JPH10132574A - Oscillating gyroscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sensitive oscillating gyroscope to detect a rotation angular speed. SOLUTION: An oscillating gyroscope 10 includes an oscillator 12, which produces a phase difference of 45 degrees between its input and output signal. Two split electrodes 16a and 16b (or output ends of the oscillator 12) are connected to an input end of a 45 degrees phase-shifting circuit 32 (or an oscillation circuit 30) through resistances 24a and 24b. An output end of a 90 degrees phase-shifting circuit 36 (or the oscillation circuit 30) is connected to a common electrode 18 (or an input end of the oscillator 12). The oscillation circuit 30 produces a phase difference of 315 degrees between its input and output signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibrating gyroscope, and more particularly to, for example, a navigation system that detects a position of a moving body by detecting a rotational angular velocity and performs appropriate guidance, or a rotational angular velocity due to external vibration such as camera shake. The present invention relates to a vibration gyro that can be applied to a vibration isolation system such as a camera shake prevention device that detects vibrations and performs appropriate vibration suppression.

[0002]

2. Description of the Related Art FIG. 7 is an illustrative view showing one example of a conventional vibrating gyroscope. The vibrating gyroscope 1 shown in FIG. The vibrator 2 includes a regular quadrangular prism-shaped vibrating body 3. The vibrating body 3 is a strip-shaped first piezoelectric substrate 3 that is laminated and bonded.
a and the second piezoelectric substrate 3b. The first piezoelectric substrate 3a and the second piezoelectric substrate 3b are polarized in directions opposite to each other as indicated by an arrow P in FIG. On the main surface of the first piezoelectric substrate 3a, two divided electrodes 4a and 4b are formed at intervals in the width direction. A common electrode 5 is formed on the main surface of the second piezoelectric substrate 3b. Further, a dummy electrode 6 is formed between the first piezoelectric substrate 3a and the second piezoelectric substrate 3b.

The two divided electrodes 4a and 4b of the vibrator 2
Has one output terminal of the oscillation circuit 7 connected to the resistors 8a and 8
b. Further, the common electrode 5 of the vibrator 2
Is connected to the other output terminal of the oscillation circuit 7. Also,
The two divided electrodes 4a and 4b of the vibrator 2 have a resistance 8c
And 8d, a differential amplifier circuit 9 as a detection circuit
Are connected to the non-inverting input terminal and the inverting input terminal, respectively. Further, a resistor 8e is connected between the output terminal and the inverted input terminal of the differential amplifier circuit 9.

In a vibrating gyroscope 1 shown in FIG. 7, a driving signal output from an oscillation circuit 7 is supplied between a common electrode 5 and two divided electrodes 4a and 4b of a vibrator 2 via resistors 8a and 8b. Applied. Due to this drive signal, the first piezoelectric substrate 3a and the second piezoelectric substrate 3b vibrate in opposite directions to each other. As a result, the vibrator 2 moves the first piezoelectric substrate 3a and the second piezoelectric substrate 3b. Bending vibration occurs in the direction perpendicular to the main surface. When the vibrator 2 is not rotating,
Similar detection signals are obtained from the divided electrodes 4a and 4b. When a non-zero rotational angular velocity about the center axis of the vibrating body 3 is applied to the vibrator 2, the direction of the bending vibration of the vibrator 2 changes due to the Coriolis force, and the two divided electrodes 4a
And 4b, a detection signal corresponding to the rotational angular velocity is obtained. In this case, for example, the voltage of the detection signal from one divided electrode 4a increases and the voltage of the detection signal from the other divided electrode 4b decreases according to the rotational angular velocity. Therefore, in the vibration gyro 1, the signal between the divided electrodes 4a and 4b, that is, the differential amplifier 9
, The rotational angular velocity can be detected.

[0005]

However, in the vibrating gyroscope 1 shown in FIG. 7, the phase of the signal between the common electrode 5, the two divided electrodes 4a and 4b of the vibrator 2 and the oscillation circuit 7 is not considered. , Stable oscillation is not performed. Therefore, the vibrator 2 does not bend and vibrate with a large amplitude, and the sensitivity for detecting the rotational angular velocity is low.

[0006] Therefore, a main object of the present invention is to provide a vibrating gyroscope with high sensitivity for detecting a rotational angular velocity.

