A dual-mode control method for a hemispherical resonator gyroscope

Abstract

The application discloses a dual-mode control method of a hemispherical resonator gyro, which comprises the following steps: firstly, calculating the position angle θ of a vibration mode; and then, calculating the rotational angular velocity Ω in a force feedback control mode or a full-angle control mode through θ; thus, the calculation of the force feedback control mode can be applied, and the calculation of the full-angle control mode can also be applied. The control system can switch between the two modes to cope with different working conditions, and the complementary effects of the two control modes can be realized.

Description

Technical Field

[0001] This invention relates to the field of gyroscope technology, and in particular, to a dual-mode control method for a hemispherical resonant gyroscope. Background Technology

[0002] Hemispherical resonator gyroscopes can be used to measure the angular velocity and rotation angle of an object. Currently, their control modes are mainly force feedback control and full-angle control. Each of these modes has its advantages and disadvantages. Force feedback mode has the advantages of high control accuracy and good tolerance to manufacturing-introduced errors; its disadvantages are slow angular velocity measurement response, small output bandwidth, and unsuitability for measuring highly mobile objects. Full-angle mode has the advantages of fast angular velocity measurement response, high output bandwidth, and wider applicability; its disadvantages are that manufacturing-introduced errors have a significant impact on measurement accuracy when measuring low speeds. Currently, most hemispherical resonator gyroscope products utilize one of these two methods. 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 force feedback control mode and full-angle control mode.

[0004] To achieve the above objectives, the technical solution of the present invention is as follows:

[0005] 2. A dual-mode control method for a hemispherical resonant gyroscope, characterized by comprising:

[0006] a. Calculate the angle θ value of the position of the mode shape of the harmonic oscillator;

[0007] b. First, switch to force feedback control mode and calculate the rotational angular velocity Ω: using the current value of θ. fb The feedback quantity is obtained by using a preset first PI controller when θ fb When = 0, f y The value of f y Substitute the values ​​into the expression for force feedback control mode to calculate the gyroscope's rotational angular velocity Ω;

[0008] c. When the rotational angular velocity Ω exceeds the set value, switch to full-angle control mode based on the θ value before the switch: using the current amplitude α. fb The feedback quantity and the target value are set as the target amplitude α. ref Current angle θ fb The input quantity is f, which is obtained by a preset second PI controller. a The value of f a This indicates the magnitude of the force required to maintain the amplitude α;

[0009] f a Substituting into the expression for the full-angle control mode, f is calculated. x f y ;

[0010] By θ fb The output of the gyroscope is the rotation angular velocity Ω.

[0011] Preferably, the calculation of the mode shape of the resonator includes the following steps:

[0012] The current θ value is θ t1 ; the next calculated θ value is 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 last calculation period.

[0018] Preferably, 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 element, a first derivative element, a first integral limiting element, a first addition element, and a first output limiting element; one input end of the first adder is input with a target angle θ fb ; the input ends of the first proportional element and the first derivative element are connected to the output end of the first adder; the input end of the first integral limiting element is connected to the output end of the first derivative element; one input end of the first addition element is connected to the output end of the first proportional element, and the other input end is connected to the output end of the first integral limiting element; the input end of the first output limiting element is connected to the output end of the first addition element.

[0020] Preferably, the second PI controller includes a second adder, a second proportional element, a second derivative element, a second integral limiting element, a second addition element, a second output limiting element, and a synthetic calculation element; one input end of the second adder is input with a target amplitude α ref = 0, and the other input end is input with a current amplitude α fb; the input end of the second proportional link, the input end of the second differential link are connected with the output end of the second adder; the input end of the second integral limiting link is connected with the output end of the second differential link; one of the input ends of the second adding link is connected with the output end of the second proportional link, and the other input end is connected with the output end of the second integral limiting link; the input end of the second output limiting link is connected with the output end of the second adding link; one of the input ends of the synthetic calculation link is connected with 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 synthetic calculation link is: f x = U a cos θ ref , f y = U a sin θ ref ; wherein, U a is the output value of the second output limiting link.

