JPH0814913A - Vibration controller - Google Patents

Abstract

PURPOSE:To provide a vibration controller where a detection accuracy can be improved by eliminating the temperature dependency of a detection sensitivity for an input angular velocity when a stable self-excitation vibration without any amplitude fluctuation is performed even if an ambient temperature changes and is applied to a vibration gyro. CONSTITUTION:The vibration controller for exciting and vibrating a vibrator 4 with virtually a pair of piezoelectric elements 2 and 3 on the side surface of a vibrator 1 with a resonance point is provided with a drive device 60 having an automatic gain control circuit and excites and vibrates the vibrator 4 while maintaining the synthesized current value of each current passing through virtually a pair of piezoelectric elements 2 and 3 by the drive device 60.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration control device used in, for example, a piezoelectric vibration gyro, and more particularly to a vibration control device having stable angular velocity detection sensitivity.

[0002]

2. Description of the Related Art As a conventional vibrating gyroscope, for example,
There is one as shown in FIG. In this vibrating gyro, the piezoelectric elements 2 and 3 forming the vibrator 4 are connected to the output side of the driving device 6 via impedance elements Z ₁ and Z ₂ , respectively, and the output side of the driving device 6 is further connected. The capacitor C is also connected via another impedance Z _{3 so} that the driving voltage from the driving device 6 is simultaneously applied to the piezoelectric elements 2 and 3 and the capacitor C.

The outputs at the connection points of the impedance elements Z ₁ and Z ₂ and the piezoelectric elements 2 and 3 are combined, and the combined output and the output at the connection point of the impedance element Z ₃ and the capacitive element C are combined. By supplying the differential output to the differential amplifier 7 and feeding back the differential output to the driving device 6, the vibrator 4 is caused to self-oscillate, and further, these impedance elements Z ₁ and Z ₂ and the piezoelectric elements 2 and 3 are connected. The outputs at the respective connection points are supplied to the other differential amplifier 8 so that the angular velocity detection signal is obtained based on the output of the differential amplifier 8.

Here, for example, as shown in FIG. 14, the vibrator 4 has a quadrangular cross section, and the piezoelectric element 2 is adjacent to one side surface 1a of the vibrating body 1 having a resonance point. The piezoelectric element 3 is formed on each of the other side surfaces 1b, and the piezoelectric elements 2 and 3 are formed on the same side surface of the vibrating body 1 in the width direction as shown in FIG.
1, the piezoelectric elements 2 and 3 are formed on the opposite side surfaces of the vibrating body 1 so as to be displaced in the width direction, or
As shown in FIG. 7, piezoelectric elements 2a and 2b are formed and connected in parallel so that they substantially act as one piezoelectric element 2 on the opposite side surfaces of the vibrating body 1, and
Piezoelectric elements 3a and 3b are formed and connected in parallel so that they substantially act as one piezoelectric element 3 on the other opposing side surfaces.

Further, as another vibrator 4, as shown in FIG. 18, one having piezoelectric elements 2 and 3 formed on two side surfaces of a vibrating body 1 having a triangular cross section and having a resonance point, As shown in FIG. 19, on the side surface of a vibrating body having various cross-sectional shapes, such as one in which the piezoelectric elements 2 and 3 are formed on the circumferential side surface of the vibrating body 1 having a circular cross-sectional shape and having a resonance point. Substantially two piezoelectric elements are used.

Here, as for the vibrator 4, for one piezoelectric element, as shown in an equivalent circuit of FIG. 20, a series resonance circuit of a coil L1, a capacitor C1 and a resistor R1 is connected in parallel with a braking capacitance Cd. Represented as a resonant circuit.
Note that here, as illustrated in FIGS. 14 to 19, a vibrator in which two piezoelectric elements 2 and 3 are substantially formed on the vibrating body 1 is represented as shown in FIG.

In the conventional vibration gyro shown in FIG. 13, the drive signal from the drive device 6 is applied to the impedance element Z.
_{Since the} voltage is applied to the piezoelectric elements 2 and 3 via ₁ and Z ₂ , when the impedance of the piezoelectric elements 2 and 3 decreases near the mechanical series resonance frequency fs of the vibrator 4, the piezoelectric element 2 There is a problem that the frequency at which the output of the differential amplifier 7 is maximized and the mechanical series resonance frequency fs of the oscillator 4 do not match because the level of the signal applied to the signals 3 and 3 decreases.

