JP2007285886A - Voltage vibration type yaw rate sensor, and its driving method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a voltage vibration type yaw rate sensor capable of performing highly-accurate yaw rate detection even when being used in the atmosphere, by suppressing an influence on a detection signal caused by the charge in a vibrator, and its driving method. <P>SOLUTION: The first driving electrode 2 and the second driving electrode 3 are provided as driving electrodes for vibrating the vibrator 1, and mutually symmetrical driving signals Vd1, Vd2 are applied to the driving electrodes. Then, information of the vibrator charge is taken out from an output signal OUT from a charge amplifier 8, and the amplitude of either of the driving signals Vd1, Vd2 is adjusted thereby. Hereby, each charge quantity in the first driving electrode 2 and in the second driving electrode 3 is allowed to agree excellently with each other, to thereby suppress generation of the vibrator charge. Consequently, even if the vibrator 1 is driven by a great driving force, the detection signal is not influenced by the vibrator charge. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a yaw rate sensor that detects a yaw rate, that is, an angular velocity. More specifically, the present invention relates to a voltage oscillation type yaw rate sensor that detects a yaw rate while vibrating a vibrating body with a voltage signal, and a driving method thereof.

  Conventionally, a vibration type yaw rate sensor that utilizes the fact that a vibrating body is displaced by Coriolis force when yaw is applied has been used. An example of a conventional vibration type yaw rate sensor is described in Patent Document 1. The angular velocity sensor of Patent Document 1 detects a displacement caused by a Coriolis force when a yaw is applied to a vibrator that is vibrated by an electrostatic attraction of an electrode voltage, based on a change in capacitance. Thereby, the magnitude of the Coriolis force, that is, the yaw rate is detected.

In this yaw rate sensor, the primary vibrator and the secondary vibrator are connected by a beam, and the primary vibrator is excited. Due to vibration transmission from the primary vibrator, the secondary vibrator also vibrates, and their vibration directions are the same. The Coriolis force is detected when the secondary vibrator is vibrating. As a result, the effect of air damping is suppressed, and the secondary vibrating body can be vibrated with a large amplitude even in the atmosphere.
JP 2000-97708 A

  However, the conventional vibration type yaw rate sensor which detects the yaw rate using the potential of the vibrator has the following problems. In other words, when it is actually used in the atmosphere, the noise is large and the detection accuracy is not good. The cause is that charges are generated in the vibrating body by applying a driving voltage for excitation. This charge influences the signal detection. When used in the atmosphere, a greater electrostatic attraction is required to overcome the air resistance. For this reason, the amount of electric charge generated in the vibrating body by driving often exceeds the amount of electric charge caused by the change in capacitance that is originally to be detected. This is basically the same even when the vibration amplitude in the atmosphere is improved as in the angular velocity sensor of Patent Document 1.

  The present invention has been made to solve the problems of the above-described conventional vibration type yaw rate sensor. That is, the problem is to provide a voltage oscillation type yaw rate sensor that can suppress the influence on the detection signal due to the charge of the vibrating body and can detect the yaw rate with high accuracy even when used in the atmosphere, and a driving method thereof. .

  The voltage oscillation type yaw rate sensor of the present invention, which has been made for the purpose of solving this problem, is based on a vibrating body, first and second drive electrodes that form a capacitance with respect to the vibrating body, and an electrical signal of the vibrating body. A vibration generated by the drive unit based on an electric signal of the vibrating body, having a yaw rate detection unit for detecting the yaw rate and a drive unit for applying a reverse phase vibration voltage to the first and second drive electrodes An amplitude adjustment unit that adjusts the amplitude of the voltage, a timing determination unit that determines the frequency and phase of the oscillating voltage generated by the drive unit based on the electrical signal of the vibrating body, and an electric charge of the vibrating body from the electrical signal of the vibrating body And a correction unit that outputs a correction signal that suppresses generation of electric charges of the vibrator based on the extracted signal.

  The present invention also provides an adjustment of the amplitude of the oscillating voltage generated by the drive unit based on the electrical signal of the vibrating body, the determination of the frequency and phase of the oscillating voltage generated by the driving unit based on the electrical signal of the vibrating body, and the vibrating body. Method of driving voltage oscillation type yaw rate sensor for extracting signal corresponding to electric charge of vibrating body from electric signal of, and outputting correction signal for suppressing generation of electric charge of vibrating body based on extracted signal It extends to.