[0021] The technical effects of the present application mainly embody in the following aspects:

[0022] The calculation of the force feedback control mode can be applied, and the calculation of the full angle control mode can also be applied. The control system can switch between the two modes to cope with different working conditions, and the complementary effects of the two control modes are realized. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is a mode shape change diagram in the embodiment (the mode shape and the shaft included angle are not 0°);

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

[0025] Figure 3 is a mode shape change diagram in the embodiment (the mode shape and the shaft included angle are 0°);

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

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

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

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

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

[0031] Reference numerals: 11, first adder; 12, first proportional element; 13, first differential element; 14, first integral limiting element; 15, first adding element; 16, first output limiting element; 21, second adder; 22, second proportional element; 23, second differential element; 24, second integral limiting element; 25, second adding element; 26, second output limiting element; 27, synthetic calculation element. DETAILED DESCRIPTION

[0032] The specific embodiments of the present application are further described in detail below with reference to the accompanying drawings, so that the technical scheme of the present application is easier to understand and master.

[0033] The embodiment provides a dual-mode control method of a hemispherical resonator gyroscope, comprising:

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

[0035] b. Switch to the force feedback control mode to calculate the rotation angular velocity Ω first;

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

[0037] In the following, the embodiment will explain the principle of the above control method in detail.

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

[0039]

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

[0041] The force feedback control mode of the gyroscope: by applying a sinusoidal excitation signal on the y-axis, the position angle θ of the vibration mode is 0, at this time, the position of the vibration mode is as shown in Figure 3 and Figure 4 At this time, the vibration displacements of the x-axis and the y-axis are as follows:

[0042]

[0043] (where A0 is the target amplitude in the x-axis direction) is substituted into equation (1-1), and the following equation is obtained:

[0044]

[0045] Ω in formula (1-3) is the rotation angular velocity of the gyroscope body, which is an unknown quantity to be measured, and thus a first PI controller is designed, as shown in the figure: taking θ (the included angle between the gyroscope mode and the x axis) as the feedback quantity and 0 as the target value, the required value of Ω when θ = 0 is obtained through the first PI controller. Figure 5 ref = 0, the required value of Ω when θ = 0 is obtained through the first PI controller.

[0046] Specifically as follows:

[0047] Referring to Figure 5 , the first PI controller adopts a position type PI controller, specifically including a first adder 11, a first proportional element 12, a first differential element 13, a first integral limiting element 14, a first addition element 15 and a first output limiting element 16; wherein one input end of the first adder 11 respectively inputs the target angle θ ref = 0, and the other input end inputs the current angle θ fb ; the input ends of the first proportional element 12 and the first differential element 13 are connected to the output end of the first adder 11; the input end of the first integral limiting element 14 is connected to the output end of the first differential element 13; one input end of the first addition element 15 is connected to the output end of the first proportional element 12, and the other input end is connected to the output end of the first integral limiting element 14; the input end of the first output limiting element 16 is connected to the output end of the first addition element 15.

[0048] The output of the above-mentioned first PI controller after discretization at the nth beat: 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. In order to stabilize the control system, the first integral limiting element and the first output limiting element are set, and finally

[0049] Returning to the above force feedback calculation formula (1-3), wherein 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 is kept as a set value by the amplitude ring control, and the vibration frequency ω n is obtained by the frequency ring, so the size of the rotation angular velocity Ω can be finally calculated through the first PI controller.