In order to solve such a problem, the applicant of the present invention has filed Japanese Patent Application Nos. 6-2364 and 6-10348.
No. 6, the oscillator can vibrate and self-excitate stably at the frequency set to the mechanical series resonance frequency fs, and when applied to a vibration gyro, the generation and fluctuation of null voltage can be effectively reduced. A control device has already been proposed.

FIG. 22 shows an example of the configuration of the vibration control device proposed by the applicant. This vibration control device forms substantially two piezoelectric elements 2 and 3 on the side surface of a vibrator 4 as shown in FIGS. 14 to 19, that is, a vibrator 1 having various cross-sectional shapes having resonance points. The signal output terminal 9 of the driving device 6 is used for controlling the vibration of the vibrator 4 formed as described above, and the signal input terminal 1 of the feedback amplifiers 10L and 10R is used.
These feedback amplifiers 10 are connected to 1L and 11R, respectively.
The feedback input terminals 12L and 12R of L and 10R are respectively connected to one electrodes of the piezoelectric elements 2 and 3 to apply a drive signal. The other electrodes of the piezoelectric elements 2 and 3 are connected to the compensation signal output terminal 13 of the driving device 6 which outputs the compensation signal of the braking capacity of the vibrator 4 via the capacitor Cc, whereby the other electrodes of the piezoelectric elements 2 and 3 are connected. The signal on the electrode side and the compensation signal are combined. This combined output is amplified by the summing amplifier 17, and the output terminal 18 of the summing amplifier 17 is amplified.
Is connected to the input terminal 14 of the driving device 6 so that the vibrator 4 is self-excited.

The output of the summing amplifier 17 and the driving signal at the signal output terminal 9 of the driving device 6 are supplied to the differential amplifier 22 for differential amplification, and the output of the differential amplifier 22 is changed to the variable resistor VR. Is supplied to the feedback input terminals 12L and 12R of the feedback amplifiers 10L and 10R, and the feedback input terminals 12L and 12R correspond to the current values flowing through the equivalent resistances of the piezoelectric elements 2 and 3 and their temperature dependence. By causing the currents that change in accordance with the characteristics to flow in and supplying the outputs of the feedback amplifiers 10L and 10R to the differential amplifier 20, the Coriolis force generated by the angular velocity acting on the oscillator 4 is detected as a voltage. I am trying to do it. Between the respective feedback amplifiers 10L, feedback input terminals 12L and the corresponding output of the 10R, 12R side, respectively the feedback resistor Rf _l, connecting the Rf _R.

FIG. 23 shows an example of the configuration of the driving device 6 having the compensation signal output terminal 13 shown in FIG. This drive device 6 has a non-inverting amplifier 15 and an inverting amplifier 16, amplifies the signal from the input terminal 14 by the non-inverting amplifier 15, and supplies the output to the compensation signal output terminal 13 as a compensation signal. The signal is amplified by the inverting amplifier 16 and supplied to the signal output terminal 9 as a drive signal. That is, in the driving device 6, the phase of the drive signal supplied to the signal output terminal 9 and the phase of the compensation signal supplied to the compensation signal output terminal 13 are different by 180 °, and the amplitude ratio of these signals is inverted by an inverting amplifier. 16 is set appropriately.

According to the vibration control device shown in FIG. 22, of the current components flowing through the piezoelectric elements 2 and 3, the imaginary number component relating to each braking capacitance Cd is canceled by the compensation signal synthesized via the capacitor Cc. , Summing amplifier 1
The output of 7 is only the real number component of the current components flowing through the piezoelectric elements 2 and 3. Therefore, the voltage gain of the summing amplifier 17 becomes maximum at the mechanical series resonance frequency fs of the vibrator 4, so that the vibrator 4 is stably self-excited at a frequency exactly matching the mechanical series resonance frequency fs. Can be vibrated. Also, its mechanical series resonance frequency fs
The self-excited vibration can be further stabilized by using, as the capacitor Cc, one having a temperature dependence corresponding to the temperature dependence of the braking capacitance Cd of the vibrator 4.

