JPWO2005103619A1 - Vibration gyro and method for detecting angular velocity of vibration gyro - Google Patents

Abstract

Provided are a vibration gyro capable of detecting an angular velocity with higher accuracy than before and a method for detecting the angular velocity of the vibration gyro. The vibrating gyroscope includes a vibrator (1), drive means (101 to 104) for driving the vibrator (1), monitor means (91, 92) for monitoring the vibration state of the vibrator (1), and angular velocity application. Detection means (161 to 164) for detecting the vibration displacement of the vibrator (1) due to the Coriolis force at the time, the monitor signal obtained from the monitor means (91, 92) and the detection signal obtained from the detection means (161 to 164) And a synchronous detection circuit (61) that detects a detection signal that has passed through the Hilbert transform circuit (60) in synchronization with a monitor signal that has passed through the Hilbert transform circuit (60). Prepare.

Description

  The present invention relates to a vibration gyro used for detecting angular velocity, for example, and a method for detecting angular velocity of the vibration gyro.

  In recent years, a vibrating gyroscope has been used as means for detecting the posture of a vehicle, detecting the direction of travel of a navigation device, correcting camera shake, and operating a virtual reality. A circuit example of such a vibration gyro is shown in FIG.

  In this vibration gyro, the vibrator 200 as an angular velocity detection element includes a driving unit 201 that drives the vibrator 200, a monitor unit 202 that monitors the vibration state of the vibrator 200, and vibration caused by Coriolis force when the angular velocity is applied. Detection means 203 for detecting the displacement is provided. The vibrator 200 is a so-called non-resonant type in which the resonance frequency in the vibration direction generated by the Coriolis force is set to be different from the resonance frequency in the vibration direction driven by the driving unit 201. Each of the means 201 to 203 is configured by, for example, forming a drive electrode, a monitor electrode, a detection electrode, etc. on a substrate.

  Here, the monitor signal S2 obtained by the monitor unit 202 is applied as a drive signal S1 to the drive unit 201 via the signal amplification circuit 204, the phase adjustment circuit 205, and the AGC (Auto Gain Control) circuit 206. Accordingly, the monitoring means 202, the signal amplification circuit 204, the phase adjustment circuit 205, and the AGC circuit 206 constitute a closed-loop self-excited oscillation circuit, whereby the vibrator 200 is fixed by the drive signal S1 applied to the drive means 201. It is oscillated with an amplitude and a natural resonance frequency.

  On the other hand, when a vibration displacement occurs due to the Coriolis force when the angular velocity is applied, the vibration displacement is detected by the detection means 203 and a detection signal S3 is output. In this case, in the non-resonant type piezoelectric vibrator as described above, the vibration generated by the Coriolis force and the driving vibration driven by the driving means 201 have a phase difference of 90 °. S2 is output with a phase difference of 90 °. In addition, the detection signal S3 may include an error signal S9 having a phase opposite to (or in phase with) the monitor signal S2.

  In order to synchronously detect the detection signal S3, a detection reference signal in phase (or opposite) to the detection signal S3 is required. Therefore, the phase adjustment circuit 205 shifts the phase of the monitor signal S2 by 90 ° to generate a detection reference signal S6 having the same phase (or opposite phase) as the detection signal S3, and this detection reference signal S6 is sent to the synchronous detection circuit 208. Giving.

  As shown in FIG. 10A, assuming that the phase of the monitor signal S2 is exactly 90 ° shifted by the phase adjustment circuit 205, the phase of the monitor signal S2 from the phase adjustment circuit 205 is adjusted as shown in FIG. 10B. The output detection reference signal S6 is in phase with the detection signal S3. Accordingly, the output signal S7 after being synchronously detected by the synchronous detection circuit 208 has a half-wave rectified form, and if this is smoothed by the smoothing circuit 209, a signal S8 having a voltage level corresponding to the angular velocity can be obtained. The same applies when the detection reference signal S6 has a phase opposite to that of the detection signal S3.

  As shown in FIG. 10C, when the detection signal S3 includes an error signal S9 having a phase opposite to that of the monitor signal S2, the detection reference signal S6 obtained by the phase adjustment circuit 205 has a phase different from that of the error signal S9. Since it is shifted by 90 °, the output signal S7 after being synchronously detected by the synchronous detection circuit 208 is in the form of repeating positive and negative alternately at a cycle of 90 °. Therefore, if this is smoothed by the smoothing circuit 209, the error signal S9 is canceled. The same applies when the error signal S9 is in phase with the monitor signal S2.

