JP2000009475A - Angular velocity detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the angular velocity detection sensitivity, to check to see if an angular velocity sensor is abnormal, to calibrate the angular velocity sensor, and to automate the procedures. SOLUTION: The angular velocity detection device is provided with first and second vibration bodies 7, 11/17, and 21 that are floated and supported for a substrate 100 and are symmetrical, drive electrodes 5a, 6a/5b, and 6b for performing the x vibration drive of them, detection electrodes 12, 13/22, and 23 for detecting the y vibration of the vibration bodies, assisting electrodes 62, 63/72, and 73 for giving static electricity force to the vibration body in a y direction, and voltage circuits 64/74 for applying a voltage for static electricity force to them. The assisting electrodes are a pair of electrodes 62, 63/72, 73 for giving static electricity force in the opposite direction to the vibration body. A measurement controller TCR adjusts an assisting voltage Ve to be applied to the assisting electrode for calibrating x amplitude, applies a voltage for feeding a pseudo Coriolis force to the vibration bodies 11 and 21 to the assisting electrodes for reading an angular velocity detection signal and calibrates a measurement circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an angular velocity sensor having a vibrating body floatingly supported on a substrate and an angular velocity detecting device using the same. The floating semiconductor thin film formed by using is electrically attracted / released by a comb-shaped electrode and x
The present invention relates to an angular velocity sensor that excites in a direction and an angular velocity detection device using the sensor.

[0002]

2. Description of the Related Art A typical type of angular velocity sensor has a pair of floating comb electrodes (a left floating comb electrode and a right floating comb electrode) on the left side and one set on the right side of a floating thin film. And two sets of fixed comb electrodes (a left fixed comb electrode and a right fixed comb electrode that mesh with and are parallel to each set of floating comb electrodes in a non-contact manner) as left floating comb electrodes / left fixed comb electrodes. By alternately applying a voltage between the space and the right floating comb electrode / the right fixed comb electrode, the floating thin film vibrates in the x direction. When an angular velocity of rotation about the z-axis is applied to the floating thin film, Coriolis force is applied to the floating thin film, and the floating thin film becomes
An elliptical vibration that vibrates also in the y direction. If the floating thin film is used as a conductor or an electrode is bonded, and a detection electrode parallel to the xz plane of the floating thin film is provided on the substrate, the capacitance between the detection electrode and the floating thin film becomes elliptical oscillation. Vibrates according to the y component (angular velocity component). By measuring the change (amplitude) of the capacitance, the angular velocity can be determined (for example, U.S. Pat. No. 5,635,638, JP-A-5-248872, and JP-A-7-218268).
JP, JP-A 8-152327, JP-A 9-1
27148, JP-A-9-42973).

[0003]

SUMMARY OF THE INVENTION For example, US Pat. No. 56
In the micromachine yaw rate sensor shown in FIG. 4 of Japanese Patent No. 35,638, when the angular velocity detection sensitivity is increased, the excitation drive voltage is increased to increase the displacement of the vibrator, but the adjustment range of the vibration displacement by the excitation drive voltage is narrow. There is no significant improvement in sensitivity. On the other hand, in this type of angular velocity sensor, there are many parameters that change the level of the angular velocity detection signal in addition to the excitation drive voltage and the angular velocity, and an electric processing circuit for checking for abnormal operation of the sensor and generating the angular velocity detection signal. Is important, but the angular velocity detection signal does not change until the angular velocity is applied to the vibrator and Coriolis force is generated.

[0004] For example, the vibrator operates normally,
If the angular velocity detection signal shifts due to abnormal movement of the sensor due to temperature, disturbance, or the like, it cannot be identified as a change in angular velocity.
For example, since the resonance frequency difference between the excitation and angular velocity detection vibration of the dual resonance type angular velocity sensor must be within a certain range, if the frequency of the detection vibration deviates from that range, the angular velocity signal swing I don't know it. When mounted on a moving body such as a vehicle, the angular velocity is estimated from other sensors and the correctness or wrongness of the angular velocity signal of the angular velocity sensor is checked. However, it is difficult to calibrate the output of the angular velocity sensor. Even if the angular velocity sensor changes with time due to temperature or the like, and the output sensitivity is reduced, the angular velocity sensor itself cannot make a determination, so that the reliability of the angular velocity detection signal is reduced.

A first object of the present invention is to provide an angular velocity sensor capable of increasing the detection sensitivity, and a second object of the present invention is to provide an angular velocity sensor which can easily check for an abnormality or calibrate a detection signal. It is a third object of the present invention to provide an angular velocity detecting device for checking an abnormality or calibrating a detection signal.

[0006]

(1) An angular velocity detecting device according to the present invention is a floating support member (a1) having high flexibility in x and y directions.
A4, b1 to b4, c1, c2, 31 to 38) floatingly supported with respect to the substrate (100), arranged in the x direction, and symmetrical with respect to the y axis passing through the midpoint O of the arrangement. Exciting means (5a, 6a / 5b, 6b) for driving at least one of the first and second vibrating bodies in the x direction; y of the first and second vibrating bodies Displacement detecting means (12,13 / 22,23) for detecting vibration; and y displacement assisting means (62,63 / 72,73) for applying a force in the y direction to at least one of the first and second vibrating bodies. ) ;. In addition,
In order to facilitate understanding, the reference numerals of the corresponding elements in the embodiments shown in the drawings and described later are added in the parentheses for reference.

