JPH06241814A - Gyro output detection method - Google Patents

Abstract

PURPOSE:To obtain a detection circuit which can reduce drifting without using a variable resistor etc. CONSTITUTION:Two piezoelectric elements 16a and 16b for detecting a vibration gyro 12 are connected to a differential amplification circuit 38 and a cumulative amplification circuit 48. The output of the differential amplification circuit 38 is detected by a first synchronization detection circuit 40 and further is smoothed by a first smoothing circuit 42. The output of the cumulative amplification circuit 48 is detected by a second synchronization detection circuit 50 and further is smoothed by a second smoothing circuit 52. The output of the first smoothing circuit 42 and the second smoothing circuit 52 is output from a synthesis circuit 54.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gyro output detecting method, and more particularly, to a gyro output detecting method for measuring the output of a columnar vibrating gyro utilizing bending vibration.

[0002]

2. Description of the Related Art FIG. 7 is a block diagram showing an example of a detection circuit used in a conventional gyro output detection method which is the background of the present invention. The detection circuit 1 is used to measure the output of a vibrating gyro 2 having a triangular prism shape, for example.

An oscillation circuit 5 is connected between the two piezoelectric elements 3 of the vibrating gyro 2 and another piezoelectric element 4. The oscillation circuit 5 is connected to the piezoelectric element 3 via the resistor 6. Further, the outputs of these piezoelectric elements 3 are input to the differential circuit 7. The output of the differential circuit 7 is synchronously detected by the synchronous detection circuit 8. Then, the detected signal is the DC amplification circuit 9
Is amplified by.

The oscillation circuit 5 causes the vibrating gyro 2 to
Flexural vibration occurs in a direction orthogonal to the surface on which the piezoelectric element 4 is formed. In this state, when the vibration gyro 2 is rotated about the long axis, the direction of the bending vibration is changed by the Coriolis force. As a result, a difference in output occurs between the two piezoelectric elements 3 used as detection pieces, and an output is obtained from the differential circuit 7. At this time, the drive signal for driving the vibration gyro 2 is
The signals are in phase and at the same level in the two piezoelectric elements 3. Therefore, the signal for driving the vibration gyro 2 is canceled by the differential circuit 7. Therefore, the differential circuit 7
Outputs only a signal corresponding to the magnitude of the rotational angular velocity. Therefore, the rotational angular velocity applied to the vibration gyro 2 can be measured by synchronously detecting this output and measuring the DC-amplified output.

[0005]

However, due to changes in the ambient temperature and the like, a phase difference occurs between the outputs of the piezoelectric elements for detection, which causes drift. In order to correct such a phase difference, for example, a method of connecting an oscillation circuit and a vibration gyro via a variable resistor and adjusting the variable resistor has been adopted.

Therefore, a main object of the present invention is to provide a gyro output detecting method capable of reducing the drift without using a variable resistor or the like.

[0007]

The present invention provides a gyro output detecting method for measuring the output of a vibrating gyro including a vibrating body having a polygonal prism shape and detection pieces formed on two side surfaces of the vibrating body. The difference between the output signals of the two detection pieces is obtained by a differential circuit, and the sum of the output signals of the two detection pieces is obtained by a summing circuit, and the drift component included in the output signal of the differential circuit is output by the summing circuit. This is a gyro output detection method that corrects with a signal. In this method, the output signal of the synchronous detection circuit can be smoothed by the smoothing circuit, and the output signal of one or both of the detection pieces can be phase-corrected so that the output signal of the smoothing circuit becomes zero. Also, the output signal of the summing circuit is synchronously detected by the synchronous detection circuit, the output signal of the detection circuit is smoothed by the smoothing circuit, the output signal of the differential circuit is synchronously detected by another synchronous detection circuit, and another synchronous detection is performed. The output signal of the circuit may be smoothed by another smoothing circuit, and the output signal of the smoothing circuit and the output signal of the other smoothing circuit may be combined by a combining circuit.

[0008]

The function of calculating the difference and the sum of the output signals of the two detection pieces,
By synchronously detecting each of them and smoothing them, it is possible to obtain DC outputs that are proportional to each other according to the phase difference.
Therefore, if the drive signal for driving the vibrating gyro is adjusted to be 0, even if the drive signals in the two detection pieces have a phase difference due to changes in the ambient temperature or the like, the signal from which the drive signal is always removed is obtained. Can be obtained.

