KR100310140B1 - Vibratory gyroscope - Google Patents

Abstract

The present invention relates to a vibrating gyroscope (10) comprising a vibrator (12). The vibrator 12 has a vibrator 14 formed in the shape of an equilateral triangle prism. Piezoelectric elements 16a, 16b, and 16c are formed on the side surface of the vibrator 14. Two piezoelectric elements 16a and 16b are connected to the resistors 26 and 28 respectively. An oscillation circuit 30 is connected between the other feedback piezoelectric element 16c and the resistor. The antiphase signal of the signal output from the feedback piezoelectric element 16c is input to the vibrator 14 provided by the phase inverter 34 to the ground terminal. The signals output from the two piezoelectric elements 16a and 16b are input to the differential circuit 36. The differential circuit 36 is connected to the synchronous detection circuit 38 and is connected in series to the smoothing circuit 40 and the DC amplifier 42.

Description

Vibrating gyroscope

The present invention relates to a vibrating gyroscope, and more particularly, to a vibrating gyroscope for detecting the rotational angular velocity using the bending vibration of the vibrating body.

10 is a diagram illustrating one example of a conventional vibrating gyroscope. This vibrating gyroscope 1 includes a vibrator 2. The vibrator 2 includes, for example, a vibrating body 3 in the form of an equilateral triangle prism, as shown in FIG. 10. Three piezoelectric elements 4a, 4b, and 4c are formed on three sides of the vibrating body 3, respectively. The piezoelectric elements 4a and 4b are used for driving for causing the vibrator 2 to perform bending vibration and for detecting for obtaining a signal corresponding to the rotational angular velocity. In addition, the piezoelectric element 4c is used as a return loop for driving the vibrator 2.

Between the piezoelectric elements 4a and 4b and the piezoelectric element 4c, the oscillation circuit 5 is connected through a resistor. The vibrating body 3 is used as a grounding terminal and is connected to a point having an intermediate voltage of the power supply voltage. The signals output from the piezoelectric elements 4a and 4b are input to the differential circuit 6. The signal output from the differential circuit 6 is detected by the synchronous detection circuit 7 in synchronization with the signal of the oscillation circuit 5. The signal output from the synchronous detection circuit 7 is smoothed by the smoothing circuit 8 and amplified by the DC amplifier.

When the drive signal shown in FIG. 11 is input to the two piezoelectric elements 4a and 4b by the vibrating gyroscope 1, the vibrating body 3 is flexed and vibrated in a direction perpendicular to the plane on which the piezoelectric element 4c is formed. Do it. When the vibrating body 3 rotates about the axis of the vibrating body, the vibration direction of the vibrating body 3 changes due to the Coriolis force. Therefore, the signals output from the piezoelectric elements 4a and 4b are different. The signal corresponding to the rotational angular velocity can be obtained by calculating the difference between the signals output from the piezoelectric elements 4a and 4b. The signal output from the differential circuit 6 is detected by the synchronous detection circuit 7, smoothed by the smoothing circuit 8, and amplified by the DC amplifier 9. By measuring such a signal, the rotational angular velocity applied to the vibrator 2 can be detected.

In such a vibrating gyroscope, the grounding terminal is connected to a point having an intermediate voltage of the power supply voltage, so that voltage A, which is only half of the maximum power supply voltage, is applied to the piezoelectric element used for driving as shown in FIG. Therefore, when a low-voltage power source such as a battery is used, sufficient excitation of the vibrating body cannot be performed. If the vibrating body is not sufficiently excited, the sensitivity of the vibrating gyroscope is lowered. In order to cope with such a problem, the peripheral circuit compensated for the conventional sensitivity decrease. In this case, the oscillator noise and the circuit noise are also amplified, and the S / N ratio deteriorates.

Accordingly, it is an object of the present invention to provide a highly sensitive vibrating gyroscope in which the vibrating body can be sufficiently excited even at a low-voltage power supply.

The above object is a vibrating body; Drive means and feedback means for the vibrating body; A circuit connected between said drive means and a feedback means for inputting a drive signal to said drive means for vibrating a vibrating body to provide an output signal; And means for inputting an antiphase signal of the signal output from the feedback means to the grounding terminal.

In the oscillating gyroscope, the antiphase signal of the signal output from the feedback means is amplified and input to the ground terminal.

The drive means and the feedback means can be formed by piezoelectric elements. In this case, the vibrating body is used as a terminal for grounding.

