Quartz tuning fork resonant gyroscope measurement and control circuit based on time-sharing multiplexing

Abstract

The present invention, in the field of measurement and control circuit technology, discloses a quartz tuning fork resonant gyroscope measurement and control circuit based on time-sharing multiplexing. The measurement and control circuit includes a drive circuit self-excited oscillation circuit and a force feedback and detection circuit. The drive circuit self-excited oscillation circuit includes a first conversion unit, a comparison unit, a regulation unit, and an electronic switch, and the force feedback and detection circuit includes a first switch, a second switch, a third switch, a fourth switch, a second conversion unit, a fifth switch, a sixth switch, a seventh switch, an amplification unit, and a force feedback controller. This allows for high-frequency switching between the excitation of the drive channel and the vibration detection of the detection channel, thereby eliminating electrical coupling between the two. This solves the problem of the electrical coupling between the drive circuit and the detection circuit affecting the zero drift stability of the gyroscope output, thereby improving the zero drift stability of the gyroscope.

Description

Technical Field

[0001] The present invention relates to the technical field of measurement and control circuits, and in particular to a quartz tuning fork resonant gyroscope measurement and control circuit based on time-division multiplexing. Background Art

[0002] A resonant gyroscope based on the principle of Coriolis force coupling has two orthogonal resonant modes: a primary vibration mode (driving mode) and a detection vibration mode. The primary vibration mode is first excited by a driving electrode to provide the in-plane linear velocity of the tuning fork tines in the x-axis direction required to generate Coriolis force coupling. A rotational input Ω in the z-axis direction causes the vibration energy of the primary vibration mode to be coupled to the detection vibration mode via the Coriolis force coupling principle, inducing out-of-plane vibration in the detection channel in the y-axis direction. The amplitude of this coupled vibration is proportional to the rotational speed. The vibration in the detection channel is detected, amplified, and synchronously detected by the detection electrodes to obtain the rotation rate. The resonant gyroscope's measurement and control circuitry includes at least one closed-loop drive control circuit, consisting of a phase-locked loop and an automatic gain control link, for automatically tracking the resonant frequency of the primary vibration and stabilizing the vibration amplitude. The coupled vibration of the detection vibration mode can be read out in either an open-loop or closed-loop manner.

[0003] The zero-drift stability of a gyro sensor is a key performance indicator. Numerous factors influence the zero-drift stability of a gyro. Typical influencing factors include changes in the orthogonal coupling between the two vibration modes caused by ambient temperature fluctuations and changes in the quality factor of the resonator due to ambient temperature fluctuations. In the measurement and control circuit, the high input impedance of the charge-to-voltage conversion circuit makes it susceptible to coupling interference from other electrical signals in the system. The primary vibration circuit's drive signal, due to its high amplitude and frequency, couples to the detection channel, making it impossible to eliminate through orthogonal demodulation. This signal becomes the primary coupling interference signal affecting the detection vibration circuit. Furthermore, fluctuations in the resonator's quality factor caused by ambient temperature fluctuations cause corresponding fluctuations in the required primary vibration circuit drive signal, resulting in changes in the zero angular velocity output in the detection channel, known as zero-drift instability.

[0004] Increasing the drive channel amplitude and speed can significantly improve the gyroscope's signal-to-noise ratio and sensitivity, but it also increases the coupling of the primary circuit drive signal to the detection channel signal. Because the drive and detection electrodes are closest to each other, signal coupling primarily occurs in the electrode anchor area. One of the detection electrode anchors is designed to be relatively wide, thus providing a shielding function. This shielding design effectively reduces signal coupling but cannot completely eliminate it, so it remains less than ideal for bias stability. Furthermore, due to the asymmetric design of the detection electrodes, differential circuits are unsuitable for the detection circuit, hindering signal-to-noise ratio improvement. Currently, most quartz tuning fork gyros utilize an open-loop output mode with a high-frequency difference, making the calibration factor, zero offset stability, and other factors more susceptible to changes in ambient temperature. Due to the frequency difference mode, the signal-to-noise ratio is also less than ideal.