[0013]

However, as a result of various studies by the present inventor, it was found that the vibration control device proposed by the applicant has the following points to be improved. That is, in the case of the above-mentioned vibrator 4, since the piezoelectric elements 2 and 3 themselves are substantially self-excited to vibrate without providing an independent piezoelectric element for obtaining the feedback output, The amplitude does not fluctuate due to the characteristic difference of the piezoelectric element itself as in the case where a feedback piezoelectric element for self-excited vibration is provided separately from the element. However, since the current passing through the pair of piezoelectric elements 2 and 3 forming the vibrator 4 is determined by the impedance of the vibrator 4, the equivalent resistance, the braking capacity, etc. of the vibrator 4 change due to the change of the ambient temperature. Then, it will change accordingly.

In the above-mentioned vibration control device, the fluctuation due to the temperature change of the braking capacity is compensated by the capacitor Cc, and the fluctuation due to the temperature change of the equivalent resistance causes the output of the differential amplifier 22 to pass through the variable resistor VR and the feedback amplifier 10L ,. The compensation is performed by supplying the feedback input terminals 12L and 12R of 10R.
The control of the combined current value passing through is not performed in response to the temperature change.
The amplitude of the self-excited vibration fluctuates corresponding to the reciprocal of the equivalent resistance, etc., and the amplitude of the vibration corresponding to the input angular velocity in the direction orthogonal to the self-excited vibration direction also fluctuates accordingly, resulting in detection sensitivity. May fluctuate and the detection accuracy may decrease.

The present invention has been made by paying attention to the above points, and it is possible to perform stable self-excited vibration with no amplitude fluctuation even when the ambient temperature changes. Therefore, when applied to a vibration gyro. Another object of the present invention is to provide a vibration control device appropriately configured to eliminate the temperature dependence of the detection sensitivity with respect to the input angular velocity and improve the detection accuracy.

[0016]

In order to achieve the above object, the first invention is a vibration control device for self-exciting a vibrator having a pair of piezoelectric elements substantially on the side surface of a vibrator having a resonance point. A drive device having an automatic gain control circuit, and the drive device vibrates the vibrator self-excited while maintaining a constant combined current value of the respective currents passing through the pair of piezoelectric elements. It is characterized by being configured as described above.

Further, a second invention is a vibration control device for self-exciting vibration of a vibrator having substantially a pair of piezoelectric elements on a side surface of a vibrating body having a resonance point, the driving device having an automatic gain control circuit. With this driving device, the vibrator is self-excited while maintaining a constant combined current value of the currents obtained by subtracting the currents corresponding to the braking capacitances out of the respective currents that pass through the pair of piezoelectric elements. It is characterized by being configured to vibrate.

[0018]

In the first aspect of the present invention, since the combined current value of the respective currents that substantially pass through the pair of piezoelectric elements is maintained constant, the equivalent resistance of the vibrator is not affected by the ambient temperature change.
Apparently, it will be kept constant. Therefore,
Since the vibrator will always vibrate with a constant amplitude, when applied to a vibrating gyro that uses the same pair of piezoelectric elements to detect angular velocity, it vibrates in a direction orthogonal to the self-excited vibration direction. Also, the amplitude fluctuation due to the temperature change of the vibration corresponding to the input angular velocity is effectively suppressed.

According to the second aspect of the invention, of the respective currents passing through the pair of piezoelectric elements, the combined current value of the currents obtained by subtracting the current corresponding to the braking capacity, that is, the real number component of the combined currents is constant. Since it is maintained, the equivalent resistance of the vibrator is apparently kept constant regardless of the change in ambient temperature. Therefore, since the oscillator always vibrates more accurately with a constant amplitude, when applied to a vibrating gyroscope that detects angular velocity using the same pair of piezoelectric elements, the self-excited vibration direction The amplitude variation due to the temperature change of the vibration corresponding to the input angular velocity in the direction orthogonal to is also more reliably suppressed.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of the present invention, which is applied to a vibrating gyroscope for detecting an angular velocity. In FIG. 1, the same parts as those described in the above-mentioned related art are designated by the same reference numerals. In this embodiment, substantially two piezoelectric elements 2 and 3 are formed on the side surface of a vibrator 4 as shown in FIGS. 14 to 19, that is, a vibrator 1 having various cross-sectional shapes having resonance points. The vibrator 4 is self-excited.

