WO2005103619A1

WO2005103619A1 - Vibration gyroscope and angular velocity detecting method for vibration gyroscope

Info

Publication number: WO2005103619A1
Application number: PCT/JP2005/007124
Authority: WO
Inventors: Akira Mori; Iku Nagai; Kazushige Sawada; Makoto Narita
Original assignee: Murata Manufacturing Co., Ltd.; Asahi Kasei Microsystems Co., Ltd.
Priority date: 2004-04-20
Filing date: 2005-04-13
Publication date: 2005-11-03
Also published as: JPWO2005103619A1

Abstract

A vibration gyroscope and an angular velocity detecting method for a vibration gyroscope capable of detecting an angular velocity more accurately than before. The vibration gyroscope comprises a vibrator (1), driving means (101-104) for driving the vibrator (1), monitoring means (91, 92) for monitoring the vibration condition of the vibrator (1), detecting means (161-164) for detecting the vibration displacement of the vibrator (1) by a Coriolis force at an angular velocity application, a Hilbert conversion circuit (60) for receiving a monitor signals obtained from the monitoring means (91, 92) and detection signals obtained from the detecting means (161-164), and a synchronizing detection circuit (61) for detecting a detection signals passed through the Hilbert conversion circuit (60) in synchronization with monitor signals passed through the Hilbert conversion circuit (60).

Description

Specification

Vibrating gyroscope and method for detecting angular velocity of vibrating gyroscope

Technical field

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

Background art

[0002] In recent years, a vibrating gyroscope has been used as means for detecting the attitude of a vehicle, detecting the traveling direction of a navigation device, correcting camera shake, operating virtual reality, and the like. Fig. 9 shows a circuit example of such a vibrating gyroscope.

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

[0004] Here, the monitor signal S2 obtained by the monitor means 202 is supplied to the drive means 201 via a signal amplification circuit 204, a phase adjustment circuit 205, and an AGC (Auto Gain Control) circuit 206. As a squid. Therefore, the monitor 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 drives the drive signal applied to the drive means 201. It is oscillated with a constant amplitude and a unique resonance frequency by S1.

[0005] On the other hand, when a vibration displacement occurs due to the Corioliser at the time of applying the angular velocity, 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, since the vibration generated by the Corioliser and the driving vibration driven by the driving means 201 have a phase difference of 90 °, the detection signal S3 The signal S2 is output 90 ° out of phase. In addition, the detection signal S3 is the reverse of the monitor signal S2. A phase (or in-phase) error signal S9 may be included.

[0006] In order to perform synchronous detection of the detection signal S3, a detection reference signal in phase (or opposite) to the detection signal S3 is required. For this reason, the phase of the monitor signal S2 is shifted by 90 ° by the phase adjustment circuit 205 to generate a detection reference signal S6 in 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. Have given.

[0007] As shown in FIG. 10A, assuming that the phase of the monitor signal S2 is now exactly 90 ° shifted by the phase adjustment circuit 205, as shown in FIG. 10B, the monitor signal S2 is phase-shifted from the phase adjustment circuit 205. The detection reference signal S6 output after the adjustment has the same phase as the detection signal S3. Therefore, the output signal S7 after synchronous detection 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 is obtained. can get. The same applies to the case where the detection reference signal S6 has the opposite phase to the detection signal S3.

[0008] Further, 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 is different from the error signal S9. Is shifted by 90 °, the output signal S7 after the next synchronous detection by the synchronous detection circuit 208 alternately repeats positive and negative at 90 ° cycles. Therefore, if this is smoothed by the smoothing circuit 209, the error signal S9 is canceled. The same applies to the case where the error signal S9 is in phase with the monitor signal S2.

As the above-described phase adjustment circuit 205 in a conventional piezoelectric vibrating gyroscope, for example, as shown in FIG. 11A, a delay circuit such as a CR secondary low-pass filter combining a resistor and a capacitor is widely used. (See, for example, JP-A-2002-148047 (Patent Document 1)).

