JP2000283767A - Angular velocity measuring apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To vibrate a vibrator always in a resonance state at a fixed vibration amplitude to stabilize the detecting sensitivity of the angular velocity. SOLUTION: A displacement signal VB outputted through a displacement detector 14 and a capacitance-voltage converter circuit 21 is inputted to a feedback phase shifter 22, the shifter 22 outputs a correction signal VC to an AGC 27 so that a phase difference of the signal VB from a drive signal VA is approximately -90 deg., and a feedback amplifier 24 controls the amplitude of the drive signal VA so that the vibration amplitude of a vibrator 6 is constant and outputs the drive signal VA to a vibration generator 13 whereby the vibrator 6 can be vibrated in a resonance state at a fixed vibration amplitude to stabilize the detection sensitivity of the angular velocity even when the ambient temp. changes.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an angular velocity measuring device suitable for detecting an angular velocity acting on, for example, a moving object or a rotating body.

[0002]

2. Description of the Related Art Generally, an angular velocity detector used in an angular velocity measuring apparatus according to the prior art includes a base and a support beam connected to the base, and first and second orthogonal axes among three orthogonal axes. A vibrating body provided so as to be able to vibrate in the axial direction, vibration generating means for receiving the driving signal and vibrating the vibrating body in the first axial direction, and causing the vibrating body to move in the first axial direction by the vibration generating means. There is known a signal output unit configured to detect a displacement of a vibrating body that vibrates in a second axial direction when an angular velocity is applied around a third axis in a vibrated state (for example, a specific example). JP-A-6-123632 and the like).

Further, the base is formed as a substrate from a glass material, and the support beams and the vibrating body located on the substrate are formed from a silicon material.

Further, the supporting beam for displacing the vibrating body in the first axial direction and the vibrating body constitute a vibration system that vibrates in the first axial direction, and this vibration system has a vibration-side natural frequency. ing. On the other hand, the support beam and the vibrator that displace the vibrator in the second axial direction constitute a detection system that vibrates in the second axial direction,
This detection system has a detection-side natural frequency.

In this angular velocity detector, a drive signal output from an external oscillation circuit is received by vibration generating means, and the vibration generating means vibrates the vibrating body in a first axial direction parallel to the substrate. Let it. In this state, when an angular velocity is applied around the third axis, the vibrating body vibrates in the second axial direction by Coriolis force corresponding to the angular velocity. The signal output means detects an angular velocity applied around the third axis by detecting a displacement when the vibrating body vibrates in the second axis direction.

[0006]

By the way, in the angular velocity detector according to the prior art described above, the natural frequency on the vibration side of the vibration system and the natural frequency on the detection side of the detection system are brought close to each other in order to improve the detection accuracy. And the frequency of the drive signal is set to a frequency close to, for example, the vibration-side natural frequency.
Thereby, the vibrating body vibrates in the first axial direction in a resonance state, and the vibration width of the vibrating body is increased.

The natural frequency f of the spring vibration is
It is generally defined by Equation 1 below.

[0008]

(Equation 1) k: Spring constant of support beam M: Mass of vibrating body

Here, the angular velocity detector according to the prior art is:
Since the substrate is formed of a glass material, and the supporting beams and the vibrator provided on the substrate are formed of a silicon material, both materials have different coefficients of thermal expansion. As a result, when the ambient temperature rises, for example, in the portion of the support beam fixed to the substrate, a difference is generated between the extension on the substrate side and the extension of the support beam, the vibrating body, and the like.

[0010] When the coefficient of thermal expansion of the glass material on the substrate side is larger than that of silicon, the elongation of the substrate increases, a tensile stress is applied to the support beam, and the spring constant of the support beam increases, resulting in an increase in the intrinsic modulus. The frequency increases.

As a result, in the angular velocity detector, the difference between the frequency of the drive signal and the vibration-side natural frequency increases due to a change in the ambient temperature, and the vibration width of the vibrating body that vibrates in the first axial direction decreases. I will. For this reason, the angular velocity detector has a problem that the detection sensitivity of the angular velocity varies and the reliability is reduced.

Further, in the angular velocity detector according to the prior art, the frequency of a driving signal added from the oscillation circuit to the vibration generating means is set to a frequency close to the vibration-side natural frequency, and the vibrating body is resonated using this driving signal. Vibrating in the state. Thus, the vibrating body can be vibrated greatly even when a drive signal having a small amplitude is used.

However, since the electronic components forming the oscillation circuit have temperature characteristics, the frequency of the drive signal output from the oscillation circuit may change due to a change in the ambient temperature. For this reason, the difference between the frequency of the drive signal and the vibration-side natural frequency increases, and the vibration width of the vibration body may decrease. As a result, the angular velocity measuring device has a problem that the angular velocity detection sensitivity is reduced.

The present invention has been made in view of the above-mentioned problems of the prior art, and the present invention eliminates variations in detection sensitivity by constantly vibrating a vibrating body in a resonance state, thereby improving the angular velocity measuring apparatus. It is intended to provide.

[0015]

In order to solve the above-mentioned problems, an angular velocity measuring device according to the present invention vibrates in a first axis direction among three orthogonal axes upon receiving a drive signal, A vibrating body that vibrates in the second axial direction when an angular velocity is applied around the third axis in this state; signal output means for detecting vibration of the vibrating body and outputting a displacement signal according to displacement; Phase correcting means for correcting the phase difference between the drive signal and the displacement signal output from the signal output means and outputting a correction signal, in order to cause the vibrating body to vibrate in a resonance state; In order to make the oscillation width constant when the driving is performed, the driving signal obtained by amplifying the correction signal output from the phase correcting means is output to the vibrating body by feedback amplification means.