  In this voltage vibration type yaw rate sensor and its driving method, the vibrating body is vibrated by applying a vibration voltage to the first and second drive electrodes by the drive unit. When yaw is applied in this state, the information appears in the electrical signal of the vibrating body. This is detected by the yaw rate detector. The amplitude, frequency, and phase of the oscillating voltage are controlled by the amplitude adjusting unit and the timing determining unit based on the electrical signal of the vibrating body. As a result, optimum driving can be performed regardless of manufacturing variations. Here, the correction unit extracts a signal corresponding to the electric charge of the vibrating body from the electrical signal of the vibrating body, and outputs a correction signal based on the extracted signal. Due to this correction signal, the generation of electric charges on the vibrator is suppressed. As a result, even when the vibrating body is driven with a large amplitude vibration voltage, that is, with a large driving force, the generation of charges on the vibrating body is suppressed. For this reason, the accuracy of yaw rate detection is high even when the vibrator is driven with a large driving force. Therefore, highly accurate yaw rate detection can be performed even in the atmosphere.

  Here, the correction unit may include a detection unit that detects an electrical signal of the vibrator at a frequency twice that frequency, and a correction signal generation unit that generates a correction signal based on the output signal of the detection unit. desirable. This is because information on the electric charge generated in the vibrating body can be obtained by detecting the electric signal of the vibrating body at a frequency twice that frequency. Thereby, it is possible to generate a correction signal for suppressing the charge of the vibrating body.

  In that case, it is desirable that the detection unit performs detection at a frequency twice the frequency determined by the timing determination unit. The frequency determined by the timing determination unit is a frequency obtained from an actual measurement signal of the vibrating body. For this reason, by detecting at twice the frequency, information on the charges generated in the vibrator can be obtained correctly.

  In the voltage oscillation type yaw rate sensor of the present invention, it is desirable that the drive unit corrects one amplitude of the oscillation voltage to the first and second drive electrodes by a correction signal output from the correction unit. Thereby, the electric charge generated in the drive electrode by the oscillating voltage is adjusted, and the generation of the electric charge of the vibrating body is suppressed.

  According to the present invention, there is provided a voltage oscillation type yaw rate sensor capable of detecting a yaw rate with high accuracy even when used in the atmosphere by suppressing the influence on the detection signal due to the charge of the vibrating body, and a driving method thereof. .

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the best mode for embodying the present invention will be described in detail with reference to the accompanying drawings. The voltage oscillation type yaw rate sensor according to this embodiment is configured as shown in FIG.

  That is, the voltage vibration type yaw rate sensor of FIG. 1 has a vibrating body 1, a first drive electrode 2, and a second drive electrode 3 as semiconductor portions. The vibrating body 1 is a sensor element formed on a semiconductor substrate so as to float from the substrate while being held by a beam. The vibrating body 1 is provided with a first driven electrode 4 and a second driven electrode 5. The first driving electrode 2 and the first driven electrode 4 face each other to form a first capacitor 6. Similarly, the second driving electrode 3 and the second driven electrode 5 face each other to form a second capacitor 7. The first capacitor 6 and the second capacitor 7 are enlarged and shown in FIG. Actually, each electrode has a known comb-teeth shape.

  The voltage oscillation type yaw rate sensor shown in FIG. 1 includes a charge amplifier 8, a yaw rate detection circuit 9, a drive unit 10, a control unit 25, and a correction unit 22 as circuit portions. The charge amplifier 8 is a circuit that detects, amplifies and outputs the potential of the vibrator 1. The yaw rate detection circuit 9 is a circuit that detects the yaw rate applied to the vibrating body 1 based on the output of the charge amplifier 8. The specific calculation contents are not particularly different from known ones. The drive unit 10 is a circuit that outputs drive signals Vd 1 and Vd 2 to the first drive electrode 2 and the second drive electrode 3 based on the output of the charge amplifier 8. The drive signals Vd1 and Vd2 are oscillating voltages, and the frequency fd and the like are determined by the control unit 25 as described later. The correction unit 22 is a circuit for correcting the drive signal Vd2 in order to suppress the generation of charges in the vibrating body 1.