Patent Document 1: Japanese Patent Application Laid-Open No. 2002-148047

Disclosure of the invention

Problems to be solved by the invention

[0010] However, the phase adjustment circuit 205 having such a conventional configuration has poor phase adjustment accuracy with respect to a change in the frequency of the input signal, as shown in FIG. 11B. As a result, the vibration frequency changed due to variations in characteristics between the individual vibrators 200 and temperature characteristics of the vibrator 200. In this case, the phase adjustment of 90 ° is not performed accurately, and the phase accuracy as the detection reference signal S6 deteriorates. As a result, synchronous detection cannot be performed with high accuracy, so that the efficiency of the detection output deteriorates and the canceling effect of the error signal S9 is deteriorated.As a result, it becomes difficult to accurately detect the angular velocity. .

The present invention has been made in order to solve the above-mentioned problems, and even when the vibration frequency changes due to variations in the characteristics of individual vibrators, temperature characteristics of the vibrators, etc. This ensures that the phase of the detection reference signal with respect to the detection signal is always accurately maintained without being affected by the detection signal, thereby ensuring that the detection signal can be synchronously detected by the detection reference signal, thereby achieving higher accuracy than before. An object of the present invention is to provide a vibrating gyroscope capable of detecting an angular velocity and a method for detecting a vibrating gyroscope angular velocity. Means for solving the problem

[0012] In order to solve the above problems, a vibration gyro according to an aspect of the present invention includes a vibrator, a driving unit that drives the vibrator, a monitoring unit that monitors a vibration state of the vibrator, and an angular velocity application. Detecting means for detecting the vibration displacement of the vibrator caused by Coriolis, a monitoring means force, a Hilbert conversion circuit for inputting a monitor signal obtained and a detection signal obtained by the detection means, and a detection signal passing through the Hilbert conversion circuit. And a synchronous detection circuit for detecting in synchronization with the monitor signal passed through the Hilbert conversion circuit.

[0013] In order to solve the above problem, an angular velocity detecting method for a vibrating gyroscope according to an aspect of the present invention includes a step of driving a vibrator, a monitor step of monitoring a vibration state of the vibrator, and a step of applying an angular velocity. A detection step of detecting a vibration displacement of the vibrator caused by Coriolis, a phase adjustment of a detection signal obtained in the detection step and a monitor signal obtained in the monitor step using a Hilbert transform circuit, Detecting the phase-adjusted detection signal in synchronization with the phase-adjusted monitor signal. The invention's effect

According to the present invention, by inputting both the monitor signal and the detection signal to the Hilbert transform circuit and passing the same, the phase adjustment amount of both input signals produces a phase difference of exactly 90 °. You. In other words, in the Hilbert transform circuit, since the phase adjustment difference is accurately maintained at 90 ° over a wide frequency band, variation in characteristics between individual oscillators and temperature characteristics of the oscillators Therefore, even when the vibration frequency changes due to the above, high phase adjustment accuracy can always be maintained without being affected by the change.

Brief Description of Drawings

FIG. 1 is a plan view showing a structure of a vibrator of a vibrating gyroscope according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a part of a state where a vibrator substrate and a protective substrate constituting the vibrating gyroscope of FIG. 1 are joined.

FIG. 3 is a block diagram showing a circuit configuration of a vibration gyro.

FIG. 4A is a circuit diagram illustrating an example of a CV conversion circuit.

FIG. 4B is a circuit diagram illustrating an example of a CV conversion circuit.

FIG. 5A is a diagram showing input / output signals of a Hilbert transform circuit.

FIG. 5B is a characteristic diagram showing a relationship between a signal frequency and a signal phase of the Hilbert transform circuit.

FIG. 6A is a waveform diagram of a drive signal applied to a drive electrode of a vibrator.