[0050] Full angle control mode: according to the position angle θ value of the mode, different amplitude sinusoidal excitation voltages are given on the x axis and y axis excitation electrodes to maintain the size of the mode amplitude a. For example:

[0051] ​​

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

[0053] As shown in Figure 6 , the second PI controller includes a second adder 21, a second proportional element 22, a second derivative element 23, a second integral limiting element 24, a second addition element 25, a second output limiting element 26, and a synthesis calculation element 27; wherein one input end of the second adder 21 is inputted with the target amplitude α ref = 10um, and the other input end is inputted with the current amplitude α fb ; the input ends of the second proportional element 22 and the second derivative element 23 are connected to the output end of the second adder 21; the input end of the second integral limiting element 24 is connected to the output end of the second derivative element 23; one input end of the second addition element 25 is connected to the output end of the second proportional element 22, and the other input end is connected to the output end of the second integral limiting element 24; the input end of the second output limiting element 26 is connected to the output end of the second addition element 25; one input end of the synthesis calculation element 27 is connected to the output end of the second output limiting element 26, and the other input end is inputted with the current angle θ fb .

[0054] The output of the second PI controller after discretization at the n-th beat: 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] In order to ensure the stability of the control system, the second integral limiting element 24 and the second output limiting element 26 are set, and the amplitude U a= u(n). In the full angle control mode, the mode position is not fixed on the x axis, but rotates in the whole angle period (360°) according to the input external angular velocity. The excitation voltage to maintain the gyroscope vibration is applied according to the mode position, and cannot be applied only in the fixed x axis direction as in the force feedback mode. Therefore, after the excitation voltage amplitude obtained by the second PI controller is obtained, the excitation voltage size in the x axis and y axis is allocated according to the mode position θ, so that the direction of the synthesized excitation voltage coincides with the antinode axis of the mode, thereby realizing effective amplitude maintenance. Therefore, the 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 cos θ fb

[0057] f y = U a sin θ fb

[0058] As can be seen from the above, the angular velocity measurement value of the full angle mode is directly obtained by the change amount of the mode position angle θ value in unit time.

[0059] Based on the above, it can be seen that the mode position angle θ is needed in both control modes, wherein the force feedback control mode needs θ as the feedback quantity of the corresponding PI controller; and the full angle control mode combines the values of f x and f y , and outputs the rotation angle and rotation angular velocity of the gyroscope through θ.

[0060] The embodiment will be described in detail below on how to calculate θ value.

[0061] The tan θ = M value can be obtained by collecting the x axis displacement detection electrode and the y axis displacement detection electrode, and the θ = atan M can be obtained by taking the inverse tangent. At this time, the range value of θ obtained can only represent the range of -90° to +90°, that is, only the position of sectors I and IV in Figure 7 cannot be distinguished in which sector of I and III, or which sector of II and IV, that is, the θ value obtained by analyzing the x axis vibration displacement and the y axis vibration displacement cannot distinguish the position in Figure 7 and Figure 8 . The embodiment proposes an incremental calculation method for θ, and the gyroscope control system adopts a timing cycle control, for example, the processing period is set to 1 ms. The current mode position θ value is obtained by the detection electrode, denoted as θ t1 ; the θ value obtained in the next calculation period is denoted as θ t2 . The θ value is calculated in an incremental manner, that is:

[0062] Δθ=θ t2 1θ t1

[0063] θ=θ ts +Δθ

[0064] θ ts =θ

[0065] θ ts This is used to store the θ obtained in the previous calculation cycle. Because Δθ has positive and negative values ​​and directionality, it can distinguish whether the gyroscope is rotating clockwise or counterclockwise, so the θ value obtained by this method also has directional characteristics. If the period value of θ is set to 360° (or can be set to an integer multiple of 360°), taking the remainder of θ with respect to 360° will constrain the value of θ within the set period range.

[0066] The value of θ is from the I quadrant ( Figure 7 When moving to the second quadrant, the value of θ = atanM undergoes a sign change, requiring quadrant conversion. For example, if θ is 89° in the first quadrant and jumps to -88° in the second quadrant, the incremental Δθ is -177°. In reality, this represents a 3° counterclockwise rotation (considering actual operating conditions, the rotation angle does not exceed 90° within two sampling periods). Therefore, quadrant conversion compensation is needed for Δθ: Δθ + 180° = 3°, to match the actual situation. When θ crosses quadrants within two sampling periods, Δθ may be greater than 90° or less than -90°. When Δθ is greater than 90°, an equivalent -180° conversion is needed; when Δθ is less than -90°, an equivalent +180° conversion is needed.