[0005] Closed-loop force feedback can effectively improve the nonlinear performance, detection dynamic range, zero-bias stability, and vibration performance of a gyroscope. However, the electrical coupling between the drive and detection channels mentioned above makes it difficult to implement continuous-time closed-loop force feedback in a quartz tuning fork gyroscope system. Summary of the Invention

[0006] The present invention provides a quartz tuning fork resonant gyroscope measurement and control circuit based on time-division multiplexing, which can solve the technical problems in the prior art.

[0007] The present invention provides a quartz tuning fork resonant gyroscope measurement and control circuit based on time-sharing multiplexing, wherein the measurement and control circuit includes a drive circuit self-excited oscillation circuit and a force feedback and detection circuit, wherein the drive circuit self-excited oscillation circuit includes a first conversion unit, a comparison unit, a regulation unit, and an electronic switch, and the force feedback and detection circuit includes a first switch, a second switch, a third switch, a fourth switch, a second conversion unit, a fifth switch, a sixth switch, a seventh switch, an amplification unit, and a force feedback controller, wherein:

[0008] The first conversion unit is connected to the driving part of the quartz tuning fork resonant gyroscope, the comparison unit is connected to the first conversion unit, the adjustment unit is connected to the comparison unit, and the electronic switch is connected to the comparison unit and the driving part;

[0009] The first switch, the second switch, the third switch, and the fourth switch are connected to the detection portion of the quartz tuning fork resonant gyroscope, the second conversion unit is connected to the third switch and the fourth switch, the fifth switch, the sixth switch, and the seventh switch are connected to the second conversion unit, the amplification unit is connected to the sixth switch and the seventh switch, the input end of the force feedback controller is connected to the amplification unit, and the output end of the force feedback controller is connected to the first switch;

[0010] The first conversion unit is used to convert the displacement current caused by the mechanical vibration of the quartz tuning fork resonant gyroscope into a voltage signal, the comparison unit is used to convert the voltage signal into a square wave signal, the adjustment unit is used to adjust the amplitude of the square wave signal to stabilize the vibration amplitude of the quartz tuning fork resonant gyroscope, and the electronic switch is used to perform high-frequency modulation on the adjusted square wave signal according to the modulation frequency to obtain a modulation signal;

[0011] During the driving and force feedback phase P1, the first terminal sa of the electronic switch is closed, the driving signal is connected to the driving part, the first switch and the second switch are closed, so that the force feedback signal is connected to the detection part, forming a closed force feedback loop, and at the same time the third switch and the fourth switch are opened, so that the second conversion unit is disconnected from the detection part, the second conversion unit is grounded through the fifth switch, and the amplification unit is grounded through the sixth switch;

[0012] During the reset phase P2, the second terminal sb of the electronic switch is closed, and the third switch and the fourth switch are opened, so that the second conversion unit is disconnected from the detection part and the second conversion unit is reset;

[0013] During the detection phase P3, the second terminal sb of the electronic switch is closed, the first switch and the second switch are opened, the third switch and the fourth switch are closed, and the second conversion unit is connected to the amplification unit through the seventh switch to sequentially detect and amplify the mechanical vibration of the quartz tuning fork resonant gyroscope, and the force feedback controller generates a corresponding force feedback signal based on the amplified signal.

[0014] Preferably, the first conversion unit is a transconductance amplifier, and the comparison unit is a comparator.

[0015] Preferably, the adjustment unit is an automatic gain control circuit.

[0016] Preferably, the second conversion unit is a differential charge-voltage conversion circuit.

[0017] Preferably, the modulation frequency ranges from 600 kHz to 1000 kHz.

[0018] Preferably, the time constant of the force feedback controller is at least 10 times greater than the period of the modulation signal.