Incidentally, as the phase adjustment circuit 205 in the conventional piezoelectric vibration gyro, a delay circuit such as a CR secondary low-pass filter in which a resistor and a capacitor are combined is widely used as shown in FIG. No. 2002-148047 (see Patent Document 1).
JP 2002-148047 A

  However, the phase adjustment circuit 205 having such a conventional configuration has poor phase adjustment accuracy with respect to the frequency change of the input signal, as shown in FIG. 11B. For this reason, when the vibration frequency changes due to variations in characteristics between the individual elements of the vibrator 200, temperature characteristics of the vibrator 200, etc., phase adjustment of 90 ° is not performed accurately, and the detection reference signal S6 is used as the detection reference signal S6. Phase accuracy is degraded. As a result, synchronous detection cannot be performed with high accuracy, so that the efficiency of detection output is deteriorated and the canceling effect of the error signal S9 is deteriorated. As a result, it is difficult to detect the angular velocity with high accuracy.

  The present invention has been made to solve the above-described problem, and even when the vibration frequency changes due to variations in characteristics among the individual vibrators or the temperature characteristics of the vibrator, the invention is affected. The phase of the detection reference signal with respect to the detection signal is always maintained accurately, so that the detection signal can be reliably synchronously detected by the detection reference signal, and thereby the angular velocity can be detected with higher accuracy than in the past. It is an object of the present invention to provide a vibration gyro and a method for detecting the angular velocity of the vibration gyro.

  In order to solve the above-described problems, a vibration gyro according to an aspect of the present invention includes a vibrator, a driving means for driving the vibrator, a monitor means for monitoring the vibration state of the vibrator, and a Coriolis force when an angular velocity is applied. Detecting means for detecting the vibration displacement of the vibrator by means of, a Hilbert transform circuit for inputting a monitor signal obtained from the monitor means and a detection signal obtained by the detecting means, and a detection signal passing through the Hilbert transform circuit as a Hilbert transform circuit And a synchronous detection circuit for detecting in synchronization with the monitor signal that has passed through.

  In order to solve the above-described problem, a method for detecting the angular velocity of a vibrating gyroscope according to an aspect of the present invention includes a step of driving a vibrator, a monitoring step of monitoring a vibration state of the vibrator, and a Coriolis force when the angular velocity is applied. A detection step for detecting vibration displacement of the vibrator, a phase adjustment of the detection signal obtained in the detection step and a monitor signal obtained in the monitoring step using a Hilbert transform circuit, and a phase adjustment of the phase-adjusted detection signal And detecting in synchronization with the monitor signal.

  According to the present invention, both the monitor signal and the detection signal are input to the Hilbert transform circuit and passed through the circuit, so that the phase adjustment amount of both input signals accurately produces a phase difference of 90 °. That is, in the Hilbert transform circuit, the phase adjustment difference is accurately maintained at 90 ° over a wide frequency band, so that the vibration frequency changes due to variations in characteristics among the individual vibrators, temperature characteristics of the vibrators, and the like. Even in this case, high phase adjustment accuracy can always be maintained without being affected by this.

It is a top view which shows the structure of the vibrator | oscillator of the vibration gyro in embodiment of this invention. FIG. 2 is a cross-sectional view showing a part of a state in which a vibrator substrate and a protective substrate constituting the vibration gyro of FIG. 1 are joined. It is a block diagram which shows the circuit structure of a vibration gyro. It is a circuit diagram which shows an example of a CV conversion circuit. It is a circuit diagram which shows an example of a CV conversion circuit. It is a figure which shows the input-output signal of a Hilbert conversion circuit. It is a characteristic view which shows the relationship between the signal frequency and signal phase of a Hilbert transform circuit. It is a wave form diagram of the drive signal applied to the drive electrode of a vibrator. It is a wave form diagram of the drive signal applied to the drive electrode of a vibrator. It is explanatory drawing of the vibration state of a vibrator | oscillator. It is explanatory drawing which shows the relationship between the drive vibration direction in a vibrator | oscillator, and the vibration direction by a Coriolis force. It is a block diagram which shows the circuit structure of the conventional vibration gyro. It is a wave form diagram with which it uses for description of the signal processing under the circuit structure shown in FIG. It is a wave form diagram with which it uses for description of the signal processing under the circuit structure shown in FIG. It is a wave form diagram with which it uses for description of the signal processing under the circuit structure shown in FIG. It is a figure which shows the phase adjustment circuit used with the conventional vibration gyro. It is a figure which shows the frequency dependence of the phase adjustment amount of the phase adjustment circuit used with the conventional vibration gyroscope.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Vibrator, 60 Hilbert conversion circuit, 61 Synchronous detection circuit, 91, 92 Monitor electrode (monitor means), 101-104 Drive electrode (drive means), 161-164 Detection electrode (detection means).