  The charge amplifier 8 includes a capacitor 23 and an operational amplifier 24 as shown in FIG. That is, the capacitor 23 is arranged between the negative input terminal and the output terminal of the operational amplifier 24. The potential of the vibrator 1 is input to the negative input terminal of the operational amplifier 24. The positive input terminal of the operational amplifier 24 is grounded. The signal at the output terminal of the operational amplifier 24 is output to the charge amplifier 8 and the drive unit 10.

  Examples of output waveforms of the charge amplifier 8 are shown in FIGS. FIG. 4 shows an example of a waveform under a situation where the first drive electrode 2 and the second drive electrode 3 are driven with small amplitude drive signals Vd1, Vd2, that is, with a small drive force. FIG. 5 is an example of a waveform under a situation where the driving signals Vd1, Vd2 having large amplitudes, that is, driving with a large driving force are performed. 4 and 5 both show one cycle of the drive signals Vd1 and Vd2. The curve of “OUT” in these graphs is the output signal of the charge amplifier 8. In the waveform of the signal OUT, the yaw rate detection circuit 9 detects the amplitude of the portion indicated by the arrow with the letters “yaw rate signal”. The frequency of the detected yaw rate signal is the same as the frequency of the drive signals Vd1 and Vd2.

  Returning to FIG. 1, the drive unit 10 includes a + drive signal generation unit 16, a + level shift unit 17, a + DC bias generation unit 18, a −drive signal generation unit 19, a −level shift unit 20, and a −DC bias generation. A portion 21 is provided. The control unit 25 includes an amplitude detection unit 11, a gain control unit 12, and a drive timing generation unit 13. The correction unit 22 includes a double period detection unit 14 and a correction signal generation unit 15.

  The amplitude detector 11 is a block that detects the amplitude Amp in the output signal OUT of the charge amplifier 8. The amplitude Amp indicates the displacement of the vibrating body 1 due to the drive signals Vd1 and Vd2, and the frequency thereof is the same as the frequency of the drive signals Vd1 and Vd2. The gain control unit 12 is a block that determines the driving strength of the first drive electrode 2 and the second drive electrode 3 based on the amplitude Amp detected by the amplitude detection unit 11. Specifically, the gain control unit 12 determines the amplitudes of the drive signals Vd1 and Vd2. This method for determining the amplitude itself is known. In short, when the amplitude Amp is insufficient, the amplitudes of the drive signals Vd1 and Vd2 are increased, and when the amplitude Amp is excessive, the amplitudes of the drive signals Vd1 and Vd2 are decreased. The amplitude of the drive signal Vd1 and the amplitude of the drive signal Vd2 are basically the same.

  The drive timing generation unit 13 is a block that determines the timing for driving the first drive electrode 2 and the second drive electrode 3 based on the output signal OUT of the charge amplifier 8. Specifically, the drive timing generation unit 13 determines the frequency and phase of the drive signals Vd1 and Vd2. The frequencies of the drive signals Vd1 and Vd2 should match the resonance frequency of the vibrating body 1. Since the resonance frequency is physically determined by factors such as the mass of the vibrating body 1 and the elasticity of the beam, it can be derived from design information in principle. However, it is actually affected by manufacturing variations and temperature. Therefore, it is necessary to determine the frequency based on the actual output signal OUT of the charge amplifier 8. When the phases of the drive signals Vd1 and Vd2 are shifted by 90 ° with respect to the vibration of the vibrating body 1, the driving efficiency is good. Therefore, the phases of the drive signals Vd1 and Vd2 are adjusted based on the actual output signal OUT of the charge amplifier 8. This method of determining the frequency and phase is known per se.

  The + drive signal generator 16 and the −drive signal generator 19 basically generate an oscillating voltage based on the amplitude determined by the gain controller 12 and the frequency and phase determined by the drive timing generator 13. . The signals generated by the drive signal generators 16 and 19 are oscillating voltages having the same amplitude and a phase shift of 180 °. That is, the signals are inverted from each other.

