JP5266528B2 - Angular velocity sensor, angular velocity signal correction device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce an angle error with a simple structure without sacrificing the acceleration sensitivity of a sensor. <P>SOLUTION: An angular velocity sensor includes: a drive circuit 701; a CV converter 702; a phase shifter 703; a synchronization detector 704; a low-pass filter 705; an external detection section 706; and an angular velocity output correction section 707 and a sensor 708. A turbulence detection section 706 receives signals X, Y to detect a signal (namely, disturbance) that is not an angular velocity signal and is larger than a prescribed size and to output a binary detection signal indicating a disturbance detection state or nondisturbance detection state. The angular velocity output correction section 707 receives angular velocity output X and angular velocity output Y, namely the output of the low-pass filter 705, thus correcting the angular velocity output X and angular velocity output Y when the angular velocity signal of the sensor is disturbed. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to an angular velocity sensor using a vibrator, and more particularly to an apparatus for reducing an error in angular velocity output.

  The angular velocity sensor has a weight part that can be displaced inside, and this weight part has a predetermined frequency and vibrates to detect displacement caused by Coriolis force generated in the weight part when an angular velocity is applied to the system. By doing so, there is a method of detecting the angular velocity. As a method for detecting the displacement of the weight portion, there are a method for detecting a change in capacitance due to the displacement of the weight portion, a method for detecting a change in stress due to the displacement of the weight portion by a piezoelectric effect, and the like.

  As an example, a schematic configuration of 5-Axis Motion Sensor described in Non-Patent Document 1 and Non-Patent Document 2 is shown in FIG. In the above document, 5-Axis Motion Sensor is introduced as a sensor capable of detecting triaxial acceleration and biaxial angular velocity. Here, the function as an angular velocity sensor is taken up.

  This sensor has a three-layer structure including an upper glass substrate 101, an SOI (Silicon on Insulator) substrate 102, and a lower glass substrate 103.

  The SOI substrate 102 is formed with a weight portion 104 and four beam portions 105 to 108, and the weight portion 104 is supported by the beam portions 105 to 108. Here, the beam portions 105 to 108 are thinly formed and are easily bent and deformed by stress. Therefore, the weight portion 104 is easily displaced when a force is applied.

  Upper fixed electrodes E1 to E5 are formed on the upper glass substrate 101. Lower fixed electrodes E 6 to E 10 are formed on the lower glass substrate 103. The weight portion 104 can be given a potential from the outside. Since all the electrodes are disposed so as to face the weight portion 104, capacitances C <b> 1 to C <b> 10 exist between the electrodes E <b> 1 to E <b> 10 and the weight portion 104.

  FIG. 2 shows a view 200 as seen from the side surface in the y-axis direction when no force is applied to the sensor in any axial direction.

  Next, the principle by which the sensor detects the angular velocity will be described with reference to FIGS. FIG. 3 shows a diagram 300 illustrating the principle by which the sensor detects angular velocity. FIG. 4 shows a block diagram 400 of angular velocity detection.

  First, consider the case where a force is applied in the X-axis direction of the weight portion 104. When a force is applied in the X-axis direction of the weight portion 104, the weight portion 104 is supported by the beam portions 105 to 108. Therefore, a moment about the beam portions 105 and 107 is formed at the center of mass of the weight portion. The weight portion 104 rotates about the beam portions 105 and 107 as axes. The rotation angle θ at this time is proportional to the force Fx applied in the X-axis direction. When the weight portion 104 rotates about the beam portions 105 and 107, the inter-electrode distances between the weight portion 104 and the fixed electrodes E1 to E4 and E6 to E9 change, so that the values of the corresponding capacitances C1 to C10 respectively. Changes. Therefore, for example, by detecting the difference between the capacitances C1 + C4 and C2 + C3, or the difference between the capacitances C6 + C9 and C7 + C8, an amount proportional to the force applied to the weight portion 104 in the X-axis direction can be detected. .