  FIG. 1 is a plan view showing a structure of a vibrator used in the vibration gyro according to this embodiment, and FIG. 2 is a cross-sectional view showing a part of a state in which the vibrator substrate and the protective substrate constituting the vibration gyro are joined. It is.

  The vibration gyro according to this embodiment includes a vibrator 1 as an angular velocity detection element. The vibrator 1 is an electrostatic drive / capacitance detection type and non-resonant type, and is a vibrator substrate 2 made of, for example, a single-crystal or polycrystal low-resistance silicon material, and the vibrator substrate. 2 and a protective substrate 3 made of, for example, a high-resistance silicon material or glass material, provided on the main surface and the back surface. The two substrates 2 and 3 are integrally bonded by a bonding method such as anodic bonding, for example, except for the portion where the cavity 4 is formed for securing the movable part of the vibrator substrate 2. The cavity 4 is kept in a vacuum state or a low pressure state in order to reduce vibration damping.

  The vibrator substrate 2 is subjected to fine processing such as an etching process, whereby the first to fourth mass portions 71 to 74, the driving beam 8, the first and second monitor electrodes 91 and 92, and the first to first masses. Four drive electrodes 101 to 104, first to fourth detection electrodes 161 to 164, ground electrodes 181 and 182 and the like are formed. Here, in FIG. 1, when the longitudinal direction of the vibrator 1 is the Y-axis direction, the transverse direction perpendicular to the X-axis direction is the X-axis direction, and the direction perpendicular to the paper surface perpendicular to both axes is the Z-axis direction, The first to fourth mass portions 71 to 74 are supported in series along the Y-axis direction by the driving beam 8 partially connected to the ground electrodes 181 and 182, thereby the first to fourth masses. Each mass part 71-74 is in the state which can vibrate along an X-axis direction. That is, the first to fourth mass parts 71 to 74 and the drive beam 8 are movable parts, and the first and second monitor electrodes 91 and 92, the first to fourth drive electrodes 101 to 104, and the ground. Electrodes 181 and 182 are fixed portions.

  The first mass portion 71 is a comb-like movable side electrode 111a that protrudes left and right so as to oppose the comb-like portions of the first monitor electrode 91 and the first and second drive electrodes 101 and 102. , 111b, 111c are provided.

  Further, the second mass portion 72 is a first detection having a shape in which a rectangular first drive frame 121 supported by the drive beam 8 and two rectangles supported by the upper and lower first detection beams 131 are connected to each other inside the first drive frame 121. Frame 141. Comb-like movable-side electrodes 151a and 151b are formed on the outer side of the first drive frame 121 in the vicinity of the first mass portion 71 and facing the comb-like portions of the first and second drive electrodes 101 and 102. Has been. In addition, comb-shaped movable side electrodes 171 are formed on the inner sides of the two quadrangular portions of the first detection frame 141 so as to face the first and second comb-shaped detection electrodes 161 and 162, respectively. As a result, the first detection frame 141 can be vibrated along the Y-axis direction by the first detection beam 131 together with the movable electrode 171.

  The fourth mass portion 74 is a comb-like movable side electrode 112a that protrudes left and right so as to face the comb-like portions of the second monitor electrode 92 and the third and fourth drive electrodes 103 and 104. , 112b, 112c are provided.

  In addition, the third mass portion 73 is a second detection having a shape in which a rectangular second drive frame 122 supported by the drive beam 8 and two rectangles supported by the upper and lower second detection beams 132 are connected to each other inside the second drive frame 122. Frame 142. Comb-like movable side electrodes 152a and 152b are formed on the outer side of the second drive frame 122 in proximity to the fourth mass portion 74 and facing the comb-like portions of the third and fourth drive electrodes 103 and 104. Has been. In addition, comb-shaped movable side electrodes 172 are formed on the inner sides of the two quadrangular portions of the second detection frame 142 so as to face the third and fourth comb-shaped detection electrodes 163 and 164, respectively. As a result, the second detection frame 142 can be vibrated along the Y-axis direction by the second detection beam 132 together with the movable electrode 172.