[0007]

The present invention provides, for example,
In the vibrating gyroscope 1 shown in FIG. 7, two divided electrodes 4 are set based on the signal phase at the common electrode 5 of the vibrator 2.
It was conceived by finding that the phase of the signals at a and 4b lagged 45 degrees. That is, the vibrating gyroscope according to the present invention includes a vibrator in which a signal phase at an output terminal is delayed by 45 degrees with respect to a signal phase at an input terminal, an input terminal connected to an output terminal of the vibrator, and an output terminal A vibrating gyroscope connected to the input end of the vibrator and including an oscillation circuit for bending and vibrating the vibrator, wherein a phase difference between a signal at an input / output end of the vibrator and a signal between a signal at an input / output end of the oscillator This is a vibrating gyroscope in which the sum with the phase difference is an integral multiple of 360 degrees.

In the vibrating gyroscope according to the present invention, the phase of the signal at the output terminal of the oscillation circuit is, for example, 31 with respect to the phase of the signal at the input terminal of the oscillation circuit.
5 degrees late.

In the vibrating gyroscope according to the present invention, the oscillation circuit includes, for example, a phase shift circuit.

[0010]

In the vibrating gyroscope according to the present invention, the phase of the signal at the output terminal of the vibrator is delayed by 45 degrees with respect to the phase of the signal at the input terminal of the vibrator. Since the sum of the phase difference and the phase difference between the signals at the input and output terminals of the oscillation circuit is an integral multiple of 360 degrees, stable oscillation is performed. Therefore, the vibrator bends and vibrates with a large amplitude, and the sensitivity for detecting the rotational angular velocity increases.

[0011]

According to the present invention, a vibrating gyroscope with high sensitivity for detecting a rotational angular velocity can be obtained.

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

[0013]

FIG. 1 is an illustrative view showing one example of an embodiment of the present invention, and FIG. 2 is a perspective view showing a vibrator used in the vibrating gyroscope shown in FIG. The vibrating gyroscope 10 shown in FIG.

As shown in FIG. 2, the vibrator 12 includes, for example, a regular quadrangular prism-shaped vibrator 14, and the vibrator 14 includes, for example, a strip-shaped first piezoelectric substrate 14a and a second piezoelectric substrate 14a. 14b. The first piezoelectric substrate 14a and the second piezoelectric substrate 14b are stacked and bonded. Also,
First piezoelectric substrate 14a and second piezoelectric substrate 14b
Are polarized in opposite thickness directions, as indicated by the arrow P in FIG. In addition, the first piezoelectric substrate 14a and the second
The direction of polarization of the piezoelectric substrate 14b may be a direction facing each other.

On the main surface of the first piezoelectric substrate 14a, two split electrodes 16a and 1
6b is formed. A common electrode 18 is formed on the main surface of the second piezoelectric substrate 14b. Further, between the first piezoelectric substrate 14a and the second piezoelectric substrate 14b,
A dummy electrode 20 is formed. Note that this dummy electrode 2
0 may not be formed.

In the vibrator 12, the first piezoelectric substrate 1
Since the 4a and the second piezoelectric substrate 14b are polarized in opposite thickness directions, if a drive signal such as a sine wave signal is applied between the two divided electrodes 16a and 16b and the common electrode 18, for example, The first piezoelectric substrate 14a and the second piezoelectric substrate 14b vibrate in opposite directions. In this case, when the first piezoelectric substrate 14a extends in a direction parallel to the main surface, the second piezoelectric substrate 14b contracts in a direction parallel to the main surface. Conversely, when the first piezoelectric substrate 14a is contracted in a direction parallel to its main surface, the second piezoelectric substrate 14b extends in a direction parallel to its main surface. Therefore, as shown in FIG. 3, the first piezoelectric substrate 14a and the second piezoelectric substrate 14b are arranged such that a portion slightly inside from both ends in the longitudinal direction is a node portion, and the first piezoelectric substrate 14a and the second piezoelectric substrate 14b are orthogonal to the main surface. Bending vibration. Therefore, for example, a linear support member 22 is attached near the node portion of the vibrator 12, as shown in FIG. The vibrator 12 is supported by these support members 22. Even if the support member 22 is attached near the node portion on the upper surface or the lower surface of the vibrator 12, the vibrator 12 can be supported without greatly affecting the vibration.

In order to apply the above-mentioned drive signal to the vibrator 12, between the two divided electrodes 16a and 16b of the vibrator 12 and the common electrode 18, as shown in FIG.
The oscillation circuit 30 is connected via the resistors 24a and 24b. That is, the oscillation circuit 30 sets the phase of the signal to 45.
The circuit includes a 45-degree phase shift circuit 32 for delaying the phase shifter 32, and two input electrodes 16a and 16b of the vibrator 12 are connected to input terminals of the 45-degree phase shift circuit 32 via resistors 24a and 24b. An output terminal of the 45-degree phase shift circuit 32 is an inverting amplifier circuit 3 for inverting the polarity of the signal and amplifying the amplitude of the signal.
4 is connected to the input terminal. The output terminal of the inverting amplifier 34 is a 90-degree phase shifter 3 for delaying the phase of the signal by 90 degrees.
6 is connected to the input terminal. The output terminal of the 90-degree phase shift circuit 36 is connected to the common electrode 18 of the vibrator 12. Therefore, in this oscillation circuit 30, the phase of the signal at the output terminal thereof is 31 based on the phase of the signal at the input terminal thereof.
5 degrees late.