  In order to detect the displacement in the Z-axis direction, for example, the difference between the capacitance C1 + C2 + C3 + C4 and the capacitance C6 + C7 + C8 + C9 may be detected.

  In order to detect the angular velocity, the drive circuit 401 applies an AC voltage V1 having a frequency fd to the upper fixed electrode E5. In addition, an AC voltage V2 having a phase difference of 180 degrees is applied to the lower fixed electrode E10 by the drive circuit 401. Then, since the Coulomb force that vibrates temporally at the frequency fd acts in the same direction between the upper fixed electrode E5 and the lower fixed electrode E10, the weight 104 is in the Z-axis direction. Vibrates at a frequency fz. The frequency fz of vibration in the Z-axis direction of the weight portion 104 is the same as the frequency fd of the AC voltages V1 and V2 applied by the drive circuit 401.

  As described above, when an angular velocity around the Y axis is applied to the sensor while the weight portion 104 is vibrating in the Z-axis direction at the frequency fz, a Coriolis force is generated in the weight portion 104 in the X-axis direction. The Coriolis force Fx applied to the weight portion 104 in the X-axis direction is expressed by the following equation where the angular velocity applied to the sensor is Ωy, the mass of the weight portion 104 is m, and the velocity of the weight portion 104 in the Z-axis direction is Vz. The

Since the weight portion 104 is vibrated at the frequency fz in the Z-axis direction,
v _z = v ₀ sin (f _z t)
Can be written. Accordingly, the Coriolis force generated in the weight portion 104 is modulated at the frequency fz, and the amplitude thereof is proportional to the angular velocity Ωy applied to the sensor and the velocity V0 in the Z-axis direction. This modulated Coriolis force is detected as capacitance changes of the capacitances C1 to C4 and the capacitances C6 to C10. If the amplitude of vibration in the Z-axis direction of the weight 104 is kept constant by the drive circuit 201, the speed V0 is also constant, so that the angular velocity Ωy can be detected.

  The Coriolis force in the Y-axis direction modulated by the frequency fz of vibration in the Z-axis direction generated in the weight portion 104 by the angular velocity Ωx around the X-axis is also detected, for example, by detecting the difference between the capacitance C1 + C2 and the capacitance C3 + C4 , And can be detected in the same manner as described above.

  Since the angular velocity signal based on the Coriolis force obtained as the capacitance change is modulated at the vibration frequency fz in the Z-axis direction, it needs to be demodulated. An example of a configuration for performing demodulation will be described with reference to FIG.

  First, each part will be described. The drive circuit 401 outputs an AC voltage for driving the weight 104 of the sensor at the frequency fd in the Z-axis direction so that the signal Z that is an input signal has a predetermined amplitude. The CV converter 402 converts a predetermined capacitance value into a predetermined voltage value. The phase shifter 403 changes the phase of the input signal by a predetermined angle. The synchronous detector 404 performs synchronous detection of the input signal using the output of the phase shifter 403 as a reference signal. The low-pass filter 405 attenuates a signal in a frequency band higher than a predetermined frequency included in the input signal.

Next, the function of the configuration of FIG. 4 will be described. A signal obtained by converting the capacitance (C1 + C2) − (C3 + C4) of the sensor into a voltage value using the CV converter 402 is defined as a signal X. A signal obtained by converting the capacitance (C1 + C4) − (C2 + C3) into a voltage value using the CV converter 402 is defined as a signal Y. A signal obtained by converting the electrostatic capacitance (C1 + C2 + C3 + C4) − (C6 + C7 + C8 + C9) into a voltage value using the CV converter 402 is defined as a signal Z. The signal X is proportional to the rotation angle of the weight portion 104 with the beam portions 106 and 108 as axes. The signal Y is proportional to the rotation angle of the weight portion 104 with the beam portions 105 and 107 as axes. The signal Z is proportional to the displacement of the weight portion 104 in the Z-axis direction.
Signal X = (C1 + C2)-(C3 + C4)
Signal Y = (C1 + C4)-(C2 + C3)
Signal Z = (C1 + C2 + C3 + C4) − (C6 + C7 + C8 + C9)

  Consider a case where an angular velocity is applied around the X axis of the sensor. The signal X includes a signal obtained by modulating a Coriolis force proportional to the magnitude of the angular velocity with a frequency fz. In order to extract the magnitude of the Coriolis force from this signal, it is only necessary to perform synchronous detection with a reference signal synchronized with the Coriolis force.