The excitation means (5a, 6a / 5b, 6b) drives the vibrating body to vibrate in the x direction, and when the first and second vibrating bodies vibrate at substantially equal frequencies, z When an angular velocity around the axis is applied, the vibrations of the first and second vibrators become elliptical vibrations due to Coriolis force, and also vibrate in the y direction. First
And the y-vibration of the second vibrating body has a relatively opposite phase,
The first and second vibrators perform torsional vibration around the z-axis. The positive and negative phases of the y vibration with respect to the x vibration correspond to the rotation direction of the angular velocity, and the absolute value of the amplitude of the y vibration corresponds to the magnitude (absolute value) of the angular velocity. The displacement detecting means (12, 13/22, 23) detects these y vibrations. An angular velocity signal can be generated from the detected y vibration.

When the y-displacement assisting means (62, 63/72, 73) applies a force in the y-direction to the vibrating body, the apparent spring constant of the vibrating body in the direction of the force changes, and the amount of displacement is reduced. Changes, the sensitivity of the vibrating body to the angular velocity changes, and the angular velocity detection sensitivity changes. Thereby, the sensor sensitivity, the measurement range, and the like of each specification can be arbitrarily adjusted and set by one sensor design. It is also possible to realize a high-sensitivity and low-cost sensor.

By the way, Fc = 2 × M × Ω × Acosωt Fc: Coriolis force, M: mass of vibrator, Ω: angular velocity A: amplitude of x vibration ω = 2πf, f: frequency of x vibration In order to apply the Coriolis force Fc corresponding to Ω to the vibrator, a force of 2 × M × Ω × Acosωt may be applied to the vibrator. By applying a force of 2 × M × Ω × Acosωt of each value of the angular velocity Ω to the vibrating body by the y displacement assisting means (62, 63/72, 73), the Coriolis force of each value of the angular velocity Ω is applied to the vibrating body. The same force acts as when. By comparing the y-vibration detected by the displacement detecting means (12, 13/22, 23) with the angular velocity Ω corresponding to the applied force, the operation of the angular velocity sensor is determined, and the angular velocity detection characteristics (input angular velocity versus output) (Relationship between detection signals) can be checked, and calibration (adjustment of signal processing characteristics of an electric circuit) that matches the angular velocity detection characteristics with the design characteristics can be performed.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (2) A floating support member (a1 to a4, b1 to b4, c1, c2, 31 to 38) having high flexibility in the x and y directions is used for a substrate (10).
0), the first and second vibrators (7, 1) are arranged in the x direction and symmetric with respect to the y axis passing through the midpoint O of the arrangement.
Exciting means (5a, 6a / 5b, 6b) for driving at least one of the first and second vibrators in the x direction; detecting y-vibration of the first and second vibrators Displacement detection means (12,13 / 22,
23); y for applying an electrostatic force in the y direction to the first vibrator
First electrode means (62, 63) for assisting displacement; second electrode means (72, 73) for assisting y displacement for applying an electrostatic force in the y direction to the second vibrating body; and Means (64/74) for applying a voltage for electrostatic force to the first and second electrode means (62, 63/72, 73).

A voltage for electrostatic force corresponding to a force corresponding to an angular velocity Ω is applied to the first electrode means (62, 63) for assisting y-displacement and the second electrode means (72, 73) for assisting y-displacement. Application means (6
4/74), a force similar to the Coriolis force having an angular velocity Ω is applied to the first and second vibrators. On the other hand, by comparing the y vibration detected by the displacement detecting means (12, 13/22, 23) with the angular velocity Ω corresponding to the applied force, whether the operation of the angular velocity sensor is correct or not, and the angular velocity detection characteristic ( The relationship between the input angular velocity and the output detection signal) can be checked, and the angular velocity detection characteristics can be calibrated. (3) First and second electrode means (62, 63 /
72, 73) are assisting electrodes (62/72) to which the vibrating body approaches when the vibrating body moves in one direction of the y direction and assisting electrodes (63/73) to which the vibrating body approaches when moving in the other direction. )
including.

According to this, both assisting electrodes (62, 63/72, 73)
Are applied in the y direction,
An electrostatic force (attraction force) in the opposite direction is applied to the vibrating body, and they cancel each other, so that substantially no assisting force is applied to the vibrating body. However, when an angular velocity is applied to generate y-vibration, the electrostatic force of the assisting electrode (eg, 62/72) to which the vibrating body approaches increases, and the electrostatic force of the assisting electrode (63/73) to which the vibrating body separates decreases. The y-vibration due to the angular velocity causes both supporting electrodes (62, 63
/ 72,73), and the gain of angular velocity versus y vibration is large. Depending on the DC voltage level applied to both assisting electrodes (62, 63/72, 73), the sensor sensitivity and measurement range of each specification can be arbitrarily adjusted and set by one sensor design. Therefore, a highly sensitive and low-cost sensor can be realized.

On the other hand, when an AC voltage is applied between the two supporting electrodes (62, 63/72, 73), when the electrostatic force (attraction force) of one of the supporting electrodes (eg, 62, 63) is strong, the other supporting electrode ( Since the electrostatic force (suction force) of (72, 73) is weak and is switched, the vibrating body vibrates in the same manner as when the angular velocity is applied. By comparing the y vibration detected by the displacement detecting means (12, 13/22, 23) with the angular velocity Ω corresponding to the electrostatic force of the applied AC voltage, whether the operation of the angular velocity sensor is correct and the angular velocity detection characteristics ( The relationship between the input angular velocity and the output detection signal) can be checked, and calibration (adjustment of the signal processing characteristic of the electric circuit) can be performed to match the angular velocity detection characteristic with the design characteristic.