In FIG. 1, a signal output terminal 9 of the driving device 60 is a signal input terminal 1 of the feedback amplifiers 10L and 10R.
These feedback amplifiers 10 are connected to 1L and 11R, respectively.
The feedback input terminals 12L and 12R of the L and 10R are respectively connected to one electrodes of the piezoelectric elements 2 and 3. The other electrodes of the piezoelectric elements 2 and 3 are connected to the inverting input terminal side of a summing amplifier 17 having a feedback resistance Rfy, and its output terminal 1 is connected.
A voltage corresponding to the product of the combined current passing through the piezoelectric elements 2 and 3 and the feedback resistance Rfy is output to the output circuit 8, and the output voltage is applied to the input terminal 14 of the driving device 60 to drive the oscillator 4 by itself. Make it vibrate.

FIG. 2 shows an example of the structure of the driving device 60 shown in FIG. The driving device 60 has an automatic gain control circuit (hereinafter referred to as an AGC circuit) 28, a non-inverting amplifier 25 and an inverting amplifier 26. AGC circuit 28
Has a comparator 23 and an amplitude controller 24, and the comparator 2
3, the input signal from the input terminal 14 is converted into a direct current, compared with a reference level, and a direct current signal according to the comparison result is generated and supplied to the amplitude controller 24. The amplitude controller 24 has, for example, a FET, supplies the input signal from the input terminal 14 to the source / drain path of this FET, supplies the output from the comparator 23 to the gate, and supplies the output of the comparator 23 to the output. Based on this, the amplitude of the signal from the input terminal 14 is controlled and output. It should be noted that the AGC circuit 28 is not limited to this example, and may be configured using, for example, an integrated multiplier or the like.

The signal whose amplitude is controlled by the AGC circuit 28 is
After being amplified to a predetermined size by the non-inverting amplifier 25, it is inverted by the inverting amplifier 26 and supplied to the signal output terminal 9. In addition,
The inverting amplifier 26 inverts the signal from the non-inverting amplifier 25 and inserts the oscillator 4 into the positive feedback loop as proposed by the present applicant in Japanese Patent Laid-Open No. 5-113336. It is a thing.

In this embodiment, when the equivalent resistance of each of the piezoelectric elements 2 and 3 increases or decreases due to a change in ambient temperature, the current passing through the piezoelectric elements 2 and 3 decreases or increases accordingly. Then, the level of the output signal of the comparator 23 in the drive device 60 falls or rises, for example. As a result, the resistance between the source and drain of the FET of the amplitude controller 24 increases or decreases, and the inverting amplifier 2
The magnitude of the signal supplied to 6 is increased or decreased until the signal input to the comparator 23 reaches a constant value corresponding to the reference level.

In this way, the output voltage of the summing amplifier 17, that is, the combined current passing through the piezoelectric elements 2 and 3 is maintained constant, so that the equivalent resistance of the oscillator 4 in the self-excited oscillation direction is Apparently constant. As a result, the equivalent resistance to the vibration of the vibrator 4 formed by the same piezoelectric element 2 and 3 in the sensitivity direction is apparently kept constant. It becomes constant regardless of changes in temperature, and high-precision detection is possible.

FIG. 3 shows a second embodiment of the present invention. In this embodiment, in the configuration shown in FIG. 1, the output at the output terminal 18 of the summing amplifier 17 is inverted and amplified by the inverting amplifier 19, and the output is fed through the variable resistor VR to the feedback input terminals of the feedback amplifiers 10L and 10R. 12L, 12R
It is intended to be supplied to. That is, the output of the summing amplifier 17 is inverted by the inverting amplifier 19 to have the same phase as the drive signal, and this signal is generated by the variable resistor VR by the piezoelectric element 2.
The subtle difference such as the equivalent resistance of No. 3 is adjusted and made to flow into the feedback input terminals 12L and 12R. Other configurations are the first
It is similar to the embodiment.