  The first and second monitor electrodes 91 and 92, the first to fourth drive electrodes 101 to 104, the first to fourth detection electrodes 161 to 164, and the ground electrodes 181 and 182 are protected on the transducer substrate 2. It is formed on the junction with the substrate 3 and is in a fixed state. The fixed electrodes 91, 92, 101-104, 161-164, 181, 182 are individually connected to the electrode pads 5 as shown in FIG. 5 can be electrically connected to an external electric circuit, which will be described later. The movable portion of the vibrator 1 is mechanically and electrically connected to the ground electrodes 181 and 182 via the driving beam 8 and is kept at the ground potential.

  The first to fourth drive electrodes 101 to 104 are included in the drive means in the claims, and the first and second monitor electrodes 91 and 92 are included in the monitor means in the claims. The fourth detection electrodes 161 to 164 are included in the detection means in the claims.

  FIG. 3 is a block diagram showing a circuit configuration of the vibrating gyroscope.

  The first monitor electrode 91 is connected to a first CV (capacitance voltage) conversion circuit 31, and the second monitor electrode 92 is connected to a second CV conversion circuit 32. The first and second CV conversion circuits 31 and 32 are both connected to the first differential amplifier circuit 41, and the first differential amplifier circuit 41 is connected to the AGC circuit 22 via the filter circuit 51 and the phase adjustment circuit 23. . The output of the first differential amplifier circuit 41 is connected to one input part of a Hilbert transform circuit 60 described later via a filter circuit 51. The output portion of the AGC circuit 22 is directly connected to the second drive electrode 102 and the third drive electrode 103, and is connected to the first drive electrode 101 and the fourth drive electrode 104 via the inversion circuit 21.

  On the other hand, both the first detection electrode 161 and the third detection electrode 163 are connected to the third CV conversion circuit 33, and both the second detection electrode 162 and the fourth detection electrode 164 are connected to the fourth CV conversion circuit 34. The third and fourth CV conversion circuits 33 and 34 are both connected to the second differential amplifier circuit 42. Further, the second differential amplifier circuit 42 is connected to the other input section of the Hilbert transform circuit 60 described later via the filter circuit 52.

  As the first to fourth CV conversion circuits 31 to 34, for example, a charge amplification circuit as shown in FIG. 4A or an impedance conversion circuit as shown in FIG. 4B is applied. As the first and second differential amplifiers 41 and 42, for example, operational amplifiers are applied.

  As shown in FIG. 5A and FIG. 5B, the Hilbert transform circuit 60 described above can accurately output two signals Vout1 and Vout2 over a wide frequency band Δf when the same signal Vin is input to two input terminals. It has characteristics that cause a phase difference of 90 °. For example, a phase difference of 90 ° ± 1.5 ° is generated between the two output signals Vout1 and Vout2 over a frequency band of 5 KHz to 25 KHz. That is, the Hilbert transform circuit 60 has two phase adjustment paths, and has a region where the difference between the phase adjustment amounts is always 90 °. As described above, even when the vibration frequency is changed by the Hilbert transform circuit 60 due to variations in the characteristics of the individual vibrators 1, the temperature characteristics of the vibrator 1, or the like, the phase is always high without being affected by this. Adjustment accuracy can be maintained.

  The two output units of the Hilbert conversion circuit 60 are connected to the synchronous detection circuit 61. The synchronous detection circuit 61 performs phase detection of the detection signal S5 in synchronization with the detection reference signal S4. A smoothing circuit 62 and an amplifier circuit 63 are sequentially connected to the synchronous detection circuit 61.

  Next, the operation of the vibration gyro configured as described above will be described.

  The first and fourth drive electrodes 101 and 104 are supplied with a drive signal S12 after the level of the drive signal S11 output from the AGC circuit 22 is inverted by the inverter circuit 21. The drive signal S11 output from the AGC circuit 22 is applied to the second and third drive electrodes 102 and 103 as they are. In this case, as shown in FIGS. 6A and 6B, both drive signals S11 and S12 are alternating current signals whose levels are inverted with respect to the ground potential, for example, with an offset potential of + 2.5V as a reference.