Further, an AC voltage is applied between the assisting electrodes (62, 63/72, 73) and the level is varied (amplitude modulated) at several low frequencies, and the displacement detecting means (12, 13/22) is used. , 23) by comparing the y-vibration detected with the angular velocity Ω and the modulation frequency corresponding to the electrostatic force of the applied AC voltage, to determine whether or not the angular velocity sensor is operating properly and the angular velocity detection characteristics (relationship between input angular velocity and output detection signal). ) And frequency characteristics (the relationship between the frequency of the input angular velocity and the output detection signal) can be checked.
Calibration (adjustment of signal processing characteristics of an electric circuit) that matches the angular velocity detection characteristics and the frequency characteristics with the design characteristics can be performed. (4) First and second electrode means (62, 63 /
72, 73), an AC voltage for electrostatic force at a plurality of angular velocity levels is sequentially applied, the detected value of the displacement detecting means (12, 13/22, 23) is read, and the detected value is converted into angular velocity. A measurement control unit (TCR) for setting a conversion characteristic of the electric signal processing system. According to this, the calibration of the angular velocity detection characteristics described above is automatically performed. (5) First and second electrode means (62, 63 /
72, 73), sequentially apply voltages for electrostatic force of a plurality of frequencies, read the detected value of the displacement detecting means (12, 13/22, 23), and convert the detected value into an angular velocity. A measurement control unit (TCR) for setting a frequency characteristic of the processing system; According to this, the calibration of the frequency characteristics described above is automatically performed.

Other objects and features of the present invention will become apparent from the following description of embodiments with reference to the drawings.

[0016]

FIG. 1 shows an embodiment of the present invention. In this embodiment, floating anchors a1 to a of conductive polysilicon are provided on the silicon substrate 100 on which the insulating layer is formed.
4, anchors of the drive electrodes 5a, 5b / 6a, 6b, anchors of the drive detection electrodes 15a, 15b / 16a, 16b,
The anchors of the angular velocity detecting electrodes 12, 13/22, 23 and the assisting electrodes 62, 63/72, 73 are joined, and these anchors are illustrated by wiring formed on an insulating layer on the silicon substrate 100. Not connected to the connection electrode.

Using a lithographic semiconductor process, x, y of conductive polysilicon floating from the silicon substrate 100 and continuous to the floating body anchors a1 to a4.
Spring beams b1 to b4, which have high flexibility in the directions, and strip-shaped connecting beams c1 and c2 that are continuous with these spring beams are formed. These connecting beams c1, c2 are symmetric with respect to the x-axis and the y-axis passing through the center O, and the floating body anchors a1-a
4 and the spring beams b1 to b4 are distributed symmetrically with respect to the x-axis and the y-axis.

The connecting beams c1 and c2 are provided with four spring beams 31 to 34/35 each having high flexibility in the x-direction.
The first drive frame 7 and the second drive frame 17 which are continuous with them are supported by. The first and second drive frames 7 and 17 are rectangular frames, and are integrally and internally provided with the first vibrating body 1.
The first and second vibrators 21 are continuous. These elements also float from the silicon substrate 100 and are conductive polysilicon.

The first and second drive frames 7 and 17, the first and second drive frames
Are symmetrical with respect to the x-axis and the y-axis passing through the sensor center O and are at symmetrical positions. The spring beams 31 to 34/35 to 38 are also symmetrical with respect to the x-axis and the y-axis. is there.

Y of each of the first and second drive frames 7 and 17
On the two parallel sides, there are comb-shaped movable electrodes that are distributed at equal pitches in the y direction and protrude in the x direction, and the conductive electrodes 5a and 5b / 6 made of conductive polysilicon are connected to the drive electrode anchors.
a, 6b, and the drive detection electrode anchor,
Drive detection electrodes 15a, 15b / 1 made of conductive polysilicon
In 6a and 16b, there are comb-shaped fixed electrodes protruding in the space of the movable electrode in the y direction, which are distributed in the y direction.

The potentials of the drive frames 7 and 17 (approximately the equipment ground level) are alternately applied to the drive electrodes 5a and 5b and alternately to 6a and 6b.
By applying a higher voltage, the drive frames 7, 17 vibrate in the x direction. In order to make the drive frames 7 and 17 have resonance tuning fork vibration, the x vibrations of the drive frames 7 and 17 are made to have relatively opposite phases.

The first vibration system including the drive frame 7 and the vibrating body 11 and the second vibration system including the drive frame 17 and the vibrating body 21 are caused to vibrate in a resonant tuning fork manner, thereby achieving x-excitation with high energy consumption efficiency. . The first and second drive frames 7,
The resonance frequency of the x vibration of 17 is designed to be the same, and the resonance frequency of the y vibration is designed to be a value several hundred Hz higher or lower than the resonance frequency of the x vibration in order to increase the angular velocity detection sensitivity. I have.

When the drive frames 7 and 17 vibrate in a resonance tuning fork in the x direction, the drive frame 7 and the drive detection electrodes 15a and 16b
And the capacitance between the drive frame 17 and the drive detection electrodes 15b and 16b oscillates in a phase opposite to that of the capacitance oscillation.