The two divided electrodes 16a of the vibrator 12
And 16b are connected to the detection circuit 40. That is, the detection circuit 40 includes the differential amplifier circuit 42, and the two divided electrodes 16a and 16b of the vibrator 12 are connected to the non-inverting input terminal and the inverting input terminal of the differential amplifier circuit 42, respectively. An output terminal of the differential amplifier circuit 42 is connected to a synchronous detection circuit 44 for synchronously detecting an output signal of the differential amplifier circuit 42.
Is connected to the input terminal of The output terminal of the synchronous detection circuit 44
It is connected to the input terminal of a smoothing circuit 46 for smoothing the output signal of the synchronous detection circuit 44. An output terminal of the smoothing circuit 46 is connected to an input terminal of an amplifier circuit 48 for amplifying an output signal of the smoothing circuit 46.

In the vibration gyro 10, the oscillation circuit 30
A drive signal such as a sine wave signal output from the output terminal of the vibrator 12
The driving signal is applied to a common electrode 18 used as an input terminal of the oscillator 12, and a driving signal is supplied from two divided electrodes 16 a and 16 b used as an output terminal of the vibrator 12 to a resistor 24.
The signal is fed back to the input terminal of the oscillation circuit 30, that is, the input terminal of the 45-degree phase shift circuit 32 via a and 24 b.

The first drive signal of the vibrator 12 is
The piezoelectric substrate 14a and the second piezoelectric substrate 14b are
As shown in FIG. 3, the bending vibration occurs in a direction orthogonal to the main surface.

In this state, the vibrating gyroscope 10 is
2 around a central axis O (FIG. 2), a Coriolis force corresponding to the rotational angular velocity is parallel to the main surfaces of the first piezoelectric substrate 14a and the second piezoelectric substrate 14b and the vibrator 12 In the direction orthogonal to the central axis O of Therefore, the direction of the bending vibration of the vibrator 12 changes. Therefore, the two divided electrodes 16a and 16b also used as a detection end
During that time, a signal corresponding to the rotational angular velocity is generated.

The two split electrodes 16a and 16
b occurs between the differential amplifier circuit 4 of the detection circuit 40
2 is detected. The output signal of the differential amplifier circuit 42 is synchronously detected by the synchronous detection circuit 44,
4 is smoothed by a smoothing circuit 46.
The output signal of No. 6 is amplified by the amplifier circuit.

Therefore, in this vibration gyro 10,
The rotation angular velocity can be known from the output signal of the detection circuit 40.

In this vibrating gyroscope 10, the signal phase at the two divided electrodes 16a and 16b used as output terminals is 45 based on the signal phase at the common electrode 18 used as the input terminal of the vibrator 12. And the phase of the signal at the output terminal of the oscillation circuit 30 is delayed by 315 degrees with respect to the phase of the signal at the input terminal of the oscillation circuit 30, that is, the phase difference between the signals at the input and output terminals of the vibrator 12 and Since the sum with the phase difference between the signals at the input and output terminals of the oscillation circuit 30 is 360 degrees,
Stable oscillation is performed. Therefore, the vibrator 12 bends and vibrates with a large amplitude, and the sensitivity for detecting the rotational angular velocity increases.

Further, in the vibrating gyroscope 10, the supporting member 2 attached near the node portion of the vibrator 12 is provided.
Since the vibrator 12 is supported by 2, the vibrator 12 is not easily leaked from the vibrator 12 to the outside, and the vibrator 12 can be vibrated efficiently.

In the vibrating gyroscope 10 described above, in the vibrator 12, two divided electrodes 16a and 16b are used as an input terminal and a detection terminal, and the common electrode 1
8 may be used as the output end.

Further, in order to perform stable oscillation, in the above-mentioned vibrating gyroscope 10, the sum of the phase difference between signals at the input and output terminals of the vibrator 12 and the phase difference between signals at the input and output terminals of the oscillation circuit 30 is used. Is 360 degrees, but the sum of these phase differences may be other than 360 degrees and an integral multiple of 360 degrees.