FIG. 6B is a waveform diagram of a drive signal applied to a drive electrode of the vibrator.

FIG. 7 is an explanatory diagram of a vibration state of a vibrator.

FIG. 8 is an explanatory diagram showing a relationship between a driving vibration direction of a vibrator and a vibration direction of a Corioliser.

FIG. 9 is a block diagram showing a circuit configuration of a conventional vibration gyro.

FIG. 10A is a waveform chart for explaining signal processing under the circuit configuration shown in FIG. 9.

FIG. 10B is a waveform chart for explaining signal processing under the circuit configuration shown in FIG. 9.

FIG. 10C is a waveform chart for explaining signal processing under the circuit configuration shown in FIG. 9.

FIG. 11A is a diagram showing a phase adjusting circuit used in a conventional vibrating gyroscope.

FIG. 11B is a diagram showing the frequency dependence of the amount of phase adjustment of a phase adjustment circuit used in a conventional vibrating gyroscope.

Explanation of symbols

[0016] 1 oscillator, 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) BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 1 is a plan view showing the structure of a vibrator used in the vibrating gyroscope according to the present embodiment. FIG. 2 shows a part of a state in which the vibrating gyroscope and a protective substrate are joined together. FIG.

The vibrating gyroscope according to the present embodiment includes a vibrator 1 as an angular velocity detecting element

. The vibrator 1 is of an electrostatic drive Z-capacitance detection type and a non-resonant type. For example, a vibrator substrate 2 made of a single-crystal or polycrystalline low-resistance silicon material, and the vibrator 1 And a protective substrate 3 provided on the main surface and the back surface of the sub-substrate 2, for example, a high-resistance silicon material, a glass material, and the like. The two substrates 2 and 3 are integrally joined by a joining method such as anodic joining, for example, except for a location where a cavity 4 for securing a movable portion of the vibrator substrate 2 is formed. In addition, the inside of the cavity 4 is in a vacuum state in order to reduce vibration damping, and is kept in a low pressure state.

The vibrator substrate 2 is subjected to fine processing such as etching, so that the first to fourth mass portions 71 to 74, the driving beam 8, 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 formed. Here, in FIG. 1, when the longitudinal direction of the vibrator 1 is the Y-axis direction, the transverse direction perpendicular to the Y-axis direction is the X-axis direction, and the direction perpendicular to the paper plane perpendicular to both axes is the Z-axis direction, The first to fourth mass parts 71 to 74 are supported in series along the Y-axis direction by a driving beam 8 partially connected to the ground electrodes 181, 182, whereby the first to fourth mass parts 71 to 74 are supported. Each of the mass parts 71 to 74 of 4 is in a state capable of vibrating along the 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 are provided. Electrodes 181, 182 are fixed parts

The first mass portion 71 is a comb-shaped movable member formed to project right and left so as to face the comb-shaped portions of the first monitor electrode 91 and the first and second drive electrodes 101 and 102. Side electrodes 11 la, 111 b, 111 c are provided.

The second mass section 72 is formed by connecting a rectangular first drive frame 121 supported by the drive beam 8 and two squares supported by the upper and lower first detection beams 131 inside the first drive frame 121. And a first detection frame 141. Outside the first drive frame 121, comb-shaped movable electrodes 151a, 151b are formed adjacent to the first mass portion 71 and opposed to the comb-shaped portions of the first and second drive electrodes 101, 102. Have been. Further, inside the two rectangular portions of the first detection frame 141, comb-shaped movable side electrodes 171 are formed so as to face the comb-shaped first and second detection electrodes 161, 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-side electrode 171.

[0022] The fourth mass part 74 is a comb-shaped movable member formed to protrude left and right so as to face the comb-shaped parts of the second monitor electrode 92 and the third and fourth drive electrodes 103 and 104. Side electrodes 112a, 112b, 112c are provided.