Vibrators 11 and 21 integrated with drive frames 7 and 17
Are generally frame-shaped, but a plurality of bridges extending in the x direction are present at equal pitches in the y direction, and a pair of conductive polysilicons is fixed in a space between bridges adjacent in the y direction. There are detection electrodes 12, 13/22, and 23, and there are assisting electrodes 62, 63/72, and 73 having the same structure as the fixed detection electrode, and are supported by the detection electrode anchors on the substrate 100 and electrically connected thereto. It is continuous.

Although the pair of detection electrodes 12, 13 (22, 23) are insulated, the y-vibration (y
Each of the counter electrodes 12, 13 (22, 2) for detecting
In 3), the detection electrodes at the corresponding positions between each pair are electric relays.
And the charge amplifiers 46 and 47 (56,
57).

Similarly, a pair of assisting electrodes 62, 63 (72,
73) is insulated, but y of the vibrating body 11 (21) is
Each counter electrode 62, 63 for supporting vibration (y displacement)
(72, 73) which are at corresponding positions between each pair are commonly connected to electric leads and connected to supporting voltage circuits 64, 74. The assisting voltage circuits 64 and 74 each include a voltage controlled frequency variable oscillator (VCO), an amplitude modulator, and a direct current and AC voltage output circuit.
Output the AC voltage or the DC voltage of the designated frequency at the designated frequency to the assisting electrodes 62, 63 (72, 73).

When the vibrating bodies 11 and 21 are vibrating in a tuning fork direction in the x direction, when an angular velocity about the z axis passing through the center O is applied,
The vibrating bodies 11 and 21 become relatively opposite-phase elliptical vibrations also having a y component, whereby the electrodes 12, 13/22, 2
3 produces a capacitance vibration corresponding to the y vibration. Electrodes 12, 1
The capacitance oscillations of the electrodes 22 and 2 are relatively opposite in phase.
The capacitance oscillation of No. 3 is also relatively opposite in phase. Since the y vibrations of the vibrators 11 and 21 are in opposite phases, the electrodes 12 and 2
The capacitance oscillations of the electrodes 13 and 2 are relatively opposite in phase.
The capacitance oscillation of No. 3 is in a relatively opposite phase.

At the time of measuring the angular velocity, the measurement controller TC
R generates drive signals A and B for driving the drive frames 7 and 17 at the resonance frequency in the x-direction and supplies them to the drive circuits 41 and 51, and also outputs a synchronous signal for synchronous detection to the synchronous detection circuits 45a and 45a. 45b, 50a, 50b.

The driving circuit 41 is synchronized with the driving signals A and B.
/ 51 applies a drive voltage (pulse) to the drive electrodes 5a, 6a / 5b, 6b. Accordingly, the vibrating body 11 and the vibrating body 21 together with the drive frame 17 vibrate in the x-direction in opposite phases via the first and second drive frames 7/17. Due to this vibration, the drive detection electrodes 15a, 16a /
The capacitances of 15b and 16b vibrate in opposite phases. The vibration of the capacitance is transmitted to the charge amplifiers 42a, 43a / 42b,
43b converts it into a voltage oscillation (capacitance signal), and the output adjustment (adjustable gain amplifier) adjusts the peak level of the voltage oscillation to be substantially the same, and gives it to the differential amplifiers 44a / 44b.

The differential amplifiers 44a / 44b differentially amplify a given capacitance signal (reverse phase), make the amplitude of one of the capacitance signals approximately double, and convert the differential signal with noise cancelled. After being generated and subjected to output adjustment (amplification by an adjustable gain amplifier), it is given to a measurement controller TCR and a differential amplifier 61. The differential amplifier 61 amplifies the difference and provides the same to the synchronous detection circuits 45a and 45b. The synchronous detection circuit 45a detects a differential signal provided by the differential amplifier 61, that is, an x-vibration detection voltage representing x-vibration, in synchronization with a synchronous signal having the same phase as the drive signal, and detects a phase shift of the x-vibration with respect to the drive pulse signal. A representative phase signal is generated and applied to the measurement controller TCR. Synchronous detection circuit 45b detects a differential signal provided by differential amplifier 61, that is, an x-vibration detection voltage representing x-vibration, and generates an amplitude signal representing the amplitude of x-vibration, in synchronization with a synchronous signal in phase with the drive signal. To the measurement controller TCR.

The measurement controller TCR outputs a phase shift signal for adjusting the phase represented by the phase signal to the set value and a voltage instruction signal for adjusting the amplitude of the x vibration indicated by the amplitude signal to the set value. The drive circuits 41 and 51 receiving the shift shift the phase of the output drive voltage with respect to the drive signal in response to the phase shift signal and shift the output voltage level in response to the voltage instruction signal. With the phase signals and the amplitude signals of the synchronous detection circuits 45a and 45b substantially at the set values, the x vibration of the drive frames 7 and 17, that is, the resonance tuning fork vibration becomes stable.

When an angular velocity about the z-axis passing through the center O is applied during the stable resonance tuning fork vibration, Coriolis force is applied to the drive frames 7 and 17, and an elliptical motion including y vibration in addition to x vibration is applied thereto. Wake up. By the way, the drive frames 7, 17
Are supported by spring beams 31 to 34 and 35 to 38, which have high flexibility in the x direction but high rigidity in the y direction, so that the connecting beams c1 and c2 vibrate in the y direction together with the drive frames 7 and 17. I do. Since the y-vibrations of the drive frames 7 and 17 are relatively opposite in phase, the connecting beams c1 and c2 vibrate in a torsional (turning) manner around the z-axis passing through the center O.

