JPH0979859A - Offset measurement device of vibration type angular velocity sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simply perform offset measurement even after mounting an angular velocity sensor, reduce an error due to change of the lapse of time and temperature change of the angular velocity sensor, and improve angular velocity detecting accuracy of the angular velocity sensor. SOLUTION: A signal for offset measurement of a low frequency f1 is impressed, and the output S1 at the time (S1 =Af1 +C, where A: constant) is measured (S21, 22). A signal for angular velocity detecting high frequency f2 is applied, and the output S2 at the time (S2 =Amf1 +C, where f2 =mf1 ) is measured (S23, 24). An offset value C [C=(mS1 -S2 )/(m-1)] is computed, based on both measured output S1 , S2 .

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an offset measuring device for measuring an offset value due to manufacturing variations of a vibration type angular velocity sensor.

[0002]

2. Description of the Related Art A conventional vibration type angular velocity sensor is disclosed in, for example, Japanese Patent Application Laid-Open No. 61-100608. Such a conventional example will be described with reference to FIG. FIG.
In FIG. 3, the mass part 3 is attached to the distal end side of the flexible optical fiber 2 whose base end side is fixed to the fixing part 1. A metal film is vapor-deposited on the surface of the optical fiber 2. The electrode 4 is arranged close to the optical fiber 2, and an AC voltage is applied between the optical fiber 2 and the electrode 4 by an AC power supply 5, so that the optical fiber 2 is vibrated in the y-axis direction in the figure. Light is incident from the base end side of the optical fiber 2, and the light 6 emitted from the front end side of the optical fiber 2 is projected on the photodetection element 7.

When there is no angular velocity ω (ω = 0), the optical fiber 2 oscillates parallel to the y-axis direction, so that the photodetector element 7 draws a locus as shown by 8 in FIG. When an angular velocity ω = ω ₁ occurs around the x-axis in the figure, a Coriolis force is generated in the mass part 3 in the z-axis direction in the figure, and as a result, the locus projected on the surface of the photodetector element 7 is as shown in FIG. It will be inclined like 9 of. Therefore, if the inclination of the locus 9 with respect to the locus 8 is detected by the photodetector 7, the angular velocity ω ₁ can be measured.

Further, FIGS. 12 and 13 show another conventional example of the vibration type angular velocity sensor. This is “A Micromachined Co
mb-Drive Tuning Fork Rate Gyroscope ", IEEE Micro E
lectro Mechanical Systems 1993 Proceedings pp.143-
As described in 148, a vibration type angular velocity sensor is manufactured by microfabrication of the surface of a semiconductor substrate.

The mass portions 21 and 22 are held by the beam 25 fixed to the substrate 24 by the fixing portion 23 in a state of floating from the substrate 24 as shown in FIG. In addition, another fixed part 26 and mass part 2
There is a comb-teeth-shaped electrode 27 with a minute gap between 1 and 22. By applying a voltage between the electrodes 27, the mass portions 21 and 22 are moved to the substrate in the x-axis direction by electrostatic force. Vibrate parallel to 24. Here, when the angular velocity ω = ω ₁ is applied around the y axis, Coriolis force is generated in the mass portions 21 and 22 in the z axis direction,
As a result, the mass parts 21 and 22 also vibrate in the z-axis direction perpendicular to the substrate 24. Substrate based on this z-axis displacement
The angular velocity ω ₁ is detected by measuring the change in the electrostatic capacitance between 24 and the mass parts 21 and 22 with the detection electrodes 28 and 29. By the way,
In this conventional example, the mass portions 21 and 22 are driven in opposite phases to each other so that the Coriolis force generation directions are opposite between the mass portions 21 and 22. Then, the angular velocity detection removes the in-phase external noise (for example, acceleration in the z-axis direction) by taking the differential signal of each mass portion, and at the same time enhances the detection sensitivity.