The vibrating body may be formed by a piezoelectric element. In this case, the driving means, the feedback means, and the grounding terminal are formed in the vibrating body as electrodes.

By inputting the antiphase signal of the signal output from the feedback means to the ground terminal, a signal having a large voltage is applied between the feedback means and the ground terminal, and thus the vibrating body is excited. When the signal output from the feedback means is amplified, the voltage of the signal applied between the feedback means and the ground terminal becomes large.

According to the present invention, since a large voltage signal is applied between the feedback means and the ground terminal, the driving force for flexibly vibrating the vibrating body is also generated in the feedback means. Thus, the vibrating body is driven by both means of the drive means and the feedback means, and can be sufficiently excited even if a low-voltage power source such as a battery is used. The larger the amplification of the vibration means, the higher the rotational angular velocity can be detected with high sensitivity. In addition, since the antiphase signal of the signal output from the feedback means is amplified, the vibrator can be driven with a larger voltage, and the amplification of the vibrating body can also be increased.

The above objects, other objects, features, and advantages of the present invention will become more apparent from the detailed description of the preferred embodiments described below with reference to the drawings.

1 is a diagram showing a vibrating gyroscope of the present invention.

FIG. 1A is a diagram illustrating a deformation of the oscillating gyroscope shown in FIG. 1.

FIG. 2 is a perspective view of the vibrator in the vibrating gyroscope shown in FIG. 1. FIG.

3 is a cross-sectional view of the vibrator shown in FIG. 2.

4A and 4B are waveform diagrams showing a feedback signal output from the piezoelectric element 16 and a signal input to the grounding terminal.

5 is a diagram illustrating another vibrating gyroscope of the present invention.

6 is a perspective view of another vibrator used in the vibrating gyroscope of the present invention.

FIG. 7 is a cross-sectional view of the vibrator shown in FIG. 6.

FIG. 8 is a diagram illustrating a vibrating gyroscope using the vibrator shown in FIG. 6.

FIG. 9 is a diagram illustrating another vibrating gyroscope using the vibrator shown in FIG. 6.

10 is a diagram illustrating a conventional vibrating gyroscope.

FIG. 11 is a waveform diagram illustrating a driving signal input to the vibrating gyroscope illustrated in FIG. 10.

<Description of Major Symbols in Drawing>

10: vibrating gyroscope

12: vibrator

14: vibrating body

16a, 16b, 16c: piezoelectric element

24a, 24b: support member

30: vibration circuit

34: inversion circuit

36: differential circuit

38: synchronous detection circuit

40: smoothing circuit

42: DC amplifier

50a to 50f: electrode

1 is a diagram illustrating an example of a vibrating gyroscope according to the present invention. Vibration gyroscope 10 includes a vibrator 12. The vibrator 12 has a vibrating body 14 formed in the form of an equilateral triangle prism, for example, as shown in FIG. The vibrator 14 is formed by a material that generates mechanical vibrations, such as eleven, iron-nickel alloy, quartz, glass, quartz, ceramic, and the like.

Piezoelectric elements 16a, 16b, and 16c are formed on the side surface of the vibrator 14. The piezoelectric element 16a includes a piezoelectric plate 18a formed of a piezoelectric ceramic or the like, and electrodes 20a and 22a are formed on both sides of the piezoelectric plate as shown in FIG. The electrode 22a is bonded to the vibrating body 14. In the same manner, piezoelectric elements 16b and 16c include piezoelectric plates 18b and 18c, and electrodes 20b, 22b and 20c and 22c are formed on both sides of the piezoelectric plate. The electrodes 22b and 22c are adhered to the vibrator 14. The piezoelectric elements 16a and 16b serve as driving means for providing the vibrating body 14 which is flexibly vibrated, and also as detecting means for obtaining a signal corresponding to the rotational angular velocity. The piezoelectric element 16c is used as a feedback means which acts when the vibrating body 14 vibrates flexibly.

Support members 24a and 24b are mounted on the ridge line close to the node of the vibrator 14. The support members 24a and 24b are made of metal wire, for example formed in the form of a gate, ie inverted rectangular U-shape. The support member is fixed to the support at both ends.

