JP2013068629A - Circuit for angular velocity detection device, angular velocity detection device and failure determination system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an angular velocity detection circuit, an angular velocity detection device and a failure determination system in which failure detection accuracy of an oscillator is enhanced.SOLUTION: An angular velocity detection circuit 5 is connected to an oscillator 10 excited based on a drive signal and detects the angular velocity. This circuit includes: self-vibration component extraction means 331 which receives, from the oscillator 10, a detection signal including an angular velocity component based on a Coriolis force and a self-vibration component based on the excited vibration and which extracts the self-vibration component from the detection signal; DC conversion means 332 including integration means 336 which integrates an output signal of the self-vibration component extraction means 331; and temperature characteristic compensation means 333 which compensates for a variation depending on the temperature of an output signal of the DC conversion means 332.

Description

  The present invention relates to an angular velocity detection circuit, an angle detection device, and a failure determination system.

  An angular velocity detection device that detects an angular velocity using Coriolis force acting on a vibrator is widely used. In recent years, in such an angle detection device, an angular velocity detection device capable of detecting its own failure using a self-vibration component based on excitation vibration of a vibrator has been developed.

JP 2000-171257 A

  The magnitude of the self-vibration component based on the excitation vibration of the vibrator has a temperature characteristic for each vibrator. Therefore, in the conventional angular velocity detection device, it is difficult to discriminate between fluctuation due to temperature characteristics and fluctuation due to failure, and it is difficult to accurately determine failure.

  The present invention has been made in view of the circumstances as described above, and an object thereof is to provide an angular velocity detection circuit, an angular velocity detection device, and a failure determination system with improved failure detection accuracy of a vibrator.

(1) In the circuit for an angular velocity detection device according to the present invention, a signal including a first component corresponding to the magnitude of the angular velocity and a second component based on excitation vibration is input from the vibrator. A circuit for an angular velocity detection device, comprising: self-vibration component extraction means for extracting a second component; and temperature characteristic correction means for correcting fluctuations due to temperature of an output signal of the self-vibration component extraction means.
In this circuit for an angular velocity detection device, the vibrator extends in a direction intersecting with the extending direction of the connecting arm from a connecting arm extending from the detecting base and a driving base disposed on the connecting arm. And a detection vibration piece extending from the detection base portion in a direction intersecting with the extension direction of the connecting arm.
In the circuit for angular velocity detection device, the temperature characteristic correction unit corrects a variation due to temperature of the output signal of the self-vibration component extraction unit based on a first-order term of the temperature characteristic in the output signal of the self-vibration component extraction unit. It may be characterized by.
The circuit for angular velocity detection device includes storage means for storing a first-order term of the temperature characteristic, and the temperature characteristic correction means is based on the first-order term of the temperature characteristic stored in the storage means. It may be characterized in that the fluctuation due to the temperature of the output signal of the self-vibration component extracting means is corrected.
The circuit for angular velocity detection device may include a determination unit that monitors and determines an output signal of the temperature characteristic correction unit.
This angular velocity detection device circuit may include an amplifying means for amplifying a signal in at least one of the preceding stage and the succeeding stage of the self-vibration extracting means.
The angular velocity detection device circuit may include an offset addition unit that adds an offset value to the signal before or after the temperature characteristic correction unit.
An angular velocity detection device according to the present invention is a transducer that generates a signal including a first component corresponding to the magnitude of an angular velocity and a second component based on an excitation signal, and the signal is input. An angular velocity detection apparatus comprising: a self-vibration component extraction unit that extracts a second component; and a temperature characteristic correction unit that corrects a variation due to a temperature of an output signal of the self-vibration component extraction unit.
In this angular velocity detection device, the vibrator extends from a detection arm and a driving base disposed on the connection arm in a direction intersecting the extension direction of the connection arm. A drive vibration piece and a detection vibration piece that extends from the detection base in a direction intersecting with the extension direction of the connecting arm may be included.
In this angular velocity detection device, the temperature characteristic correction unit corrects a variation due to temperature of the output signal of the self-vibration component extraction unit based on a first-order term of the temperature characteristic in the output signal of the self-vibration component extraction unit. May be a feature.
The angular velocity detection device includes storage means for storing a first-order term of the temperature characteristic, and the temperature-characteristic correction means is based on the first-order term of the temperature characteristic stored in the storage means. It is also possible to correct fluctuation due to temperature of the output signal of the component extraction means.
The angular velocity detection device may include a determination unit that monitors and determines the output signal of the temperature characteristic correction unit.
This angular velocity detection device may include an amplifying means for amplifying a signal in at least one of the preceding stage and the succeeding stage of the self-vibration component extracting means.
The angular velocity detection device may include an offset addition unit that adds an offset value to the signal before or after the temperature characteristic correction unit.
A failure determination system according to the present invention includes the above-described angular velocity detection device, and an external failure determination unit that receives the output signal of the temperature characteristic correction unit and determines whether or not the angular velocity detection device has a failure. Is a failure determination system.
(2) An angular velocity detection device circuit according to an application example is:
An angular velocity detection circuit that is connected to a vibrator that excites and vibrates based on a drive signal and detects an angular velocity,
A detection signal including an angular velocity component based on Coriolis force and a self-vibration component based on the excitation vibration is input from the vibrator, and a self-vibration component extraction unit that extracts the self-vibration component from the detection signal;
DC conversion means including integration means for integrating the output signal of the self-vibration component extraction means;
Temperature characteristic correction means for correcting fluctuations due to temperature of the output signal of the DC conversion means.
In addition, a signal including an angular velocity component corresponding to the magnitude of the angular velocity and a self-vibration component based on excitation vibration is input from the vibrator, and the self-vibration component extracting unit extracts the self-vibration component from the signal; It may be characterized by comprising DC conversion means including integration means for integrating the output signal of the self-vibration component extraction means, and temperature characteristic correction means for correcting fluctuation due to temperature of the output signal of the DC conversion means.
The vibrator includes a connecting arm extending from the detection base, and a driving vibration piece extending in a direction intersecting with the extending direction of the connecting arm from the driving base disposed on the connecting arm. And a detection vibrating piece extending in a direction crossing the extending direction of the connecting arm from the detection base.