  Then, the level shift is performed on the generated signal of the + drive signal generation unit 16 by the + level shift unit 17 to generate the drive signal Vd1. The shift amount S + at this time depends on the DC bias output from the + DC bias generator 18. Similarly, the level shift is performed on the generated signal of the −drive signal generation unit 19 by the −level shift unit 20 to generate the drive signal Vd2. The shift amount S− at that time is due to the DC bias output from the −DC bias generator 21.

  The relationship between the drive signals Vd1, Vd2, and the shift amounts S +, S− is shown in the graph of FIG. FIG. 6 shows two cycles of the drive signals Vd1 and Vd2. The amplitudes of the drive signals Vd1 and Vd2 indicated by the arrows with the letters “amplitude” in FIG. 6 are equal to the amplitudes of the generated signals of the + drive signal generator 16 and the −drive signal generator 19. That is, this is the amplitude determined by the gain control unit 12. The drive signal Vd1 thus generated is applied to the first drive electrode 2 of the first capacitor 6, and the drive signal Vd2 is applied to the second drive electrode 3 of the second capacitor 7. As a result, the vibrating body 1 is driven to vibrate. FIG. 6 shows that the waveforms of the drive signals Vd1 and Vd2 are symmetric.

  The double period detection unit 14 is a block that detects the output signal OUT of the charge amplifier 8 at a frequency twice the frequency of the drive signals Vd1 and Vd2. The correction signal generation unit 15 is a block that generates a correction signal based on the output signal of the double period detection unit 14. The reason why the double period detection unit 14 and the correction signal generation unit 15, that is, the correction unit 22 are provided is to correct the influence of the electric charge of the vibrator 1.

  For this purpose, first, the generation of charges in the vibrator 1 will be described. When the drive signal Vd1 is at a higher potential (+) than its average value, positive charges are generated at the first drive electrode 2 of the first capacitor 6. As a result, a negative charge is induced in the first driven electrode 4 of the vibrating body 1. The amount of negative charge on the first driven electrode 4 is equal to the amount of positive charge on the first drive electrode 2. Here, if the vibrating body 1 is driven only by the driving signal Vd 1, a positive charge corresponding to the negative charge generated in the first driven electrode 4 is generated in the main body portion of the vibrating body 1. .

  However, actually, the vibrator 1 is driven not only by the drive signal Vd1 but also by the drive signal Vd2. When the drive signal Vd1 is higher in potential (+) than its average value, the drive signal Vd2 is lower in potential (−) than its average value. For this reason, a negative charge is generated at the second drive electrode 3 of the second capacitor 7. As a result, a positive charge is induced in the second driven electrode 5 of the vibrating body 1. The amount of positive charge of the second driven electrode 5 is equal to the amount of negative charge of the second drive electrode 3. This acts to generate a negative charge in the main body portion of the vibrator 1. For this reason, in the main body portion of the vibrator 1, the charge due to the action of the drive signal Vd1 and the charge due to the action of the drive signal Vd2 cancel each other.

  Here, if the amplitudes of the drive signals Vd1 and Vd2 are equal, the amount of positive charge of the first drive electrode 2 and the amount of negative charge of the second drive electrode 3 should be equal. For this reason, the amount of negative charge of the first driven electrode 4 and the amount of positive charge of the second driven electrode 5 should be equal. Accordingly, no electric charge should be generated in the main body portion of the vibrating body 1 excluding the driven electrodes 4 and 5. This is because the influence of the electric charge of the first driven electrode 4 and that of the second driven electrode 5 cancel each other. The symbols “+” and “−” attached to each part in FIG. 3 indicate the state of such charge generation.

  Note that it is possible to drive the vibrator 1 with only one of the drive signals Vd1 and Vd2. However, charges are generated properly in the main body portion of the vibrator 1. By driving the vibrating body 1 with both the drive signals Vd1 and Vd2, the generation of electric charges in the main body portion of the vibrating body 1 is prevented.

  However, the charge is completely canceled in this way when the symmetry between the drive signal Vd1 and the drive signal Vd2 and the identicalness of the characteristics of the first capacitor 6 and the second capacitor 7 are both complete. is there. In practice, the influence of manufacturing variations is inevitable on the processing status of each part of the circuit. For this reason, the symmetry of the drive signals Vd1 and Vd2 actually applied to the drive electrodes 2 and 3 may not be so high. The same applies to the identity of the capacitor characteristics.