  A signal synchronized with the Coriolis force can be generated from the signal Z which is a displacement signal of the weight portion 104 in the Z-axis direction. The Coriolis force is proportional to the speed Vz of the weight portion 104. The velocity Vz is obtained by differentiating the displacement of the weight portion 104. That is, if the signal Z, which is a displacement signal of the weight 104 in the Z-axis direction, is phase-shifted by 90 ° or −90 ° with respect to the signal Z by the phase shifter 403, it can be used as a reference signal synchronized with the Coriolis force. it can.

  The Coriolis force can be detected by synchronously detecting the signal X at the output of the phase shifter 403 and passing through the low-pass filter 405 limited to a predetermined band. The Coriolis force is proportional to the velocity Vz of the weight portion 104 in the Z-axis direction and the angular velocity Ω applied to the sensor. Now, the speed Vz of the weight 104 in the Z-axis direction is controlled to a constant amplitude by the drive unit 401. Therefore, a proportional relationship is established between the detected Coriolis force and the applied angular velocity. Accordingly, the angular velocity output X is obtained by multiplying the output of the low-pass filter 405 by the angular velocity sensitivity around the X axis measured in advance. The angular velocity around the Y axis can be detected in the same manner as described above.

  FIG. 5 shows a signal waveform. The left side of FIG. 5 shows a waveform when no angular velocity is applied to the sensor. The right side of FIG. 5 shows a waveform when an angular velocity is applied to the sensor.

  FIG. 5A shows a waveform (solid line) representing the displacement when the weight portion 104 is driven in the Z-axis direction and a waveform (broken line) representing the speed of the weight portion 104. The waveform representing the displacement corresponds to the waveform of the signal Z in FIG. The waveform representing the displacement and the waveform representing the velocity are 90 ° out of phase.

  FIG. 5B is a waveform obtained by detecting a change in capacitance due to the displacement of the weight portion 104 due to the Coriolis force applied to the weight portion 104 by the CV converter 202 when the weight portion 104 is driven in the Z-axis direction. 4 corresponds to signal X. When no angular velocity is applied to the sensor, no Coriolis force is generated, so its output is zero. When an angular velocity ω is applied around the X axis of the sensor, the signal X has an amplitude proportional to the angular velocity ω and oscillates with a phase shifted by 90 ° from the signal Z.

  FIG. 5 (c) is a signal obtained by synchronously detecting the signal X with a signal obtained by shifting the signal Z by 90 °, and is an output of the synchronous detector 204 of FIG. Since the Coriolis force and the signal obtained by shifting the signal Z by 90 ° have the same phase, as shown in the figure, the waveform is folded around zero.

  FIG. 5D shows an output waveform of the low-pass filter when the waveform after the synchronous detection is input to the low-pass filter having a predetermined band. When the angular velocity applied to the sensor is zero, the output is zero. When the angular velocity applied to the sensor is Ω = ω, an output value proportional to the angular velocity ω can be obtained.

  As described above, angular velocities around the X axis and the Y axis can be detected.

Micromachined 5-axis Motion Sensor with Electrostatic Drive and Capacitive Detection, Taniguchi et al., Tech Dig Sens Symp, 2001. SOI MICROMACHINED 5-AXIS MOTION SENSOR USING RESONANT ELECTROSTATIC DRIVE AND NON-RESONANT CAPACITIVE DETECTION MODE, Yoshiyuki Watanabe, et al., Digest of Papers, Tranceducers '05, pp. 511-514, 2005.