  According to the application example, by providing the temperature characteristic correction unit, it is possible to correct the fluctuation due to the temperature characteristic of the magnitude of the self-vibration component based on the excitation vibration of the vibrator. For this reason, the fluctuation | variation by failure can be detected accurately. Therefore, it is possible to realize an angular velocity detection circuit with improved vibrator failure detection accuracy.

(3) A circuit for this angular velocity detection device,
The temperature characteristic correction unit may correct a variation due to temperature of the output signal of the DC conversion unit based on a first-order term of the temperature characteristic in the output signal of the DC conversion unit.

(4) A circuit for this angular velocity detection device,
Storing means for storing a first-order term of the temperature characteristic;
The temperature characteristic correcting unit may correct a variation due to a temperature of an output signal of the DC converting unit based on a first-order term of the temperature characteristic stored in the storage unit.

(5) A circuit for this angular velocity detection device,
Self-failure determining means for determining whether or not the angular velocity detecting device has failed based on an output signal of the temperature characteristic correcting means may be included.

(6) A circuit for this angular velocity detection device,
The DC converting means may include an amplifying means for amplifying a signal at at least one of the preceding stage and the succeeding stage of the integrating means.

(7) A circuit for this angular velocity detection device,
The temperature characteristic correction unit may include an offset addition unit that adds an offset value to the signal before or after the temperature characteristic correction unit.

  The offset value can be a positive value, a negative value, or any value including zero.

(8) An angular velocity detection device according to an application example is:
An angular velocity detection device having a vibrator and an angular velocity detection circuit connected to the vibrator and detecting an angular velocity,
The vibrator is excited and oscillated based on a drive signal to obtain a Coriolis force generated by a rotational motion and the excitation vibration, an angular velocity component based on the Coriolis force, an excitation vibration component based on the excitation vibration, Output a detection signal containing
The angular velocity detection circuit receives the detection signal, and extracts the self-vibration component from the detection signal;
DC conversion means including integration means for integrating the output signal of the self-vibration component extraction means;
Temperature characteristic correction means for correcting fluctuations due to temperature of the output signal of the DC conversion means.
Also, a vibrator that generates a signal including an angular velocity component corresponding to the magnitude of the angular velocity and a self-vibration component based on an excitation signal, and a self-vibration that receives the signal and extracts the self-vibration component from the signal Component extraction means, DC conversion means including integration means for integrating the output signal of the self-vibration component extraction means, and temperature characteristic correction means for correcting fluctuation due to temperature of the output signal of the DC conversion means. It may be a feature.
The vibrator includes a connecting arm extending from the detection base, and a driving vibration piece extending in a direction intersecting with the extending direction of the connecting arm from the driving base disposed on the connecting arm. And a detection vibrating piece extending in a direction intersecting with the extending direction of the connecting arm from the detection base.
Further, the temperature characteristic correcting means may correct fluctuations due to temperature of the output signal of the DC converting means based on a first-order term of temperature characteristics in the output signal of the DC converting means.
The temperature characteristic correcting unit includes a storage unit that stores a first-order term of the temperature characteristic, and the temperature characteristic correction unit outputs an output signal of the DC conversion unit based on the first-order term of the temperature characteristic stored in the storage unit. It is also possible to correct fluctuations due to temperature.
The apparatus may further include self-failure determining means for determining whether or not the angular velocity detecting device has failed based on an output signal of the temperature characteristic correcting means.
The direct current converting means may include an amplifying means for amplifying a signal in at least one of the preceding stage and the succeeding stage of the integrating means.
The temperature characteristic correction unit may include an offset addition unit that adds an offset value to the signal before or after the temperature characteristic correction unit.

(9) The failure determination system according to the application example is:
This angular velocity detection device,
And an external failure determination unit that receives an output signal of the temperature characteristic correction unit and determines whether or not the angular velocity detection device has failed.

The circuit block diagram which shows an example of the angular velocity detection apparatus which concerns on this Embodiment. 2A to 2G are timing charts when attention is paid to the angular velocity component of the detection signal. FIGS. 3A to 3G are timing charts when attention is paid to the self-vibration component of the detection signal. The graph which shows an example of the relationship between temperature and the output signal voltage of a direct-current conversion means and a temperature characteristic correction means. The circuit diagram which shows an example of a temperature characteristic correction | amendment means. The circuit block diagram which shows an example of the self-failure determination means which has a some failure determination function. The circuit block diagram which shows the structural example of the angular velocity detection apparatus which provided the offset addition means in the back | latter stage of the temperature characteristic correction means. The graph which shows an example of the relationship between temperature and the output signal voltage of a DC conversion means, a temperature characteristic correction means, and an offset addition means. The circuit diagram which shows an example of an offset addition means. 10A and 10B are circuit block diagrams illustrating an example of a failure determination system according to this embodiment. The top view which shows an example of a vibrator | oscillator. The top view which shows an example of a vibrator | oscillator. The circuit diagram which shows an example of the synchronous detection circuit which has an offset input means.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. The embodiments described below do not unduly limit the contents of the present invention described in the claims. Also, not all of the configurations described below are essential constituent requirements of the present invention.

1. Angular Velocity Detection Device FIG. 1 is a circuit block diagram showing an example of an angular velocity detection device according to the present embodiment.

  The angular velocity detection device 1 according to the present embodiment includes an angular velocity detection circuit 5 including a drive circuit 20 and a detection circuit 30 and a vibrator 10. The drive circuit 20 and the detection circuit 30 can be configured on the same substrate.

