JPH09159459A - Vibrating gyro - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vibrating gyro which comprises a stable temperature- sensitivity change-rate characteristic. SOLUTION: A vibrating gyro 20 comprises a vibrator 22. Piezoelectric elements 26a, 26b at the vibrator 22 are grounded via resistances 28a, 28b. The piezoelectric elements 26a, 26b are connected to two input ends of an oscillation circuit 30. One output end of the oscillation circuit 30 is connected to a piezoelectric element 26c. The piezoelectric elements 26a, 26b are connected to the noninverting input terminal and the inverting input terminal of a differential amplifier circuit 32. The output end of the differential amplifier circuit 32 is connected to one input end of a synchronous detection circuit 34. The other output end of the oscillation circuit 30 which outputs a synchronizing signal is connected to the other input end of the synchronous detection circuit 34 via a phase-shifting circuit 36 which adjusts the phase of the synchronizing signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration gyro, and more particularly to a vibration gyro that detects a detection signal corresponding to a rotational angular velocity in synchronization with a synchronization signal.

[0002]

2. Description of the Related Art FIG. 9 is an illustrative view showing one example of a conventional vibrating gyroscope. The vibration gyro 1 shown in FIG. 9 includes a vibrator 2. The vibrator 2 includes a vibrator 3 having a regular triangular prism shape. The vibrating body 3 is formed of a constant elastic metal material such as elinvar. Three piezoelectric elements 4a, 4b and 4c are respectively formed in the substantially center of the three side surfaces of the vibrating body 3. Each of these piezoelectric elements 4a to 4c includes a piezoelectric body layer made of ceramic, electrodes are formed on both main surfaces of the piezoelectric body layer, and an electrode on one main surface of the piezoelectric body layer is formed on a side surface of the vibrating body 3. The electrodes are adhered and the electrodes on the other main surface of the piezoelectric layer are used for input / output of signals.

In this vibrator 2, the two piezoelectric elements 4a and 4b are used for feedback and detection, and the other piezoelectric element 4c is used for driving. for that reason,
The two piezoelectric elements 4a and 4b are grounded via resistors 5a and 5b serving as detection resistors. Further, the two piezoelectric elements 4 a and 4 b are respectively connected to the two input ends of the oscillation circuit 6. One output end of the oscillation circuit 6 is connected to the piezoelectric element 4c. Further, the two piezoelectric elements 4a and 4b are connected to the non-inverting input terminal and the inverting input terminal of the differential amplifier circuit 7, respectively. The output terminal of the differential amplifier circuit 7 is connected to one input terminal of the synchronous detection circuit 8. The other output end of the oscillation circuit 6 is connected to the other input end of the synchronous detection circuit 8. The output end of the synchronous detection circuit 8 is connected to the input end of the smoothing circuit 9. The output end of the smoothing circuit 9 is connected to the input end of the DC amplification circuit 10.

In the vibrating gyro 1 shown in FIG. 9, the drive signal output from one output end of the oscillation circuit 6 is the piezoelectric element 4.
When applied to c, the vibrating body 3 vibrates in a direction orthogonal to the main surface of the piezoelectric element 4c. When the vibrating gyro 1 rotates about the axis of the vibrating body 3 in this state, the vibration direction of the vibrating body 3 changes due to the Coriolis force. Then, a detection signal corresponding to the rotational angular velocity is generated between the two piezoelectric elements 4a and 4b. This detection signal is a signal of the difference between the output signal of the piezoelectric element 4a and the output signal of the piezoelectric element 4b, and is detected by the differential amplifier circuit 7. The output signal of the differential amplifier circuit 7, that is, the detection signal, is detected by the synchronous detection circuit 8 in synchronization with the synchronous signal output from the other output end of the oscillation circuit 6, and the output signal of the synchronous detection circuit 8 is a smoothing circuit. Smoothed at 9,
The output signal of the smoothing circuit 9 is amplified by the DC amplifier circuit 10. Therefore, the vibration gyro 1 can detect the rotational angular velocity from the output signal of the DC amplification circuit 10.