With this configuration, when the driving signal output from the phase correction means and the feedback amplification means is added to the vibrating body, the vibrating body vibrates with a constant vibration width in the first axial direction. When an angular velocity is applied around the third axis in this state, the vibrating body vibrates in the second axial direction. The displacement signal output from the signal output means includes a signal corresponding to a displacement when the vibrating body vibrates in the first axial direction and a second signal when the vibrating body is applied with an angular velocity about the third axis. And the signal corresponding to the displacement when vibrating in the axial direction, the angular velocity can be measured by the signal when the vibrating body is displaced in the second axial direction.

The vibrating body vibrating in the first and second axial directions has a vibration-side natural frequency vibrating in a resonance state in the first axial direction, and a detecting body vibrating in a resonance state in the second axial direction. Side natural frequency. Therefore, the phase correction means may, for example, reduce the phase difference of the displacement signal with respect to the drive signal by approximately
°). That is, when a drive signal having a phase advanced (90 °) from the phase of the displacement signal is output, the vibrating body vibrates in the first axial direction at a frequency substantially equal to the vibration-side natural frequency, and the vibrating body resonates. Self-excited vibration in the state.

Further, since the feedback amplifying means outputs to the vibrating body a drive signal for keeping the vibration width constant when the vibrating body vibrates in the first axial direction, the ambient temperature changes and the characteristic of the vibrating body changes. Even when the frequency changes, the vibration width of the vibrating body can be kept constant, and the detection sensitivity of the angular velocity applied around the third axis can be stabilized.

According to the second aspect of the present invention, the correction signal output from the phase correction means is caused to vibrate the vibrating body in the first axial direction in a resonance state, so that the phase difference of the displacement signal with respect to the drive signal is substantially (-90). °).

With this configuration, the phase correction means outputs a correction signal whose phase has been corrected so that the phase difference between the drive signal and the displacement signal becomes a reference phase difference (approximately -90 °). This correction signal is output to the vibrator as a new drive signal through the feedback amplifier. Therefore, the vibrating body that vibrates in response to a new drive signal vibrates in a resonance state in the first axial direction.

According to a third aspect of the present invention, a vibration-side fixed frequency that vibrates the vibrating body in a resonance state in a first axial direction and a detection-side natural frequency that vibrates in a resonance state in a second axial direction are provided. Have
The correction signal output from the phase correction means is caused to vibrate the vibrating body in the second axial direction in a resonance state. Therefore, when the vibration-side natural frequency is equal to the detection-side natural frequency, the phase difference is substantially (−90). °), and when the vibration-side natural frequency is higher than the detection-side natural frequency, the phase difference is set to a reference phase difference of (−90 ° + α °). When the frequency is lower than the detection-side natural frequency, the phase difference is set to a reference phase difference of (−90 ° −α °).

With this configuration, the phase correction means can determine the phase difference between the drive signal and the displacement signal based on the level relationship between the vibration-side natural frequency of the vibrating body and the detection-side natural frequency. A correction signal whose phase has been corrected so as to have a phase difference is output, and this correction signal is output to the vibrator as a new drive signal through the feedback amplifier. Therefore, the vibrating body that vibrates in response to the new drive signal vibrates in the first axial direction at a frequency substantially equal to the detection-side natural frequency. In this state, when an angular velocity is applied around the third axis and the vibrating body vibrates in the second axial direction, the vibrating body vibrates in a resonance state in the second axial direction.

According to a fourth aspect of the present invention, the feedback amplifying means includes a rectifier for outputting a rectified signal obtained by rectifying the displacement signal output from the signal output means, and a rectified signal output from the rectifier. Control signal output means for comparing with a reference signal and outputting an amplification rate control signal corresponding to these signals; and receiving the amplification rate control signal output from the control signal output means, controlling the amplification rate, and performing phase correction. And amplification control means for outputting a drive signal in which the amplitude of the correction signal output from the means is adjusted.

With this configuration, the correction signal output from the phase correction means is output to the vibrating body as a drive signal through the feedback amplifying means, so that the vibrating body vibrates in a resonance state with a constant vibration width. be able to. Thereby, even when the ambient temperature changes, the vibration width of the vibrating body can be kept constant, and the detection sensitivity can be stabilized.

According to a fifth aspect of the present invention, there is provided an angular velocity signal for outputting only an angular velocity signal corresponding to an angular velocity in a displacement signal by synchronously detecting a displacement signal output from the signal output means at a subsequent stage of the signal output means. The output means is provided.

With this configuration, the angular velocity signal output means outputs only the angular velocity signal corresponding to the angular velocity in the displacement signal by synchronously detecting the displacement signal, and detects the angular velocity applied around the third axis. Can be detected.

According to a sixth aspect of the present invention, the displacement signal output from the signal output means includes a monitor signal corresponding to the displacement of the vibrating body when vibrating in the first axial direction and a monitor signal corresponding to the displacement in the second axial direction. And an angular velocity signal corresponding to the displacement of the vibrator.

With this configuration, the signal output means uses the displacement when the vibrating body vibrates in the first axial direction as a monitor signal and uses the displacement when the vibrating body vibrates in the second axial direction as a monitor signal. As an angular velocity signal, a displacement signal combining the monitor signal and the angular velocity signal can be output. By outputting only the angular velocity signal in the displacement signal, the third
Angular velocity applied around the axis can be measured.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the angular velocity measuring device according to the present invention will be described in detail with reference to FIGS.

First, an angular velocity measuring device according to a first embodiment will be described with reference to FIGS. The angular velocity measuring device according to the present embodiment includes an angular velocity detector 1 described later.
A feedback phase shifter 22 connected to the angular velocity detector 1;
It comprises a feedback amplifier 24, an angular velocity detector 28 and the like.

Here, the angular velocity detector 1 used in the present embodiment will be described with reference to FIGS.