[0006]

However, such a conventional vibration type angular velocity sensor has the following problems. The vibration type angular velocity sensor has a Coriolis force Fc (= 2 ×) generated when a certain mass m is vibrated at a velocity v.
m × v × ω) is used to measure the displacement of the mass part and the strain of the beam that occurs with it by various methods (capacitance, strain gauge, piezoelectric effect, etc.), but generally, we try to miniaturize the angular velocity sensor. Then, the size of the mass portion and the beam that supports it also inevitably becomes small, and when detecting a small angular velocity, the Coriolis force generated becomes a very small value. As a result, the displacement of the mass portion due to the Coriolis force is also extremely small, and therefore generally highly accurate displacement (or strain) detection is required.

For example, as shown in FIG. 14, the mass part (200 μm)
A single crystal silicon of × 200 μm × 10 μm (about 1 μg) is supported by a double-supported beam (two single crystal silicon of 600 μm length, 10 μm width, and 10 μm thickness), and this mass part has an amplitude of 10 μm.
oscillate parallel to the substrate at mp-p and frequency f = 20 kHz,
If an angular velocity ω = 1 degree / sec is given in the direction perpendicular to the vibration direction,
Only a displacement of about 3 nm appears (when Q = 1000,
Q: Quality factor). This is a displacement of only 0.3% when the distance between the substrate and the mass part (initial gap) when ω = 0 is 1 μm.

Therefore, in such a high-accuracy sensor, the angular velocity ω = 0 due to a slight deviation in structure or the like.
There is a possibility that output may occur even in the state of. In other words, the designer usually decides the structure so that the output is zero or a certain value is generated in the state of the angular velocity ω = 0. However, there are variations in the manufacturing of the structure, the uneven driving force, and the heat due to the temperature change. The generation of stress does not necessarily cause the vibration as designed, and the variation of the offset value (output value when the angular velocity ω = 0) differs for each product. Especially, when a highly sensitive angular velocity sensor is designed, this variation becomes a serious problem.

FIG. 15 shows a case where an offset occurs in the conventional example shown in FIG. Due to the slight deviation generated when fixing the optical fiber 2, the deviation of the driving electrode, and the nonuniformity of the driving electrostatic force, the same as the ideal locus 8 (shown by the dotted line in the figure) when the angular velocity ω = 0. A locus inclination (offset) occurs as shown by 8'in the figure. In addition, FIG.
In the conventional example shown in FIG. 12, an offset occurs and the angular velocity ω = 0
This shows the case where the displacement change appears even in the state of. Also in this case, the tilt of the mass part (offset) is caused by the slight distortion of the beam 25 supporting the mass parts 21 and 22, the non-uniformity of the electrostatic driving force, and the distortion caused by the thermal stress from the substrate 24.
Has occurred.

Such an offset varies among individual products. Conventionally, in order to realize a highly accurate angular velocity sensor, offset adjustment must be performed in a state in which a known angular velocity is applied to each product. However, the cost increases. Further, even if such an offset adjustment is made at the time of manufacturing the product, it is possible that the offset may change due to a change over time during use of the product or a temperature change. In particular, when the signal of the angular velocity sensor is used to estimate the vehicle position in a navigation system of an automobile or the like, a high-sensitivity and low-offset angular velocity signal is required. It was difficult to get a signal.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide an offset measuring device for a vibration type acceleration sensor which can perform offset measurement extremely easily and can perform offset measurement even when an angular velocity sensor is used. To aim.

[0012]

For this reason, in the invention according to claim 1, the mass portion supported so as to be displaceable is vibrated, and the Coriolis force generated in the mass portion in the vibrating state when the angular velocity is input is detected. An offset measuring device for measuring an offset value of a vibration type angular velocity sensor A for detecting an input angular velocity based on the detected value, which generates at least one offset measuring signal having a predetermined frequency as shown in FIG. And an exciting unit B for vibrating the mass unit and an offset calculating unit C for calculating an offset value based on an output value when the mass unit is driven by an offset measuring signal of the exciting unit B.