[0005]

However, in the vibration gyro 1 shown in FIG. 9, the condition around the vibrator 2, for example, the phase rotation degree between the piezoelectric elements and the resistance value of the resistance such as the detection resistance connected to the piezoelectric element. If the value is changed, the detection signal and the synchronization signal are out of phase, the detection signal detection efficiency changes, and the sensitivity, the temperature-sensitivity change rate characteristic, and the temperature-drift characteristic change.

For example, in the vibration gyro 1 shown in FIG. 9, when the impedances of the resistors 5a and 5b are matched to the impedances of the piezoelectric elements 4a and 4b in the matching state (when matched to the impedances in the matching state). Piezoelectric elements 4a and 4
FIG. 1 shows the phase relationship between each output signal of FIG.
0 (A), each of the piezoelectric elements 4a and 4b when the impedance of each of the resistors 5a and 5b is made larger than the impedance of each of the piezoelectric elements 4a and 4b in the matching state (when set to be larger than the impedance of the matching state). 10 (B) shows the phase relationship between the output signal and the synchronizing signal of FIG.
The respective impedances of b are set to the piezoelectric elements 4a and 4
FIG. 10 (C) shows the phase relationship between the output signals of the piezoelectric elements 4a and 4b and the synchronization signal when the impedances are made smaller than the respective impedances in the matching state of b (when the impedances are made smaller than the impedance in the matching state). FIG. 11 shows the temperature-sensitivity change rate characteristics based on the sensitivity of 25 ° C. at that time. The impedance Z of the matching state of the piezoelectric element is f
And the capacitance of the piezoelectric element is C, Z = 1 /
It is represented by (2πfC). Further, the piezoelectric elements 4a and 4b when the rotational angular velocity is not applied to the vibration gyro 1
Output signals are almost the same, but in FIG.
FIG. 10B and FIG. 10C show an example of output signals of the piezoelectric elements 4a and 4b when the rotational angular velocity is applied to the vibration gyro 1.

Further, in the vibration gyro 1 shown in FIG. 9, when the temperature changes, the phase of the detection signal and the synchronization signal are deviated due to the temperature characteristics of the piezoelectric element of the vibrator, and the temperature-sensitivity change rate characteristics. Will change.

For example, in the vibration gyro 1 shown in FIG. 9, the phase relationship between the output signals of the piezoelectric elements 4a and 4b and the synchronizing signal at room temperature is shown in FIG. 12 (A).
FIG. 12B shows the phase relationship between the output signals of the piezoelectric elements 4a and 4b at high temperature and the synchronization signal, and shows the phase relationship between the output signals of the piezoelectric elements 4a and 4b at low temperature and the synchronization signal. FIG. 12C shows the temperature-sensitivity change rate characteristics based on the sensitivity of 25 ° C. as shown in FIG. 12 (A), 12 (B) and 12 (C) show examples of output signals from the piezoelectric elements 4a and 4b when the rotational angular velocity is applied to the vibration gyro 1.

Therefore, a main object of the present invention is to provide a vibrating gyro having stable temperature-sensitivity change rate characteristics.

[0010]

According to the present invention, in a vibrating gyroscope for detecting a detection signal corresponding to a rotational angular velocity in synchronization with a synchronization signal, a phase shift circuit for adjusting the phase of the synchronization signal is provided. A characteristic is a vibrating gyro.

In the vibrating gyroscope according to the present invention, the phase shift circuit may be provided with temperature compensating means.

[0012]

In the vibrating gyroscope according to the present invention, the phase of the synchronizing signal is adjusted by the phase shift circuit, and the detection signal is detected with substantially constant efficiency. Therefore, the vibrating gyroscope according to the present invention can obtain stable temperature-sensitivity change rate characteristics.