The piezoelectric elements 16a and 16b are connected to the resistors 26 and 28, respectively. The oscillation circuit 30 is connected between the feedback piezoelectric element 16c and these resistors 26 and 28. The phase inverter 34 having an input connected to the feedback piezoelectric element 16c is connected to the ground terminal of the vibrator 12, so that the antiphase signal of the signal output from the feedback piezoelectric element 16c is Input to ground terminal. The vibrator 14 is used as a terminal for grounding, and the supporting members 24a and 24b are used, for example, as signal input terminals.

The piezoelectric elements 16a and 16b are connected to the input terminal of the differential circuit 36. The signal output from the differential circuit 36 is detected by the synchronous detection circuit 38, for example, in synchronization with the signal of the oscillation circuit. The synchronous detection circuit 38 is connected to the smoothing circuit 40, and the smoothing circuit 40 is connected to the DC amplifier 42.

When the drive signal shown in FIG. 11 is input to two piezoelectric elements 16a and 16b in the vibrating gyroscope 10, the piezoelectric elements 16a and 16b repeat expansion and contraction, and the vibrating body 14 Bends vibration in a direction perpendicular to the plane on which the piezoelectric element 16c is formed. The feedback signal is inverted by the phase inversion circuit 34, and the antiphase signal of the feedback signal is input to the ground terminal. When the feedback signal has a shape with an amplitude of B as shown in FIG. 4A, a signal having an amplitude of B and an antiphase of the drive signal is applied to the vibrator 14 as shown in FIG. 4B. Therefore, a signal having an amplitude of 2B is input to the piezoelectric element 16c. With this signal, a driving force for bending and vibrating the vibrating body 14 is generated in the piezoelectric element 16c, so that the piezoelectric element 16c is accompanied by the driving force by the driving piezoelectric elements 16a and 16b. Bend vibrate. At this driving force, the vibrator 14 vibrates flexibly in a direction perpendicular to the plane on which the piezoelectric element 16c is formed. In this case, since the signals generated by the piezoelectric elements 16a and 16b have the same phase and the same level, the differential circuit 36 does not output the signal. Thus, the oscillating gyroscope 10 shows that the rotational angular velocity is not detected.

When the vibrating body 14 rotates about the axis of the vibrating body in this state, the vibration direction of the vibrating body 14 changes due to the force of Coriolis. Therefore, the signals output from the piezoelectric elements 16a and 16b are different, and the difference is output from the differential circuit 36. This signal corresponds to the rotational angular velocity. The signal output from the differential circuit is detected by the synchronous detection circuit 38 and smoothed by the smoothing circuit 40 to obtain a DC signal corresponding to the rotational angular velocity. This signal is amplified by the DC amplifier 42. By measuring the signal output from the DC amplifier 42, the rotational angular velocity applied to the oscillating gyroscope 10 can be detected.

Since the antiphase signal of the feedback signal is input to the ground terminal in the oscillating gyroscope 10, the driving force is generated not only in the driving piezoelectric elements 16a and 16b but also in the feedback piezoelectric element 16c. Thus, even when a low-voltage power source such as a battery is used, the vibrating body 14 can be sufficiently excited. In other words, the amplitude of the vibrating body 14 is made larger than in the conventional vibrating gyroscope, and the sensitivity for detecting the rotational angular velocity can also be improved.

The feedback signal output from the piezoelectric element 16c is amplified by the oscillation circuit 30 and applied to the piezoelectric elements 16a and 16b. The amplitude B of the feedback signal is smaller than the amplitude A of the drive signal. Therefore, the voltage 2B applied to both surfaces of the piezoelectric element 16c is smaller than the maximum power supply voltage. However, when the feedback signal is inverted and amplified, the maximum power supply voltage can be applied to both sides of the piezoelectric element 16c. Therefore, the amplitude of the bending vibration of the vibrating body 14 can be made larger compared with the case where the feedback signal is inverted and input to the vibrating body 14 without amplification. Conveniently for this purpose, an amplifier 34a is provided as shown in FIG. 1A.

In the vibrating gyroscope 10 described above, the piezoelectric elements 16a and 16b of the vibrator 12 are used as drive means and detection means, and the piezoelectric element 16c serves as a feedback means. As shown in Fig. 5, a vibrating gyroscope is constructed so that the piezoelectric elements 16a and 16b serve as detection means and feedback means, and the piezoelectric element 16c is used as driving means. In this case, the signals output from the piezoelectric elements 16a and 16b are combined and returned to the oscillation circuit 30. The signals output from the piezoelectric elements 16a and 16b are added by the adder 44 and the phase is reversed, and then input to the vibrator 14. When a signal having a large voltage is input to the feedback piezoelectric elements 16a and 16b, a driving force for bending and vibrating the vibrating body 14 is generated. Therefore, the amplitude of the bending vibration of the vibrator 14 can be large. Thus, the rotational angular velocity can be detected with high sensitivity.

