Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
  • G01C19/00—Gyroscopes; Turn-sensitive devices using vibrating masses; Turn-sensitive devices without moving masses; Measuring angular rate using gyroscopic effects
  • G01C19/56—Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces
  • G01C19/5607—Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces using vibrating tuning forks
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
  • G01C19/00—Gyroscopes; Turn-sensitive devices using vibrating masses; Turn-sensitive devices without moving masses; Measuring angular rate using gyroscopic effects
  • G01C19/56—Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
  • G01C19/00—Gyroscopes; Turn-sensitive devices using vibrating masses; Turn-sensitive devices without moving masses; Measuring angular rate using gyroscopic effects
  • G01C19/56—Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces
  • G01C19/5607—Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces using vibrating tuning forks
  • G01C19/5614—Signal processing

Definitions

• the present invention relates to a detection signal processing method of a vibration type inertial force detection sensor and a vibration type inertial force detection sensor employing this method.
• a vibration type angle sensor which is an example of a conventional vibration type inertial force detection sensor includes a sensor element 203 provided with a drive unit 201 and a detection unit 202, as shown in a block diagram of FIG.
• the configuration includes a drive control circuit 204 that applies a control voltage to the unit 201 to vibrate the sensor element 203 and controls the vibration, and a detection system circuit 205 that processes a detection signal output from the detection unit 202.
• the detection signal output from the detection unit 202 is differentially amplified using the differential amplifier 206, and the differentially amplified signal and this detection signal are inverted using the inverting amplifier 207.
• the signal is synchronously detected using the synchronous detector 208. Thereafter, a method of outputting a signal in which disturbance noise such as an external impact is suppressed by performing smoothing using a low-pass filter 209 is known.
• the conventional low-pass filter 209 first amplifies the signal after synchronous detection by the inverting amplifier 220 as a preamplifier and smoothes the force using the smoothing circuit 221 or an active filter (not shown). Smoothed while amplifying with.
• the signal after the synchronous detection in the synchronous detector 208 becomes a sawtooth waveform as shown by the synchronous detection output 208a in FIG. I'm stuck. Therefore, in this waveform switching portion 210, the amplification processing capability of the inverting amplifier 220, which is the preamplifier of the low-pass filter 209, and the active filter cannot fully follow, and the waveform is shown as the inverting amplifier output 220a in FIG. I was in trouble.
• the horizontal axis represents time
• the vertical axis represents the potential of each output signal. As shown in FIG.
• the inverting amplifier output 220a after the amplification processing includes a waveform error 212 that causes an offset 211 in the sensor output 205a after smoothing.
• the smoothing circuit 221 of the low-pass filter 209 cannot perform smoothing processing with high accuracy, and as a result, the performance of the vibration type inertial force detection sensor is reduced by internal processing of the detection system circuit 205! I have a problem!
• the present invention provides a detection signal processing method for solving such problems and improving the detection accuracy of the vibration type inertial force detection sensor, and a vibration type inertial force detection sensor employing this method. .
• the present invention removes harmonic components from a signal that has been synchronously detected, particularly in a detection system circuit of a vibration type inertial force detection sensor, amplifies the signal from which this harmonic component has been removed, The signal was smoothed.
• the detection accuracy of the vibration type inertial force detection sensor can be improved.
• FIG. 1 is a block diagram showing a vibration type inertial force detection sensor according to an embodiment of the present invention.
• FIG. 2 is a top view showing a sensor element used in a vibration type inertial force detection sensor.
• FIG. 3 is a waveform diagram showing a transition of a detection waveform in the vibration type inertial force detection sensor.
• FIG. 4 is a waveform diagram showing the transition of the detected waveform in the processing after synchronous detection in the vibration type inertial force detection sensor.
• FIG. 5 is a schematic diagram showing waveform components after synchronous detection.
• FIG. 6 is a block diagram of a vibration type angle sensor which is an example of a conventional vibration type inertial force detection sensor.
• FIG. 7 is a waveform diagram showing a transition of a waveform after synchronous detection in a conventional vibration type inertial force detection sensor.
• FIG. 1 is a block diagram showing a vibration type angular velocity sensor which is an example of a vibration type inertial force detection sensor of the present invention.
• the basic configuration includes a sensor element 103, a drive control circuit 104 that controls vibration of the sensor element 103, and a detection system circuit 105 that processes a signal output from the sensor element 103.
• FIG. 2 is a top view showing a detailed configuration of the sensor element 103 used in the vibration type angular velocity sensor of the present embodiment.
• the sensor element 103 is connected to a pair of drive arms 114 extended from a tuning fork type vibrator 113 having a silicon substrate force as shown in FIG. )