[0013]

According to the present invention, a vibration gyro having a stable temperature-sensitivity change rate can be obtained.

Further, in the vibrating gyroscope according to the present invention, if the temperature compensation means is provided in the phase circuit, a more stable temperature-sensitivity change rate characteristic can be obtained.

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

[0016]

FIG. 1 is an illustrative view showing one example of an embodiment of the present invention. The vibrating gyro 20 shown in FIG. 1 includes a vibrator 22.

The vibrator 22 includes a vibrating body 24 in the shape of a regular triangular prism, for example. The vibrating body 24 is formed of a constant elastic metal material such as elinvar or iron-nickel alloy.

At the center of the three side surfaces of the vibrating body 24,
Three piezoelectric elements 26a, 26b and 26c are formed respectively. Each of these piezoelectric elements 26a to 26c includes a piezoelectric body layer made of ceramic, electrodes are formed on both main surfaces of the piezoelectric body layer, and an electrode on one main surface of the piezoelectric body layer is formed on a side surface of the vibrating body 24. The electrodes are adhered and the electrodes on the other main surface of the piezoelectric layer are used for input / output of signals.

In this vibrator 22, two piezoelectric elements 26 are provided.
a and 26b are used for feedback and detection, and another piezoelectric element 26c is used for driving. Therefore, the two piezoelectric elements 26a and 26b are grounded via the resistors 28a and 28b serving as detection resistors.

Two piezoelectric elements 26a and 26b are also provided.
Are respectively connected to two input ends of the oscillation circuit 30. One output end of the oscillation circuit 30 is connected to the piezoelectric element 26c.

Further, two piezoelectric elements 26a and 26 are provided.
b is connected to the non-inverting input terminal and the inverting input terminal of the differential amplifier circuit 32, respectively. The output end of the differential amplifier circuit 32 is connected to one input end of the synchronous detection circuit 34. The other output end of the oscillation circuit 30 is connected to the other input end of the synchronous detection circuit 34 via a phase shift circuit 36. The phase shift circuit 36 is for adjusting the phase of the synchronization signal output from the other output end of the oscillation circuit 30, and for example, as shown in FIG.
b.

The output terminal of the synchronous detection circuit 34 is connected to the smoothing circuit 3
8 input terminals. The output end of the smoothing circuit 38 is connected to the input end of the DC amplification circuit 40.

In this vibrating gyro 20, the oscillation circuit 30
The drive signal output from one output end of the piezoelectric element 26
When applied to c, the vibrating body 24 vibrates in a direction orthogonal to the main surface of the piezoelectric element 26c. Vibration gyro 2 in this state
When 0 rotates about the axis of the vibrating body 24, the vibration direction of the vibrating body 24 changes due to the Coriolis force. Therefore, the two piezoelectric elements 26a and 2a that function as detection elements
A detection signal corresponding to the rotational angular velocity is generated between 6b.

This detection signal is a difference signal between the output signal of the piezoelectric element 26a and the output signal of the piezoelectric element 26b, and is detected by the differential amplifier circuit 32. The output signal of the differential amplifier circuit 32, that is, the detection signal is detected by the synchronous detection circuit 34 in synchronization with the synchronous signal. This synchronizing signal is transmitted to the oscillation circuit 30.
Is output from the other output end of the phase shift circuit 36, and the phase thereof is adjusted by the phase shift circuit 36 so as to be substantially in phase with the phase of the detection signal.
Therefore, the detection signal is detected by the synchronous detection circuit 34 with a substantially constant and substantially maximum efficiency.

The output signal of the synchronous detection circuit 34 is
The output signal of the smoothing circuit 38 is smoothed by the smoothing circuit 38, and is amplified by the DC amplification circuit 40. Therefore, in the vibration gyro 20, the rotational angular velocity can be detected from the output signal of the DC amplification circuit 40.