  For this reason, for example, when one drive signal S12 is at a high level and the other drive signal S11 is at a low level, the first and fourth drive electrodes 101, 104 and the movable-side electrodes 111a, The electrostatic attractive force of 151a and 112b and 152b is in a “strong” state, while the second and third drive electrodes 102 and 103 and the movable side electrodes 111b, 151b and 112a and 152a facing these electrodes 102 and 103 The electrostatic attractive force is in a “weak” state. Naturally, when the levels of the two signals S12 and S11 are opposite, the state described above is reversed. For this reason, due to the difference in electrostatic attraction, as shown in FIG. 7A, the first to fourth mass portions 71 to 74 are driven in the opposite phase to each other in the X-axis direction and vibrate.

  Depending on this vibration, the capacitance between the movable side electrode 111c and the first monitor electrode 91 provided in the first mass part 71 and the movable side electrode 112c and the second monitor provided in the fourth mass part 74 are dependent on this vibration. The capacitance between the electrodes 92 changes.

  Capacitance changes in the first and second monitor electrodes 91 and 92 that monitor the driving vibration state in the X-axis direction of the vibrator 1 have voltage levels corresponding to the respective capacitance changes by the first and second CV conversion circuits 31 and 32. Converted to monitor signals S21 and S22. In this case, since both monitor signals S21 and S22 are opposite in phase, they are amplified and converted into one monitor signal S2 by the first differential amplifier circuit 41 in the next stage.

  The monitor signal S2 is input to one input section of the Hilbert transform circuit 60 after unnecessary noise components are removed by the filter circuit 51, and the phase adjustment circuit 23 performs phase adjustment necessary for self-excited oscillation. Is input to the AGC circuit 22. The AGC circuit 22 automatically adjusts the amplification factor of the AGC circuit 22 so that the input signal amplitude of the AGC circuit 22 is constant. Therefore, drive signals S11 and S12 having appropriate amplitudes are always applied to the first to fourth drive electrodes 101 to 104, respectively.

  In this way, the drive signals S11 and S12 are generated from the monitor signal S2 obtained by the first and second monitor electrodes 91 and 92, respectively, and the drive signals S11 and S12 are applied to the first to fourth drive electrodes. Thus, a closed-loop self-excited oscillation circuit is configured, and the vibrator 1 continues to vibrate at the same resonance frequency as the drive signal.

  In this state, when a rotational angular velocity with the Z axis as the central axis is applied to the vibrator 1, a Coriolis force is generated in each mass portion 71 to 74 in the Y axis direction orthogonal to the vibration direction. As shown in FIG. 7B, the first and second detection frames 141 and 142 supported by the first and second detection beams 131 and 132 are opposite to each other in the Y-axis direction due to Coriolis force. Driven to vibrate at the same frequency as the drive vibration in the X-axis direction. Depending on this vibration, the capacitance between the movable side electrodes 171 and 172 and the first to fourth detection electrodes 161 to 164 provided in the first and second detection frames respectively changes. In FIG. 7B, the vibration in the X-axis direction of each of the mass parts 71 to 74 is omitted.

The Coriolis force F generated when the angular velocity is applied is given by the following equation.
F = 2Mωv
Here, M is the mass of the entire first to fourth mass parts 71 to 74, ω is the angular velocity, and v is the driving vibration speed of the entire first to fourth mass parts 71 to 74.

  In the non-resonant type vibrator 1, the structural resonance frequency in the Y-axis direction of the vibrator 1 is sufficiently separated from the vibration frequency when driven in the X-axis direction by the drive signal. The vibration in the Y-axis direction and the driving vibration in the X-axis direction driven by the drive signals S11 and S12 have a phase difference of 90 °. For this reason, if vibration in the Y-axis direction occurs while driving and vibrating in the X-axis direction, the first to fourth mass parts 71 to 74 perform elliptical motion as shown in FIG. Therefore, the capacitance change generated in the first and second monitor electrodes 91 and 92 due to the drive vibration and the capacitance change generated in the detection electrodes 161 to 164 due to the vibration due to the Coriolis force are 90 ° in phase difference. Will occur.

  On the other hand, the capacitance change generated in the first and third detection electrodes 161 and 163 due to the vibration due to the Coriolis force is converted by the third CV conversion circuit 33 into a detection signal S31 having a voltage level corresponding to the capacitance change. Similarly, the capacitance change generated in the second and fourth detection electrodes 162 and 164 due to the vibration due to the Coriolis force is converted into a detection signal S32 having a voltage level corresponding to the capacitance change by the fourth CV conversion circuit 34.