Reference numeral 2 denotes a rectangular substrate serving as a base of the angular velocity detector 1, and the substrate 2 is formed of, for example, a glass material.

Reference numeral 3 denotes a movable portion formed of low-resistance polysilicon or single-crystal silicon doped with P, S, Sb or the like on the substrate 2, and the movable portion 3 is located at four corners of the substrate 2. Four support members 4 provided on the substrate 2, four support beams 5 provided at the base end side of the support portion 4, and the front end side extending toward the center of the substrate 2, The beam 5 is supported on the tip end side, and is supported by each support beam 5 in a first axis (hereinafter, referred to as X axis) direction and a second axis (hereinafter, referred to as Y axis).
The vibrating body 6 is provided so as to be capable of vibrating in a direction.
And a movable-side detection electrode 8 are provided. Further, the movable portion 3 has only the support portions 4 fixed on the substrate 2,
Each support beam 5 and the vibrating body 6 are separated from the substrate 2.

Here, the vibrating body 6 is supported on the substrate 2 by four supporting beams 5. As shown in FIG. 3, each support beam 5 extends one by one from each support portion 4 and is bent in a substantially U-shape having a portion parallel to the X axis and a portion parallel to the Y axis. It is formed. As a result, each support beam 5 displaces the vibrating body 6 in the Y-axis direction by bending a portion parallel to the X-axis, and flexes the vibrating body 6 by bending the portion parallel to the Y-axis. Displace in the direction.
Therefore, the vibrating body 6 is supported by the support beams 5 so as to be able to vibrate in the X-axis and Y-axis directions with respect to the substrate 2.

The part of each support beam 5 that vibrates the vibrating body 6 in the X-axis direction and the vibrating body 6 constitute a vibration system that vibrates in the X-axis direction. The vibration-side natural frequency f set by the constant and the mass of the vibrating body 6
Have one. On the other hand, the vibrating body 6 of each support beam 5 is set to Y
The part to be vibrated in the axial direction and the vibrating body 6 constitute a detection system that vibrates in the Y-axis direction. This detecting system is a natural frequency on the detection side set by the spring constant of the support beam 5 and the mass of the vibrating body 6. f2.

Reference numeral 7 denotes a movable-side vibrating electrode provided on the right side of the vibrating body 6. The movable-side vibrating electrodes 7 are formed on one side of the vibrating body 6 at predetermined intervals, and include, for example, four vibrating electrodes 7 extending in the X-axis direction. The movable-side vibrating electrode 7 is formed in a comb shape together with a fixed-side vibrating electrode 10 to be described later.
3.

Reference numeral 8 denotes a movable detection electrode which is provided on the front side of the vibrating body 6 and includes, for example, four antenna-like electrodes. The movable detection electrode 8 is formed on one side of the vibrating body 6 at predetermined intervals. The support 8A includes, for example, four pillars 8A extending in the Y-axis direction, and three electrode plates 8B extending in the X-axis direction arranged on one side of each of the pillars 8A. In addition, the movable-side detection electrode 8 constitutes a displacement detection unit 14 together with a fixed-side detection electrode 12 described later.

Numeral 9 denotes a vibration fixing portion. The vibration fixing portion 9 is provided on the substrate 2 facing the movable vibration electrode 7. A comb-shaped fixed-side vibration electrode 10 is provided on a long side of the vibration fixing portion 9, and the fixed-side vibration electrode 10 is
Separation dimension d0 equal to each electrode plate 7A of movable side vibrating electrode 7
It is composed of, for example, four electrode plates 10A protrudingly formed on the vibration fixing portion 9 so as to face each other alternately.

Reference numeral 11 denotes a detection fixing portion, and the detection fixing portion 1
1 is provided on the substrate 2 facing the movable side detection electrode 8. The fixed portion 11 for detection is provided with a fixed side detection electrode 12 composed of, for example, four antenna-like electrodes. The fixed side detection electrode 12 is provided on the long side of the fixed portion 11 for detection at predetermined intervals. For example, four columns 12A are formed and extend in the Y-axis direction, and are formed on one side of each column 12A so as to alternately face the respective electrode plates 8B of the movable-side detection electrode 8 with separation dimensions d1 and d2. For example, three electrode plates 12B (see FIG. 4).

Numeral 13 denotes a vibration generator for vibrating the vibrating body 6 in the direction of arrow a. The vibration generator 13 is composed of the movable vibration electrode 7 and the fixed vibration electrode 10. An equal distance d0 is formed between each electrode plate 7A and each electrode plate 10A of the fixed-side vibrating electrode 10. Here, the vibration generating unit 13 receives the drive signal VA such as a pulse wave or a sine wave to receive the electrode plates 7A and 10A.
In this case, an electrostatic attractive force is generated intermittently to vibrate the vibrating body 6 in the X-axis direction.

Reference numeral 14 denotes a displacement detection unit serving as a signal output unit. The displacement detection unit 14 includes the movable detection electrode 8 and the fixed detection electrode 12. Further, as shown in FIG. 4, at the initial stage when the vibrating body 6 is not displaced, the effective area of the electrode plates 8B and 12B adjacent to the displacement detecting unit 14 is S0, and the electrode plates 8B and 12B The narrow separation dimension d1 and the wide separation dimension d2 with the gap are in a state where they are positioned with respect to each other.

Here, the displacement detecting section 14 is configured as a parallel plate capacitor with only the separation dimension d1 having a small gap. As a result, the displacement detection unit 14
When the vibrating body 6 is vibrating in the X-axis direction by supplying a drive signal VA to the X-axis direction, the effective area S0 of the adjacent electrode plates 8B and 12B changes, so that the displacement of the vibrating body 6 in the X-axis direction is Output as a monitor signal based on the capacitance.