[0019] The above technical solution enables time-sharing multiplexing of high-frequency switching between the drive channel's excitation and the detection channel's vibration detection, eliminating electrical coupling between the two. This resolves the issue of electrical coupling between the drive and detection circuits affecting the gyro's output zero-drift stability, thereby improving the gyro's zero-drift stability. Furthermore, when not in use as detection electrodes, the detection channel's electrodes can function as force feedback electrodes, enabling closed-loop force feedback without the need for dedicated electrodes, thereby improving stability and vibration performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings are included to provide a further understanding of the embodiments of the present invention, constitute a part of the specification, illustrate the embodiments of the present invention, and together with the description, explain the principles of the present invention. Obviously, the drawings described below are only some embodiments of the present invention, and those skilled in the art can derive other drawings based on these drawings without inventive effort.

[0021] Figure 1 A schematic structural diagram of a quartz tuning fork resonant gyroscope according to an embodiment of the present invention is shown;

[0022] Figure 2 A schematic diagram of a self-excited oscillation circuit of a driving circuit in a quartz tuning fork resonant gyroscope measurement and control circuit based on time-division multiplexing according to an embodiment of the present invention is shown;

[0023] Figure 3 A schematic diagram of a force feedback and detection circuit in a quartz tuning fork resonant gyroscope measurement and control circuit based on time-division multiplexing according to an embodiment of the present invention is shown;

[0024] Figure 4 A time-division multiplexing timing diagram of driving, detection, and force feedback according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0025] It should be noted that, in the absence of conflict, the embodiments in this application and the features in the embodiments can be combined with each other. The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present invention and its application or use. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0026] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0027] Unless otherwise specifically stated, the relative arrangement of the parts and steps, the numerical expressions and the numerical values ​​set forth in these embodiments do not limit the scope of the present invention. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. The techniques, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the techniques, methods and equipment should be considered as part of the authorization specification. In all examples shown and discussed here, any specific values ​​should be interpreted as being merely exemplary and not as limiting. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following figures, and therefore, once an item is defined in one figure, it does not need to be further discussed in subsequent figures.

[0028] Figure 1 A schematic structural diagram of a quartz tuning fork resonant gyroscope according to an embodiment of the present invention is shown.

[0029] like Figure 1 As shown, the quartz tuning fork resonant gyroscope includes a first tuning fork tine 1, a second tuning fork tine 2, a third tuning fork tine 3, a fourth tuning fork tine 4, a first driving electrode 5, a second driving electrode 6, a first detection electrode 7, a second detection electrode 8, an electrode anchor point area 9, a first electrode anchor point 10, a second electrode anchor point 11, a third electrode anchor point 12 and a fourth electrode anchor point 13.

[0030] like Figure 2-4 As shown, an embodiment of the present invention provides a quartz tuning fork resonant gyroscope measurement and control circuit based on time-sharing multiplexing, wherein the measurement and control circuit includes a drive circuit self-excited oscillation circuit and a force feedback and detection circuit, wherein the drive circuit self-excited oscillation circuit includes a first conversion unit 14, a comparison unit 15, an adjustment unit 19 and an electronic switch (for example, a high-speed electronic switch), and the force feedback and detection circuit includes a first switch S1, a second switch S2, a third switch S3, a fourth switch S4, a second conversion unit 17, a fifth switch S5, a sixth switch S6, a seventh switch S7, an amplification unit 18 and a force feedback controller 20, wherein,

[0031] The first conversion unit 14 is connected to the driving part 21 (the first driving electrode 5 and the second driving electrode 6) of the quartz tuning fork resonant gyroscope, the comparison unit 15 is connected to the first conversion unit 14, the adjustment unit 19 is connected to the comparison unit 15, and the electronic switch is connected to the comparison unit 15 and the driving part 21;

[0032] The first switch S1, the second switch S2, the third switch S3, and the fourth switch S4 are connected to the detection portion 22 (the first detection electrode 7 and the second detection electrode 8) of the quartz tuning fork resonant gyroscope. The second conversion unit 17 is connected to the third switch S3 and the fourth switch S4. The fifth switch S5, the sixth switch S6, and the seventh switch S7 are connected to the second conversion unit 17. The amplification unit 18 is connected to the sixth switch S6 and the seventh switch S7. The input end of the force feedback controller 20 is connected to the amplification unit 18, and the output end of the force feedback controller 20 is connected to the first switch S1.