2. The vibrator 10 is excited and oscillated based on the drive signals input from the drive vibration terminals 13 and 14, and obtains Coriolis force when the angular velocity motion works in the excited vibration state. The vibrator 10 outputs a detection signal including an angular velocity component based on the Coriolis force and an excitation vibration component based on the excitation vibration. Here, the excitation vibration component and the angular velocity component based on the Coriolis force are 90 ° out of phase.

Next, an example of the vibrator 10 formed from a thin plate of a piezoelectric material such as quartz will be described with reference to FIGS. In the vibrator 10, a drive vibration arm 11 (drive vibration piece in a broad sense) extends from the drive base 44 in the Y-axis direction of the crystal. The drive base 44 is connected to the detection base 49 via a connecting arm 45 extending in the X-axis direction of the crystal. The detection vibration arm 12 (detection vibration piece in a broad sense) extends from the detection base 49 in the Y-axis direction.

  When a drive signal composed of alternating voltage / alternating current is applied between the drive electrode 41 on the side surface of the drive vibration arm 11 and the drive electrode 42 on the top surface of the drive vibration arm 11, the drive vibration arm 11 is moved to an arrow by the piezoelectric effect. Flexurally vibrates like B. Here, as shown in FIG. 12, when the vibrator 10 rotates about the crystal Z-axis as the rotation axis, the driving vibration arm 11 correlates in the direction perpendicular to both the bending vibration direction indicated by the arrow B and the Z-axis. Get the power of. As a result, the connecting arm 45 vibrates as indicated by an arrow C. Then, the detection vibrating arm 12 performs bending vibration like the arrow D with the connecting arm 45 in conjunction with the vibration of the connecting arm 45 (arrow C).

  Further, the vibration of the drive vibration arm 11 is transmitted through the drive base 44, the connecting portion 45, and the detection base 49, and causes the detection vibration arm 12 to generate a leakage vibration. This leakage vibration is a bending vibration indicated by an arrow D, similar to the vibration based on the Coriolis force, but is 90 degrees out of phase.

  An alternating voltage / alternating current is generated between the detection electrode 47 on the side surface of the detection vibration arm and the detection electrode 46 on the upper surface by the inverse piezoelectric effect generated based on these bending vibrations. One of the detection electrode 47 on the side surface of the detection vibrating arm and the detection electrode 46 on the upper surface is connected to the ground terminal 17, and the other is connected to the detection terminals 15 and 16. As described above, the detection signals output to the detection terminals 15 and 16 include an angular velocity component based on Coriolis force and a leakage component (self-vibration component) based on excitation vibration of drive vibration.

  11 and 12, in order to improve the balance of the vibrator, the detection base 49 is arranged in the center, and the detection vibrating arm 12 is extended from the detection base 49 in both the + Y axis and −Y axis directions. I am letting. Further, the connecting arm 45 extends from the detection base 49 in both the + X-axis and −X-axis directions, and the drive vibrating arm 11 extends from each of the connecting arms in both the + Y-axis and −Y-axis directions.

  Further, the distal end of the drive vibrating arm 11 is formed into a wide portion 43, and a weight is attached to increase the Coriolis force. Also, due to the weight effect, a desired resonance frequency can be obtained with a short vibrating arm. For the same reason, the tip end of the detection vibrating arm 12 is formed into a wide portion 48 and further a weight is attached.

  The vibrator 10 is not limited to the above-described configuration, and may be any vibrator that outputs a detection signal including an angular velocity component based on Coriolis force and a leakage component based on excitation vibration. For example, it may be configured to serve as both the drive vibration arm and the detection vibration arm, or may be configured such that a piezoelectric film is formed on the drive vibration arm and the detection vibration arm.

3. Angular Velocity Detection Circuit The angular velocity detection circuit includes a drive circuit 20 and a detection circuit 30. The detection vibrating piece 12 is provided with detection terminals 15 and 16 and a ground terminal 17, and the detection terminals 15 and 16 are connected to a detection circuit 30. The detection terminals 15 and 16 are configured to output detection signals having opposite phases to each other.

  2A to 2G are timing charts when attention is paid to the angular velocity component of the detection signal at each point (A) to (G) in the circuit block diagram shown in FIG. FIGS. 3A to 3G are timing charts when attention is paid to the self-vibration component of the detection signal at each point (A) to (G) in the circuit block diagram shown in FIG. 1. The horizontal axis represents time, and the vertical axis represents voltage.

  The drive circuit 20 outputs a drive signal to drive the vibrator 10 and receives a feedback signal from the vibrator 10. Thereby, the vibrator 10 is excited. The detection circuit 30 receives a detection signal from the vibrator 10 driven by the drive signal, and extracts an angular velocity component based on the Coriolis force from the detection signal.

  The drive circuit 20 in the present embodiment includes a current-voltage converter 21, an AC amplifier 22, an automatic gain control circuit 23, and a comparator 24.

  When the drive vibration piece 11 vibrates, a current based on the piezoelectric effect is output as a feedback signal from the drive terminal 14 and input to the current-voltage converter 21. The current-voltage converter 21 outputs an AC voltage signal having the same frequency as the vibration frequency of the drive vibrating piece 11 (FIGS. 2A and 3A).

  The AC voltage signal output from the current-voltage converter 21 is input to the AC amplifier 22. The AC amplifier amplifies an input AC voltage signal.

  The AC voltage signal output from the AC amplifier 22 is input to the automatic gain control circuit 23. The automatic gain control circuit 23 controls the gain so that the amplitude of the input AC voltage signal is kept at a constant value, and outputs the AC voltage signal after gain control to the drive terminal 13. The vibrator 10 is driven by the AC voltage signal input to the drive terminal 13.

  The AC voltage signal amplified by the AC amplifier 22 is input to the comparator 24, and a square wave voltage signal (with the center of the amplitude of the AC voltage signal as a reference voltage) that switches the output level according to the comparison result between the AC voltage signal and the reference voltage signal ( 2B is output to the detection circuit 30.