As shown in FIGS. 6 and 7, the vibrator 12 may use a cylindrical vibrating body 14. The vibrator 14 is formed of a piezoelectric material. Six electrodes 50a, 50b, 50c, 50d, 50e, and 50f are formed on the side of the vibrator 14. These electrodes 50a to 50f are formed in the longitudinal direction of the vibrator 14. The electrodes 50b, 50d, and 50f alternately arranged on the side surfaces are connected to both ends and serve as ground terminals. Polarization is applied to the vibrating body 14 between the electrodes 50a, 50c, and 50e and the adjacent electrode (grounding terminal).

As shown in Fig. 8, such a vibrator 12 is formed so that the electrodes 50a and 50c are used as drive means and detection means, and the electrode 50e is provided as feedback means. Also in this case, the rotational angular velocity can be detected in the same manner as in the oscillating gyroscope shown in FIG. 1. The vibrator 12 is also formed as shown in Fig. 9 so that the electrodes 50a and 50c are used as feedback means and detection means, and the electrode 50e serves as a drive means. In this case, the rotational angular velocity can also be detected in the same way as in the oscillating gyroscope shown in FIG. 5.

In addition, in such a vibrating gyroscope 10, an antiphase signal of a feedback signal is input to the electrodes 50b, 50d, and 50f serving as the ground terminal. A signal having a large voltage can be applied between the feedback electrode and the ground electrode to increase the amplitude of the bending vibration of the vibrating body 14. Thus, the rotational angular velocity can be detected with higher sensitivity than in conventional vibrating gyroscopes. In such a vibrating gyroscope, the feedback signal can be inverted as well as amplified and input to the electrodes 50b, 50d, and 50f. The larger the amplitude of the bending vibration of the vibrating body 14, the more sensitive the vibration gyroscope can be obtained.

The vibrator 14 may have other forms, such as a hexagonal prism and a hexagonal prism. By applying an antiphase signal of a feedback signal to the grounding terminal of the vibrator, the amplitude of the vibrating body can be increased, and a highly sensitive vibrating gyroscope can be obtained.

Although the present invention has been described in detail with reference to specific embodiments thereof, it will be apparent to those skilled in the art that various changes and modifications can be made in the present invention within the spirit and scope of the invention. It will be appreciated that changes and variations are included.

According to the present invention, since a large voltage signal is applied between the feedback means and the ground terminal, the driving force for flexibly vibrating the vibrating body is also generated in the feedback means. Thus, the vibrating body is driven by both means of the drive means and the feedback means, and can be sufficiently excited even if a low-voltage power source such as a battery is used. The larger the amplification of the vibration means, the higher the rotational angular velocity can be detected with high sensitivity. Further, since the antiphase signal of the signal output from the feedback means is amplified, the vibrator can be driven with a larger voltage, and the amplification of the vibrating body can also be made larger.

Claims (27)