  One feature of the above-described sensor is that it is possible to simultaneously detect three axes of acceleration and two axes of angular velocity by providing only one weight portion.

  For example, when acceleration is applied to this sensor in the X-axis direction, an inertial force is generated in the X-axis direction of the weight portion 104. If this acceleration is in a frequency band that includes the vibration frequency fz of the weight portion 104 in the Z-axis direction, the detection method shown in FIG. 4 detects the displacement of the weight portion 104 due to the inertial force as a capacitance change. As a result, an inertial force signal due to acceleration is superimposed on the angular velocity signal as noise. The magnitude of the noise depends on the acceleration sensitivity of the sensor. Since this sensor can detect acceleration and angular velocity at the same time, it cannot significantly reduce acceleration sensitivity. In addition, since such a sensor is mounted on a portable device, the demand for downsizing is severe. When the size is reduced, the electrode area is reduced, so that the resonance frequency of the weight portion 104 must be lowered in order to maintain acceleration sensitivity. Then, the influence by the inertial force is more noticeable.

  FIG. 6 shows an angular velocity output 600 when a pulse acceleration having a width of about 1 millisecond and a magnitude of about 1 G is applied to a sensor having the same structure without applying an angular velocity. Since no angular velocity is applied, the output is expected to be zero, but an angular velocity output equivalent to about 4000 deg / s is instantaneously output.

  In many cases, the output of the angular velocity sensor is integrated and converted into an angle. When the angular velocity output in FIG. 6 is integrated, an angular error of about 40 ° is obtained. This is not a practically acceptable error. An object of the present invention is to reduce such an angular error with a simple mechanism without impairing the acceleration sensitivity of the sensor.

In order to solve the above problem, the angular velocity sensor of the present invention, the second axis orthogonal to the upper Symbol first axis, and a third axis perpendicular respectively to said first axis and said second axis A displacement signal output unit that detects a force applied to the first axis direction, outputs a displacement signal in the first axis direction, the second axis direction, and the third axis direction; and the displacement in the second and third axis directions A disturbance signal detector for detecting an inertial force signal due to acceleration as a disturbance signal, and a displacement signal in the second and third axial directions based on the disturbance detection signal output from the disturbance signal detector. And a disturbance signal detector that detects the angular velocity signal by detecting a signal including the angular velocity signal with a reference signal that is 90 ° out of phase with the angular velocity. Detects the above disturbance signal in the same band as And wherein the Rukoto.

  Further, a first phase shift section that changes the phase of the first axial displacement signal by a predetermined phase shift amount, and an output signal from the phase shift section as a reference signal, the second or third It is also possible to include a synchronous detector that detects a displacement signal in the axial direction, and a low-pass filter that outputs an angular velocity signal based on an output signal from the synchronous detector.

  The amount of phase shift in the first phase shift section may be 90 degrees or -90 degrees.

  Further, the disturbance signal detection unit uses a second phase shift unit that changes the phase of the displacement signal in the first axial direction by a predetermined phase shift amount, and an output signal from the phase shift unit as a reference signal, A synchronous detector that detects a displacement signal in the second or third axial direction, and a comparator that compares the amplitude of the output signal from the synchronous detector with a predetermined threshold value may be provided.

  Further, the amount of phase shift in the second phase shift section may be 0 degree or 180 degrees.