  The detection circuit 30 in the present embodiment includes a detection signal amplification unit 31, an angular velocity component extraction unit 32, and a self-vibration component extraction unit 33.

  The detection signal amplifying unit 31 includes charge amplifiers 311 and 312, a differential amplifier 313, and an AC amplifier 314.

  The charge amplifiers 311 and 312 are connected to the detection terminals 15 and 16, respectively, and receive detection signals with opposite phases. The signals subjected to charge-voltage conversion by the charge amplifiers 311 and 312 are input to the differential amplifier 313. The differential amplifier 313 performs differential amplification as (output signal of charge amplifier 311) − (output signal of charge amplifier 312). The output signal of the differential amplifier 313 is further amplified by the AC amplifier 314. Note that the phase of the signal advances by 90 degrees during amplification by the charge amplifiers 311 and 312.

  The detection signals output from the detection terminals 15 and 16 include an angular velocity component based on the Coriolis force acting on the vibrator 10 and a self-vibration component (leakage signal component) based on the excitation vibration of the vibrator 10. The angular velocity component extraction unit 32 extracts an angular velocity component from the output signal of the detection signal amplification unit 31. The self-vibration component extraction unit 33 extracts a self-vibration component from the output signal of the detection signal amplification unit 31.

The angular velocity component extraction unit 32 includes a synchronous detection circuit 321, an AC amplifier 325, an integration circuit 322, a DC amplifier 323, and an output terminal 324. The synchronous detection circuit 321 extracts an angular velocity component by synchronously detecting the output signal of the detection signal amplification unit 31 based on the square wave voltage signal (FIG. 2B) output from the comparator 24. The angular velocity component signal extracted by the synchronous detection circuit 321 is amplified by the AC amplifier 325, integrated by the integration circuit 322, amplified by the DC amplifier 323, and output from the output terminal 324 as a DC voltage signal.

  The self-vibration component extraction unit 33 includes self-vibration component extraction means 331, direct current conversion means 332, and temperature characteristic correction means 333.

  The self-vibration component extracting unit 331 includes a phase shifter 334 that advances the phase by 90 degrees and a synchronous detection circuit 335. The self-vibration component extracting unit 331 outputs the output signal of the detection signal amplifying unit 31 based on a signal obtained by advancing the phase of the square wave voltage signal (FIG. 2B) output from the comparator 24 by 90 degrees. The self-vibration component is extracted by synchronous detection.

  The DC conversion unit 332 includes an integration circuit 336 that functions as an integration unit that integrates the output signal of the self-vibration component extraction unit 331, and converts the output signal of the self-vibration component extraction unit 331 into a DC voltage signal. Further, an AC amplifier 343 is provided before the integrating circuit 336, and a DC amplifier 339 is provided after the integrating circuit 336.

  The operation of these circuits will be described with reference to FIGS. 2A to 2G and FIGS. 3A to 3G. 2A to 2G for the operation when focusing on the angular velocity component of the detection signal, and FIGS. 3A to 3G for the operation when focusing on the self-vibration component of the detection signal. ). In the present embodiment, the angular velocity component of the detection signal output from the detection terminal 15 is a signal whose phase is 90 degrees behind the feedback signal output from the drive terminal 14 and is output from the detection terminal 15. It is assumed that the self-vibration component of the detection signal is a signal having the same phase as the feedback signal output from the drive terminal 14.

  First, the operation when focusing on the angular velocity component of the detection signal will be described. The angular velocity component of the detection signal output from the detection terminal 15 is converted into a charge voltage by the charge amplifier 311. At this time, the phase advances by 90 degrees. Therefore, the signal after being amplified by the differential amplifier 313 and the AC amplifier 314 has the same phase as the feedback signal shown in FIG. 2A, as shown in FIG.

  When the output signal of the AC amplifier 314 is synchronously detected by the synchronous detection circuit 321 based on the output signal of the comparator 24 shown in FIG. 2B, the output signal of the synchronous detection circuit 321 is the full wave shown in FIG. It becomes a rectified waveform. By integrating the output signal of the synchronous detection circuit 321 by the integration circuit 322, the angular velocity component of the detection signal can be detected as a DC voltage. Thus, the angular velocity component extraction unit 32 can extract the angular velocity component of the detection signal. Further, the sensitivity is adjusted by amplifying the signal with an AC amplifier circuit in the preceding stage of the integrating circuit 322 or a DC amplifier 323 in the subsequent stage.

  On the other hand, when the synchronous detection circuit 335 synchronously detects the output signal of the AC amplifier 314 and the output signal of the comparator 24 based on the signal (FIG. 2E) whose phase is advanced by 90 degrees by the phase shifter 334, the synchronous detection circuit The output signal 335 has the waveform shown in FIG. When the output signal of the synchronous detection circuit 335 is integrated by the integration circuit 336, the DC voltage becomes 0 as shown in FIG. Thus, the self-vibration component extracting unit 33 cancels the angular velocity component of the detection signal.

  Next, the operation when focusing on the self-vibration component of the detection signal will be described. The self-vibration component of the detection signal output from the detection terminal 15 is converted into a charge voltage by the charge amplifier 311. At this time, the phase advances by 90 degrees. Therefore, the signal after being amplified by the differential amplifier 313 and the AC amplifier 314 is a signal whose phase is advanced by 90 degrees from the feedback signal shown in FIG. 3A, as shown in FIG.

  When the output signal of the AC amplifier 314 is synchronously detected by the synchronous detection circuit 321 based on the output signal of the comparator 24 shown in FIG. 3B, the output signal of the synchronous detection circuit 321 has the waveform shown in FIG. Become. When the output signal of the synchronous detection circuit 321 is integrated by the integration circuit 322, the DC voltage becomes zero. As described above, the angular velocity component extraction unit 32 cancels the self-vibration component of the detection signal.