In this way, the feedback amplifiers 10L, 1
The 0R feedback input terminals 12L and 12R correspond to the current values flowing through the equivalent resistances of the respective piezoelectric elements 2 and 3,
And it means that the current which varies in response to the temperature dependence flows, feedback amplifiers 10L, 10R feedback resistor Rf _l of the Rf _R, so that only the current corresponding to the Coriolis force flow. Therefore, the feedback amplifier 10L,
In 10R, the generation of null voltage can be effectively reduced, and the phase component corresponding to the input angular velocity can be effectively amplified. Therefore, in addition to the effect of the first embodiment, the angular velocity can be detected with higher accuracy.

FIG. 4 shows a third embodiment of the present invention. In this embodiment, in the configuration shown in FIG.
Instead of the driving device 60, a driving device 61 having a compensation signal output terminal 13 that outputs a compensation signal for the braking capacity of the vibrator 4
, And the compensation signal is combined with the signal on the other electrode side of the piezoelectric elements 2 and 3 via the capacitor Cc. Further, the output of the summing amplifier 17 and the drive signal from the driving device 60 are supplied to the differential amplifier 22 to be differentially amplified, and the output thereof is fed back via the variable resistor VR in the same manner as in FIG. It is supplied to the input terminals 12L and 12R. Other configurations are the first
It is similar to the embodiment.

FIG. 5 shows an example of the structure of the driving device 61 shown in FIG. The driving device 61 is the same as the driving device 60 shown in FIG. 2 except that it supplies the output of the non-inverting amplifier 25 to the inverting amplifier 26 and also supplies it to the compensation signal output terminal 13 as a compensation signal. The configuration is similar to that of FIG. That is, in the drive device 61, the phase of the drive signal output to the signal output terminal 9 and the phase of the compensation signal output to the compensation signal output terminal 13 are different by 180 °, and the amplitude ratio thereof is inverted by the inverting amplifier 26. Set appropriately by.

According to this embodiment, of the current components flowing in the piezoelectric elements 2 and 3, the imaginary number component relating to each braking capacitance Cd is canceled by the compensation signal synthesized via the capacitor Cc, so that the sum amplifier. The output of 17 is only a real number component of the current components flowing through the piezoelectric elements 2 and 3. Therefore, the voltage gain of the summing amplifier 17 becomes maximum at the mechanical series resonance frequency fs of the vibrator 4, so that the vibrator 4 is stably self-excited at a frequency exactly matching the mechanical series resonance frequency fs. Can be vibrated. Further, the self-excited vibration at the mechanical series resonance frequency fs is further stabilized by using, as the capacitor Cc, one having a temperature dependence corresponding to the temperature dependence of the braking capacitance Cd of the vibrator 4. You can

Further, since the output of the summing amplifier 17 is only the real number component of the current components flowing through the piezoelectric elements 2 and 3, the equivalent resistance of each of the piezoelectric elements 2 and 3 increases due to the change in ambient temperature. Or when it decreases, the current passing through the piezoelectric elements 2 and 3 decreases or increases accordingly,
The level of the output signal of the comparator 23 in the drive device 61 falls or rises, for example. As a result, the amplitude controller 24
The source-drain resistance of the FET increases or decreases to increase the magnitude of the signal supplied to the inverting amplifier 26 until the signal input to the comparator 23 reaches a constant value corresponding to the reference level. Or reduce.

In this way, the output voltage of the summing amplifier 17, that is, the composite current value of the current obtained by subtracting the current corresponding to the braking capacitance from the composite current passing through the piezoelectric elements 2 and 3 is maintained constant. Therefore, the equivalent resistance of the vibrator 4 in the self-excited vibration direction is apparently constant. As a result, the equivalent resistance to the vibration of the vibrator 4 formed of the same piezoelectric element 2 and 3 in the sensitivity direction is apparently kept constant. Therefore, the detection sensitivity to the input angular velocity is equal to the ambient temperature. It becomes constant regardless of the change of, and high-precision detection becomes possible.

FIG. 6 shows a fourth embodiment of the present invention. In this embodiment, in the configuration shown in FIG. 1, instead of the driving device 60, the compensation signal output terminal 13 shown in FIG.
The driving device 61 having the above is used, and its compensation signal is combined with the signal on the other electrode side of the piezoelectric elements 2 and 3 via the capacitor Cc. Other configurations are the same as in FIG.