  Therefore, in practice, a difference may occur in the charges of the driven electrodes 4 and 5. Then, a charge corresponding to the difference is generated in the main body portion of the vibrator 1. Of course, the sign is the same as the smaller of the charges generated on the driven electrodes 4 and 5. That is, although it has been described in the graph of FIG. 6 that the waveforms of the drive signals Vd1 and Vd2 are symmetric, the charges generated in the driven electrodes 4 and 5 are not necessarily completely symmetric. Thus, the amount of electric charge (hereinafter referred to as “vibrating body charge”) generated in the main body of the vibrating body 1 increases as the amplitude of the drive signals Vd1 and Vd2 increases.

  Therefore, the influence is only slight when the amplitude of the drive signals Vd1 and Vd2 is small (left side in FIG. 3). However, in the situation where the amplitudes of the drive signals Vd1 and Vd2 are large (right side in FIG. 3), the influence of the vibrator charge cannot be ignored. In particular, when this voltage oscillation type yaw rate sensor is used in the atmosphere, a large driving force is required. For this reason, the drive signals Vd1 and Vd2 are used with an increased amplitude. For this reason, the influence of the vibrator charge is a big problem.

  In the output signal OUT in the case where the driving force shown in FIG. That is, the signal LF is superimposed on the waveform of the output signal OUT in FIG. This signal LF is the influence of the vibrator charge. The frequency of the signal LF is twice the frequency of the drive signals Vd1 and Vd2. This is because the fluctuation of the vibrator charge is affected by the displacement of the vibrator 1 in addition to the influence of the drive signals Vd1 and Vd2. Therefore, the signal LF for two periods appears in FIG.

  In the case of FIG. 5, the amplitude of the signal LF is large. Therefore, the place where the output signal OUT is inverted from the original polarity is conspicuous. Therefore, in the situation as shown in FIG. 5, the accuracy of the yaw rate detection by the yaw rate detection circuit 9 is not good. In the situation where the driving force is small as shown in FIG. 4, the amplitude of the signal LF superimposed on the output signal OUT is small. In the situation of FIG. 4, the accuracy of yaw rate detection by the yaw rate detection circuit 9 is good.

  However, as described above, when the voltage oscillation type yaw rate sensor is used in the atmosphere, it must be used with a large driving force. Therefore, it is desired to obtain an output signal OUT as shown in FIG. 4 even when the driving force is large. The correction unit 22 is provided to correct the drive signal for that purpose.

  The basic principle is to adjust the amplitude of at least one of the drive signals Vd1 and Vd2 so that the vibrator charge does not appear as much as possible. In this embodiment, the drive signal Vd2 is adjusted. That is, when the vibrating body charge appears, the driving force of the first driving electrode 2 and the second driving electrode 3 that has the charge having the same polarity as that of the vibrating body charge is excessive. is there. Accordingly, it can be determined which of the drive signals Vd1 and Vd2 is excessive based on the relationship between the polarity of the vibrator charge and the drive signal. If the drive signal Vd2 is more than the drive signal Vd1, the amplitude of the drive signal Vd2 may be reduced. Conversely, if the drive signal Vd2 is insufficient with respect to the drive signal Vd1, the amplitude of the drive signal Vd2 may be increased. Thus, the amplitude of the drive signal Vd2 may be determined so that the vibrator charge is minimized.

For this reason, in the correction unit 22, the double period detection unit 14 first detects the output signal OUT of the charge amplifier 8 at a frequency twice the frequency of the drive signals Vd1 and Vd2. The clock signal CK 2 _fd indicating the actual frequency and phase of the drive signals _{Vd 1 and Vd 2 necessary for this} is supplied from the drive timing generation unit 13. Thereby, the detection signal shown in FIG. 7 is obtained. The double period detection unit 14 is configured as shown in FIG. 8, for example. That is, the signal as it is and the signal obtained by inverting the output signal OUT are alternately output according to the clock signal CK _2fd .

  By smoothing the signal of FIG. 7 by the correction signal generator 15, only the amplitude information of the signal LF is extracted from the output signal OUT. This magnitude represents the magnitude of the vibrator charge. The sign indicates the polarity of the vibrator charge. This signal may be used as a correction signal. For example, the correction signal generation unit 15 is configured as shown in FIG.