  On the other hand, when the output signal of the AC amplifier 314 is synchronously detected by the synchronous detection circuit 335 based on the output signal of the comparator 24 shown in FIG. The output signal 335 is a full-wave rectified waveform shown in FIG. When the output signal of the synchronous detection circuit 335 is integrated by the integration circuit 336, a DC voltage proportional to the wave height of the full-wave rectification waveform shown in FIG. 3F is obtained as shown in FIG. As described above, the self-vibration component extracting unit 33 can extract the self-vibration component of the detection signal.

  When there is a failure in the vibrator 10, for example, when a foreign object adheres to the vibrator 10 or the vibrator 10 is damaged, the magnitude of the self-vibration component based on the excitation vibration of the vibrator 10 changes. . Accordingly, the self-vibration component of the detection signal is extracted by the self-vibration component extraction unit 33, and the magnitude of the self-vibration component of the detection signal is monitored inside or outside the angular velocity detection device 1, whereby the vibrator 10 has a failure. It can be determined whether or not. For example, when the magnitude of the self-vibration component of the detection signal exceeds the upper limit reference value or falls below the lower limit reference value, it can be determined that the vibrator 10 has a failure.

  However, the magnitude of the self-vibration component based on the excitation vibration of the vibrator 10 has temperature characteristics for each vibrator. Therefore, in the conventional angular velocity detection device, it is difficult to discriminate between fluctuation due to temperature characteristics and fluctuation due to failure, and it is difficult to accurately determine failure.

  The angular velocity detection circuit 5 according to the present embodiment has a temperature characteristic correction unit 333. The temperature characteristic correction unit 333 corrects the variation of the output signal of the DC conversion unit 332 due to the temperature. For example, the temperature characteristic correction unit 333 can correct the magnitude of the output signal of the DC conversion unit 332 so that it is constant regardless of the temperature. For this reason, the fluctuation due to the temperature of the output signal of the DC conversion means 332 can be canceled, and the fluctuation due to the failure can be detected with high accuracy. Therefore, it is possible to realize an angular velocity detection circuit with improved vibrator failure detection accuracy.

  FIG. 4 is a graph showing an example of the relationship between the temperature and the output signal voltage of the DC conversion unit 332 and the temperature characteristic correction unit 333. The horizontal axis represents temperature, and the vertical axis represents the output signal voltage.

  The output signal voltage of the DC conversion means 332 varies depending on the temperature, as indicated by the solid line 1001 in FIG. The temperature characteristic correcting means 333 corrects and outputs the output signal voltage in a direction that is constant regardless of the temperature (for example, the direction of the white arrow in FIG. 4) as indicated by a two-dot broken line 1002 in FIG. FIG. 4 shows an example in which the output signal voltage is corrected based on the output signal voltage at 25 ° C.

  In addition, the inventors of the present application have found that the variation of the output signal of the DC conversion means 332 due to temperature can be approximated by a first-order gradient. Therefore, the temperature characteristic correcting unit 333 can be configured to correct the variation due to the temperature of the output signal of the DC converting unit 332 based on the first order term of the temperature characteristic of the output signal of the DC converting unit 332. .

Further, the angular velocity detection circuit 5 includes storage means 337 for storing the first-order term of the temperature characteristic, and the temperature characteristic correction means 333 is the primary of the temperature characteristic stored in the storage means 337 as the output signal of the DC conversion means 332. Based on the term, it may be configured to correct the variation of the output signal of the DC conversion means 332 due to the temperature. The storage unit 337 can be configured by a nonvolatile memory such as an EEPROM, for example. Thereby, for example, in the inspection process of the angular velocity detection device 1, the output voltage of the temperature characteristic correction means 333 is measured, and the first term of the temperature characteristic such that the output voltage becomes a substantially constant value regardless of the temperature is stored in the storage means. 337 can be written. Therefore, even when the vibrator has different temperature characteristics, appropriate temperature characteristic correction can be performed.

  FIG. 5 is a circuit diagram showing an example of temperature characteristic correction means 333 applicable to the angular velocity detection circuit 5 according to the present embodiment. The temperature characteristic correction unit 333 shown in FIG. 5 includes an operational amplifier 401, a control circuit 402, resistors 403 and 404, and a variable resistor 405.

  The output signal of the DC conversion unit 332 is input to the non-inverting input terminal of the operational amplifier 401 through the resistor 403. The control circuit 402 controls the resistance value of the variable resistor 405 based on the first-order term of the temperature characteristic stored in the storage unit 337 and the temperature detected by the temperature sensor 406. The operational amplifier 401 differentially amplifies the signal input to the non-inverting input terminal and the potential input to the inverting input terminal, and outputs it as the output voltage Vout1. The output voltage Vout1 is also fed back to the inverting input terminal of the operational amplifier 401 through the resistor 404.

  The amplification factor A of the operational amplifier 401 is expressed as A = 1 + R5 / R4 using the resistance value R4 of the resistor 404 and the resistance value R5 of the variable resistor 405. Therefore, the amplification factor of the operational amplifier 401 can be controlled by controlling the resistance value R5 of the variable resistor 405.

  As described above, when the temperature characteristic correcting unit 333 is configured as shown in FIG. 5, the output voltage Vout1 is set to the temperature by appropriately setting the first-order term of the temperature characteristic stored in the storage unit 337. Regardless, it can be made almost constant.

  The angular velocity detection circuit 5 according to the present embodiment may further include a self-failure determination unit 338 that determines whether or not the angular velocity detection device 1 has failed based on the output signal Vout1 of the temperature characteristic correction unit 333. The self-failure determination means 338 determines that the vibrator 10 has a failure when the output signal Vout1 of the temperature characteristic correction means 333 exceeds the upper limit reference value or falls below the lower limit reference value, and is based on the determination result. Output the output signal. In the circuit block diagram shown in FIG. 1, an output signal is output to the outside of the angular velocity detection circuit 5 via the output terminal 341. Since the angular velocity detection circuit 5 includes the self-failure determination means 338, the angular velocity detection device 1 itself can determine whether or not the vibrator 10 has a failure.