FIG. 2 shows drive signals A and B and x and y vibrations. Referring to FIG. 1 again, a pair of detection electrodes 12 and 1 for detecting y vibration of the vibrating body 11 integrated with the drive frame 7.
3 oscillates in opposite phases, and the charge amplifiers 46 and 47 generate capacitance signals representing the same, and the output adjustment (adjustable gain amplifier) makes the peak level of the voltage oscillation substantially the same. It is adjusted and given to the differential amplifier 48. The differential amplifier 48 substantially doubles the amplitude of the differential signal of the two signals, that is, one of the capacitance signals, generates a differential signal in which noise is canceled out, and adjusts the level by output adjustment (adjustable gain amplifier). After that, it is given to the differential amplifier 49. Similarly, a pair of detection electrodes 2 for detecting y vibration of the vibrating body 21 integrated with the drive frame 17
2, 23 are provided to the differential amplifier 49.
Therefore, the differential output of the differential extender 49 is
Noises acting on the respective signal processing circuits of the first and second vibrating bodies 21 at substantially the same level at the same time are canceled out, and the same direction is applied to the first and second vibrating bodies 11 and 21 simultaneously, such as acceleration, deceleration, and vibration. Is a detection signal obtained by amplifying the y-vibration caused by the angular velocity, which also cancels out the y-displacement component (also corresponding to noise) of the vibrating body due to the external force acting on the vibrating body.
N is high.

The differential output, that is, the detection signal is applied to synchronous detection circuits 50a and 50b, and the synchronous detection circuit 50a
Detects a detection signal in synchronization with a synchronization signal having the same phase as the drive signal, and generates a phase signal representing the direction of the angular velocity. Synchronous detection circuit 50b generates an amplitude signal representing the absolute value of the angular velocity.

The assisting voltage circuit 64/74 is connected to the assisting electrode 6
When the same DC voltage is applied to 2, 63/72, 73, an electrostatic force (attraction force) in the y direction but in the opposite direction is applied to the vibrating body 11/21. Has virtually no support. However, when an angular velocity is applied to generate y-vibration, the electrostatic force of the fixed electrode (for example, 62/72) to which the vibrating body approaches increases, and the electrostatic force of the fixed electrode (63/73) to which the vibrating body separates decreases.
The y-vibration caused by the angular velocity is caused by the two supporting electrodes
3, the gain of angular velocity versus y vibration is large. The gain of angular velocity versus y vibration can be set by the DC voltage level applied to both assisting electrodes 62, 63/72, 73.

On the other hand, when the assisting voltage circuit 64/74 applies an AC voltage between the assisting electrodes 62, 63/72, 73, the electrostatic force (attraction force) of one of the assisting electrodes (eg, 62, 63) is strong. At this time, the electrostatic force (attraction force) of the other assisting electrodes (72, 73) is weak, and this is switched, so that the vibrating body 11/21 vibrates in the same manner as when the angular velocity is applied.

FIG. 7 shows the y-displacement and y-vibration speed of the vibrators 11 and 21 when a pseudo Coriolis force indicating a sine curve change is applied to the vibrators 11 and 21.

By comparing the output of the differential amplifier 48/58 with the angular velocity Ω corresponding to the electrostatic force of the applied AC voltage, whether the operation of the angular velocity sensor is correct or not, and the angular velocity detection characteristics (input angular velocity versus output detection signal) Can be checked, and calibration (adjustment of the signal processing characteristics of the electric circuit) that matches the angular velocity detection characteristics with the design characteristics can be performed. Also, the level of the AC voltage applied between the two assisting electrodes 62, 63/72, 73 is varied (amplitude modulated) at several low frequencies, and the output of the differential amplifier 48/58 and the electrostatic force of the applied AC voltage are changed. By comparing the corresponding angular velocity Ω and the modulation frequency, whether the angular velocity sensor operates correctly, angular velocity detection characteristics (relationship between input angular velocity and output detection signal) and frequency characteristics (relationship between frequency of input angular velocity and output detection signal)
Can be checked, and calibration (adjustment of the signal processing characteristics of the electric circuit) that matches the angular velocity detection characteristics and the frequency characteristics with the design characteristics can be performed.

In this embodiment, since an output adjustment (gain-adjustable amplifier) is provided, even if the imbalance of the signal of the differential configuration occurs for various reasons, the drive signal and the charge are not controlled.
It can be adjusted at the output stage of the di-amplifier and, if necessary, at the input stage of the differential amplifier to reduce the noise of the drive detection and angular velocity detection signals and adjust the imbalance between the detection signals. Not only can the S / N be increased, but also the sensor yield can be increased and the cost can be reduced.

The measuring controller TCR is a computer system including a micro computer and an input / output electric circuit, and automatically performs an abnormality check of the angular velocity sensor, a calibration of the angular velocity detection characteristic, and a calibration of the frequency characteristic. This embodiment is mounted on a vehicle,
A signal from an on-vehicle state information generator (not shown) for determining whether the vehicle is stopped or running is also supplied to the measurement controller TCR. An operating voltage (power supply) is applied to the measurement controller TCR when the on-vehicle ignition key is turned on (during engine operation).