Therefore, according to this embodiment, as in the third embodiment, the equivalent resistance to the vibration in the sensitivity direction of the vibrator 4 formed of the same piezoelectric elements 2 and 3 is apparently constant. Since it can be maintained, the detection sensitivity to the input angular velocity can be made constant regardless of changes in the ambient temperature, and the angular velocity can be detected with high accuracy.

FIG. 7 shows a fifth embodiment of the present invention. In this embodiment, in place of the driving device 60 in the second embodiment shown in FIG. 3, a driving device 61 having the compensation signal output terminal 13 shown in FIG. 5 is used, and the compensation signal is passed through a capacitor Cc to generate a piezoelectric signal. It is configured to be combined with the signal on the other electrode side of the elements 2 and 3, and other configurations are the same as in FIG.

Therefore, according to this embodiment, in addition to the effect of the second embodiment, similarly to the third embodiment, the vibration of the vibrator 4 formed of the same piezoelectric elements 2 and 3 in the sensitivity direction is suppressed. Equivalent resistance, regardless of changes in ambient temperature
Since it is possible to maintain the apparent constant and the detection sensitivity to the input angular velocity can be constant, the angular velocity can be detected with higher accuracy.

FIG. 8 shows a sixth embodiment of the present invention. In this embodiment, in the configuration shown in FIG. 1, instead of the driving device 60, the compensation signal output terminal 13 shown in FIG.
Using the driving device 61 having the above, the compensation signal is combined with the signal on the other electrode side of the piezoelectric elements 2 and 3 via the capacitor Cc. Also, the output of the summing amplifier 17 and the compensation signal are combined by the summing amplifier 21, and the output is fed through the variable resistor VR in the same manner as in FIG.
Supply to 12R. Other configurations are the same as those in FIG.

Therefore, according to this embodiment, as in the third embodiment, the equivalent resistance of the vibrator 4 formed of the same piezoelectric elements 2 and 3 to the vibration in the sensitivity direction is changed by the change of the ambient temperature. Regardless, since it is possible to maintain the apparent constant, it is possible to make the detection sensitivity to the input angular velocity constant. Further, the output of the summing amplifier 17 and the compensation signal are combined, and the combined signal is adjusted by the variable resistor VR to adjust the subtle difference in the equivalent resistance of the piezoelectric elements 2 and 3.
Since it is made to flow into the feedback input terminals 12L and 12R, the feedback input terminals 12L and 12R correspond to the current values flowing through the equivalent resistances of the piezoelectric elements 2 and 3, and their temperature dependence. A current that changes corresponding to the current will flow in. Therefore, the feedback amplifiers 10L and 10L
R feedback resistor Rf _l of the Rf _R, it means that only the current corresponding exactly to the Coriolis force flows, feedback amplifiers 10L, in 10R, the input angular velocity to reduce the occurrence of null voltage more effectively Amplifies the corresponding phase component,
Coupled with the above-mentioned constant detection sensitivity, the angular velocity can be detected with higher accuracy.

FIG. 9 shows a seventh embodiment of the present invention. In this embodiment, the signal output terminal 9 of the driving device 62 is connected to the signal input terminal 11 of the feedback amplifiers 10L and 10R.
These feedback amplifiers 10 are connected to L and 11R respectively.
The feedback input terminals 12L and 12R of the L and 10R are respectively connected to one electrodes of the piezoelectric elements 2 and 3 to apply a drive signal. The other electrodes of the piezoelectric elements 2 and 3 are grounded.
The outputs of the feedback amplifiers 10L and 10R are combined and supplied to the input terminal 14 of the driving device 62 so that the vibrator 4 is self-oscillated and the outputs of the feedback amplifiers 10L and 10R are differentiated. It is supplied to the dynamic amplifier 20 so that the Coriolis force generated by the angular velocity acting on the oscillator 4 is detected as a voltage.