The correction unit samples and holds the displacement signal in the second or third axial direction based on the disturbance detection signal, and the second or second based on the disturbance detection signal. 3 may be provided with a signal switching unit that outputs one of the angular velocity signal based on the axial displacement signal of 3 and the output signal from the sample and hold circuit unit.
In addition, the detection signal output unit includes a capacitance type sensor including a weight, a beam supporting the weight, and an electrode formed to face the weight, and a weight orthogonal to the electrode surface. A force applied to a drive unit that drives in the axial direction of one, a second axis that is orthogonal to the first axis, and a third axis that is respectively orthogonal to the first axis and the second axis, A capacitance conversion unit that detects a capacitance between the weight and the electrode and outputs displacement signals in the first axial direction, the second axial direction, and the third axial direction. It is good.
In addition, the detection signal output unit has a weight part that can be displaced inside, and the weight part is vibrated with a predetermined frequency. The displacement that occurs may be detected by a change in capacitance due to the displacement of the weight, and output as a displacement signal in the first axial direction, the second axial direction, and the third axial direction.
Further, the detection signal output unit has a weight part that can be displaced inside, and the weight part is vibrated with a predetermined frequency, so that the Coriolis force generated in the weight part when an angular velocity is applied to the system. The displacement that occurs may be detected as a displacement signal in the first axial direction, the second axial direction, and the third axial direction by detecting a change in stress due to the displacement of the weight portion by the piezoelectric effect.
Of the second axis orthogonal to the first axis, and the third axis orthogonal to the first axis and the second axis, the displacement signals in the second and third axial directions. Based on a disturbance signal detection unit for detecting an inertial force signal due to acceleration as a disturbance signal, and a disturbance detection signal output from the disturbance signal detection unit, to the displacement signals in the second and third axial directions. And a disturbance signal detector that detects the signal including the angular velocity signal with a reference signal that is 90 ° out of phase with the angular velocity signal, thereby detecting the angular velocity signal The disturbance signal in the same band may be detected.
A first phase shift section that changes the phase of the displacement signal in the first axial direction by a predetermined phase shift amount; and an output signal from the phase shift section is used as a reference signal, and the second or third axis A synchronous detection unit that detects a displacement signal in a direction and a low-pass filter that outputs an angular velocity signal based on an output signal from the synchronous detection unit may be further provided.
The phase shift amount in the first phase shift section may be 90 degrees or -90 degrees.
Further, the disturbance signal detection unit uses a second phase shift unit that changes the phase of the displacement signal in the first axial direction by a predetermined phase shift amount, and an output signal from the phase shift unit as a reference signal, A synchronous detector that detects a displacement signal in the second or third axial direction, and a comparator that compares the amplitude of the output signal from the synchronous detector with a predetermined threshold value may be provided.
Further, the amount of phase shift in the second phase shift section may be 0 degree or 180 degrees.
The correction unit samples and holds the displacement signal in the second or third axial direction based on the disturbance detection signal, and the second or second based on the disturbance detection signal. 3 may be provided with a signal switching unit that outputs one of the angular velocity signal based on the axial displacement signal of 3 and the output signal from the sample and hold circuit unit.

  The present invention has an effect of reducing errors due to a disturbance by a configuration including a disturbance detection unit that detects a disturbance with respect to an angular velocity signal and an angular velocity output correction unit that corrects the angular velocity signal.

It is a figure which shows schematic structure of 5-axis Motion Sensor by a prior art. It is the figure which looked at the sensor shown in FIG. 1 from the side. It is a figure which shows the principle in which the sensor shown in FIG. 2 detects angular velocity. It is a block diagram of the circuit which performs angular velocity detection with the sensor by a prior art. It is a figure which shows the outline of each signal shown in FIG. FIG. 5 is an angular velocity output diagram of the circuit shown in FIG. 4. It is a block diagram of the circuit of the angular velocity sensor by one Embodiment of this invention. It is a detailed block diagram of the disturbance detection part shown in FIG. It is a detailed block diagram of another form of the disturbance detection part shown in FIG. It is a detailed block diagram of another form of the disturbance detection part shown in FIG. FIG. 8 is a detailed block diagram of an angular velocity output correction unit shown in FIG. 7. It is a detailed block diagram of another form of the angular velocity output correction | amendment part shown in FIG.

  Hereinafter, the present invention will be described based on the illustrated embodiments.