Further, when an angular velocity Ω is applied around a third axis (hereinafter, referred to as a Z axis), the vibrating body 6 vibrates in the Y axis direction due to Coriolis force. For this reason, the displacement detecting section 14 outputs the displacement of the vibrating body 6 in the Y-axis direction as an angular velocity signal based on the capacitance because the distance d1 between the electrode plates 8B and 12B changes. As described above, the displacement signal VB output from the displacement detection unit 14 includes the monitor signal corresponding to the displacement when the vibrating body 6 vibrates in the X-axis direction and the displacement signal when the vibrating body 6 vibrates in the Y-axis direction. And an angular velocity signal corresponding to.

In this embodiment, since the angular velocity signal is sufficiently smaller than the monitor signal (for example, about 1/100 or less), the displacement signal VB is regarded as the monitor signal.

The angular velocity detector 1 according to the present embodiment is configured as described above. Next, a basic detection operation when an angular velocity Ω is applied around the Z axis will be described.

First, when the drive signal VA is supplied to the vibration generator 13, the electrostatic attraction between the electrode plates 7A and 10A acts intermittently, and the vibrating body 6 vibrates in the direction of the arrow a which is the X-axis direction. I do.

In this state, when an angular velocity Ω is applied around the Z-axis, a Coriolis force F (inertial force) shown in the following equation 2 is generated in the Y-axis direction. Vibrates in the direction.

[0048]

F = 2 mΩv m: mass of the vibrating body 6 Ω: angular velocity v: velocity of the vibrating body 6 in the X direction

Further, the displacement detecting section 14 is provided with a monitor signal corresponding to the displacement of the vibrating body 6 vibrating in the X-axis direction (the direction of the arrow a) and the vibrating body 6 vibrating in the Y-axis direction (the direction of the arrow F). And outputs a displacement signal VB including an angular velocity signal corresponding to the displacement.

Here, generally, when the vibrating body 6 is vibrating in a resonance state in the X-axis direction, the position of the displacement signal VB output from the displacement detecting section 14 with respect to the drive signal VA supplied to the vibration generating section 13. The phase difference becomes (−90 °), that is, the phase of the displacement signal VB becomes (90 °) than the phase of the drive signal VA.
°) It is known to be delayed (see FIG. 5). It is also known that the phase of the angular velocity signal included in the displacement signal VB is delayed (90 °) from the phase of the displacement signal VB (monitor signal).

The angular velocity detector 1 is hermetically covered by a cover (not shown) provided on the substrate 2, and the inside of the space defined by the substrate 2 and the cover is substantially in a vacuum state. Thereby, when the vibrating body 6 vibrates,
The Q value representing the sharpness of resonance can be increased to 1000 to 5000.

Next, a peripheral circuit for controlling the angular velocity detector 1 will be described with reference to FIG.

Numeral 21 is a capacitance-voltage conversion circuit connected to the output side of the displacement detection unit 14.
Is configured by an electronic component such as a field-effect transistor, and converts the capacitance output from the displacement detection unit 14 into a voltage value. Thus, the capacitance-voltage conversion circuit 21 outputs the displacement signal VB including the monitor signal and the angular velocity signal to the feedback phase shifter 22 and the amplification circuit 23, which will be described later.

Reference numeral 22 denotes a feedback phase shifter as a phase correcting means. The feedback phase shifter 22 receives the displacement signal VB and determines the phase difference of the displacement signal VB as a reference phase difference (for example, -90).
°), the phase of the drive signal VA is advanced and delayed.
7 is output. For example, as shown in FIG.
The phase difference between the drive signal VA and the displacement signal VB is (−90
(° + θ °), the feedback phase shifter 22 outputs a correction signal VC with the phase set to (+ θ °). Thus, the correction signal VC is a signal that advances the phase of the drive signal VA substantially (90 °) with respect to the phase of the displacement signal VB.

Reference numeral 23 denotes an amplification circuit connected to the next stage of the capacitance-voltage conversion circuit 21. The amplification circuit 23 outputs a displacement signal VB obtained by amplifying the displacement signal VB output from the capacitance-voltage conversion circuit 21. (For convenience, use the same symbols).

Reference numeral 24 denotes a feedback amplifying unit connected to the input side of the vibration generating unit 13 as feedback amplifying means.
Reference numeral 4 denotes a rectified signal V obtained by full-wave rectifying the displacement signal VB output from the capacitance-voltage conversion circuit 21 via the amplifier circuit 23.
Full-wave rectification circuit 25 as rectification means for changing to D and outputting
And a smoothed signal VD 'obtained by smoothing the rectified signal VD output from the full-wave rectifier circuit 25, and a predetermined reference signal VD.
re as a control signal output means for outputting an amplification factor control signal VE corresponding to these signals.
Amplification control for controlling the amplification factor in response to the amplification factor control signal VE output from the comparator 26 and outputting a drive signal VA in which the amplitude of the correction signal VC output from the feedback phase shifter 22 is adjusted. The automatic gain control circuit 27 (hereinafter, referred to as a means)
AGC 27).

Numeral 28 is an angular velocity detector as angular velocity signal output means. The angular velocity detector 28 receives the displacement signal VB amplified by the amplifier circuit 23 and delays the phase of the displacement signal VB by (90 °). A detection phase shifter 29 for outputting a signal VF (reference signal VF ') and a displacement signal VB output from the amplifier circuit 23 are synchronously detected with a reference signal VF' output from the detection phase shifter 29. And a low-pass filter circuit 31 (hereinafter referred to as LP) connected to an output side of the synchronous detection circuit 30.
F31) and connected to the output side of the LPF 31;
And an amplifier circuit 32 for performing offset compensation. The output signal V output from the amplifier circuit 32
H corresponds to the angular velocity Ω applied around the Z-axis of the angular velocity detector 1.