[0033] The first conversion unit 14 is used to convert the displacement current caused by the mechanical vibration of the quartz tuning fork resonant gyroscope into a voltage signal (the frequency of the vibration signal is generally between 10 kHz and 20 kHz), the comparison unit 15 is used to convert the voltage signal into a square wave signal, the adjustment unit 19 is used to adjust the amplitude of the square wave signal to stabilize the vibration amplitude of the quartz tuning fork resonant gyroscope, and the electronic switch is used to perform high-frequency modulation on the adjusted square wave signal according to the modulation frequency to obtain a modulation signal 16;

[0034] During the driving and force feedback phase P1, the first terminal sa of the electronic switch is closed, the driving signal is connected to the driving part, the first switch S1 and the second switch S2 are closed, so that the force feedback signal is connected to the detection part, forming a closed-loop force feedback loop, and at the same time the third switch S3 and the fourth switch S4 are opened, so that the second conversion unit 17 is disconnected from the detection part 22, the second conversion unit 17 is grounded through the fifth switch S5, and the amplification unit 18 is grounded through the sixth switch S6 (clearing and resetting, the detection circuit is in a reset state);

[0035] During the reset phase P2, the second terminal sb of the electronic switch is closed, and the third switch S3 and the fourth switch S4 are opened, so that the second conversion unit 17 is disconnected from the detection part and the second conversion unit 17 is reset;

[0036] During the detection phase P3, the second terminal sb of the electronic switch is closed, the first switch S1 and the second switch S2 are disconnected (the driving signal is at a low level of high-frequency modulation, and the force feedback signal is disconnected by the first switch S1 and the second switch S2), the third switch S3 and the fourth switch S4 are closed, and the second conversion unit 17 is connected to the amplification unit 18 through the seventh switch S7 to sequentially detect and amplify the mechanical vibration of the quartz tuning fork resonant gyroscope, and the force feedback controller 20 generates a corresponding force feedback signal based on the amplified signal.

[0037] The above technical solution enables high-frequency switching between the excitation of the drive channel and the vibration detection of the detection channel (i.e., the drive phase and the detection phase are time-shared at a high-frequency modulation frequency), thereby eliminating the electrical coupling between the two. This solves the problem of electrical coupling between the drive and detection circuits affecting the zero-drift stability of the gyroscope output, thereby improving the zero-drift stability of the gyroscope. Furthermore, when not in use as detection electrodes, the electrodes of the detection channel can be used as force feedback electrodes, thus achieving closed-loop force feedback without the need for designing dedicated electrodes, thereby improving stability and vibration performance.

[0038] According to an embodiment of the present invention, the first conversion unit 14 is a transconductance amplifier, and the comparison unit 15 is a comparator.

[0039] According to an embodiment of the present invention, the adjustment unit 19 is an automatic gain control circuit AGC.

[0040] According to an embodiment of the present invention, the second conversion unit 17 is a differential charge-voltage conversion circuit.

[0041] The use of differential charge-voltage conversion circuit can improve the signal-to-noise ratio of the system.

[0042] The amplifying unit 18 is an amplifying circuit.

[0043] According to an embodiment of the present invention, the modulation frequency ranges from 600 kHz to 1000 kHz.

[0044] That is, the modulation frequency is much higher than the frequency of the vibration signal, so it does not affect the oscillation.

[0045] According to an embodiment of the present invention, the time constant of the force feedback controller 20 is at least 10 times greater than the period of the modulation signal.