  The correction signal is input to the −drive signal generator 19. Then, the amplitude determined by the gain control unit 12 is corrected. That is, when the detection signal in FIG. 7 indicates that the drive signal Vd2 is excessive from the drive signal Vd1, the amplitude of the drive signal Vd2 is decreased. Conversely, when the drive signal Vd2 is insufficient with respect to the drive signal Vd1, the amplitude of the drive signal Vd2 is increased.

  On the other hand, the correction signal from the correction signal generation unit 15 is not input to the + drive signal generation unit 16. For this reason, the amplitude of the drive signal Vd1 follows the determination of the gain control unit 12 as it is regardless of the state of the vibrator charge. For this reason, a difference corresponding to the correction occurs between the amplitude of the drive signal Vd1 and the amplitude of the drive signal Vd2. As a result, charge cancellation between the first drive electrode 2 and the second drive electrode 3 is more complete.

  Therefore, even when the vibrator 1 is driven with a large driving force, a good signal OUT as shown in FIG. 4 can be obtained. For this reason, the voltage oscillation type yaw rate sensor of this embodiment can detect the yaw rate with high accuracy even when used in the atmosphere.

  As described in detail above, in the present embodiment, the first drive electrode 2 and the second drive electrode 3 are provided as drive electrodes for vibrating the vibrating body 1. Then, drive signals Vd1 and Vd2 that are symmetrical to each other are applied to these drive electrodes. Here, the information on the vibrator charge is extracted from the output signal OUT of the charge amplifier 8. As a result, the amplitude of one of the drive signals Vd1 and Vd2 is adjusted. In this way, the amounts of charge in the first drive electrode 2 and the second drive electrode 3 are matched better, and the generation of vibratory charges is suppressed. In this way, even if the vibrator 1 is driven with a large driving force, the influence of the vibrator charge does not appear on the detection signal. Thus, a yaw rate sensor capable of highly accurate yaw rate detection in the atmosphere has been realized.

  In addition, this form is only an illustration and does not limit this invention at all. Therefore, the present invention can naturally be modified and improved in various ways without departing from the spirit of the present invention.

  For example, in this embodiment, the correction signal from the correction unit 22 acts on the drive signal Vd2. However, the correction signal may act on the drive signal Vd1 instead of the drive signal Vd2. However, in that case, the relationship between the sign of the detection signal and the increase / decrease in the amplitude of the drive signal is opposite to that described above. Further, the correction signal may act on both the drive signals Vd1 and Vd2. In this case, however, the increase / decrease in amplitude is reversed between the drive signal Vd1 and the drive signal Vd2.

  In this embodiment, a + drive signal generator 16 and a −drive signal generator 19 are provided for the first drive electrode 2 and the second drive electrode 3, respectively. And the correction | amendment by the correction | amendment part 22 acts on the-drive signal production | generation part 19 of them. However, the present invention is not limited to this, and only one drive signal generation unit may be provided. In that case, the output is branched, and one is used with the same polarity and the other is inverted. In this case, the correction shall be applied to one after branching. Configuration examples in that case are shown in FIGS. Or you may make it act reversely with respect to both after a branch. In any case, the order of inversion, adjustment, and level shift is arbitrary.

  In this embodiment, the correction by the correction unit 22 acts on the amplitudes of the drive signals Vd1 and Vd2, but it is also conceivable that the correction acts on the circuit elements. For example, it is conceivable to adjust the capacitance of the first capacitor 6 or the second capacitor 7 by dividing the first drive electrode 2 or the second drive electrode 3.