A start circuit 33 adds a signal necessary for giving vibration to the vibrating body 6 to the vibration generator 13 only at the time of starting.

The angular velocity measuring device according to the present embodiment is configured so that the phase of the drive signal VA added to the vibration generating section 13 is advanced by approximately (90 °) with respect to the phase of the displacement signal VB. When the vibrator 6 vibrates in the X-axis direction, it vibrates itself at the vibration-side natural frequency f1 (hereinafter referred to as self-excited vibration). Thereby, the vibrating body 6 is brought into a resonance state and vibrates in the direction of the arrow a with a large vibration width.

Next, the operation of the angular velocity measuring device will be described with reference to the characteristic lines shown in FIGS. 5 to 7. First, the operation when the vibrating body 6 is vibrated in the direction of arrow a in a resonance state. State.

First, in order to vibrate the vibrating body 6, for example, a pulse signal is output from the start circuit 33 to the vibration generating section 13.
And vibrates the vibrating body 6 in the direction of arrow a. As a result, the vibrating body 6 has an arbitrary frequency (vibration-side natural frequency f
(Not necessarily 1).

At this time, the displacement detector 14 outputs a displacement signal VB corresponding to the displacement of the vibrating body 6 in the direction of the arrow a to the feedback phase shifter 22 via the capacitance-voltage conversion circuit 21. The frequency of the displacement signal VB is substantially equal to an arbitrary frequency at which the vibrating body 6 vibrates.

Here, the feedback phase shifter 22 outputs the drive signal V
A correction signal VC for correcting the phase difference of the displacement signal VB with respect to A to a reference phase difference (for example, -90 °) is output. That is, as shown in FIG. 6, the feedback phase shifter 22 determines that the phase difference between the displacement signal VB and the drive signal VA is (-).
(90 ° + θ °), the correction signal V obtained by correcting the phase of the drive signal VA by (θ °) to advance the phase of the drive signal VA by (90 °) with respect to the phase of the displacement signal VB.
C is output to the AGC 27. And the AGC 27
A new drive signal VA whose amplitude has been adjusted by an operation described later is output to the vibration generator 13.

As a result, as shown in FIG. 5, the displacement signal VB for the new drive signal VA proportional to the correction signal VC
Is approximately (−90 °). As a result, the frequency of the drive signal VA gradually approaches the vibration-side natural frequency f1 of the vibration body 6, and the frequency of the vibration body 6 also changes to the vibration-side natural frequency f1.
Converges to 1. For this reason, since the vibrating body 6 self-oscillates at the vibration-side natural frequency f1, the driving signal VA added to the vibration generating unit 13 can be made small in amplitude.

Next, the operation of the feedback amplifier 24 for adjusting the amplitude of the drive signal VA input to the vibration generator 13 will be described with reference to FIG.

First, the full-wave rectifier circuit 25 is
And outputs a rectified signal VD obtained by full-wave rectifying the displacement signal VB to the comparator 26. The comparator 26 compares a smoothed signal VD 'obtained by smoothing the rectified signal VD with a preset reference signal Vre, and outputs an amplification factor control signal VE corresponding to these signals to the AG.
Output to C27. Further, the AGC 27 controls the amplification factor in response to the amplification factor control signal VE. The AGC 27 adjusts the amplitude of the correction signal VC output from the feedback phase shifter 22 based on the amplification factor, thereby obtaining a drive signal VA. VA is output to the vibration generator 13.

That is, the reference signal V input to the comparator 26
re is a value that regulates the vibration width when the vibrating body 6 vibrates in the direction of the arrow a. Therefore, when the smoothed signal VD 'is higher than the reference signal Vre, the comparator 26 outputs an amplification factor control signal VE for reducing the amplitude of the drive signal VA supplied to the vibration generator 13, and outputs the smoothed signal. VD 'is the reference signal V
If it is lower than re, an amplification factor control signal VE for increasing the amplitude of the drive signal VA supplied to the vibration generator 13 is output.

As described above, the feedback amplifying unit 24 monitors the vibration width when the vibrating body 6 vibrates in the direction indicated by the arrow a from the amplitude of the displacement signal VB, and determines the driving signal VA supplied to the vibration generating unit 13. Adjust the amplitude. Thereby, the vibrating body 6
It always vibrates in the direction of arrow a with a constant vibration width.

Further, an angular velocity detector 28 for detecting an angular velocity signal in the displacement signal VB output from the displacement detector 14
Will be described with reference to FIGS. 5 and 6.

As described above, the displacement of the vibrating body 6 in the direction of arrow F has a phase difference of (−90 °) with respect to the displacement in the direction of arrow a. Is the amplification circuit 23
The phase difference of the displacement signal VB inputted through (−90
°) to the corrected synchronizing signal VF.
The reference signal VF 'formed from F is output to the synchronous detection circuit 30. In this case, the synchronization signal VF output from the detection phase shifter 29 is a signal obtained by inverting the displacement signal VB.

The reference signal VF 'has a plus-side pulse when it is positive and a minus-side pulse when it is negative by comparing the synchronization signal VF with a zero voltage value (V = 0). It becomes a pulse wave. Further, the synchronous detection circuit 30 synchronously detects the displacement signal VB with the reference signal VF 'to output a signal obtained by full-wave rectifying the angular velocity signal VG in the displacement signal VB. And this angular velocity signal VG
Becomes an output signal VH via the LPF 31 and the amplifier circuit 32, and this output signal VH corresponds to the angular velocity Ω applied around the Z axis of the angular velocity detector 1.

Further, as described above, since the vibrating body 6 is vibrating with a large vibration width in a resonance state in the direction indicated by the arrow a by the feedback phase shifter 22 when the angular velocity Ω is applied around the Z axis. The displacement of the vibrating body 6 in the direction indicated by the arrow F due to the Coriolis force can be increased. As a result, the output signal VH output from the angular velocity detector 28 can be increased to increase the angular velocity Ω detection sensitivity.