[0067] This incremental calculation method allows the obtained θ to be adapted to the entire 360° angular period, and the position represented is unique, thereby realizing the control and measurement results of the mode shape at any angle in force feedback mode and full angle mode.

[0068] Of course, the above are just typical examples of the present invention. In addition, the present invention may have many other specific embodiments. All technical solutions formed by equivalent substitution or equivalent transformation fall within the scope of protection claimed by the present invention.

Claims

1. A method of dual mode control of a hemispherical resonator gyroscope, characterized by, Comprising: a、calculating the value of the angle θ of the position of the mode of the resonator; b. First, switch to force feedback control mode and calculate the rotational angular velocity Ω: using the current value of θ. fb The feedback quantity is obtained by using a preset first PI controller when θ fb When = 0, f y The value of f y Substitute the values ​​into the expression for force feedback control mode to calculate the gyroscope's rotational angular velocity Ω; c. When the rotational angular velocity Ω exceeds a set value, switch to the full angle control mode based on the θ value before the switch: switch to the full angle control mode based on the current amplitude α of α fb , the target value being a set target amplitude α ref , the current angle θ fb , the input quantity, the value of f a being obtained by a preset second PI controller, f a indicating the magnitude of force required to maintain the amplitude α; f a Substituting into the expression for the full angle control mode gives f x , f y ; By θ fb The rotation angular velocity Ω of the gyro is output.

2. The dual mode control method of a hemispherical resonator gyroscope according to claim 1, characterized in that, The value of the angle θ of the position of the mode of the resonator is calculated in an incremental manner, that is: the current θ value is θ t1 ; the θ value extracted in the next calculation cycle is θ t2 ; In two sampling periods, when Δθ is greater than 90°, -180° is equivalent; when Δθ is less than -90°, +180° is equivalent. Δθ = θ t2 -θ t1 ; θ = θ ts + Δθ; θ ts = θ; θ ts For storing the value of θ obtained in the previous calculation cycle.

3. The dual mode control method of a hemispherical resonator gyroscope according to claim 2, wherein the step of ​ 4. The dual mode control method of a hemispherical resonator gyroscope according to claim 1, characterized in that, The first Pl controller comprises 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 end of the first adder is inputted with a target angle θ = 0 and the other input end is inputted with a current angle θ fb ; the input ends of the first proportional link and the first differential link are connected with the output end of the first adder; the input end of the first integral limiting link is connected with the output end of the first differential link; one input end of the first adding link is connected with the output end of the first proportional link and the other input end is connected with the output end of the first integral limiting link; the input end of the first output limiting link is connected with the output end of the first adding link.

5. The dual mode control method of a hemispherical resonator gyroscope according to claim 1, characterized in that, The second PI controller comprises a second adder, a second proportional element, a second differential element, a second integral limiting element, a second adding element, a second output limiting element and a synthetic calculation element; wherein one input end of the second adder is respectively inputted a target amplitude α ref =0, and the other input end is inputted a current amplitude α fb ; input ends of the second proportional element and the second differential element are connected with an output end of the second adder; an input end of the second integral limiting element is connected with an output end of the second differential element; one input end of the second adding element is connected with an output end of the second proportional element, and the other input end is connected with an output end of the second integral limiting element; an input end of the second output limiting element is connected with an output end of the second adding element; one input end of the synthetic calculation element is connected with an output end of the second output limiting element, and the other input end is inputted a current angle θ fb； A calculation formula of the synthetic calculation element is: f x =U a cosθ ref , f y =U a sinθ ref ; wherein U a is an output value of the second output limiting element.

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