  Note that the self-failure determination means 338 may have a failure determination function based on another failure determination signal. FIG. 6 is a circuit block diagram showing an example of self-failure determination means 338 having a plurality of failure determination functions. In the example shown in FIG. 6, the self-failure determining unit 338 is used for determining whether or not the drive circuit 20 has failed, in addition to the output signal Vout1 of the temperature characteristic correcting unit 333 used for determining whether or not the vibrator 10 has failed. It is assumed that a drive circuit diagnosis determination signal and a detection circuit diagnosis determination signal used for determining whether or not the detection circuit 30 has failed are input.

  The self-failure determination means 338 shown in FIG. 6 includes failure determination circuits 501 to 503 and an OR circuit 504. The failure determination circuits 501 to 503 output a high-level output signal when it is determined that there is a failure based on the respective input signals, and a low-level output signal when it is determined that there is no failure. Shall.

The failure determination circuit 501 determines that the vibrator 10 has a failure when the output signal Vout1 of the temperature characteristic correction unit 333 exceeds the upper limit reference value or falls below the lower limit reference value, and outputs based on the determination result. The signal is output to the OR circuit 504. The failure determination circuit 502 determines that the drive circuit 20 has a failure when the drive circuit diagnosis determination signal exceeds the upper limit reference value or falls below the lower limit reference value, and outputs an output signal based on the determination result to the OR circuit. Output to 504. The failure determination circuit 503 determines that the detection circuit 30 has a failure when the detection circuit diagnosis determination signal exceeds the upper limit reference value or falls below the lower limit reference value, and outputs an output signal based on the determination result to the OR circuit. Output to 504.

  The OR circuit 504 outputs a high-level output signal Vout2 when a high-level output signal is input from any of the failure determination circuits 501 to 503. When a low level output signal is input from any of the failure determination circuits 501 to 503, a low level output signal Vout2 is output.

  As described above, when the self-failure determination circuit 338 is configured as shown in the circuit block diagram of FIG. 6, it can be determined whether or not any of the angular velocity detection devices 1 has a failure and can be output as the output signal Vout2. .

  The direct current conversion means 332 of the angular velocity detection circuit 5 according to the present embodiment amplifies or attenuates the signal at a desired magnification to the AC amplifier 343 at the front stage or the DC amplifier 339 at the rear stage of the integration circuit 336 functioning as the integration means. Means may be included. In the circuit block diagram shown in FIG. 1, a DC amplifier 339 provided at the subsequent stage of the integrating circuit 336 functions as an amplifying unit.

  The magnitude of the self-vibration component based on the excitation vibration of the vibrator 10 varies depending on the failure mode of the vibrator 10. For example, the fluctuation of the self-vibration component based on the excitation vibration of the vibrator 10 when the vibrator 10 is broken is larger than the fluctuation of the self-vibration component based on the excitation vibration of the vibrator 10 when a foreign object adheres to the vibrator 10. .

  When the AC amplifier 343 at the front stage of the integration circuit 336 or the DC amplifier 339 at the rear stage is provided, the output sensitivity of the DC conversion means 332 can be changed by changing the amplification factor of the DC amplifier 339. Accordingly, by setting the amplification factor of the DC amplifier 339 according to the failure mode to be detected, failure determination corresponding to the desired failure mode can be performed.

  Further, a gain adjustment circuit for adjusting the gain of the DC amplifier 339 may be provided as the temperature characteristic correction means. In that case, the temperature dependence of the output of the DC amplifier 339 is reduced.

  The angular velocity detection circuit 5 according to the present embodiment may include an output terminal 340 that outputs the output signal Vout1 of the temperature characteristic correction unit 333. By outputting the output signal Vout1 of the temperature characteristic correction means 333 to the outside of the angular velocity detection circuit 5, a more detailed failure determination can be performed outside the angular velocity detection device 1. For example, more detailed failure determination can be performed by performing a complicated calculation process that cannot be performed inside the angular velocity detection device 1 due to restrictions such as the size of the angular velocity detection device 1 using a microcomputer provided outside the angular velocity detection device 1. It becomes possible.

  The output terminal 340 can also be used for measuring the output voltage of the temperature characteristic correction means 333 in the inspection process of the angular velocity detection device 1.

[Modification]
In addition to the configuration of the angular velocity detection device 1 described above, an offset addition unit 342 that adds an offset value to the signal may be included before or after the temperature characteristic correction unit 333. FIG. 7 is a circuit block diagram showing a configuration example of the angular velocity detection device 2 in which the offset addition unit 342 is provided in the subsequent stage of the temperature characteristic correction unit 333. In addition, the same code | symbol is attached | subjected about the structure same as the angular velocity detection apparatus 1 demonstrated using FIG. 1, and the detailed description is abbreviate | omitted.

The magnitude of the self-vibration component based on the excitation vibration of the vibrator 10 has individual differences for each vibrator.
Therefore, in the conventional angular velocity detection circuit, accurate failure determination is difficult unless the determination condition is changed according to the vibrator.

  The angular velocity detection circuit 6 according to the present embodiment has an offset addition unit 342. The offset adding unit 342 adds a desired offset value to the output signal of the temperature characteristic correcting unit 333.

  FIG. 8 is a graph showing an example of the relationship between the temperature and the output signal voltage of the DC conversion unit 332, the temperature characteristic correction unit 333 and the offset addition unit 342. The horizontal axis represents temperature, and the vertical axis represents the output signal voltage.

  The output signal voltage of the DC conversion means 332 varies depending on the temperature, as indicated by the solid line 2001 in FIG. The temperature characteristic correcting unit 333 corrects and outputs the output signal voltage in a direction (for example, the direction of the white arrow in FIG. 8) in which the output signal voltage is constant regardless of the temperature as indicated by a two-dot broken line 2002 in FIG. FIG. 8 shows an example in which the output signal voltage is corrected based on the output signal voltage at 25 ° C.