As described above, the angular velocity measuring apparatus according to the present embodiment uses the feedback phase shifter 22 and the feedback amplifier 24 to
The frequency of the drive signal VA supplied to the vibration generator 13 is
It can be made to substantially match the vibration-side natural frequency f1, and the vibrating body 6 can be self-excited at the vibration-side natural frequency f1 in the direction of arrow a. Thus, even when the vibration-side natural frequency f1 of the vibrating body 6 changes due to aging, temperature change, or the like, the frequency of the drive signal VA can be made closer to the changed vibration-side natural frequency f1. The vibrating body 6 can always be vibrated in the direction of arrow a in a resonance state.

The feedback phase shifter 22 outputs the drive signal VA
And outputs a correction signal VC (drive signal VA) obtained by correcting the phase difference of the displacement signal VB to (−90 °).
The vibrating body 6 can resonate at the frequency of the vibration-side natural frequency f1. Moreover, by vibrating the vibrating body 6 in a resonance state, the amplitude voltage of the drive signal VA supplied to the vibration generating unit 13 can be reduced.

Further, since the feedback amplifying section 24 always keeps the vibration width when the vibrating body 6 vibrates in the direction of the arrow a, the fluctuation of the detection sensitivity of the angular velocity Ω can be suppressed and stabilized. The reliability of the angular velocity measuring device can be improved.

Next, a second embodiment will be described with reference to FIGS. 8 to 12. The features of this embodiment are as follows.
A vibration body that vibrates in the second axial direction (Y-axis direction) when an angular velocity is applied around the third axis (Z-axis) is configured to vibrate in a resonance state. In the present embodiment, the same components as those in the above-described first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

A variable phase shifter 41 is used in place of the feedback phase shifter 22. The variable phase shifter 41 determines the phase difference between the drive signal VA and the displacement signal VB as a reference phase difference (for example, -90).
(° ± α °), the correction signal VC ′ obtained by correcting the phase of the drive signal VA is output to the AGC 27 of the feedback amplifier 24. Here, α is α ≧ 0. Also,
The reference phase difference is set using known data obtained from individual characteristics of the angular velocity detector 1 described later.

Here, FIGS. 9 to 11 show known data used to set the reference phase difference of the variable phase shifter 41, and show the characteristics of the angular velocity detector 1. FIG. 9 to 11, the horizontal axis represents the frequency, the vertical axis represents the displacement and the phase difference (°), and the frequency characteristic based on the vibration-side natural frequency f1, the frequency characteristic based on the detection-side natural frequency f2, The figure describes a frequency characteristic based on a phase difference between the drive signal VA and the displacement signal VB when the vibrating body 6 vibrates in the direction indicated by the arrow a.

First, FIG. 9 shows the characteristics when the vibration-side natural frequency f1 and the detection-side natural frequency f2 are equal. When the reference phase difference is set to approximately (-90 °), that is, when the displacement signal V
When the phase of the drive signal VA is advanced by (90 °) with respect to the phase of B, the vibrating body 6 vibrates in the direction of arrow a in a resonant state, and also vibrates in the direction of arrow F in a resonant state.

FIG. 10 shows the characteristics when the vibration-side natural frequency f1 is higher than the detection-side natural frequency f2. When the reference phase difference is set to (−90 °), the vibrating body 6 is indicated by an arrow. Resonance occurs when vibrating in the a direction. On the other hand, when the reference phase difference is set to (−90 ° + α °), the vibrating body 6 vibrates in the direction of arrow a at the detection-side natural frequency f2.
At this time, the displacement amount of the vibrating body 6 is the vibration-side natural frequency f1.
Therefore, the vibration width of the vibrating body 6 is also reduced. When the angular velocity Ω is applied around the Z axis, the vibrating body 6 vibrates in the direction indicated by the arrow F in a resonance state.

FIG. 11 shows the vibration-side natural frequency f1.
Is a characteristic when the reference-side natural frequency f2 is lower than the detection-side natural frequency f2. When the reference phase difference is set to approximately (-90 °), a resonance state occurs when the vibrating body 6 vibrates in the direction of arrow a. On the other hand, when the reference phase difference is set to (−90 ° −α °), the vibrating body 6 vibrates at the detection-side natural frequency f2 in the direction indicated by the arrow a, and the vibration width of the vibrating body 6 decreases.

As described above, when the characteristic of the angular velocity detector 1 is previously as shown in FIG. 10, for example, it corresponds to the intersection of the frequency characteristic due to the phase difference and the detection-side natural frequency f2 (−90 ° + α). °) is set as the reference phase difference of the variable phase shifter 41.

As a result, the variable phase shifter 41 converts the correction signal VC 'obtained by correcting the phase difference of the displacement signal VB with respect to the drive signal VA into the reference phase difference (-90 ° + α °) by the AGC.
27.

Next, the operation of the angular velocity measuring apparatus according to the present embodiment when the vibrating body 6 is vibrated in the direction of arrow a at the detection-side natural frequency f2 will be described. However, it is assumed that the angular velocity detector 1 has the characteristics shown in FIG.

First, in order to vibrate the vibrating body 6, the start circuit 33 supplies, for example, a pulse signal to the vibration generating unit 13, and vibrates the vibrating body 6 in the direction of arrow a at an arbitrary frequency. At this time, the displacement detector 14 outputs a displacement signal VB corresponding to the displacement of the vibrating body 6 in the direction of arrow a to the variable phase shifter 41 via the capacitance-voltage conversion circuit 21. And
The frequency of the displacement signal VB is substantially equal to an arbitrary frequency at which the vibrating body 6 vibrates.