[0046] It can be seen from the above embodiments that the measurement and control circuit of the present invention has at least the following advantages: (1) Since the electrical coupling from the drive signal to the detection channel is eliminated, the zero-bias stability of the gyroscope is improved. (2) Based on the elimination of electrical coupling, the charge-voltage conversion of the detection channel can adopt a fully symmetrical differential structure, thereby improving the signal-to-noise ratio of the gyroscope output. (3) By time-division multiplexing of the detection electrodes, closed-loop force feedback control is achieved, which can improve the stability and vibration performance of the gyroscope. (4) Due to the use of closed-loop force feedback control, the gyroscope can be designed in frequency matching mode, thereby improving the signal-to-noise ratio and resolution.

[0047] In the description of the present invention, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "horizontal, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention; the directional words "inside and outside" refer to the inside and outside relative to the outline of each component itself.

[0048] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used herein to describe the spatial positional relationship of a device or feature to other devices or features as shown in the figures. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figures. For example, if the device in the drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0049] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0050] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A quartz tuning fork resonant gyroscope measurement and control circuit based on time-division multiplexing, characterized in that: The measurement and control circuit includes a drive circuit self-excited oscillation circuit and a force feedback and detection circuit, wherein the drive circuit self-excited oscillation circuit includes a first conversion unit, a comparison unit, an adjustment unit and an electronic switch, and the force feedback and detection circuit includes a first switch, a second switch, a third switch, a fourth switch, a second conversion unit, a fifth switch, a sixth switch, a seventh switch, an amplification unit and a force feedback controller, wherein: The first conversion unit is connected to the driving part of the quartz tuning fork resonant gyroscope, the comparison unit is connected to the first conversion unit, the adjustment unit is connected to the comparison unit, and the electronic switch is connected to the comparison unit and the driving part; The first switch, the second switch, the third switch, and the fourth switch are connected to the detection portion of the quartz tuning fork resonant gyroscope, the second conversion unit is connected to the third switch and the fourth switch, the fifth switch, the sixth switch, and the seventh switch are connected to the second conversion unit, the amplification unit is connected to the sixth switch and the seventh switch, the input end of the force feedback controller is connected to the amplification unit, and the output end of the force feedback controller is connected to the first switch; The first conversion unit is used to convert the displacement current caused by the mechanical vibration of the quartz tuning fork resonant gyroscope into a voltage signal, the comparison unit is used to convert the voltage signal into a square wave signal, the adjustment unit is used to adjust the amplitude of the square wave signal to stabilize the vibration amplitude of the quartz tuning fork resonant gyroscope, and the electronic switch is used to perform high-frequency modulation on the adjusted square wave signal according to the modulation frequency to obtain a modulation signal; During the driving and force feedback phase P1, the first terminal sa of the electronic switch is closed, the driving signal is connected to the driving part, the first switch and the second switch are closed, so that the force feedback signal is connected to the detection part, forming a closed force feedback loop, and at the same time the third switch and the fourth switch are opened, so that the second conversion unit is disconnected from the detection part, the second conversion unit is grounded through the fifth switch, and the amplification unit is grounded through the sixth switch; During the reset phase P2, the second terminal sb of the electronic switch is closed, and the third switch and the fourth switch are opened, so that the second conversion unit is disconnected from the detection part and the second conversion unit is reset; During the detection phase P3, the second terminal sb of the electronic switch is closed, the first switch and the second switch are opened, the third switch and the fourth switch are closed, and the second conversion unit is connected to the amplification unit through the seventh switch to sequentially detect and amplify the mechanical vibration of the quartz tuning fork resonant gyroscope, and the force feedback controller generates a corresponding force feedback signal based on the amplified signal.

2. The measurement and control circuit according to claim 1, characterized in that: The first conversion unit is a transconductance amplifier, and the comparison unit is a comparator.

3. The measurement and control circuit according to claim 2, characterized in that: The adjustment unit is an automatic gain control circuit.

4. The measurement and control circuit according to claim 1, characterized in that: The second conversion unit is a differential charge-voltage conversion circuit.

5. The measurement and control circuit according to any one of claims 1 to 4, characterized in that: The modulation frequency ranges from 600 kHz to 1000 kHz.

6. The measurement and control circuit according to claim 5, characterized in that: The time constant of the force feedback controller is at least 10 times greater than the period of the modulation signal.

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