According to this structure, the mass portion of the angular velocity sensor can be excited by the signal of the predetermined frequency, and the offset value can be obtained based on the output value based on this exciting operation, so that the offset measurement is extremely simple. In addition, offset measurement is possible even when the angular velocity sensor is mounted and used. Specifically, as in the invention described in claim 2, the excitation means B generates one offset measuring signal of low frequency having a Coriolis force of substantially zero, and the offset calculation means C causes the offset calculation signal to be generated. The output value based on the measurement signal may be set as the offset value. Further, as in the invention of claim 3, the excitation means B generates two offset measurement signals having different frequencies, and the offset The calculation means C may be configured to calculate the offset value based on the difference between the output values based on the respective offset measurement signals.

According to the second aspect of the invention, the offset value can be directly obtained from the output value of the angular velocity sensor A. Further, according to the third aspect of the invention, even if it is difficult in the circuit to vibrate the mass part of the angular velocity sensor with a signal having an extremely low frequency such that the Coriolis force becomes substantially zero, it is possible to perform the offset measurement. Become.

According to a fourth aspect of the present invention, the excitation means B may generate the offset measuring signal once just before the activation of the angular velocity sensor. In this invention,
Immediately before starting the angular velocity sensor, perform offset measurement once,
By storing the offset value at that time and correcting the output of the angular velocity sensor using the offset value stored during the angular velocity measurement by the angular velocity sensor, it becomes possible to continuously perform the angular velocity measurement during the angular velocity measurement of the angular velocity sensor.

According to a fifth aspect of the present invention, the exciting means B may be configured to periodically generate an offset measuring signal during use of the angular velocity sensor A. According to this invention, the offset measurement is periodically performed during use of the angular velocity sensor A, the latest offset measurement value is stored, and the output of the angular velocity sensor is obtained using the latest offset value stored when the angular velocity sensor A measures the angular velocity. By correcting,
It is possible to suppress an error in the sensor output value due to a change in the offset value due to a change with time or a change in temperature of the angular velocity sensor A, and the reliability of the angular velocity sensor A can be improved.

According to the sixth aspect of the invention, one of the two offset measuring signals generated from the exciting means B has the same frequency as the angular velocity detecting signal used in the angular velocity sensor A. Good. According to this invention, when the offset measuring function according to the present invention is added to the angular velocity sensor A, it is possible to simplify the excitation mechanism and reduce the cost.

Further, as in the invention described in claim 7, the exciting means B continuously generates a plurality of cycles for the offset measuring signal, and the offset calculating means C calculates the offset value calculated for each cycle. It is preferable that the average value in the plurality of cycles is used as the offset value. According to this invention, the accuracy of the offset measurement can be improved, and the reliability of the offset measuring device can be improved.

[0019]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is a diagram showing a first embodiment of an offset measuring device according to the present invention. In FIG. 2, the driving oscillator 51 sends a signal for offset measurement or angular velocity detection having a constant amplitude to the angular velocity sensor 52. The angular velocity sensor 52 drives the mass portion by a signal from the driving oscillator 51, and converts the Coriolis force generated in proportion to the input angular velocity into the displacement of the mass portion and outputs the displacement.
The displacement of the mass portion of the angular velocity sensor 52 is converted into an analog electric signal by the displacement detector 53 and converted into a digital signal by the A / D converter 54. The angular velocity sensor 52
In the case of the method of detecting the Coriolis force corresponding to the input angular velocity by converting it into the strain of the beam, the displacement detector 53 becomes a strain detector.