Here, the variable phase shifter 41 outputs the drive signal VA
A correction signal VC for setting the phase difference of the displacement signal VB with respect to the reference phase difference (for example, -90 ° + α °) to AG
Output to C27. Then, the AGC 27 outputs a new drive signal VA whose amplitude has been adjusted to a constant value to the vibration generator 13.

At this time, when the phase difference between the drive signal VA and the displacement signal VB is (−90 ° + α °), the vibrating body 6 vibrates at a frequency lower than the vibration-side natural frequency f1, and the phase difference becomes ( (−90 ° −α °), the vibrating body 6 vibrates at a frequency higher than the vibration-side natural frequency f1.

For this reason, the phase difference between the displacement signal VB and the new drive signal VA changes from (−90 °) to (−90 ° +
α °), the vibrating body 6 vibrates in the direction of the arrow a at a frequency lower than the vibration-side natural frequency f1. As a result, the frequency of the drive signal VA gradually approaches the detection-side natural frequency f2, which is lower than the vibration-side natural frequency f1, and the frequency of the vibrating body 6 also converges on the detection-side natural frequency f2. As a result, although the vibration width of the vibrating body 6 is smaller than that at the time of vibrating at the vibration-side natural frequency f1, the vibrating body 6 self-oscillates at the detection-side natural frequency f2 in the direction of arrow a.

Thus, the angular velocity detector 1 according to the embodiment vibrates the vibrating body 6 in the direction indicated by the arrow a with a small vibration width, but vibrates self-excitedly at the detection-side natural frequency f2. Accordingly, when an angular velocity Ω is applied around the Z axis, the vibrating body 6 vibrates in the resonance direction at the detection-side natural frequency f2 in the direction of arrow F due to the Coriolis force. For this reason, since the vibrating body 6 can be vibrated with a large vibration width with respect to the angular velocity Ω, the detection sensitivity of the angular velocity Ω can be increased.

On the other hand, in the case of the angular velocity detector 1 whose characteristics are unknown as shown in FIGS. 9 to 11, as shown in a modification of FIG. 5
1 is connected, and the angular velocity measuring device is mounted on a rotating plate, etc.
By recording data of the phase difference with respect to the actual angular velocity, it is also possible to obtain characteristics as shown in FIGS. Note that the range of the variable phase shift generator 51 may be a range of (−90 ° ± 45 °).

As described above, by setting the reference phase difference of the variable phase shifter 41 from the characteristics of the angular velocity detector 1 obtained by the variable phase shift generator 51, the vibrating body 6 is indicated by an arrow as described above. By vibrating at the detection-side natural frequency f2 in the direction a, the vibration width in the direction indicated by the arrow F can be increased to increase the detection sensitivity.

In each embodiment, the displacement detector 14
Has been described as a structure for simultaneously detecting a monitor signal when vibrating in the direction of arrow a and an angular velocity signal when vibrating in the direction of arrow F. However, the present invention is not limited to this. A displacement detection unit that detects separately may be used as a signal output unit.

In the first embodiment, the vibration generator 13 is provided on one side of the vibrator 6 and the displacement detector 14 is provided on the other side. However, the present invention is not limited to this. Vibration generators 13 may be provided on both sides facing each other,
The displacement detector 14 may also be provided on both sides of the vibrating body 6 facing each other.

[0094]

As described in detail above, according to the first aspect of the present invention, in order to vibrate the vibrating body in a resonance state, the phase correcting means for correcting the phase difference of the displacement signal with respect to the drive signal and outputting a correction signal is provided. And a feedback amplifying means for outputting a drive signal obtained by amplifying the correction signal output from the phase correction means to the vibrating body, so that the angular velocity detector is provided by the correction signal output from the phase correction means. Can be vibrated with a large vibration width in a resonance state. In addition, the feedback amplifying means can stabilize the vibration width of the vibrating body and stabilize the angular velocity detection sensitivity even when the natural frequency of the vibrating body changes due to a change in ambient temperature or the like, thereby improving reliability. Can be.

According to the second aspect of the present invention, the correction signal output from the phase correction means is caused to vibrate the vibrating body in the first axial direction.
Since the reference phase difference is set to (0 °), the vibrating body is vibrated at the natural frequency when vibrating in the first axial direction, so that the angular velocity detection sensitivity can be improved.

According to a third aspect of the present invention, the correction signal output from the phase correction means is used to cause the phase difference between the displacement signal and the drive signal to vibrate in the second axial direction in a resonance state. When the frequency is equal to the detection-side natural frequency, the phase difference is set to a reference phase difference of approximately (−90 °), and when the vibration-side natural frequency is higher than the detection-side natural frequency, the phase difference is set to (− (90 ° + α °), and when the vibration-side natural frequency is lower than the detection-side natural frequency, the phase difference is set to a reference phase difference of (−90 ° −α °). Thereby, the vibrating body can be vibrated at the detection-side natural frequency in the first axial direction. Therefore, when the vibrating body vibrates in the second axial direction due to an angular velocity applied around the third axis, the vibrating body can vibrate in a resonance state in the second axial direction, and the detection sensitivity of the angular velocity can be reduced. Can be enhanced.

According to a fourth aspect of the present invention, the vibrating body is caused to vibrate in a resonance state with a constant vibration width by outputting the correction signal output from the phase correcting means to the vibrating body as a drive signal through the feedback amplifying means. Can be. Thereby, even when the ambient temperature changes, the vibration width of the vibrating body can be kept constant, and the detection sensitivity can be stabilized.

According to a fifth aspect of the present invention, an angular velocity signal that outputs only an angular velocity signal corresponding to the angular velocity in the displacement signal by synchronously detecting the displacement signal output from the signal output means at the next stage of the signal output means. Since the output means is provided, only the angular velocity signal is output by the angular velocity signal output means, and the angular velocity applied around the third axis can be detected.