  The offset adding means 342 outputs an offset value such that the output voltage of the offset adding means 342 becomes a desired value in addition to the output signal of the temperature characteristic correcting means 333. For example, by adding the offset value in the direction of the black arrow in FIG. 8, the output signal voltage of the offset adding means 342 indicated by the one-dot broken line 2003 can be set to a desired value.

  As a result, in addition to correcting the fluctuation due to the temperature characteristics of the magnitude of the self-vibration component based on the excitation vibration of the vibrator 10, the variation in the magnitude of the self-vibration component based on the excitation vibration due to the individual difference of the vibrator 10 is corrected. Thus, the output voltages can be made uniform. Therefore, it is possible to realize an angular velocity detection device that further increases the failure detection accuracy of the vibrator without changing the determination condition for each angular velocity detection device.

  Further, the angular velocity detection device 2 may include a storage unit that stores an offset value, and the offset addition unit 342 may be configured to add the offset value stored in the storage unit 337 to the output signal of the temperature characteristic correction unit 333. . The storage unit can also be configured to be used as the storage unit 337 that stores the first-order term of the temperature characteristic used in the temperature characteristic correction unit 333. Thereby, for example, in the inspection process of the angular velocity detection device 2, the output voltage of the offset adding means 342 is measured, and an offset value at which this output voltage becomes a desired value is written in the storage means 337. Variations in the magnitude of the self-vibration component based on the excitation vibration due to the difference can be corrected, and the magnitudes of the output voltages can be made uniform.

  Further, a gain adjustment circuit for adjusting the gain of the DC amplifier 339 may be provided as the temperature characteristic correction means. In that case, the temperature dependence of the output of the DC amplifier 339 is reduced.

  FIG. 9 is a circuit diagram showing an example of the offset adding means 342 applicable to the angular velocity detecting device 2 according to the present embodiment. 9 includes an operational amplifier 601, a D / A converter 602, and resistors 603 to 605.

The output signal of the temperature characteristic correction unit 333 is input to the non-inverting input terminal of the operational amplifier 601 through the resistor 603. The D / A converter 602 outputs a voltage signal based on the offset value stored in the storage unit 337. The voltage signal output from the D / A converter 602 is input to the inverting input terminal of the operational amplifier 401 via the resistor 604. The operational amplifier 601 differentially amplifies the signal input to the non-inverting input terminal and the signal input to the inverting input terminal, and outputs it as an output voltage Vout3. The output voltage Vout3 is connected to the operational amplifier 6 via the resistor 605.
It is also fed back to the inverting input terminal of 01.

  In this way, when the offset adding means 342 is configured as shown in FIG. 9, the output voltage Vout3 can be set to a desired value by appropriately setting the offset value stored in the storage means 337. it can.

  As the synchronous detection circuit 335, a synchronous detection circuit having offset input means for adding an offset value to the output signal of the synchronous detection circuit 335 (self-vibration extraction means 331) as shown in FIG. 13 may be used. The synchronized detection signal signal (C) is branched, one is not inverted and input to the switch 359 as a non-inverted signal, and the other is inverted by the inverting amplifier 357 and input to the switch 358. The switches 358 and 359 are alternately connected by the reference signal, so that the non-inverted signal and the inverted signal are alternately output to output the synchronous detection signal (F). Further, the offset signal is superimposed on the inverted signal from the offset input terminal 351. As a result, at the timing when the switches 358 and 359 select and output the inverted signal of the synchronized signal, the offset signal is superimposed on the synchronous detection signal (F), and the switches 358 and 359 select the non-inverted signal of the synchronized signal. Thus, the offset signal is not superimposed on the synchronous detection signal (F) at the output timing. In this way, the offset signal repeats superimposition / non-superimposition, but is smoothed by the integration circuit 336 at the subsequent stage, and an offset value of a certain level is obtained. Note that it is possible to superimpose the offset signal on the non-inverted signal.

  Similarly, a synchronous detection circuit having an offset signal input means may be used for the synchronous detection circuit 321 of the angular velocity detection unit 32.

4). Failure Determination System FIGS. 10A and 10B are circuit block diagrams illustrating an example of a failure determination system according to this embodiment.

  A failure determination system 3 according to the present embodiment shown in FIG. 10A includes an angular velocity detection device 1. Since the configuration and operation of the angular velocity detection device 1 are as described with reference to FIGS. 1 to 6, the same components are denoted by the same reference numerals, and detailed description thereof is omitted.

  The failure determination system 3 according to the present embodiment includes external failure determination means 700 that determines whether or not there is a failure in the angular velocity detection device 1 based on an output signal Vout1 from the output terminal 340 of the angular velocity detection device 1. The external failure determination means 700 can be constituted by a microcomputer, for example.

  For example, when the output signal Vout1 of the angular velocity detection device 1 exceeds the upper limit reference value or falls below the lower limit reference value, the external failure determination unit 700 determines that the vibrator 10 of the angular velocity detection device 1 has a failure. can do. Further, for example, the external failure determination unit 700 can perform more detailed failure determination by performing complicated arithmetic processing that cannot be performed inside the angular velocity detection device 1 due to restrictions such as the size of the angular velocity detection device 1.

[Modification]
It is also possible to replace the angular velocity detection device 1 of the failure determination system 3 described above with the angular velocity detection device 2. A failure determination system 4 according to the present embodiment shown in FIG. 10B includes an angular velocity detection device 2. Since the configuration and operation of the angular velocity detection device 2 are as described with reference to FIGS. 1 to 9, the same components are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the failure determination system 4 according to the present embodiment, the external failure determination means determines the presence / absence of a failure in the angular velocity detection device 2 based on the output signal Vout3 from the output terminal 340 of the angular velocity detection device 2.