• a driving electrode 101a serving as a driving unit 101 and an detecting electrode 102a serving as a detecting unit 102 are provided.
• the base portion of the drive arm 114 is also provided with a monitor electrode 115a connected to the monitor unit 115, with the upper and lower surfaces of the piezoelectric thin film made of PZT sandwiched between electrodes.
• the drive arm 114 vibrates laterally as indicated by an arrow 116.
• Coriolis causes the drive arm 114 to stagnate in the front-rear direction in FIG. 2, and this detection causes the detection signal from the detection electrode 102a to be detected as shown in FIG. This is output to the output circuit 105.
• the monitor electrode 115a shown in FIG. 2 detects the amplitude amount of the drive arm 114, and feeds back the information to the drive control circuit 104 via the monitor unit 115, so that the amplitude described above is obtained.
• FIG. 3 shows the transition of the waveform of each signal in each vibration type speed sensor of the present embodiment.
• the horizontal axis represents time
• the vertical axis represents the potential of each signal. The same applies to Figs. 4 and 5.
• the detection signals (detection outputs 102b and 102c shown in FIG. 3) output from the two detection electrodes 102a provided in the sensor element 103 are first converted into current amplifiers. Amplification is performed using an amplifier 110 configured by a charge amplifier or the like. Next, the two amplified signals are differentially amplified using the differential amplifier 106, and the phase of the differentially amplified signal (the differential amplifier output 106a in FIG. 3) is adjusted by the phase shifter 117. Delay 0 degrees. The phase-delayed signal (phase shifter output 117a in FIG.
• the detection clock unit 118 converts the monitor signal 115b output from the monitor unit 115 into the detection CLK output (detection clock output) 118a of FIG.
• the configuration of the low-pass filter 109 shown in FIG. 1 that smooths the sawtooth synchronous detection output 108a is a passive filter that removes the harmonic components of the synchronous detection output 108a. Then, the signal is amplified by an amplifier 120 and then smoothed by using a smoothing circuit 121 such as an integrator. As a result, a decrease in detection accuracy in the detection system circuit 105 can be suppressed as compared with the conventional case where the synchronous detection output 208a of FIG. As a result, the detection accuracy of the vibration type inertial force detection sensor can be improved.
• a noisy filter is a filter composed of only passive components such as capacitors.
• a sawtooth synchronous detection output 208a is obtained as shown in FIG. Is amplified by a preamplifier or an active filter, resulting in a time lag 210a in the waveform switching portion 210 due to the followability of the amplifier.
• a waveform error 212 is generated between the actual waveform and the amplified waveform, and smoothing in a state including the waveform error 212 results in an offset 211 in the output.
• the synchronous detection outputs 108a and 208a output from the synchronous detector 108 shown in Fig. 1 and the synchronous detector 208 shown in Fig. 6 are fundamentally applied to the fundamental wave component 219a as shown in Fig. 5.
• This is a signal in which harmonic components such as second harmonic component 219b and third harmonic component 219c are synthesized. Therefore, as shown in FIG. 4, the synchronous detection output 108a is input to a passive filter 119 that removes harmonic components, and after the harmonic components are removed through this passive filter 119, a sinusoidal and smooth fundamental wave remains. Passive filter output 119a containing only component 219a is output.
• the passive filter output 119 a is amplified by the amplifier 120 as shown in FIG. 4, and the amplified amplifier output 120 a is smoothed by the smoothing circuit 121.
• the output of this vibration type angular velocity sensor becomes the sensor output 105a shown in FIG. 4 and does not include the waveform error 212 as shown in FIG. Can be suppressed.
• a decrease in detection accuracy in the detection system circuit 105 can be suppressed, and as a result, the detection accuracy of the vibration type inertial force detection sensor can be improved.
• the configuration of the noisy filter 119 for removing the harmonic component of the detection signal is not shown, but a resistance element is arranged in series with the detection signal path. This can be realized by using a general harmonic suppression circuit in which a capacitor element is arranged at least between one end and a reference potential.
• the vibration type angular velocity sensor is described as an example of the vibration type inertial force detection sensor.
• the present invention is not limited to this, and the drive arm is vibrated. By doing so, the same action and effect can be achieved in any configuration that detects inertial force, such as acceleration.
• the present invention enables higher detection accuracy in a vibration-type inertial force detection sensor, and is particularly useful for applications for electronic devices that require high detection accuracy with respect to inertial force. [0026] Therefore, the industrial applicability of the present invention is extremely high.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Radar, Positioning & Navigation (AREA)
• Remote Sensing (AREA)
• Signal Processing (AREA)
• Gyroscopes (AREA)

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• 2005
  • 2005-10-11 JP JP2005296283A patent/JP5458462B2/ja not_active Expired - Lifetime
• 2006
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  • 2006-10-10 EP EP06811477.6A patent/EP1936324B1/en active Active
  • 2006-10-10 KR KR1020087002684A patent/KR100985315B1/ko active Active
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• 2009
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