FIG. 3 shows an outline of the measurement control of the measurement controller TCR. When the operating voltage is applied, the microcomputer of the measurement controller TCR performs "setting of the frequency f of x excitation, the voltages V and Ve" A after initialization. Here, first, via the drive circuits 41 and 51,
The output of the voltage pulse with the initial frequency f0 which is the lower limit of the design range and the initial voltage V0 which is the middle value of the design range is started, and the assisting electrodes 62, 63/72 and 73 have the middle value of the design range. An initial assist DC voltage Ve0 is applied (step 1). Hereinafter, the word “step” is omitted in parentheses, and step No. Write only numbers.

Thereafter, the frequency f of the x excitation is increased by a small value Δf in the period t0, and the x vibration detection signal (output of the differential amplifiers 44a and 44b) for the drive signal A (frequency f) applied to the drive circuits 41 and 51 is output. Is shifted from 90 ° (the frequency f is lower than the resonance frequency of the x vibration of the drive frames 11 and 21) to 90 ° lag (the frequency f is x
It is checked whether the frequency has been switched to (higher than the resonance frequency of the vibration), and the number N0 of upshifts of the frequency f is counted (repetition of 2 to 7). That is, until the frequency slightly exceeds the resonance frequency of the drive frames 11 and 21, the x excitation frequency f
Higher. When the number of upshifts N0 reaches the set value PN0 (when the frequency f exceeds the design upper limit value), it is regarded as a sensor failure, an error is notified, and the system stands by (1).
1).

If the x-vibration detection signal switches to a delay of 90 ° before reaching the set value PN0, the x-excitation frequency f at that time is the resonance frequency of the drive frames 11 and 21 or a slightly higher frequency. . Upon recognizing this, the measurement controller TCR outputs the x vibration detection signal (differential amplifiers 44a and 44a).
It is checked whether the amplitude (detection amplitude) of the output 4b is within a comparatively wide setting range R0 (8). If not, the output voltage V of the drive circuits 41 and 51 and, if necessary, the supporting electrode The supporting DC voltage Ve of 62, 63/72, 73 is
The detection amplitude is adjusted so as to fall within the set range R0 (9). If the output voltage level V or the assisting DC voltage Ve is out of the design range, it is regarded as a sensor failure, an error is notified, and the process waits (11), but both the output voltage level V and the assisting DC voltage Ve are in the design range. When the detected amplitude falls within the set range R0 within the range, the “x vibration stability determination” (1
Perform 2).

In "determination of stability of x vibration" (12), the measurement controller TCR detects m continuous peak values of the detected amplitude and calculates an average value thereof. Then, it is checked whether the difference between each peak value with respect to the average value exceeds ± 0.1% of the average value, and if it exceeds, the frequency is reduced by Δf and the variation of the peak value is checked (12 to 12). 15). Even if the frequency is lowered to the initial frequency f0, the variation is ± 0.1
%, It is regarded as a sensor failure, an error is notified, and there is a wait (11).
When the variation is within ± 0.1% by 0, the amplitude (detection amplitude) of the x-vibration detection signal (the output of the differential amplifiers 44a and 44b) falls within the second setting range R1 which is extremely narrower than the setting range R0. (16). If not within the setting range R1, the output voltage level V of the drive circuits 41 and 51 and, if necessary, the assisting DC voltage Ve are adjusted so that the detected amplitude falls within the setting range R1 (17). This adjustment is performed finely. That is, the amount of voltage change at one time is a small value. If the detected voltage does not fall within the set range R1 and the output voltage level V or the assisting DC voltage Ve is out of the design range, it is regarded as a sensor failure, an error is notified, and the process stands by (11). When the detected amplitude falls within the set range R1, the process proceeds to “zero point drift determination” B. In the “zero point drift determination” B, the angular velocity Ω = +
A voltage obtained by adding an AC voltage having a frequency f that applies an electrostatic force of 0.5 ° / sec to the vibrators 11 and 21 is applied to the assisting voltage circuit 6.
4, 74 applied to the assisting electrodes 62, 63/72, 73 via the y-vibration of the vibrators 11, 21 (differential amplifiers 48, 4).
9/58, 59), and an AC voltage having a frequency f that applies an electrostatic force equivalent to an angular velocity Ω = −0.5 ° / sec to the vibrators 11 and 21 is added to the assisting DC voltage Ve. Vibrating body 1 is applied to assisting electrodes 62, 63/72, 73
The y-vibration of 1,21 is read, the midpoint of the two read values is calculated, and it is checked whether the midpoint value (drift zero point value) is within the allowable range. Proceeding to “drift adjustment” C, the gain reaching the inputs of the differential amplifiers 48 and 49 and the supporting DC voltage V applied to the supporting electrodes 62, 63/72 and 73 as necessary to make the midpoint value zero.
e is differentially adjusted. In the difference adjustment, the assisting electrodes 62 and 63
With respect to, only one is raised or lowered and, if necessary, one is raised and the other is lowered. The same applies to the assisting electrodes 72 and 73.

Then, "zero point drift determination" B is performed. Here, a voltage obtained by adding an assisting voltage Ve to a DC voltage that gives an electrostatic force equivalent to an angular velocity Ω = ± 0.5 ° / sec is applied to the vibrating body 11, the assisting electrode. 62, 63/72, 73. Until the voltage (DC voltage + assisting voltage Ve) is out of the set range or the midpoint value is within the allowable range (a range that can be regarded as 0), “zero point drift determination” B and “drift adjustment”
C is repeated, and when the voltage (DC voltage + assisting voltage Ve) is out of the set range, it is regarded as a sensor failure, an error is notified, and the process stands by (11). When the midpoint value falls within the allowable range, the assisting voltage Ve is saved as a bias value in a register (one area of the internal memory), and the process proceeds to “detection sensitivity adjustment” D.