The third mass part 73 has a shape in which a square second drive frame 122 supported by the drive beam 8 and two squares supported by upper and lower second detection beams 132 inside the square are connected. A second detection frame 142. Outside the second drive frame 122, comb-shaped movable electrodes 152a and 152b are formed adjacent to the fourth mass portion 74 and opposed to the comb-shaped portions of the third and fourth drive electrodes 103 and 104. Have been. Further, inside the two quadrangular portions of the second detection frame 142, comb-shaped movable side electrodes 172 are formed so as to face the comb-shaped third and fourth detection electrodes 163, 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-side 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 connected to the It is formed on the joint with the protective substrate 3 on 2 and is fixed. Each of the electrodes 91, 92, 101-104, 161-164, 181, 182 on the fixed side is individually connected to each electrode node 5 as shown in FIG. Electrical connection to an external electric circuit described later via 5 is enabled. The movable part 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.

[0025] The first to fourth drive electrodes 101 to 104 are included in the driving means of the claims, and the first and second monitor electrodes 91 and 92 are included in the monitoring means of the claims. The first to 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 vibration gyro.

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, 32 are both connected to a first differential amplifier circuit 41, and the first differential amplifier circuit 41 is connected to an AGC circuit 22 via a filter circuit 51 and a phase adjustment circuit 23. I have. The output of the first differential amplifier circuit 41 is connected to one input section of a Hilbert transform circuit 60 described later via a filter circuit 51. The output of the AGC circuit 22 is directly connected to the second drive electrode 102 and the third drive electrode 103, and is also connected to the first drive electrode 101 and the fourth drive electrode 104 via the inversion circuit 21.

On the other hand, the first detection electrode 161 and the third detection electrode 163 are both connected to the third CV conversion circuit 33, and the second detection electrode 162 and the fourth detection electrode 164 are both connected to the fourth CV conversion circuit 34 Has been done. 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 via a filter circuit 52 to the other input of a Hilbert transform circuit 60 described later.

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.

[0030] As shown in Figs. 5A and 5B, when the same signal Vin is input to two input terminals, the Hilbert transform circuit 60 outputs two signals Voutl output over a wide frequency band Δί. , Vout2, and has a characteristic of generating a phase difference of exactly 90 °. For example, a phase difference of 90 ° ± 1.5 ° is generated between the two output signals Voutl 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 respective phase adjustment amounts is always 90 °. As described above, even when the Hilbert transform circuit 60 causes variations in the characteristics between the individual vibrators 1 and changes in the vibration frequency due to the temperature characteristics of the vibrator 1 and the like, it is not affected by this. High phase adjustment accuracy can always be maintained.

Two output sections of the Hilbert transform circuit 60 are connected to a 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. is there. To the synchronous detection circuit 61, a smoothing circuit 62 and an amplification circuit 63 are sequentially connected.

Next, the operation of the vibrating gyroscope having the above configuration will be described.

The first and fourth drive electrodes 101 and 104 are supplied with a drive signal S12 obtained by inverting the level of the drive signal S11 output from the AGC circuit 22 by the inverting circuit 21. The drive signal S11 output from the AGC circuit 22 is directly applied to the second and third drive electrodes 102 and 103. In this case, as shown in FIG. 6A and FIG. 6B, both drive signals Sl 1 and S12 are AC signals whose levels are in an inverting relationship with each other with reference to an offset potential of, for example, +2.5 V with respect to the ground potential.

[0034] Therefore, for example, when one drive signal S12 is at the high level and the other drive signal S11 is at the oral level, the first and fourth drive electrodes 101, 104 and the electrodes 101, 104 are opposed to each other. The electrostatic attraction of the movable electrodes 111a, 151a and 112b, 152b becomes "strong", while the second and third drive electrodes 102, 103 and the movable electrode 1 facing the electrodes 102, 103 The electrostatic attraction of l ib, 151b and 112a, 152a is in a "weak" state. Naturally, if the levels of the two signals S12 and S11 are opposite, the state is reversed. For this reason, as shown in FIG. 7A, the first to fourth mass portions 71 to 74 are driven in opposite phases in the X-axis direction between each other, as shown in FIG. Vibrate.