FIG. 10 shows an example of the structure of the drive unit 62 shown in FIG. The driving device 62 is configured such that, in the driving device 60 shown in FIG. 2, the inverting amplifier 30 is provided in front of the comparator 23 to invert the signal supplied to the input terminal 14 and supply the inverted signal to the comparator 23. The other configuration is similar to that of FIG. That is, in the above-described embodiment, the feedback signal input to the input terminal of the driving device is the output of the summing amplifier 17 and the phase of which is inverted from that of the driving signal. The feedback signal input to the input terminal 14 of 62 is the feedback amplifier 10L,
Since the output signal of 10R has the same phase as the drive signal, the feedback signal is inverted by the inverting amplifier 30 and supplied to the comparator 23.

In this embodiment, the feedback amplifier 10L,
The output of the 10R includes a respective current passing through the piezoelectric elements 2 and 3, the corresponding feedback resistance Rf _l, since the voltage of the product of the Rf _R, output their synthesis pass through the piezo The voltage depends on the magnitude of the combined current. Therefore, if the amplitude of the driving signal to be output is controlled in the driving device 62 having the AGC circuit 28 so that this voltage becomes constant, the same piezoelectric elements 2 and 3 are formed as in the first embodiment. Since the equivalent resistance against the vibration in the sensitivity direction of the vibrator 4 can be apparently kept constant regardless of the change of the ambient temperature, the detection sensitivity with respect to the input angular velocity can be made constant, and the angular velocity can be highly accurate. Can be detected with.

FIG. 11 shows an eighth embodiment of the present invention. In this embodiment, in the configuration shown in FIG.
Instead of the driving device 62, a driving device 63 having a compensation signal output terminal 13 for outputting a compensation signal for the braking capacity of the vibrator 4
Is used to synthesize the compensation signal into a synthesized signal of the outputs of the feedback amplifiers 10L and 10R, and the input terminal 14 of the driving device 63 is synthesized.
It is intended to be returned to.

FIG. 12 shows an example of the structure of the driving device 63 shown in FIG. This drive device 63 is shown in FIG.
In the driving device 62 shown in 0, in addition to supplying the output of the non-inverting amplifier 25 to the inverting amplifier 26, it is also supplied to the non-inverting input terminal of the feedback amplifier 27, and the capacitor Cc is connected to the inverting input terminal of the feedback amplifier 27. Then, the output of the feedback amplifier 27 is supplied to the compensation signal output terminal 13 as a compensation signal, and other configurations are similar to those of FIG. That is, in the driving device 63, the phase of the drive signal output to the signal output terminal 9 and the phase of the compensation signal output to the compensation signal output terminal 13 are different by 180 °, and the amplitude ratio thereof is inverted by the inverting amplifier 26. Set appropriately by.

According to this embodiment, in the feedback signal supplied to the input terminal 14, the imaginary number component related to each braking capacitance Cd among the signal components corresponding to the currents flowing in the piezoelectric elements 2 and 3 is the capacitor Cc. Since it is canceled by the compensating signal synthesized through the above, only the real number component of the current components flowing through the piezoelectric elements 2 and 3 becomes. Therefore, it is possible to stably vibrate the vibrator 4 at a frequency that exactly matches the mechanical series resonance frequency fs. The self-excited vibration at the mechanical series resonance frequency fs is
It is possible to further stabilize by using, as c, one having a temperature dependence corresponding to the temperature dependence of the braking capacitance Cd of the vibrator 4.

Further, the driving device 6 having the AGC circuit 28
3, the amplitude of the drive signal to the signal output terminal 9 is controlled so that the level of the feedback signal supplied to the input terminal 14 becomes constant, so that the vibration formed by the same piezoelectric elements 2 and 3 is controlled. The equivalent resistance to vibration of the child 4 in the sensitivity direction is
Regardless of the change in ambient temperature, it is apparently kept constant, so that the detection sensitivity to the input angular velocity is constant, and the angular velocity can be detected with high accuracy.

[0046]

As described above, according to the first invention,
Since the combined current value of the respective currents passing through the pair of piezoelectric elements is kept constant, the equivalent resistance of the vibrator can be apparently kept constant regardless of the ambient temperature change. . Therefore, the vibrator can always be self-excited with a constant amplitude. Therefore, when the vibrator is applied to a vibration gyro that detects angular velocities using the same substantially pair of piezoelectric elements, a direction orthogonal to the self-excited vibration direction is obtained. The detection sensitivity can be made constant regardless of changes in ambient temperature, and the input angular velocity can always be detected with high accuracy.