FIG. 4 shows the contents of "detection sensitivity adjustment" D.
Proceeding to this, the measurement controller TCR becomes ± 0.5, ± 0.5
1.0, ± 10.0, ± 20.0, ± 50.0, ± 10
A voltage obtained by adding the previously saved bias value (Ve) to an AC voltage having a frequency f that gives an electrostatic force equivalent to 0 ° / sec is sequentially applied to the assisting electrodes 62, 63/72, and 73. The outputs (angular velocity signals) of the synchronous detection circuits 50a and 50b are read (21). This is the application of a total of 12 pseudo angular velocity voltages and reading of the angular velocity signal. The relationship between the pseudo angular velocities (horizontal axis) corresponding to 12 applied voltages and the angular velocity signals at each point is approximated by a straight line (linear expression), and an approximate linear function, angular velocity signal (level) = a × angular velocity + b, is obtained. (22). Then, it is checked whether the value b of the approximate linear function is within a set range (substantially zero area) (23, 24). If it is out of the setting range, the first "setting of the frequency f of x excitation and the voltage V"
Return to A.

If the value b is within the set range, it is checked whether the value a (slope) of the approximate linear function is within the set range (25, 26). If it is out of the setting range, the input and output gains of the differential amplifier 49 and / or the input and output gains of the synchronous detection circuit 50b are adjusted in the direction of entering the setting range (27). Every time one adjustment (gain change) is performed, the process returns to the above-described sampling of 12 points (21). If the value a does not fall within the setting range and goes out of the adjustment range, the process returns to the initial "setting of the frequency f of x excitation and the voltage V" A (28). When the value a falls within the set range, the process proceeds to “linearity adjustment” E (2
6).

FIG. 5 shows the contents of the “linearity adjustment” E.
Proceeding to this, the measurement controller TCR becomes ± 0.5, ± 0.5
1.0, ± 10.0, ± 20.0, ± 50.0, ± 10
A voltage obtained by adding the previously saved bias value (Ve) to an AC voltage having a frequency f that gives an electrostatic force equivalent to 0 ° / sec is sequentially applied to the assisting electrodes 62, 63/72, and 73. The outputs (angular velocity signals) of the synchronous detection circuits 50a and 50b are read (31). This is the application of a total of 12 pseudo angular velocity voltages and reading of the angular velocity signal. The relationship between the pseudo angular velocity (horizontal axis) corresponding to 12 applied voltages and the angular velocity signal at each point is approximated by a straight line (linear expression), and an approximate linear function, angular velocity signal (level) = A × angular velocity + B, is obtained. (32). Then 12
The distance of each point to the approximate straight line is calculated (3
3) Check if they are within the setting range (3
4) If there is something outside the setting range, the process returns to the initial "setting of the frequency f of x excitation and the voltage V" A (34). If all the calculated distances (12 points) are within the set range, a quadratic curve function that approximates a series of 12 points is calculated (35).
Then, an inverse function (detection value correction function) for moving the calculated point on the quadratic curve to the approximate straight line calculated in step 32 is calculated (36). Then, the measured values at the above 12 points are given to the inverse function to calculate respective inverse function values (correction values) (by performing linear correction on the measured values) (37), and the linearity of the calculated correction values at the 12 points is calculated. A determination is made (38). Here, the distance of each correction value from the approximate straight line is calculated. Then, it is checked whether or not the calculated distance (12 points) is within the set range (39). If all the distances are within the set range, the process proceeds to “frequency characteristic adjustment” F. When the value is out of the setting range, the process returns to the initial "setting of frequency f and voltage V of x excitation" A.

FIG. 6 shows the contents of "frequency characteristic adjustment" F. Here, first, frequency 0 (DC), 1, 3, 5, 1
A bias value Ve is added to a voltage f of a frequency f that gives an electrostatic force equivalent to ± 100 ° / sec, modulated at 0 and 30 Hz, and voltages are sequentially applied to output voltages (angular velocity signals) of the synchronous detection circuits 50a and 50b. Read (41). This is a total of six points of application of pseudo angular velocity voltages having different frequencies and reading of angular velocity signals. Next, the measurement controller TCR calculates an approximate elliptic function that represents a series of measured values at six points and has an angular velocity frequency on the horizontal axis and an angular velocity on the vertical axis (42).
Then, the variance of the six measurement values with respect to the elliptic function is calculated (43), and it is checked whether it is within the set range (44). If it is within the setting range, at the angular velocity frequency within the design range,
The gain corresponding to the frequency for shifting the measurement value on the elliptic function to a straight line parallel to the horizontal axis passing through the intersection of the ellipse and the vertical axis is set in the output amplifier of the differential amplifier 49 (4).
5). Then, the process proceeds to “angular velocity measurement” G.