  FIG. 7 shows a basic configuration 700 for reducing the influence of disturbance according to the present invention. The basic configuration 700 includes a drive circuit 701, a CV converter 702, a phase shifter 703, a synchronous detector 704, a low-pass filter 705, an external detection unit 706, an angular velocity output correction unit 707, and a sensor 708. . The description of the same configuration as that in FIG. 4 described above is omitted.

  The disturbance detection unit 706 receives the signal X and the signal Y, detects a signal (that is, disturbance) larger than a predetermined magnitude that is not an angular velocity signal, and detects a binary detection signal indicating whether the disturbance is detected or not. Is output. The angular velocity output correction unit 707 receives the angular velocity output X and the angular velocity output Y, which are the outputs of the low-pass filter 705, as inputs. If the disturbance detection signal is not detected, the angular velocity output X and the angular velocity output Y are output as they are. When the disturbance detection signal is in the detection state, the angular velocity output X and the angular velocity output Y are corrected. Thereby, when a disturbance enters the angular velocity signal of the sensor, the angular velocity output X and the angular velocity output Y are corrected.

  Next, details of the disturbance detection unit 706 will be described. FIG. 8 shows a configuration example of the disturbance detection unit 706. First, the function of each part will be described. The high pass filter 801 is a filter that attenuates a signal having a frequency lower than a predetermined cutoff frequency. The cutoff frequency is set to be sufficiently higher than the band for detecting the acceleration signal of the sensor and lower than the frequency for driving the weight portion in the Z-axis direction. The phase shifter 802 outputs a signal obtained by shifting the phase of the input signal by a predetermined angle. The synchronous detector 803 receives the output signal of the high-pass filter 801 and performs synchronous detection using the output signal of the phase shifter 802 as a reference signal. The amplitude detection circuit 804 detects the amplitude of the input signal and outputs it. The comparator 805 compares the output of the amplitude detection circuit 804 with a predetermined threshold value that is predetermined in order to determine whether there is a disturbance. When the output of the amplitude detection circuit 804 is larger than the threshold value, the disturbance detection signal X is set to a disturbance detection state. When the output of the amplitude detection circuit 804 is smaller than the threshold value, the disturbance detection signal X is set to a non-disturbance detection state.

  Next, the function of the disturbance detection unit 706 will be described. The signal Z representing the displacement of the vibration in the Z-axis direction of the weight 104 input to the phase shifter 802 and the angular velocity signal included in the signal X input to the high-pass filter 801 both have the same frequency fz, and the phase Is shifted by 90 °. When the amount of phase shift in the phase shifter 802 is set to 0 ° or 180 °, the phase of the angular velocity signal included in the output of the high-pass filter 801 and the phase of the reference signal output from the phase shifter 802 are shifted by 90 °. become. Therefore, even when a certain angular velocity is applied to the sensor, the output of the synchronous detector 803 is zero if there is no disturbance. If a disturbance unrelated to the phase of the reference signal (for example, acceleration due to vibration in a frequency band including the frequency fz) is applied to the weight portion 104, a signal having a finite value is output to the synchronous detector 803. Is output. The amplitude of this signal is detected by the amplitude detection circuit 804. Then, the signal is input to the comparator 805, and if it is larger than a predetermined threshold value, the disturbance detection signal X is set in the disturbance detection state for a predetermined time τ. Here, the time τ is set larger than the time constant of the low-pass filter 805. The same applies to the signal Y. In this way, the disturbance detection unit 706 can detect a disturbance in the same band as the angular velocity signal by detecting the signal including the angular velocity signal with the reference signal that is 90 ° out of phase with the angular velocity signal.

Next, another example of the configuration of the disturbance detection unit 706 is shown in FIG.
In FIG. 9, the disturbance detection unit 706 includes a high-pass filter 901, a synchronous detector 903, an amplitude detection circuit 904, and a comparator 905. In this embodiment, the phase shift amount of the phase shifter is set to 0 °, and the phase shifter is omitted.