According to a sixth aspect of the present invention, the displacement signal output from the signal output means includes a monitor signal indicating a displacement when the vibrating body vibrates in the first axial direction, and a vibration signal in which the vibrating body vibrates in the second axial direction. Since the displacement at that time includes the angular velocity signal, the angular velocity applied around the third axis can be measured by outputting only the angular velocity signal in the displacement signal.

[Brief description of the drawings]

FIG. 1 is a circuit configuration diagram showing an angular velocity measuring device according to a first embodiment.

FIG. 2 is a perspective view showing an angular velocity detector.

FIG. 3 is a plan view showing an angular velocity detector.

FIG. 4 is an enlarged plan view showing a displacement detection unit of the angular velocity detector.

FIG. 5 is a characteristic diagram showing waveforms of a drive signal, a displacement signal, a correction signal, a synchronization signal, a reference signal, an angular velocity signal, and an output signal when the vibrating body vibrates in a resonance state in the X-axis direction. .

FIG. 6 is a characteristic diagram showing waveforms of a drive signal, a displacement signal, a correction signal, a synchronization signal, a reference signal, an angular velocity signal, and an output signal when the vibrating body is vibrating out of a resonance state in the X-axis direction. It is.

FIG. 7 is a characteristic diagram showing waveforms of a drive signal, a displacement signal, a rectified signal, a smoothed signal, a correction signal, an amplification factor control signal, and a drive signal when the vibrating body is vibrating in a resonance state in the X-axis direction. It is.

FIG. 8 is a circuit configuration diagram showing an angular velocity measuring device according to a second embodiment.

FIG. 9 is a characteristic diagram illustrating a frequency characteristic based on each natural frequency and a frequency characteristic based on a phase difference when the vibration-side natural frequency is equal to the detection-side natural frequency.

FIG. 10 is a characteristic diagram showing a frequency characteristic based on each natural frequency and a frequency characteristic based on a phase difference when the vibration-side natural frequency is higher than the detection-side natural frequency.

FIG. 11 is a characteristic diagram showing frequency characteristics based on each natural frequency and frequency characteristics based on a phase difference when the vibration-side natural frequency is lower than the detection-side natural frequency.

FIG. 12 is a circuit configuration diagram showing a modification of the angular velocity measuring device according to the second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Angular velocity detector 2 Substrate 3 Movable part 4 Support part 5 Support beam 6 Vibrating body 8 Movable detection electrode 12 Fixed side detection electrode 13 Vibration generation part 14 Displacement detection part (signal output means) 22 Feedback phase shifter (Phase correction) Means) 24 Feedback amplification unit (feedback amplification unit) 25 Full-wave rectification circuit (rectification unit) 26 Comparator (control signal output unit) 27 Automatic gain control circuit (amplification control unit) 28 Angular velocity detection unit (angular velocity signal output unit) 29 Detection phase shifter 30 Synchronous detection circuit 41 Variable phase shifter (phase correction means) 51 Variable phase shift generator f1 Oscillating natural frequency f2 Detecting natural frequency

Claims (6)

[Claims] An orthogonal signal is received by receiving a driving signal.
A vibrating body that vibrates in a first axial direction among the shafts and vibrates in a second axial direction when an angular velocity is applied around a third axis in this state; A signal output means for outputting a displacement signal, and a phase correction means for correcting the phase difference of the displacement signal output from the signal output means with respect to the drive signal and outputting a correction signal in order to vibrate the vibrating body in a resonance state. A drive signal obtained by amplifying a correction signal output from the phase correction unit is output to the vibrating body in order to keep a vibration width when the vibrating body vibrates in the first axial direction. An angular velocity measuring device constituted by feedback amplification means. 2. The correction signal output from the phase correction means vibrates the vibrating body in a first axial direction in a resonance state, so that the phase difference between the displacement signal and the drive signal is substantially (−90 °). The angular velocity measuring device according to claim 1, wherein the reference phase difference is set to: 3. The vibrating body has a vibration-side fixed frequency that vibrates in a resonance state in a first axial direction, and a detection-side natural frequency that vibrates in a resonance state in a second axial direction. The correction signal output from the phase correcting means causes the vibrating body to vibrate in the second axial direction in a resonance state. Therefore, when the vibration-side natural frequency is equal to the detection-side natural frequency, the phase difference is substantially (−90). °), and when the vibration-side natural frequency is higher than the detection-side natural frequency, the phase difference is set to a reference phase difference of (−90 ° + α °). The angular velocity measuring device according to claim 1, wherein the phase difference is set to a reference phase difference of (-90 ° -α °) when the frequency is lower than the detection-side natural frequency. 4. A rectifier for outputting a rectified signal obtained by rectifying a displacement signal output from the signal output means, a rectified signal output from the rectifier and a predetermined reference signal. Control signal output means for outputting an amplification rate control signal corresponding to these signals, and an amplification rate control signal output from the control signal output means to control the amplification rate, and from the phase correction means 4. The angular velocity measuring device according to claim 1, further comprising amplification control means for outputting a drive signal in which the amplitude of the output correction signal is adjusted. 5. An angular velocity signal output means for outputting only an angular velocity signal corresponding to an angular velocity in the displacement signal by synchronously detecting a displacement signal output from the signal output means at a stage subsequent to the signal output means. 5. The angular velocity measuring device according to claim 1, wherein the angular velocity measuring device is provided. 6. A displacement signal output from said signal output means includes a monitor signal corresponding to a displacement of said vibrating body when vibrating in a first axial direction, and a vibration signal when vibrating in a second axial direction. 6. The angular velocity measuring device according to claim 1, further comprising an angular velocity signal corresponding to the displacement of the body.