinguished. Figure 7 and Figure 8 The present embodiment proposes that θ is calculated by an incremental method, and the gyroscope control system adopts a timing cycle control, for example, setting the processing cycle to 1ms. The current vibration mode θ value is obtained by analyzing the detection electrode, and is recorded as θ t1 ; The value of θ obtained in the next calculation cycle is recorded as θ t2 The θ value is calculated in an incremental manner, namely:

[0062] Δθ = θ t2 minus θ t1

[0063] θ = θ ts +Δθ

[0064] θ ts = θ

[0065] θ ts Used to store the θ obtained in the previous calculation cycle; since Δθ has positive and negative values and has a directionality, it can distinguish whether the gyroscope rotates clockwise or counterclockwise, so that the θ value obtained by this method also has the characteristic of representing the direction. If the periodic value of θ is set to 360° (it can also be set to an integer multiple of 360°), taking the remainder of θ with respect to 360°, the value of θ can be constrained within the set periodic range.

[0066] When the θ value moves from the first quadrant ( Figure 7 ), there is a sign jump in the value of θ = atanM when moving to the second quadrant, and quadrant conversion is required. For example: when the θ value is 89° in the first quadrant and jumps to -88° in the second quadrant at the next moment, the Δθ obtained according to the incremental formula is -177°. In practice, it rotates counterclockwise by 3° (combined with the actual working condition, within two sampling periods, the rotation angle does not exceed 90°). It is necessary to perform quadrant jump compensation on Δθ: Δθ + 180° = 3°, so as to be the same as the actual situation. When the θ value crosses quadrants within two sampling periods, it will cause Δθ to be greater than 90° or less than -90°. When Δθ is greater than 90°, -180° needs to be performed for equivalence; when Δθ is less than -90°, +180° needs to be performed for equivalence.

[0067] Through this incremental calculation method, the obtained θ can be adapted to the entire 360° angle cycle, and the represented position is unique, so as to realize the control of the vibration mode at any angle and the output of the measurement result in the force feedback mode and the full angle mode.

[0068] Of course, the above are only typical examples of the present invention. In addition, the present invention can also have many other specific implementation manners. Any technical solution formed by equivalent replacement or equivalent transformation falls within the scope of protection required by the present invention.

Claims

1. A dual-mode control method for a hemispherical resonant gyroscope, characterized in that, including: a. calculating the angle θ value of the position where the vibration mode of the harmonic oscillator is located; b. First, switch to the force feedback control mode to calculate the rotational angular velocity Ω: Using the current value θ of θ fb as the feedback quantity, obtain the value of f fb when θ y = 0 through a preset first PI controller, and substitute f y into the expression in the force feedback control mode to calculate the rotational angular velocity Ω of the gyroscope; c. When the rotational angular velocity Ω exceeds the set value, switch to the full-angle control mode based on the θ value before switching: with the current amplitude α of α fb as the feedback quantity, the target value being the set target amplitude α ref , and the current angle θ fb as the input quantity, obtain the value of f through a preset second PI controller a , where f a represents the magnitude of the force required to maintain the amplitude α; Substitute f a into the expression of the full-width control mode to calculate f x and f y ; Through θ fb Output the rotational angular velocity Ω of the gyroscope.

2. The dual-mode control method of a hemispherical resonant gyroscope as claimed in claim 1, wherein, The calculating of the angle θ value of the position where the vibration mode of the harmonic oscillator is located specifically includes: Set the current θ value as θ t1 ; Denote the θ value extracted in the next calculation cycle as θ t2 ; The θ value is calculated in an incremental manner, that is: Δθ = θ t2 -θ t1 ; θ = θ ts + Δθ; θ ts = θ; θ ts Used to store the θ value obtained in the previous calculation cycle.

3. The dual-mode control method of a hemispherical resonant gyroscope according to claim 2, characterized in that, in Within two sampling periods, when Δθ is greater than 90°, it is equivalent to -180°; when Δθ is less than -90°, it is equivalent to +180°.

4. The dual-mode control method of a hemispherical resonant gyroscope as claimed in claim 1, wherein The first Pl controller includes a first adder, a first proportional link, a first derivative link, a first integral limiting link, a first summing link, and a first output limiting link; wherein, one input end of the first adder inputs the target angle θ = 0 respectively, and the other input end inputs the current angle θ fb ; the input ends of the first proportional link and the first derivative link are both connected to the output end of the first adder; the input end of the first integral limiting link is connected to the output end of the first derivative link; one input end of the first summing link is connected to the output end of the first proportional link, and the other input end is connected to the output end of the first integral limiting link; the input end of the first output limiting link is connected to the output end of the first summing link.

5. The dual-mode control method of a hemispherical resonant gyroscope according to claim 1, characterized in that, The second PI controller includes a second adder, a second proportional link, a second differential link, a second integral limiting link, a second summing link, a second output limiting link, and a synthesis calculation link; wherein, one input terminal of the second adder inputs the target amplitude α ref = 0, and the other input terminal inputs the current amplitude α fb ; the input terminals of the second proportional link and the second differential link are both connected to the output terminal of the second adder; the input terminal of the second integral limiting link is connected to the output terminal of the second differential link; one input terminal of the second summing link is connected to the output terminal of the second proportional link, and the other input terminal is connected to the output terminal of the second integral limiting link; the input terminal of the second output limiting link is connected to the output terminal of the second summing link; one input terminal of the synthesis calculation link is connected to the output terminal of the second output limiting link, and the other input terminal inputs the current angle θ fb . The calculation formula of the synthesis calculation link is: f x = U a cosθ ref , f y = U a sinθ ref ; wherein, U a is the output value of the second output limiting link.

Images