In the vibrating gyro 10, the phase of the synchronizing signal is adjusted by the phase shift circuit 36, and the detection signal is detected by the synchronous detecting circuit 34 with substantially constant efficiency. Therefore, in the vibrating gyro 10, stable temperature-sensitivity change rate characteristics can be obtained.

That is, in this vibrating gyro 10, the sensitivity of 25 ° C. is obtained when the phase shift circuit 36 is not provided (before the phase compensation of the synchronizing signal) and when the phase circuit 36 is provided (after the phase compensation of the synchronizing signal). FIG. 3 shows the temperature-sensitivity change rate characteristics based on the standard. As is clear from the graph shown in FIG. 3, if the phase of the synchronizing signal is compensated by the phase shift circuit 36, stable temperature-sensitivity change rate characteristics can be obtained.

Further, in this vibrating gyro 10, the phase of the sync signal is adjusted to be substantially in phase with the phase of the detection signal, so that the detection signal is detected with almost maximum efficiency,
High sensitivity. That is, when the angular velocity of the detection signal and the synchronization signal is ω and the phase difference between the detection signal and the synchronization signal is α, the detection efficiency of the detection signal detected in synchronization with the synchronization signal is expressed by the following equation. .

[0029]

[Equation 1]

From the above equation, if the phase of the synchronization signal is adjusted to be substantially in phase with the phase of the detection signal, the phase difference α between the detection signal and the synchronization signal becomes almost 0, and the detection efficiency of the detection signal is almost the same. It turns out to be the maximum.

Further, in this vibrating gyroscope 10, if the phase shift circuit 36 is provided with temperature compensating means, more stable temperature-sensitivity change rate characteristics can be obtained.

That is, in the vibrating gyro 10, the capacitor 36a and the resistor 36b of the phase shift circuit 36 are arranged.
As a result, a case of using a capacitor and a resistor having flat temperature characteristics (before temperature compensation) and a case of using a temperature compensating capacitor and a resistor having a positive temperature coefficient of resistance (after temperature compensation) are used. FIG. 4 shows the temperature-sensitivity change rate characteristics based on the sensitivity of ° C. As is clear from the graph shown in FIG. 4, if the phase shift circuit 36 is provided with the temperature compensation means, a more stable temperature-sensitivity change rate characteristic can be obtained.

The phase shift circuit is not limited to the phase shift circuit shown in FIG. 2, but a phase shift circuit using resistors, capacitors and inductors as shown in FIG. 5 and an operational amplifier, a resistor, as shown in FIG. A phase shift circuit using a capacitor may be used.

Further, as the resistance and the capacitor serving as the temperature compensating means provided in the phase shift circuit, a thermistor, a temperature compensating resistor, a diffusion resistor having a temperature characteristic and a temperature compensating capacitor are used.

FIG. 7 is an illustrative view showing another example of the embodiment of the present invention. The vibrating gyro shown in FIG. 7 is different from the vibrating gyro shown in FIG. 1 in that only two piezoelectric elements 26a and 26b are formed in the vibrating body 24, and these piezoelectric elements 26a and 26b are used for driving and detecting. To be Therefore, the two output terminals of the oscillation circuit 30 are connected to the two piezoelectric elements 26a and 26b, respectively. In the vibration gyro shown in FIG. 7, the resistors 28a and 28b, the differential amplifier circuit 32, the synchronous detection circuit 34, the phase shift circuit 36, the smoothing circuit 38, and the DC amplification circuit 40 are
It is connected similarly to the vibrating gyro shown in FIG.

In the vibration gyro shown in FIG. 7, the oscillation circuit 3
The drive signals output from the two output terminals of 0 are given to the two piezoelectric elements 26a and 26b, but operate in the same manner as the vibration gyro shown in FIG. 1, and a stable temperature-sensitivity change rate characteristic is obtained and sensitivity is increased. Is high.