It is a block diagram which shows the structure of the voltage oscillation type | mold angular velocity sensor which concerns on embodiment. It is an enlarged view which shows the part of the electrode in the voltage oscillation type angular velocity sensor which concerns on embodiment. It is a figure which shows the structure of the charge amplifier in the voltage oscillation type | mold angular velocity sensor which concerns on embodiment. 5 is a graph showing an example of an output waveform of a charge amplifier in a situation where the driving force is small in the voltage oscillation type angular velocity sensor according to the embodiment. 6 is a graph showing an example of an output waveform of a charge amplifier in a situation where the driving force is large in the voltage oscillation type angular velocity sensor according to the embodiment. It is a graph which shows the waveform of the oscillating voltage applied to a drive electrode in the voltage oscillation type | mold angular velocity sensor which concerns on embodiment. It is a graph which shows the signal which detected the output waveform of the charge amplifier with the frequency twice as high as a drive signal. It is a figure which shows the structure of the double period detection part in embodiment. It is a figure which shows the structure of the correction signal generation part in embodiment. It is a partial block diagram which shows the structure of the voltage oscillation type | mold angular velocity sensor which concerns on a modification. It is a partial block diagram which shows the structure of the voltage oscillation type | mold angular velocity sensor which concerns on a modification.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vibrator 2 1st drive electrode 3 2nd drive electrode 9 Yaw rate detection circuit 10 Drive part 11 Amplitude detection part 12 Gain control part 13 Drive timing generation part 14 Double period detection part 15 Correction signal generation part 22 Correction part

Claims (8)

A vibrating body; first and second drive electrodes that form capacitance with respect to the vibrating body; a yaw rate detector that detects a yaw rate based on an electrical signal of the vibrating body; and the first and second drive electrodes. In a voltage oscillation type yaw rate sensor having a drive unit for applying an oscillating voltage of opposite phase to
An amplitude adjusting unit that adjusts an amplitude of an oscillating voltage generated by the driving unit based on an electric signal of the vibrating body;
A timing determining unit that determines a frequency and a phase of an oscillating voltage generated by the driving unit based on an electrical signal of the vibrating body;
A correction unit that extracts a signal corresponding to the charge of the vibrating body from the electrical signal of the vibrating body and outputs a correction signal that suppresses the generation of the charge of the vibrating body based on the extracted signal. A voltage oscillation type yaw rate sensor. 2. The voltage oscillation type yaw rate sensor according to claim 1, wherein the correction unit includes:
A detector for detecting the electric signal of the vibrator at a frequency twice that frequency;
A voltage oscillation type yaw rate sensor, comprising: a correction signal generation unit that generates a correction signal based on an output signal of the detection unit. The voltage oscillation type yaw rate sensor according to claim 2, wherein the detection unit includes:
A voltage oscillation type yaw rate sensor, wherein detection is performed at a frequency twice as high as the frequency determined by the timing determination unit. The voltage oscillation type yaw rate sensor according to claim 1, wherein the drive unit includes:
A voltage oscillation type yaw rate sensor, wherein the amplitude of one of the oscillation voltages to the first and second drive electrodes is corrected by a correction signal output from the correction unit. A vibrating body; first and second drive electrodes that form capacitance with respect to the vibrating body; a yaw rate detector that detects a yaw rate based on an electrical signal of the vibrating body; and the first and second drive electrodes. In a driving method of a voltage oscillation type yaw rate sensor having a driving unit for applying an oscillating voltage of opposite phase to
Adjusting the amplitude of the oscillating voltage generated by the drive unit based on the electrical signal of the oscillating body;
Determining the frequency and phase of the oscillating voltage generated by the drive unit based on the electrical signal of the oscillating body;
Extraction of a signal corresponding to the charge of the vibrator from the electrical signal of the vibrator;
A voltage oscillation type yaw rate sensor driving method comprising: outputting a correction signal that suppresses generation of electric charges of the vibrating body based on the extracted signal. In the voltage oscillation type yaw rate sensor driving method according to claim 5,
A method of driving a voltage oscillation type yaw rate sensor, wherein extraction of a signal corresponding to the electric charge of the vibrating body is performed by detecting an electric signal of the vibrating body at a frequency twice the frequency thereof. In the driving method of the voltage oscillation type yaw rate sensor according to claim 6,
Detection for extracting a signal corresponding to the electric charge of the vibrator is performed at a frequency twice the frequency of the vibration voltage generated by the drive unit, which is determined based on the electric signal of the vibrator. Driving method of voltage oscillation type yaw rate sensor. In the voltage oscillation type yaw rate sensor driving method according to claim 5,
A method of driving a voltage oscillation type yaw rate sensor, wherein the amplitude of one of oscillation voltages to the first and second drive electrodes is corrected by the correction signal.

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