  The failure determination system 4 can perform failure determination with higher accuracy by using the angular velocity detection device 2 instead of the angular velocity detection device 1.

  In addition, this invention is not limited to this embodiment, A various deformation | transformation implementation is possible within the range of the summary of this invention.

  The present invention includes configurations that are substantially the same as the configurations described in the embodiments (for example, configurations that have the same functions, methods, and results, or configurations that have the same objects and effects). In addition, the invention includes a configuration in which a non-essential part of the configuration described in the embodiment is replaced. In addition, the present invention includes a configuration that exhibits the same operational effects as the configuration described in the embodiment or a configuration that can achieve the same object. Further, the invention includes a configuration in which a known technique is added to the configuration described in the embodiment.

DESCRIPTION OF SYMBOLS 1, 2 Angular velocity detection apparatus, 3, 4 Failure determination system, 5, 6 Angular velocity detection circuit, 10 vibrator, 11 Drive vibration piece (drive vibration arm), 12 Detection vibration piece (detection vibration arm), 13, 14 Drive terminal, 15, 16 detection terminal, 17 ground terminal, 20 drive circuit, 21 current-voltage converter, 22 AC amplifier, 23 automatic gain control circuit, 24 comparator, 41, 42 drive electrode, 43, 48 wide part, 44 drive Base, 45 Connecting arm, 46, 47
Detection electrode, 49 detection base, 30 detection circuit, 31 detection signal amplification unit, 32 angular velocity signal extraction unit, 33 self-vibration component extraction unit, 311, 312 charge amplifier, 313 differential amplifier, 314 AC amplifier, 321 synchronous detection circuit 322 integration circuit, 323 DC amplifier, 324 output terminal, 331 self-vibration component extraction means, 332 DC conversion means, 333 temperature characteristic correction means, 334 phase shifter, 335 synchronous detection circuit, 336 integration circuit, 337 storage means, 338 Self-failure determination means, 339 DC amplifier, 340, 341
Output terminal, 342 Offset addition means, 343 AC amplifier, 351 Offset input terminal, 357 Inverting amplifier, 358, 359 Switch, 401 Operational amplifier, 402
Control circuit, 403, 404 resistance, 405 variable resistance, 406 Temperature sensor, 501, 502, 503 Fault judgment circuit, 504 OR circuit, 601 operational amplifier, 602 D / A converter, 603, 604, 605 resistance, 700 External fault judgment means

Claims (15)

A signal including a first component corresponding to the magnitude of angular velocity and a second component based on excitation vibration is input from the vibrator, and self-vibration component extracting means for extracting the second component from the signal;
A circuit for an angular velocity detection device, comprising: temperature characteristic correction means for correcting fluctuation due to temperature of an output signal of the self-vibration component extraction means. In claim 1,
The vibrator includes a connecting arm extending from a detection base, a driving vibration piece extending from a driving base disposed on the connecting arm in a direction crossing the extending direction of the connecting arm, An angular velocity detection device circuit comprising: a detection vibrating piece extending from a detection base in a direction intersecting with an extension direction of the connecting arm. In claim 1 or 2,
The temperature characteristic correcting means corrects a variation due to the temperature of the output signal of the self-vibration component extracting means on the basis of a first-order term of the temperature characteristic in the output signal of the self-vibration component extracting means. Device circuit. In claim 3,
Storing means for storing a first-order term of the temperature characteristic;
The temperature characteristic correcting unit corrects a variation due to a temperature of an output signal of the self-vibration component extracting unit based on a first-order term of the temperature characteristic stored in the storage unit. circuit. In any one of Claims 1 thru | or 4,
A circuit for an angular velocity detection device, comprising: a determination unit that monitors and determines an output signal of the temperature characteristic correction unit. In any one of Claims 1 thru | or 5,
A circuit for an angular velocity detection device comprising amplification means for amplifying a signal in at least one of a front stage and a rear stage of the self vibration extraction means. In any one of Claims 1 thru | or 6,
A circuit for an angular velocity detection device, comprising offset addition means for adding an offset value to a signal before or after the temperature characteristic correction means. A vibrator that generates a signal including a first component corresponding to the magnitude of the angular velocity and a second component based on the excitation signal;
Self-vibration component extraction means for receiving the signal and extracting the second component from the signal;
An angular velocity detection device comprising: temperature characteristic correction means for correcting fluctuation due to temperature of an output signal of the self-vibration component extraction means. In claim 8,
The vibrator includes a connecting arm extending from a detection base, a driving vibration piece extending from a driving base disposed on the connecting arm in a direction crossing the extending direction of the connecting arm, An angular velocity detecting device comprising: a detection vibrating piece extending from a detection base in a direction intersecting with an extending direction of the connecting arm. In claim 8 or 9,
The temperature characteristic correcting means is a temperature characteristic 1 in the output signal of the self-vibration component extracting means.
An angular velocity detecting apparatus, wherein fluctuations due to temperature of the output signal of the self-vibration component extracting means are corrected based on the following term. In claim 10,
Storing means for storing a first-order term of the temperature characteristic;
The angular velocity detecting device, wherein the temperature characteristic correcting unit corrects a variation due to a temperature of an output signal of the self-vibration component extracting unit based on a first-order term of the temperature characteristic stored in the storage unit. In any one of Claims 8 thru | or 11,
An angular velocity detection apparatus comprising: a determination unit that monitors and determines an output signal of the temperature characteristic correction unit. In any one of claims 8 to 12,
An angular velocity detection apparatus comprising amplification means for amplifying a signal in at least one of a front stage and a rear stage of the self-vibration component extraction means. In any one of Claims 8 thru | or 13,
An angular velocity detection apparatus comprising offset addition means for adding an offset value to a signal before or after the temperature characteristic correction means. The angular velocity detection device according to any one of claims 8 to 14,
An external failure determination unit that receives an output signal of the temperature characteristic correction unit and determines whether or not the angular velocity detection device has failed.

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