The CPU 55 controls the frequency of the transmission signal of the driving oscillator 51, reads the digital output of the A / D converter 54, reads data from the memory 56, and controls / calculates. In the present embodiment, as the offset measurement signal transmitted from the driving oscillator 51 to the angular velocity sensor 52, one low-frequency signal that is sufficiently lower than the frequency of the angular velocity detection signal and hardly causes Coriolis force is generated. ,
The output value of the angular velocity sensor 52 based on the offset measurement signal is directly determined as the offset value. Here, the driving oscillator 51 and the CPU 55 correspond to the excitation means, and the CPU 55
Corresponds to the offset calculation means.

Next, the offset measuring operation of this embodiment will be described with reference to the flowchart of FIG. Step 1
In (indicated by S1 in the figure, the same applies hereinafter), the oscillation frequency of the drive oscillator 51 is set to a frequency f for offset measurement that is sufficiently lower than the drive frequency f ₂ for angular velocity detection as shown in FIG.
_It is set to ₁ and applied to the angular velocity sensor 52.

In step 2, the angular velocity sensor 52 at that time is
The output value S _{1 of} is read from the A / D converter 54. In step 3, the read output value S ₁ is stored in the memory 56 as the offset value C. The offset value C measured as described above is used to correct the angular velocity detection output of the angular velocity sensor. This correction operation will be described with reference to the flowchart of FIG.

In step 11, the oscillation frequency of the driving oscillator 51 is switched to the high frequency f ₂ for angular velocity detection as shown in FIG. 4 and applied to the angular velocity sensor 52. Step 12
Then, the output value S ₂ of the angular velocity sensor 52 at that time is fetched from the A / D converter 54. In step 13, the offset value C stored in the memory 56 is subtracted from the sensor output value S ₂ fetched in step 12, and the sensor output correction value S (= S ₂ −
C) is calculated.

In step 14, the correction value S calculated in step 13 is output as the true sensor output value of the angular velocity sensor 52. In this way, by applying a signal of an extremely low frequency at which almost no Coriolis force is generated to the angular velocity sensor, it does not depend on the vibration velocity of the mass portion due to structural variations of the angular velocity sensor or uneven driving force. The offset component can be directly extracted. Moreover, the offset measurement is extremely simple, and since the angular velocity sensor can be mounted, it is possible to suppress an error in the sensor output due to a change with time or a change in temperature, and thus it is possible to provide a highly accurate angular velocity sensor.

Such an offset measuring operation is performed once immediately before the activation of the angular velocity sensor 52, the value is stored in the memory 56, and the sensor output is corrected by always using it as an offset value for the subsequent angular velocity measurement by the angular velocity sensor 52. Alternatively, in some cases, during the angular velocity detection by the angular velocity sensor 52, the transmission frequency of the driving oscillator 51 is periodically switched to perform the offset measurement by applying the low frequency, and the offset is stored in the memory 56. The offset value C may be periodically updated to the latest value.

The former case has an advantage that the angular velocity can be continuously detected although the angular velocity detection error increases when the offset changes due to a change with time or a temperature change during the angular velocity measurement. On the other hand, in the latter case where the offset measurement is regularly performed during the angular velocity detection, the angular velocity cannot be detected during the offset measurement at the low frequency f ₁ where the Coriolis force does not occur, and therefore the angular velocity cannot be continuously detected. Although not possible, there is an advantage that an error in the sensor output due to a change over time or a change in temperature can be reduced.

Although the offset measuring signal is performed at the frequency f ₁ of the sine wave shown in FIG. 4, which is sufficiently low, of course,
A rectangular wave as shown in FIG. 6 may be used. In this case, the velocity increases and Coriolis force is generated when the displacement of the mass part changes rapidly at the rising and falling edges of the rectangular wave, so when the displacement is sufficiently settled, the output is taken in or the rising edge of the drive waveform rises. Also, it is necessary to take measures such as making the falling edge gentle.