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

The capacitance change at the first and second monitor electrodes 91 and 92 for monitoring the driving vibration state of the vibrator 1 in the X-axis direction corresponds to each capacitance change by the first and second CV conversion circuits 31 and 32. It is converted into monitor signals S21 and S22 having the obtained voltage levels. In this case, since both monitor signals S21 and S22 are signals having phases opposite to each other, they are amplified and converted into one monitor signal S2 by the first differential amplifier circuit 41 in the next stage.

The monitor signal S 2 is input to one input unit of the Hilbert conversion circuit 60 after unnecessary noise components are removed by the filter circuit 51, and the monitor signal S 2 is necessary for self-excited oscillation by the phase adjustment circuit 23. After the phase is adjusted, it is input to the AGC circuit 22. AGC circuit 22 The gain of the AGC circuit 22 is automatically adjusted so that the input signal amplitude of the C circuit 22 becomes constant. For this reason, the first to fourth drive electrodes 101 to 104 are always supplied with drive signals Sll and S12 having appropriate amplitudes.

[0038] In this manner, the drive signals Sll and S12 are generated from the monitor signals S2 obtained at the first and second monitor electrodes 91 and 92, respectively, and the respective drive signals Sll and S12 are converted into the first to fourth drive signals. By applying the voltage to the electrodes, a closed-loop self-excited oscillation circuit is formed, and the vibrator 1 continues to vibrate at the resonance frequency of the same frequency as the drive signal.

In this state, when a rotational angular velocity about the Z axis as a central axis is applied to the vibrator 1, Corioliska is generated in each of the mass portions 71 to 74 in the Y axis direction orthogonal to the vibration direction. The first and second detection frames 141 and 142 supported by the first and second detection beams 131 and 132 are driven by Coriolisers in directions opposite to each other in the Y-axis direction, as shown in FIG. And vibrates at the same frequency as the drive vibration in the X-axis direction. The capacitance between the movable electrodes 171 and 172 provided on the first and second detection frames and the first to fourth detection electrodes 161 to 164 changes depending on the vibration. In FIG. 7 (b), the vibration of the mass parts 71 to 74 in the X-axis direction is omitted.

[0040] Coriolis F generated when an angular velocity is applied is given by the following equation.

F = 2M ov

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 velocity of the entire first to fourth mass parts 71 to 74.

In the non-resonant type vibrator 1, since the structural resonance frequency in the Υ-axis direction of the vibrator 1 is sufficiently separated from the vibration frequency when driven in the X-axis direction by the driving signal, There is a 90 ° phase difference between the Υ-axis vibration generated by Corioca and the X-axis vibration driven by the drive signals Sll and S12. For this reason, when vibration in the Υ-axis direction occurs while driving and oscillating in the X-axis direction, the first to fourth mass portions 71 to 74 perform elliptical motion as shown in FIG. Therefore, a phase difference of 90 ° between the capacitance change generated at the first and second monitor electrodes 91 and 92 due to the drive vibration and the capacitance change generated at each of the detection electrodes 161 to 164 due to the vibration caused by Corioliska. Will occur.

On the other hand, the capacitance change generated in the first and third detection electrodes 161 and 163 due to the vibration caused by Coriolis is detected by the third CV conversion circuit 33 by a detection signal having a voltage level corresponding to the capacitance change. No. S31. Similarly, the change in capacitance generated at the second and fourth detection electrodes 162 and 164 due to the vibration by Coriolis is converted by the fourth CV conversion circuit 34 into a detection signal S32 having a voltage level corresponding to the change in capacitance.