[0009]

According to the present invention, since the drive signal for driving the vibration gyro can be removed, only the signal corresponding to the rotational angular velocity can be taken out. Therefore, even if there is a phase difference between the drive signals of the two detection pieces as a drift amount due to a change in the ambient temperature, the rotational angular velocity can be detected independently of the phase difference. Further, since the influence of such a phase difference is removed, a variable resistor for adjustment or the like becomes unnecessary.

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

[0011]

1 is a block diagram showing an example of a detection circuit used in the gyro output detection method of the present invention. The detection circuit 10 is used to detect the output of the vibration gyro 12, for example. The vibration gyro 12 is shown in FIG.
As shown in (A) and FIG. 2 (B), for example, a vibrating body 14 having a regular triangular prism shape is included. The vibrating body 14 is formed of a material that generally causes mechanical vibration, such as elinvar, iron-nickel alloy, quartz, glass, crystal, and ceramic.

Piezoelectric elements 16a, 16b and 16c are formed in the central portions of the three side surfaces of the vibrating body 14, respectively.
The piezoelectric element 16a includes a piezoelectric layer 18a made of, for example, a piezoelectric ceramic, and electrodes 20 are provided on both surfaces of the piezoelectric layer 18a.
a and 22a are formed. And one electrode 22a
Are bonded to the side surface of the vibrating body 14. Similarly, the piezoelectric elements 16b and 16c include piezoelectric layers 18b and 18c, and electrodes 20b and 22b and electrodes 20c and 22c are formed on both surfaces thereof. Then, one electrodes 22b and 22c of the piezoelectric elements 16b and 16c are bonded to the side surface of the vibrating body 14. Further, the vibrating body 14 is supported near the node points by supporting members 24 and 26 made of, for example, metal wires. These supporting members 24 and 26 are fixed to the vibrating body 14 in the vicinity of the node points by welding, for example.

Piezoelectric elements 16a, 16b and piezoelectric element 16c
An oscillator circuit 34 is connected between the two via resistors 30 and 32. A synchronization signal transmission circuit 36 is connected to the oscillation circuit 34, and a synchronization signal for detection by a synchronization detection circuit described later is transmitted. The piezoelectric elements 16a and 16b are also used as detection pieces for detecting a signal corresponding to the rotational angular velocity. The piezoelectric elements 16a and 16b are the differential amplifier circuit 3
8 and the difference between the output signals of the piezoelectric elements 16a and 16b is obtained. Further, the differential amplifier circuit 38 is connected to the first synchronous detection circuit 40. In the first synchronous detection circuit 40, the output signal of the differential amplifier circuit 38 is synchronously detected by the synchronous signal from the synchronous signal sending circuit 36. The output signal of the first synchronous detection circuit 40 is the first smoothing circuit 4
Smoothed by 2.

The piezoelectric elements 16a and 16b are made up of a resistor 4
The sum of the output signals of the piezoelectric elements 16a and 16b is obtained by being connected to the summing amplification circuit 48 via 4,46. Further, the sum amplification circuit 48 is connected to the second synchronous detection circuit 50. In the second coherent detection circuit 50, the summing amplifier circuit 4 receives the sync signal from the sync signal sending circuit 36.
8 output signals are synchronously detected. Second synchronous detection circuit 5
The output signal of 0 is smoothed by the second smoothing circuit 52.

The output signals of the first smoothing circuit 42 and the second smoothing circuit 52 are input to the combining circuit 54. In the synthesis circuit 54, the output signals of the first smoothing circuit 42 and the second smoothing circuit 52 are synthesized.

In this vibrating gyro 12, the oscillation circuit 34
Thus, the vibrating body 14 flexurally vibrates in the direction orthogonal to the surface on which the piezoelectric element 16c is formed. When the vibrating body 14 is rotated about the major axis in this state, the direction of the flexural vibration is changed by the Coriolis force. As a result, a difference occurs between the output signals of the piezoelectric element 16a and the piezoelectric element 16b. Therefore, the rotational angular velocity applied to the vibration gyro 12 can be detected by measuring the difference between the output signals of the piezoelectric elements 16a and 16b.

The difference between the drive signals in the piezoelectric elements 16a and 16b and the signal generated by the Coriolis force is obtained by the differential amplifier circuit 38, and the sum is obtained by the summing amplifier circuit 48. If there is no drift in the vibrating gyro 12,
As shown in, the drive signals at the output end A1 of the piezoelectric element 16a and the output end A2 of the piezoelectric element 16b are in phase. Therefore, the output signal of the differential amplifier circuit 38 becomes 0, and the output signal of the summing amplifier circuit 48 has the same phase as the drive signal and a high level.