Further, in FIGS. 4 and 6, the mass section is only reciprocated once during the offset measurement, but in order to improve the accuracy of the offset measurement, a plurality of cycles for the offset measurement signal are generated and obtained at each cycle. Obviously, the average value of the obtained output values may be used as the offset value. As a concrete numerical value, the driving frequency f ₂ at the time of detecting the angular velocity is, for example, 10 k.
Hz, and the frequency f ₁ at the time of offset measurement is 100 Hz, the velocity of the mass part at the time of offset measurement is 1% of that at the time of normal angular velocity measurement, and Coriolis force is only 1% of that at the time of normal angular velocity measurement. The Coriolis force at the time of offset measurement can be regarded as almost zero, and it can be considered that only the offset is measured. Even if the offset measurement is performed 10 times and the average value is used as the offset value, the time required for the offset measurement is 0.1 second, and it is used in a system that measures a relatively low frequency angular velocity, such as a navigation system for a car or the like. Can be applied without problems.

In each of the above-described examples, the low-frequency driving at the time of offset measurement is driven at the same amplitude as that at the angular velocity detection, but it is not always necessary to drive at the same amplitude. That is, as shown in FIG. 7, when the offset component that does not depend on the drive frequency (broken line of ω = 0 in the figure) is proportional to the amplitude of the vibrating body such as the mass part, it is different from the angular velocity detection. Low frequency drive of mass part with known amplitude,
The offset value C may be calculated by the following calculation.

That is, when measuring the offset, the frequency f
_If the output when driven with ₁ (Coriolis force 0) and amplitude k (driving amplitude for angular velocity detection is 1) is S ₁ , then S ₁ = kC (1), so C = S C (offset value) is obtained by the calculation of ₁ / k (2).

In practical use, the optimum measuring method may be selected from among the various offset measuring methods described above while considering the target specification value of the angular velocity sensor and the like. Second
An embodiment will be described. In the first embodiment, the offset measurement is measured by one offset measurement signal, that is, a signal having a frequency f ₁ extremely lower than the frequency f ₂ of the angular velocity detection signal is used, and the generated Coriolis force Fc is substantially determined. Is almost zero and the output of the angular velocity sensor at that time is directly used as the offset value C.

The second embodiment shows an offset measuring device in the case where it is difficult to drive at an extremely low frequency f _{1 as} in the _first embodiment. In the case of the present embodiment, when the offset is measured from the driving oscillator 51, the frequency of 2
Generates two offset measurement signals. The offset measuring operation according to this embodiment will be described with reference to the flowchart of FIG.

In step 21, a signal of low frequency f ₁ is applied. In step 22, the output S ₁ of the angular velocity sensor when the low frequency f ₁ is applied is read. In step 23,
A signal having a frequency f ₂ higher than f ₁ is applied. Step 24
Then, the output S ₂ of the angular velocity sensor when the high frequency f ₂ is applied is read.

In step 25, the read outputs S ₁ , S
_The offset value C is calculated based on ₂ . That is, the output S ₁ when driven by the signal of the low frequency f ₁ is: S ₁ = Af ₁ + C (3) where A is a constant.

The output S ₂ when driven using the angular velocity detection frequency of the angular velocity sensor as the high frequency f ₂ is S ₂ = Amf ₁ + C (4) However, f ₂ = mf ₁ . From the equations (3) and (4), the offset value C is obtained by the calculation of C = (mS ₁ −S ₂ ) / (m−1) (5).

The above example shows the case where the vibrating body of the angular velocity sensor 52 is driven in a state where it does not resonate. However, in order to enhance the sensitivity, when the angular velocity sensor 52 is driven at the natural resonance frequency of the vibrating mass portion. The offset may be calculated by the procedure shown in the flowchart of FIG. In step 31, a signal of frequency f ₁ is applied.

In step 32, the output S ₁ of the angular velocity sensor when the frequency f ₁ is applied is read. In step 33, a signal having the same frequency f ₂ as the natural resonance frequency of the vibrating mass section is applied. In step 34, the output S ₂ of the angular velocity sensor when the resonance frequency f ₂ is applied is read.