FIG. 10 shows still another example of the configuration of the disturbance detection unit 706.
In FIG. 10, the disturbance detection unit 706 includes a high-pass filter 1001, a synchronous detector 1003, an amplitude detection circuit 1004, a comparator 1005, and an inverting amplifier 1006. This form shows a case where the phase amount of the phase shifter is set to 180 ° and the phase shifter is an inverting amplifier.

Next, details of the angular velocity output correction unit 707 will be described.
FIG. 11 shows an example of a configuration for realizing the angular velocity output correction unit 707.

  A sample and hold circuit (S / H circuit) 1101 receives the output of the low-pass filter 705 that is the angular velocity signal X before correction. When the disturbance detection signal X is in the non-disturbance detection state, the sampling operation is performed at every predetermined time interval T. When the disturbance detection signal X is in the disturbance detection state, the sampling operation is not performed and the previous value is held. The time interval T seconds at which the sample operation is performed is set to be larger than the time required for the disturbance detection unit to detect the disturbance. By setting T in this way, the sample and hold circuit can reliably output the value before being affected by the disturbance. The signal switcher 1102 receives the output of the low-pass filter 705 that is the angular velocity signal X before correction and the output of the sample and hold circuit 1101 as inputs. If the disturbance detection signal X is in the non-disturbance detection state, the angular velocity signal X before correction is output, and if the disturbance detection signal X is in the disturbance detection state, the output of the sample and hold circuit 1101 is output.

Next, FIG. 12 shows another example of a configuration for realizing the angular velocity output correction unit 707.
In FIG. 12, the angular velocity output correction unit 707 includes a signal switcher 1202. In this embodiment, when the disturbance detection signal is in the non-disturbance detection state, the pre-correction angular velocity signal X is output, and when the disturbance detection signal X is in the disturbance detection state, a zero signal is output, thereby omitting the sample and hold circuit. Shows the case.

  With the above configuration, the error generated in the angular velocity output can be reduced by continuously outputting the value immediately before the disturbance is detected until the disturbance is detected and the influence is settled.

701 Drive circuit 702 CV converter 703 Phase shifter 704 Synchronous detector 705 Low pass filter 706 External detection unit 707 Angular velocity output correction unit 801 High pass filter 802 Phase shifter 803 Synchronous detector 804 Amplitude detection circuit 805 Comparator 901 S / H circuit 902 Signal selector

Claims (15)