Then, in the first synchronous detection circuit 40 and the second synchronous detection circuit 50, the output signals of the differential amplifier circuit 38 and the summing amplifier circuit 48 are detected in synchronization with the drive signal. When there is no drift component, both drive signals are in phase, so the output terminal B1 of the first synchronous detection circuit 40 is
Becomes 0, and the positive and negative parts of the drive signal are canceled at the output terminal B2 of the second synchronous detection circuit 50. Therefore, the output signal becomes 0 at the output terminal C1 of the first smoothing circuit 42 and the output terminal C2 of the second smoothing circuit 52, respectively. Therefore, at the output terminal D of the combining circuit 54,
The drive signal component becomes zero.

When a rotational angular velocity is applied to the vibrating gyro 12, a voltage is generated in the piezoelectric elements 16a and 16b due to a change in the bending vibration direction of the vibrating body 14 due to the Coriolis force.
These signals, as shown in FIG.
Have a phase difference of. The amplitude and polarity of the signal due to these Coriolis forces change depending on the magnitude and direction of the rotational angular velocity. For example, in the case of FIG. 3, a high level signal is output from the differential amplifier circuit 38, and the output signal from the summing amplifier circuit 48 becomes zero. Therefore, the output signal of the output terminal B1 of the first synchronous detection circuit 40 is the differential amplifier circuit 38.
The positive part of the output signal of is output. Further, the output signal of the output terminal B2 of the second synchronous detection circuit 50 becomes zero.

When such a signal is smoothed, a DC output appears on the positive side at the output terminal C1 of the first smoothing circuit 42, and
The signal at the output terminal C2 of the smoothing circuit 52 becomes 0.
Of course, if the level of the output signal of the piezoelectric element 16b changes, a DC output appears at the output end C1. Then, in the synthesis circuit 54, the first smoothing circuit 42 and the second smoothing circuit 5
The two output signals are differentially combined. Therefore, in the embodiment shown in FIG. 3, the same signal as the signal of the output terminal C1 of the first smoothing circuit 42 is output to the output terminal D of the combining circuit 54.

Next, when there is a drift component in the vibration gyro 12, as shown in FIG. 4, a phase difference occurs between the drive signals in the piezoelectric elements 16a and 16b. in this case,
When the differential amplifier circuit 38 and the summing amplifier circuit 48 output the difference and the sum of the drive signals, signals having a phase difference of 90 ° are obtained, as shown by B1 and B2 in FIG. Then, when these signals are detected in synchronization with the drive signal, the output terminal B1 of the first synchronous detection circuit 40 and the second
From the output terminal B2 of the synchronous detection circuit 52, a signal having a positive portion and a negative portion is output.

When these signals are smoothed, at the output terminal C1 of the first smoothing circuit 42, the difference between the positive and negative parts of the signal at the output terminal B1 is obtained as a DC output. Further, at the output end C2 of the second smoothing circuit 52, the difference between the positive part and the negative part of the signal at the output end B2 is obtained as a DC output. The signals at the output terminals C1 and C2 are transmitted to the piezoelectric elements 16a, 16a.
Since it is proportional to the phase difference of the drive signal in b, if the synthesis circuit 54 performs differential synthesis and adjusts so that the output of the output terminal D becomes 0, the drive signal component changes even if the phase difference of the drive signal changes. It is not output from the detection circuit 10.

As shown in FIG. 4, the signals due to the Coriolis force generated in the piezoelectric elements 16a and 16b have a phase difference of 90 ° with the respective drive signals. Then, the differential circuit 38
When the difference and sum of these signals are output by the summing circuit 48, signals having a phase difference of 90 ° with each other appear. In this embodiment, the level of the output signal of the differential amplifier circuit 38 is smaller than that in the case where there is no phase shift, and the level is generated in the output signal of the sum amplification circuit 48. When these signals are detected in synchronism with the drive signal, a signal including a positive portion and a negative portion is output from the output end B1 of the first synchronous detection circuit 40 and the output end B2 of the second synchronous detection circuit 50, respectively. Is output. When these signals are smoothed, the difference between the positive part and the negative part of the signals at the output terminals B1 and B2 is DC from the output terminal C1 of the first smoothing circuit 42 and the output terminal C2 of the second smoothing circuit 52, respectively. Obtained as output.