Further, in the vibrating gyroscope 10 described above, the vibrating body 14 of the vibrator 12 whose signal phase at the output end is delayed by 45 degrees with respect to the phase of the signal at the input end is formed of a piezoelectric body. As described above, the vibrating body 14 of the vibrator 12 whose signal phase is delayed by 45 degrees may be formed of a metal such as a Ni alloy as shown in FIGS. 4, 5 and 6, for example.

The vibrator 12 shown in FIG. 4 includes a vibrating body 14 formed of a metal such as a Ni alloy into a regular triangular prism shape. Two piezoelectric elements 50a and 50b are formed substantially at the center of two side surfaces of the vibrating body 14, respectively.
Piezoelectric elements 50a and 50b include piezoelectric layers 52a and 52b polarized in the thickness direction. Electrodes 54a and 54b are formed on one main surface of piezoelectric layers 52a and 52b, and the other of piezoelectric layers 52a and 52b. Electrodes 56a and 56b are formed on the main surface. The electrode 54a
And 54b are adhered to the side surface of the vibrating body 14.

In the vibrator 12 shown in FIG. 4, the vibrating body 14 is used as an input terminal, and the electrodes 56a and 56b
Are used as output and detection ends, or
The vibrating body 14 is used as an output terminal, and the electrode 56a
And 56b are used as an input end and a detection end.

In the vibrator 12 shown in FIG. 4, the electrodes 54a and 54b need not be formed. This is because the vibrating body 14 also functions as those electrodes.

The vibrator 12 shown in FIG. 5 includes a vibrating body 14 formed of a metal such as a Ni alloy in a regular quadrangular prism shape. A piezoelectric layer 58 polarized in the thickness direction is formed substantially at the center of one side surface of the vibrating body 14, and two electrodes 60a and 60b are formed on the surface of the piezoelectric layer 58 with a space therebetween. Is done.

The vibrator 12 shown in FIG. 6 includes a vibrating body 14 formed of a metal such as a Ni alloy into a regular triangular prism shape. A piezoelectric layer 58 polarized in the thickness direction is formed substantially at the center of one side surface of the vibrating body 14, and two electrodes 60a and 60b are formed on the surface of the piezoelectric layer 58 with an interval therebetween. Is done.

In the vibrator 12 shown in FIGS. 5 and 6, the vibrator 14 is used as an input terminal and the electrodes 60a and 60b are used as an output terminal and a detection terminal, respectively. It is used as an output end, and the electrodes 60a and 60b are used as an input end and a detection end.

[Brief description of the drawings]

FIG. 1 is an illustrative view showing one example of an embodiment of the present invention;

FIG. 2 is a perspective view showing a vibrator used in the vibrating gyroscope shown in FIG.

FIG. 3 is an illustrative side view showing a state of bending vibration of the vibrator shown in FIG. 2;

FIG. 4 is an illustrative view showing another example of the vibrator;

FIG. 5 is an illustrative view showing still another example of the vibrator.

FIG. 6 is an illustrative view showing a modified example of the vibrator;

FIG. 7 is an illustrative view showing one example of a conventional vibrating gyroscope;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Vibration gyroscope 12 Vibrator 14 Vibrator 14a First piezoelectric substrate 14b Second piezoelectric substrate 16a, 16b Split electrode 18 Common electrode 20 Dummy electrode 22 Support members 24a, 24b Resistance 30 Oscillation circuit 32 45 degree phase shift circuit 34 inverting amplifier circuit 36 90-degree phase shift circuit 40 detection circuit 42 differential amplifier circuit 44 synchronous detection circuit 46 smoothing circuit 48 amplifier circuit 50a, 50b piezoelectric element 52a, 52b piezoelectric layer 54a, 54b electrode 56a, 56b electrode 58 piezoelectric body Layer 60a, 60b Electrode

Claims (3)

[Claims] 1. A vibrator wherein the phase of a signal at an output terminal is delayed by 45 degrees with respect to the phase of a signal at an input terminal, and an input terminal is connected to an output terminal of the vibrator, and an output terminal is an input terminal of the vibrator. A vibrating gyroscope connected to an end of the vibrator, the vibrating gyroscope including an oscillator circuit for bending the vibrator, wherein a phase difference between signals at input / output terminals of the vibrator and a phase difference between signals at input / output terminals of the oscillator circuit. Sum with the difference is 36
A vibrating gyro that is an integral multiple of 0 degrees. 2. The vibrating gyroscope according to claim 1, wherein a phase of a signal at an output terminal of the oscillation circuit is delayed by 315 degrees with respect to a phase of a signal at an input terminal of the oscillation circuit. 3. The vibrating gyroscope according to claim 1, wherein the oscillation circuit includes a phase shift circuit.