At step 35, the read outputs S ₁ , S
_The offset value C is calculated based on ₂ . That is, the output S ₁ when driven at the frequency f ₁ (non-resonance frequency) for offset measurement is: S ₁ = Af ₁ + C (6) Further, the angular velocity detection frequency f ₂ of the angular velocity sensor (resonance frequency) The output S ₂ when driven by) is S ₂ = AQmf ₁ + C (7) However, f ₂ = mf ₁ and Q: Quality factor.

The offset value C is obtained from the equations (6) and (7) by the calculation of C = (QmS ₁ -S ₂ ) / (Qm-1) (8). Further, the offset value C can be estimated by the following calculation even if both the drive frequency and the amplitude are made different.

That is, the frequency f for offset measurement
The output when driven with a signal of ₁ (non-resonant frequency) and amplitude k (the amplitude when driven at the angular velocity detection frequency f ₂ is 1) is S _1, and the output is at the detection frequency f ₂ (resonance frequency). When the output at this time is S ₂ , S ₁ = Akf ₁ + kC ... (9) S ₂ = AQmf ₁ + QC ... (10) where f ₂ = mf ₁ , Q: Quality factor, A, k: It is a constant.

From the equations (9) and (10), the offset value C is obtained by the calculation of C = (QmS ₁ -kS ₂ ) / (kQ (m-1)) (11). And
By using the offset value C obtained by the offset measuring method for calculating the offset value using such two mass section drive signals, the sensor for detecting the angular velocity by the angular velocity sensor 52 as shown in the flowchart of FIG. Correct the output.

Also in the case of such an offset measuring device, the first
Similar to the embodiment described above, the offset measurement may be performed immediately before the activation of the angular velocity sensor, or may be performed periodically during the angular velocity detection. As described above, when driving the oscillating mass part, by applying signals having different frequencies and measuring the output difference at that time, the oscillating mass part caused by the structural variation and the non-uniformity of the driving force is measured. It is possible to extract the offset component that does not depend on the speed.

The above-mentioned offset measuring method can be applied to almost any vibration type angular velocity sensor which measures the angular velocity by converting the Coriolis force generated in the vibrating mass portion into the displacement or strain by the angular velocity and detecting it. It is a thing. That is,
The angular velocity sensor uses a piezoelectric effect as a driving method of the mass portion (for example, Japanese Patent Laid-Open No. 142764/1992).
Which uses electrostatic attraction (for example, Japanese Patent Publication No.
No. 74,926), one utilizing electromagnetic force (for example, Japanese Patent Laid-Open No. 5-240874), one utilizing thermal strain (for example, Japanese Patent Laid-Open No. 60-113105), and sensor output. As a detection method of the above, a method utilizing a piezoelectric effect (for example, JP-A-4-233468) and a method utilizing electrostatic capacitance (for example, JP-A-60-
-113105 gazette), utilizing light (for example,
JP-A-61-100608), utilizing the piezoresistive effect (for example, JP-B-3-74926)
The offset measuring device of the present invention can be applied to such a vibration type angular velocity sensor.

[0044]

As described above, according to the present invention, an offset measuring signal having a frequency different from the angular velocity detection frequency can be applied to the angular velocity sensor, and the offset value can be measured based on the output value at that time. The offset value can be easily measured even after mounting the sensor. Therefore, not only the offset value due to the structure of each angular velocity sensor but also the offset value that varies with time or temperature change, the varied offset value can be measured, and the accuracy of the output correction of the angular velocity sensor can be improved. Can be improved.

According to the second aspect of the invention, by applying the offset measuring signal to the angular velocity sensor, the offset value can be directly measured from the output value at that time. According to the third aspect of the invention, the offset value can be obtained even if it is difficult to drive the vibrating mass portion of the angular velocity sensor at an extremely low frequency at which the Coriolis force becomes substantially zero. Further, since it is not necessary to use a low frequency signal for offset measurement, the time required for offset measurement can be short even if the offset measurement is regularly performed during normal angular velocity detection.