In this case, since the detection signals S31 and S32 output from the third and fourth CV conversion circuits 33 and 34 are signals having phases opposite to each other with respect to the component that depends on Coriolis, the second differential signal at the next stage is used. The signal is amplified and converted into one detection signal S3 by the amplifier circuit 42. The 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 their phase characteristics are the same. Therefore, the monitor signal S2 ′ and the detection signal S3 ′ input to the Hilbert transform circuit 60 are respectively

S2 '= Asin ot

S3, = Bsin (ot + πΖ2)

(However, A and B are amplitudes).

[0045] When both signals S2, S3, and the Hilbert transform circuit 60 are input, the Hilbert transform circuit 60 adjusts the phases of the input monitor signal S2 'and detection signal S3', respectively. A phase difference of exactly 90 ° is generated in each phase adjustment amount over the frequency band Δf. Therefore, assuming that the monitor signal after passing through the Hilbert transform circuit 60 is S4 and the detection signal is S5,

S4 = Asin ot—)

S5 = Bsin (ot + πΖ2— (α + πΖ2)) = Bsin (ot— a)

(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 exactly in phase (or opposite phase).

The monitor signal S4 after passing through the Hilbert transform circuit 60 is provided to the next-stage synchronous detection circuit 61 as a detection reference signal S4. The synchronous detection circuit 61 performs synchronous detection of the detection signal S5 that has passed through the Hilbert conversion circuit 60, based on the detection reference signal S4. In this case, the two signals S4 and S5 are always exactly in phase (or opposite phase). The detection signal S7 output after synchronous detection by the phase detection circuit 61 is correctly half-wave rectified, and if this is smoothed by the smoothing circuit 62, the desired voltage level corresponding to the magnitude of the angular velocity can be obtained. Is obtained. Then, the detection signal S8 is output after being amplified by the amplification circuit 63 in the next stage. The detection signal amplified by the amplifier circuit 63 is subjected to an output adjustment circuit 64 at the next stage to remove the influence of temperature drift and the influence of temperature change of sensitivity, and then calculate the actual angular velocity. Given to the circuit.

When the detection signal S3 output from the second differential amplifier circuit 42 includes an error signal S9 having a phase opposite to or the same as that of the monitor signal S2, the error signal S9 is converted to a Hilbert transform circuit. After passing through 60, the phase is shifted by 90 ° with respect to the detection reference signal S4.Therefore, the output signal S7 after being synchronously detected by the synchronous detection circuit 61 in the next stage alternates between positive and negative with a 90 ° cycle. If this is smoothed by the smoothing circuit 62, the error signal S9 is cancelled.

[0048] In the above embodiment, the vibration gyro provided with the vibrator 1 of the electrostatic drive Z-capacitance detection type has been described. However, the present invention is not limited to this. The present invention can also be applied to a vibrating gyroscope having a vibrating piece type vibrator or a vibrating gyroscope having a tuning fork vibrator.

Claims

The scope of the claims

[1] a vibrator (1),

Driving means (101 to 104) for driving the vibrator (1);

Monitoring means (91, 92) for monitoring a vibration state of the vibrator (1);

Detecting means (161 to 164) for detecting a vibration displacement of the vibrator (1) due to Corioliser when an angular velocity is applied;

A Hilbert transform circuit (60) for inputting a monitor signal obtained by the monitoring means (91, 92) and a detection signal obtained by the detection means (161 to 164);

A vibration gyroscope comprising: a synchronous detection circuit (61) for detecting a detection signal passed through the Hilbert conversion circuit (60) in synchronization with a monitor signal passed through the Hilbert conversion circuit (60).

[2] driving the vibrator (1);

A monitoring step of monitoring a vibration state of the vibrator (1);

A detection step for detecting a vibration displacement of the vibrator (1) by Corioliser when applying an angular velocity;

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 adjusting the phase-adjusted detection signal to the phase adjustment. Detecting the angular velocity of the vibrating gyroscope in synchronization with the detected monitor signal.