Vibrating body; Drive means on the vibrating body for driving the vibrating body; Feedback means for generating a feedback signal based on the vibration of the vibrating body; A circuit connected between the drive means and the feedback means, for generating a drive signal based on the feedback signal and applying the drive signal to the drive means; And And a phase inversion circuit for directly receiving a feedback signal without adjusting the amplitude or the phase of the amplitude, and for applying an antiphase signal of the feedback signal from the feedback means to a ground terminal. The vibratory gyroscope according to claim 1, wherein the driving means and the feedback means are formed by a piezoelectric element, and the vibrating body is used as the grounding terminal. The vibratory gyroscope according to claim 1, wherein the vibrating body is formed by a piezoelectric body, and the driving means, the feedback means, and the grounding terminal are formed as electrodes on the vibrating body. The vibratory gyroscope according to claim 1, wherein said means for inputting an antiphase signal of a signal output from said feedback means comprises a phase inverter. 5. The vibratory gyroscope according to claim 4, wherein said means for inputting an antiphase signal of the signal output from said feedback means comprises an amplifier in between said phase inverter and said ground terminal. 2. The vibrating body according to claim 1, wherein the vibrating body has three sides in the form of a triangular cross section; The drive and feedback means comprise first, second and third piezoelectric elements on the three sides, respectively; The vibrating gyroscope is used as the grounding terminal. 7. The vibratory gyroscope according to claim 6, wherein the first piezoelectric element is used as the feedback means, and the second and third piezoelectric elements are used as the driving means. 8. A vibratory gyroscope according to claim 7, wherein said means for inputting an antiphase signal of the signal output from said feedback means comprises a phase inverter. 9. The vibratory gyroscope according to claim 8, wherein said means for inputting an antiphase signal of a signal output from said feedback means further comprises an amplifier in between said phase inverter and said ground terminal. 10. The device of claim 9, wherein the second and third piezoelectric elements are respectively connected to the second and third piezoelectric elements for providing an output signal and for detecting a difference in the output signal from the second and third piezoelectric elements. Vibration gyroscope further comprises a differential circuit. 11. The apparatus of claim 10, further comprising: a synchronous detection circuit connected to the output of the differential circuit; A smoothing circuit connected to an output of the synchronous detection circuit; And an amplifier connected to the output of said smoothing circuit. 12. The vibratory gyroscope of claim 11, wherein the circuit comprises an oscillating circuit. 13. The vibratory gyroscope according to claim 12, wherein an output of the power generation circuit is connected to an input of the synchronous detection circuit. 7. A vibratory gyroscope according to claim 6, wherein the first piezoelectric element is used as the driving means, and the second and third piezoelectric elements are used as the feedback means. 15. The apparatus of claim 14, further comprising an adder for adding signals from the second and third piezoelectric elements, the output of the adder being connected to the means for inputting an antiphase signal of the signal output from the feedback means. Oscillating gyroscope, characterized in that. 16. The vibratory gyroscope according to claim 15, wherein said means for inputting an antiphase signal of a signal output from said feedback means further comprises a phase inverter. 17. The vibratory gyroscope according to claim 16, wherein said means for inputting an antiphase signal of a signal output from said feedback means further comprises an amplifier in between said phase inverter and said ground terminal. 18. The device of claim 17, wherein the second and third piezoelectric elements are respectively connected to the second and third piezoelectric elements to provide an output signal and to detect a difference in the output signal from the second and third piezoelectric elements. Vibration gyroscope further comprises a differential circuit. 19. The apparatus of claim 18, further comprising: a synchronous detection circuit connected to the output of the differential circuit; A smoothing circuit connected to an output of the synchronous detection circuit; And an amplifier connected to the output of said smoothing circuit. 20. The vibratory gyroscope of claim 19, wherein the circuit comprises an oscillating circuit. 21. The vibratory gyroscope according to claim 20, wherein an output of the power generation circuit is connected to an input of the synchronous detection circuit. A vibrating body made of a conductive material and used as a grounding terminal; A plurality of first piezoelectric elements formed on the vibrating body, for receiving a driving signal and driving the vibrating body; A second piezoelectric element formed on the vibrating body and configured to generate a feedback signal based on driving of the vibrating body; An oscillation circuit for receiving the feedback signal and generating the drive signal based on the feedback signal; And And a phase inversion circuit electrically connected between the second piezoelectric element and the vibrating body and inverting the phase of the feedback signal and applying the inverted phase signal to the vibrating body. . The vibratory gyroscope according to claim 22, wherein the second piezoelectric element vibrates the vibrating body according to a potential difference between the signal applied to the vibrating body and the feedback signal. 24. The vibratory gyroscope according to claim 23, further comprising a third piezoelectric element formed on said vibrating body and electrically connected to said oscillation circuit in series with said first piezoelectric element. 25. The method of claim 24, further comprising a differential circuit connected between said first piezoelectric element and said third piezoelectric element, said differential circuit for detecting a difference in output from said first piezoelectric element and said second piezoelectric element. Vibration gyroscope characterized by. 24. The vibratory gyroscope according to claim 23, further comprising a third piezoelectric element formed on said vibrating body and electrically connected to said phase inversion circuit in series with said second piezoelectric element. 27. The apparatus of claim 26, further comprising a differential circuit connected between said second piezoelectric element and said third piezoelectric element, said differential circuit for detecting a difference in output from said first piezoelectric element and said second piezoelectric element. Vibration gyroscope.