  In this case, the detection signals S31 and S32 output from the third and fourth CV conversion circuits 33 and 34 are signals having opposite phases with respect to the components depending on the Coriolis force. 42 is amplified and converted to one detection signal S3. This detection signal S3 is input to the other input section of the Hilbert transform circuit 60 after unnecessary noise components are removed by the filter circuit 52.

As described above, in the non-resonant type vibrator 1, the monitor signal S2 and the detection signal S3 are originally output with a phase difference of 90 °. The filter circuit 51 and the filter circuit 52 are designed so that the phase characteristics thereof are the same. Therefore, the monitor signal S2 ′ and the detection signal S3 ′ input to the Hilbert transform circuit 60 are respectively
S2 ′ = Asinωt
S3 ′ = Bsin (ωt + π / 2)
(Where A and B are amplitudes).

When both signals S2 ′ and S3 ′ are input to the Hilbert transform circuit 60, the Hilbert transform circuit 60 adjusts the phase of the input monitor signal S2 ′ and detection signal S3 ′, and covers a wide frequency band Δf. A phase difference of exactly 90 ° is generated in each phase adjustment amount. For this reason, when the monitor signal after passing through the Hilbert transform circuit 60 is S4 and the detection signal is S5,
S4 = Asin (ωt−α)
S5 = Bsin (ωt + π / 2− (α + π / 2)) = Bsin (ωt−α)
(Α is the amount of phase change common to both signals). That is, both signals S4 and S5 after passing through the Hilbert transform circuit 60 are always accurately in phase (or out of phase).

  The monitor signal S4 after passing through the Hilbert transform circuit 60 is given to the next-stage synchronous detection circuit 61 as a detection reference signal S4. The synchronous detection circuit 61 synchronously detects the detection signal S5 that has passed through the Hilbert transform circuit 60 by using the detection reference signal S4. In this case, since both the signals S4 and S5 are always in the same phase (or opposite phase), the detection signal S7 output after synchronous detection by the synchronous detection circuit 61 is correctly half-wave rectified. If this is smoothed by the smoothing circuit 62, a detection signal S8 having an intended voltage level corresponding to the magnitude of the angular velocity is obtained. The detection signal S8 is amplified by the amplification circuit 63 at the next stage and then output. The detection signal amplified by the amplifier circuit 63 is removed from the influence of the temperature drift and the influence of the temperature change of the sensitivity by the output adjustment circuit 64 in the next stage, and is then sent to an arithmetic circuit (not shown) that calculates the actual angular velocity. Given.

  Further, when the detection signal S3 output from the second differential amplifier circuit 42 includes an error signal S9 having a phase opposite to or in phase with the monitor signal S2, when the error signal S9 passes through the Hilbert transform circuit 60, detection is performed. Since the phase is shifted by 90 ° with respect to the reference signal S4, the output signal S7 after being synchronously detected by the synchronous detection circuit 61 at the next stage has a form of repeating positive and negative alternately at a cycle of 90 °. If smoothing is performed at 62, the error signal S9 is canceled.

  In the above embodiment, the vibration gyro provided with the electrostatic drive / capacitance detection type vibrator 1 has been described. However, the present invention is not limited to this, for example, a sound made of a piezoelectric material or a single crystal. The present invention can also be applied to a vibration gyro provided with a single-type vibrator and a vibration gyro provided with a tuning fork vibrator.

Claims (2)

A vibrator (1);
Driving means (101 to 104) for driving the vibrator (1);
Monitoring means (91, 92) for monitoring the vibration state of the vibrator (1);
Detection means (161 to 164) for detecting vibration displacement of the vibrator (1) due to Coriolis force at the time of angular velocity application;
A Hilbert transform circuit (60) for inputting a monitor signal obtained from the monitor means (91, 92) and a detection signal obtained by the detection means (161 to 164);
A vibration gyro comprising a synchronous detection circuit (61) for detecting a detection signal that has passed through the Hilbert transform circuit (60) in synchronization with a monitor signal that has passed through the Hilbert transform circuit (60). Driving the vibrator (1);
A monitoring step for monitoring a vibration state of the vibrator (1);
A detection step of detecting vibration displacement of the vibrator (1) due to Coriolis force at the time of angular velocity application;
Adjusting the phase of the detection signal obtained in the detection step and the monitor signal obtained in the monitoring step using a Hilbert transform circuit (60);
And detecting the phase-adjusted detection signal in synchronization with the phase-adjusted monitor signal.

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