FIG. 8 is an illustrative view showing still another example of the embodiment of the present invention. Compared with the vibration gyro shown in FIG. 1, the vibration gyro shown in FIG. 8 has two piezoelectric elements 26a.
And 26b are used for driving and detection, and the other one piezoelectric element 26c is used for feedback. Therefore, the piezoelectric element 26c is connected to the input end of the oscillation circuit 30 via the resistance 29 serving as a load resistance, and one output end of the oscillation circuit 30 is connected to the piezoelectric elements 26a and 26b via the resistances 28a and 28b serving as detection resistances. Connected to. In addition,
In the vibration gyro shown in FIG. 8, the differential amplifier circuit 32, the synchronous detection circuit 34, the phase shift circuit 36, the smoothing circuit 38, and the DC amplification circuit 40 are connected in the same manner as the vibration gyro shown in FIG.

In the vibration gyro shown in FIG. 8, the oscillation circuit 3
The drive signal output from one output terminal of 0 is applied to the two piezoelectric elements 26a and 26b, but operates in the same manner as the vibration gyro shown in FIG. 1 to obtain stable temperature-sensitivity change rate characteristics and sensitivity. Is high.

In each of the above-described embodiments of the present invention, a regular triangular prism-shaped vibrating body is used. However, in the present invention, a cylindrical vibrating body, a rectangular prism-shaped vibrating body, or others. The columnar vibrating body may be used.

In each of the above-described embodiments of the invention, a vibrator in which a piezoelectric element is formed on a vibrating body made of a metal material is used, but in the present invention, a columnar vibrating body made of a piezoelectric body is used. A vibrator having electrodes formed on the surface of the body may be used.

[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 circuit diagram showing a phase shift circuit used in the vibration gyro shown in FIG.

FIG. 3 is a graph showing temperature-sensitivity change rate characteristics before and after phase compensation of the synchronization signal of the vibration gyro shown in FIG.

FIG. 4 is a graph showing temperature-sensitivity change rate characteristics of the vibration gyro shown in FIG. 1 before and after temperature compensation.

FIG. 5 is a circuit diagram showing another example of a phase shift circuit.

FIG. 6 is a circuit diagram showing another example of a phase shift circuit.

FIG. 7 is an illustrative view showing another example of the embodiment of the present invention.

FIG. 8 is an illustrative view showing still another example of the embodiment of the present invention.

FIG. 9 is an illustrative view showing one example of a conventional vibrating gyroscope;

10 is an output of the piezoelectric element when the impedance of the resistance is matched with the impedance of the matching state of the piezoelectric element, when the impedance of the matching element is larger than the impedance of the matching state, and when the impedance of the resistance is smaller than the impedance of the matching state in the vibration gyro shown in FIG. It is a graph which shows the phase relationship of a signal and a synchronizing signal.

FIG. 11 is a graph showing the temperature-sensitivity change when the impedance of the resistor is matched with the impedance of the matching state of the piezoelectric element, when the impedance of the matching element is larger than the impedance of the matching state and when the impedance of the resistance is smaller than the impedance of the matching state in the vibration gyro shown in FIG. It is a graph which shows a rate characteristic.

12 is a graph showing the phase relationship between the output signal of the piezoelectric element and the synchronizing signal at normal temperature, high temperature, and low temperature of the vibration gyro shown in FIG.

13 is a graph showing temperature-temperature change rate characteristics of the vibration gyro shown in FIG.

[Explanation of symbols]

 20 Vibration Gyro 22 Vibrator 24 Vibrator 26a, 26b, 26c Piezoelectric element 28a, 28b Resistance 30 Oscillation circuit 32 Differential amplification circuit 34 Synchronous detection circuit 36 Phase shift circuit 38 Smoothing circuit 40 DC amplification circuit

Claims (2)

[Claims] 1. A vibrating gyroscope for detecting a detection signal according to a rotational angular velocity in synchronization with a synchronizing signal, wherein a phase shift circuit for adjusting the phase of the synchronizing signal is provided. 2. The vibration gyro according to claim 1, wherein temperature compensation means is provided in the phase shift circuit.