Then, in the synthesizing circuit 54, the output terminals C1, C
The two signals are differentially combined. In the embodiment shown in FIG. 4, since the signal at the output end C2 is negative, the level at the output end D of the combining circuit 54 is high. Therefore, the decrease in Coriolis detection due to the phase shift can be compensated. The level and polarity of the signal due to the Coriolis force change depending on the magnitude and direction of the rotational angular velocity applied to the vibration gyro 12, so the level and polarity of the signal appearing at the output terminals C1 and C2 also change. Along with that, the signal at the output end D of the synthesizing circuit 54 also changes, but the rotational angular velocity can be detected by measuring the change.

Although the output signal of the piezoelectric element 16a is delayed from the output signal of the piezoelectric element 16b in the above embodiment, the output signal of the piezoelectric element 16a is delayed.
When leading the output signal of 6b, a negative DC signal is output to the output terminal C1. In this case, the drive signal component can be removed by summing the signals at the output terminals C1 and C2 in the combining circuit 54.

As described above, by using this detection circuit 10, the drive signal can be removed regardless of the presence or absence of the drift component. Therefore, even if there is a phase difference between the drive signals in the piezoelectric elements 16a and 16b, the drive circuit component is not output from the detection circuit 10. Therefore, it is not necessary to attach a variable resistor or the like for adjusting the phase difference of the drive signals as in the conventional case.

Alternatively, the output signal of the output terminal C2 of the second correction circuit 52 may be set to 0 by using the circuits shown in FIGS. In this case, FIG. 5 and FIG.
By adjusting the variable resistor of the circuit shown in FIG.
As shown in, the phases of the drive signals can be matched. Therefore, the drive signal component can be removed from the output of the detection circuit 10 in the same manner as in the case where there is no drift component. Even if such a circuit is used, only the output due to the Coriolis force can be taken out, and the accurate rotational angular velocity can be detected.

In the above-described embodiment, the detection circuit 10 is used for detecting the signal of the vibrating gyro having a regular triangular prism shape. Any device that can detect the difference between the output signals of Further, although the piezoelectric element is used as the detection piece of the vibration gyro, it can also be used for signal detection of the vibration gyro in which electrodes are formed on the vibrating body made of, for example, a columnar piezoelectric ceramic. In this case, the two electrodes formed on the side surface of the vibrating body serve as the detection piece.

[Brief description of drawings]

FIG. 1 is a block diagram showing an example of a detection circuit used in a gyro output detection method of the present invention.

2A is a perspective view showing an example of a vibration gyro detected by the detection circuit shown in FIG. 1, and FIG. 2B is a sectional view thereof.

FIG. 3 is a waveform diagram of a drive signal and a signal due to Coriolis force in each unit when there is no drift amount.

FIG. 4 is a waveform diagram of a drive signal and a signal due to Coriolis force in each unit when there is a drift amount.

FIG. 5 is a circuit diagram showing another embodiment of the present invention.

FIG. 6 is a circuit diagram showing still another embodiment of the present invention.

FIG. 7 is a block diagram showing an example of a detection circuit used in a conventional gyro output detection circuit which is the background of the present invention.

[Explanation of symbols]

 10 Detection Circuit 12 Vibration Gyro 16a, 16b, 16c Piezoelectric Element 38 Differential Amplification Circuit 40 First Synchronous Detection Circuit 42 First Smoothing Circuit 48 Summation Amplifier Circuit 50 Second Synchronous Detection Circuit 52 Second Smoothing Circuit 54 Synthesis circuit

Claims (3)

[Claims] 1. A gyro output detecting method for measuring an output of a vibrating gyro including a vibrating body having a polygonal prism shape, and detection pieces formed on two side surfaces of the vibrating body, wherein outputs of the two detection pieces are provided. The difference between the signals is obtained by a differential circuit, the sum of the output signals of the two detection pieces is obtained by a summing circuit, and the drift component contained in the output signal of the differential circuit is corrected by the output signal of the summing circuit. , Gyro output detection method. 2. The output signal of the summing circuit is synchronously detected by a synchronous detection circuit, the output signal of the synchronous detection circuit is smoothed by a smoothing circuit, and the detection signal is detected so that the output signal of the smoothing circuit becomes zero. The phase correction of the output signal of one or both of one side is carried out.
Gyro output detection method. 3. An output signal of the summing circuit is synchronously detected by a synchronous detection circuit, an output signal of the detection circuit is smoothed by a smoothing circuit, and an output signal of the differential circuit is synchronously detected by another synchronous detection circuit. The gyro output detection according to claim 1, wherein the output signal of the another synchronous detection circuit is smoothed by another smoothing circuit, and the output signal of the smoothing circuit and the output signal of the other smoothing circuit are combined by a combining circuit. Method.