Measurement control in "Angular velocity measurement" G
The TCR determines whether the vehicle is stopped or running based on a signal from an on-vehicle state information generator (not shown). During running, the TCR outputs a voltage pulse of the frequency f and the voltage V set in the above-described processing to the drive electrode 5a. , 6a / 5b, 6b, and
2, 63/72, 73 are supplied with the assisting direct-current voltage Ve, and the synchronous detection circuits 50a, 50
b), the signal of the synchronous detection circuit 50b is corrected based on the inverse function set in step 36 to obtain an angular velocity value, and the angular velocity data (direction and magnitude) is obtained by a host (not shown). Output to computer.

When the vehicle is stopped, the process proceeds from "measurement of angular velocity" G to "setting of frequency f of x excitation, voltage V, Ve" A at a predetermined cycle. Then, the process proceeds to “angular velocity measurement” G via “zero point drift determination” B, “drift adjustment” C, “detection sensitivity adjustment” D, and “linearity adjustment” E.
Therefore, while the vehicle is stopped, the angular velocity sensor is checked and the measurement circuit is calibrated at a predetermined cycle.

In the angular velocity sensor shown in FIG. 1, the drive frames 7 and 17 are driven by resonance x vibration by the drive circuits 41 and 51, respectively. However, the x vibration drive may be performed by only one of the drive frames 7 and 17. In that case, the drive frames 7 and 17 are
~ 38 and the connecting beams c1 and c1
When only one drive frame 7 is driven by x vibration at the resonance frequency,
The drive frame 7 resonates at the resonance frequency. Further, the vibrating body 11,
21 is integrated with the drive frames 7 and 17,
Alternatively, the vibration bodies 11 and 21 may be separated from the drive frames 7 and 17 by spring beams.

[Brief description of the drawings]

FIG. 1 is a plan view of one embodiment of the present invention.

FIGS. 2A and 2B are time charts showing drive signals A, B and the like provided to drive circuits 41, 42 shown in FIG. 1, respectively. FIGS. 2A and 2B show drive signals A, B; Represents the x vibration of the vibrating bodies 11 and 21, and (d) represents the supporting electrode 6.
2, (e) shows the supporting voltage Ve, and (f) shows the supporting electrodes 62, 63/72, 73 when the supporting voltage Ve is not applied to the supporting electrodes 2, 63/72, 73. Vibrators 11 and 21 when no assisting voltage Ve is applied to
Y-vibration are shown.

FIG. 3 is a flowchart showing an outline of measurement control of a measurement controller TCR shown in FIG. 1;

FIG. 4 is a flowchart showing the content of “detection sensitivity adjustment” D shown in FIG. 3;

FIG. 5 is a flowchart showing the contents of “linearity adjustment” E shown in FIG. 3;

FIG. 6 is a flowchart showing the content of “frequency characteristic adjustment” F shown in FIG. 3;

FIG. 7 shows the pseudo Coriolis force, the y displacement of the vibrators 11, 21 and the y vibration velocity when a pseudo Coriolis force showing a sine curve change is applied to the vibrators 11, 21 shown in FIG. It is a graph shown.

[Explanation of symbols]

a1 to a8: anchors b1 to b8, 1 to 3, 8, 10 to 19, 20: spring beams c: connecting frame 4: driving frame 5, 6: driving electrode 7: first driving frame 11: first vibrating body 12 , 13,22,2
3: y displacement detection electrode 14, 24, 64: vibration frame 15, 16, 65, 6
6: drive displacement detection electrode 25, 26: frequency adjustment electrode 31-38: spring beam 62, 63/72, 73: assisting electrode

Claims (5)

[Claims] 1. A first and second vibrating body which is floated and supported on a substrate by a floating supporting member having high flexibility in x and y directions, is arranged in the x direction, and is symmetric with respect to a y-axis passing through an intermediate point O in the arrangement. ;
Exciting means for driving at least one of the first and second vibrators in the x direction; displacement detecting means for detecting y-vibration of the first and second vibrators; and at least one of the first and second vibrators On the other hand, an angular velocity detecting device comprising: a y displacement assisting means for applying a force in the y direction. 2. A first and second vibrating body which is supported by a floating support member having high flexibility in the x and y directions, is arranged in the x direction, and is symmetric with respect to the y-axis passing through an intermediate point O in the arrangement. ;
Exciting means for driving at least one of the first and second vibrators in the x direction; displacement detecting means for detecting y vibration of the first and second vibrators; applying an electrostatic force in the y direction to the first vibrator. First electrode means for assisting y displacement; second electrode means for assisting y displacement for applying an electrostatic force in the y direction to the second vibrator; and first and second electrode means for assisting y displacement. Means for applying a voltage for electrostatic force to the device. 3. The first and second electrode means for assisting y-displacement include an assisting electrode to which the vibrating body approaches when the vibrating body moves in one direction of the y-direction and a vibrating body when moving in the other direction. The angular velocity detecting device according to claim 2, further comprising an assisting electrode. 4. An AC voltage for electrostatic force at a plurality of angular velocity levels is sequentially applied to the first and second electrode means for assisting y displacement, and the detected value of the displacement detecting means is read, and the detected value is read. The angular velocity detection device according to claim 2, further comprising: a measurement control unit that sets a conversion characteristic of an electric signal processing system that converts the angular velocity into an angular velocity. 5. An AC voltage for electrostatic force of a plurality of frequencies is sequentially applied to the first and second electrode means for assisting y displacement, and the detected value of the displacement detecting means is read, and the detected value is converted to an angular velocity. The measurement signal control means for setting a frequency characteristic of the electric signal processing system for converting the electric signal into a signal.
The angular velocity detecting device according to any one of the preceding claims.