Forces applied to a second axis orthogonal to the first axis and a third axis orthogonal to the first axis and the second axis are detected, and the first axial direction and the second axis are detected. A displacement signal output unit for outputting displacement signals in the axial direction of the second axis and the third axial direction
A disturbance signal detector for detecting an inertial force signal due to acceleration included in the displacement signals in the second and third axial directions as a disturbance signal;
A correction unit that corrects an angular velocity signal based on the displacement signals in the second and third axial directions based on a disturbance detection signal output from the disturbance signal detection unit;
With
The disturbance signal detection unit detects the disturbance signal in the same band as the angular velocity signal by detecting a signal including the angular velocity signal with a reference signal that is 90 ° out of phase with the angular velocity. Angular velocity sensor. further,
A first phase shift section that changes the phase of the displacement signal in the first axial direction by a predetermined phase shift amount;
A synchronous detection unit that detects an output signal from the phase shift unit as a reference signal and detects a displacement signal in the second or third axial direction;
The angular velocity sensor according to claim 1, further comprising: a low-pass filter that outputs an angular velocity signal based on an output signal from the synchronous detection unit.   The angular velocity sensor according to claim 2, wherein the amount of phase shift in the first phase shift section is 90 degrees or -90 degrees. The disturbance signal detector is
A second phase shift section that changes the phase of the displacement signal in the first axial direction by a predetermined phase shift amount;
A synchronous detection unit that detects an output signal from the phase shift unit as a reference signal and detects a displacement signal in the second or third axial direction;
The angular velocity sensor according to claim 2, further comprising: a comparison unit that compares the amplitude of the output signal from the synchronous detection unit with a predetermined threshold value.   The angular velocity sensor according to claim 4, wherein an amount of phase shift in the second phase shift portion is 0 degree or 180 degrees. The correction unit is
A sample and hold circuit section that samples and holds the displacement signal in the second or third axial direction based on the disturbance detection signal;
Based on the disturbance detection signal,
An angular velocity signal based on the second or third axial displacement signal;
The angular velocity sensor according to claim 4, further comprising: a signal switching unit that outputs one of the output signals from the sample and hold circuit unit. The detection signal output unit is
A capacitance type sensor comprising a weight, a beam supporting the weight, and an electrode formed to face the beam;
A drive unit for driving the weight in a first axial direction perpendicular to the electrode surface;
A force applied to a second axis orthogonal to the first axis and a third axis orthogonal to the first axis and the second axis is applied to the electrostatic force between the weight and the electrode. 7. The capacitance converting unit that detects a capacitance and outputs a displacement signal in the first axial direction, the second axial direction, and the third axial direction. 7. Angular velocity sensor. The detection signal output unit is
Displacement caused by Coriolis force generated in the weight portion when the angular velocity is applied to the system by causing the weight portion to displace inside and vibrating the weight portion with a predetermined frequency. 7. The detection according to claim 1, wherein the displacement signal is detected as a change in capacitance and output as a displacement signal in the first axial direction, the second axial direction, and the third axial direction. Angular velocity sensor. The detection signal output unit is
Displacement caused by Coriolis force generated in the weight portion when the angular velocity is applied to the system by causing the weight portion to displace inside and vibrating the weight portion with a predetermined frequency. The change in stress is detected by a piezoelectric effect, and is output as a displacement signal in the first axial direction, the second axial direction, and the third axial direction. The angular velocity sensor described. Of a second axis orthogonal to the first axis, and a third axis orthogonal to the first axis and the second axis,
A disturbance signal detector for detecting an inertial force signal due to acceleration included in the displacement signals in the second and third axial directions as a disturbance signal;
A correction unit that corrects an angular velocity signal based on the displacement signals in the second and third axial directions based on a disturbance detection signal output from the disturbance signal detection unit;
With
The disturbance signal detection unit, a signal containing the angular speed signal, by detecting the reference signal 90 ° phase shifted with respect to the angular velocity, that you detect the disturbance signal in the same band as the angular velocity signal An angular velocity signal correction device characterized. A first phase shift section that changes the phase of the displacement signal in the first axial direction by a predetermined phase shift amount;
A synchronous detection unit that detects an output signal from the phase shift unit as a reference signal and detects a displacement signal in the second or third axial direction;
The angular velocity signal correction device according to claim 10, further comprising a low-pass filter that outputs an angular velocity signal based on an output signal from the synchronous detection unit.   The angular velocity signal correction apparatus according to claim 11, wherein an amount of phase shift in the first phase shift unit is 90 degrees or −90 degrees. The disturbance signal detector is
A second phase shift section that changes the phase of the displacement signal in the first axial direction by a predetermined phase shift amount;
A synchronous detection unit that detects an output signal from the phase shift unit as a reference signal and detects a displacement signal in the second or third axial direction;
The angular velocity signal correction apparatus according to claim 11, further comprising a comparison unit that compares an amplitude of an output signal from the synchronous detection unit with a predetermined threshold value.   The angular velocity signal correction device according to claim 13, wherein an amount of phase shift in the second phase shift unit is 0 degree or 180 degrees. The correction unit is
A sample and hold circuit section that samples and holds the displacement signal in the second or third axial direction based on the disturbance detection signal;
Based on the disturbance detection signal,
An angular velocity signal based on the second or third axial displacement signal;
The angular velocity signal correction device according to claim 13, further comprising: a signal switching unit that outputs one of the output signals from the sample and hold circuit unit.

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