According to the second aspect of the invention, the combined current value of the currents obtained by subtracting the current corresponding to the braking capacity from the respective currents passing through the pair of piezoelectric elements, that is, the real number component of the combined current is constant. Since it is maintained at, the equivalent resistance of the oscillator is apparently irrespective of the ambient temperature change.
Can be kept constant. Therefore, the oscillator always vibrates more accurately with a constant amplitude, so when applied to a vibrating gyro that detects angular velocity using the same pair of piezoelectric elements, Detection sensitivity in the orthogonal direction, regardless of changes in ambient temperature
The input angular velocity can be detected more accurately and the input angular velocity can be detected with higher accuracy.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of an example of a driving device shown in FIG.

FIG. 3 is a block diagram showing a second embodiment of the present invention.

FIG. 4 is likewise a block diagram showing a third embodiment.

5 is a block diagram showing a configuration of an example of the driving device shown in FIG.

FIG. 6 is a block diagram showing a fourth embodiment of the present invention.

FIG. 7 is likewise a block diagram showing a fifth embodiment.

FIG. 8 is likewise a block diagram showing a sixth embodiment.

FIG. 9 is likewise a block diagram showing a seventh embodiment.

10 is a block diagram showing a configuration of an example of the driving device shown in FIG.

FIG. 11 is a block diagram showing an eighth embodiment of the present invention.

12 is a block diagram showing a configuration of an example of the drive device shown in FIG.

FIG. 13 is a block diagram for explaining a conventional example.

FIG. 14 is a diagram showing a configuration of an example of a vibrator that can be used in the present invention.

FIG. 15 is a diagram similarly showing a configuration of another example.

FIG. 16 is a diagram similarly showing a configuration of another example.

FIG. 17 is a diagram similarly showing the configuration of another example.

FIG. 18 is a diagram similarly showing the configuration of another example.

FIG. 19 is a diagram similarly showing the configuration of another example.

FIG. 20 is a diagram showing an equivalent circuit of a vibrator.

FIG. 21 is a diagram for explaining display of a vibrator.

FIG. 22 is a block diagram showing the configuration of an example of a vibration control device previously proposed by the applicant.

23 is a block diagram showing the configuration of an example of the drive device shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vibrating body 2,3 Piezoelectric element 4 Vibrator 60,61,62,63 Driving device 10L, 10R Feedback amplifier 17 Summation amplifier 23 Comparator 24 Amplitude controller 28 AGC circuit

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[Procedure amendment]

[Submission date] October 7, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0028

[Correction method] Change

[Correction content]

FIG. 4 shows a third embodiment of the present invention. In this embodiment, in the configuration shown in FIG. 1, instead of the drive device 60, a drive device 61 having a compensation signal output terminal 13 for outputting a compensation signal of the braking capacity of the vibrator 4 is used, and the compensation signal is supplied to a capacitor Cc. And the signal on the other electrode side of the piezoelectric elements 2 and 3 is combined. Further, the output of the summing amplifier 17 and the drive signal from the drive device 61 are
It is supplied to the differential amplifier 22 and differentially amplified, and its output is shown in FIG.
Similarly to the above, it is supplied to the feedback input terminals 12L and 12R via the variable resistor VR. Other configurations are the same as those of the first embodiment.

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 3

[Correction method] Change

[Correction content]

[Figure 3]

Claims (2)

[Claims] 1. A vibration control device for self-oscillating a vibrator having substantially a pair of piezoelectric elements on a side surface of a vibrating body having a resonance point, the driving device having an automatic gain control circuit. Thus, the vibration control device is configured to vibrate the vibrator by self-excited while maintaining a combined current value of the respective currents passing through the pair of piezoelectric elements substantially constant. 2. A vibration control device for self-oscillating a vibrator substantially having a pair of piezoelectric elements on a side surface of a vibrating body having a resonance point, the driving device having an automatic gain control circuit, the driving device Thus, among the respective currents passing through the substantially pair of piezoelectric elements, while maintaining the combined current value of the currents obtained by subtracting the current corresponding to the braking capacity constant,
A vibration control device characterized in that the vibrator is configured to vibrate by itself.