According to the invention described in claim 4, the angular velocity can be continuously detected by the angular velocity sensor. According to the invention described in claim 5, it is possible to reduce an error in the sensor output due to a change with time or a change in temperature during angular velocity detection by the angular velocity sensor. According to the invention described in claim 7, the offset measurement can be performed with high accuracy.

[Brief description of drawings]

FIG. 1 is a block diagram illustrating a configuration of an offset measuring device of the present invention.

FIG. 2 is a configuration diagram of a first embodiment of an offset measuring device of the present invention.

FIG. 3 is a flowchart for explaining the operation of the first embodiment.

FIG. 4 is a waveform diagram of an offset measurement signal according to the first embodiment.

FIG. 5 is a flowchart illustrating a correction operation based on an offset value of an angular velocity sensor output.

FIG. 6 is another waveform diagram of the offset measurement signal.

FIG. 7 is a diagram showing a state in which an offset component is proportional to the amplitude of a drive signal.

FIG. 8 is a flowchart illustrating an offset measuring operation according to the second embodiment of the present invention.

FIG. 9 is a flowchart illustrating an offset measuring operation according to a modification of the second embodiment of the present invention.

FIG. 10 is a diagram showing a conventional angular velocity sensor.

11 is a diagram for explaining the angular velocity detection principle of the angular velocity sensor of FIG.

FIG. 12 is a diagram showing another example of a conventional angular velocity sensor.

13 is a sectional view taken along the line AA ′ of FIG.

FIG. 14 is a diagram showing a specific example of a mass part support structure of an angular velocity sensor.

FIG. 15 is an explanatory diagram of a defect of the conventional example shown in FIG.

16 is an explanatory diagram of a defect of the conventional example shown in FIG.

[Explanation of symbols]

 51 Driving oscillator 52 Angular velocity sensor 53 Displacement detector 54 A / D converter 55 CPU 56 Memory

Claims (7)

[Claims] 1. A vibrating angular velocity for vibrating a displaceably supported mass part to detect a Coriolis force generated in the vibrating mass part when an angular velocity is input, and detecting the input angular velocity based on the detected value. An offset measuring device for measuring an offset value of a sensor, comprising: an excitation unit that generates at least one offset measuring signal having a predetermined frequency to vibrate the mass unit; and a mass unit using the offset measuring signal of the exciting unit. An offset measuring device for a vibration type angular velocity sensor, comprising: an offset calculating means for calculating an offset value based on an output value when driven. 2. The excitation means generates one low-frequency offset measuring signal having a Coriolis force of substantially zero, and the offset calculating means sets an output value based on the offset measuring signal as an offset value. The offset measuring device for a vibration type angular velocity sensor according to claim 1, wherein the offset measuring device has a configuration. 3. The exciting means generates two offset measuring signals having different frequencies, and the offset calculating means calculates an offset value based on a difference between respective output values based on the respective offset measuring signals. The offset measuring device for a vibration type angular velocity sensor according to claim 1, which is configured. 4. The offset measuring device for a vibration type angular velocity sensor according to claim 1, wherein the excitation means is configured to generate an offset measuring signal once just before the activation of the angular velocity sensor. 5. The offset measurement of the vibration type angular velocity sensor according to claim 1, wherein the excitation means is configured to periodically generate an offset measurement signal during use of the vibration type angular velocity sensor. apparatus. 6. The offset measuring device for a vibration type angular velocity sensor according to claim 3, wherein one of the two offset measuring signals generated from the exciting means has the same frequency as the angular velocity detecting signal used in the angular velocity sensor. 7. The excitation means continuously generates a plurality of offset measurement signals for a plurality of cycles, and the offset calculation means comprises:
7. The configuration is such that an average value of the offset values calculated for each cycle in the plurality of cycles is used as the offset value.
An offset measuring device for a vibration type angular velocity sensor according to any one of 1.