WO2013051060A1 - Rotational vibration gyro - Google Patents

Abstract

A rotational vibration gyro is provided which is able to properly remove erroneous vibrations caused by quadrature errors. A rotational vibration gyro vibrates a movable mass released on a substrate both reciprocatingly and rotationally via driving electrodes, and detects via detection electrodes displacement of the movable mass as it swings around a detection axis due to the Coriolis effect. This rotational vibration gyro has an error correcting means for imparting electrostatic force to the movable mass to correct the erroneous vibrations caused by the reciprocating and rotational vibration in a state that does not cause angular velocity, and the error correcting means has a plurality of correcting units arranged circumferentially with respect to the movable mass and centred on an axis orthogonal to the detection axis around at least one half of the movable mass as defined by the detection axis for applying voltage to generate the electrostatic force.

Description

Rotating vibration gyro

The present invention relates to a rotary vibration gyro that detects an angular velocity using Coriolis force.

Conventionally, a double-axis gyroscope sensor capable of detecting angular velocities around the X-axis and the Y-axis is known as this type of rotational vibration gyro (see FIG. 20 of Patent Document 1).
This double-axis gyroscope sensor includes a detection mass including a rotor (movable weight) released on a substrate, a drive system (drive electrode) that rotates and vibrates the detection mass around the Z axis, and around the X axis and Coriolis force. A sensing system (detection electrode) that detects the displacement of the detected mass that swings around the Y axis, and a quadrature correction system that extends in the radial direction from the outer peripheral end of the rotor and cancels the quadrature component error.
Each quadrature correction system is formed integrally with the rotor and extends from the outer peripheral end of the rotor in the X-axis direction and the Y-axis direction, respectively, and faces each plate with a gap in the Z-axis direction. Each of the pair of fixed electrode pads is provided.

In this double axis gyroscope sensor, in order to correct the quadrature phase error, a positive DC offset voltage is applied so that one voltage of one set of fixed electrode pads is higher than the other voltage. When the rotor rotates (vibrates) clockwise, for example, one fixed electrode pad overlaps with the plate, and the plate is pulled up (suction) by the electrostatic force generated in this overlapping portion. Thereby, the quadrature phase error is canceled (corrected) by the electrostatic force. By correcting this quadrature phase error, noise is removed and the angular velocity is accurately detected.

Special Table 2002-515976

Incidentally, the quadrature error (Quadrature Error) is caused by imperfection of the detected mass based on the etching accuracy of the beam (support spring), and is generated in synchronization with the rotational vibration of the rotor. For this reason, the quadrature phase error may increase depending on the product, and in the gyro sensor as described above, the plate and the fixed electrode pad are formed to be longer in the radial direction.
That is, since the amplitude of the rotational vibration of the rotor is fixed, if the quadrature phase error is large, the plate and the fixed electrode pad can be lengthened in the radial direction to increase the overlapping area, and the electrostatic force for attraction can be increased. I have to. For this reason, there has been a problem that the outer dimension of the gyro itself becomes larger than necessary.

An object of the present invention is to provide a rotational vibration gyro capable of appropriately removing a quadrature phase error while suppressing an increase in outer dimension.

The rotational vibration gyro of the present invention causes the movable weight released on the substrate to reciprocally rotate and vibrate via the drive electrode, and the displacement of the movable weight that swings around the detection axis by the Coriolis force via the detection electrode. A rotational vibration gyro to detect, comprising error correction means for correcting an error swing of the movable weight caused by reciprocating rotational vibration without applying an angular velocity by applying an electrostatic force to the movable weight. Is applied in the circumferential direction of the movable weight around the axis orthogonal to the detection axis in at least one half of the movable weight defined by the detection axis while applying a voltage for generating an electrostatic force It has a plurality of correction parts.

According to the above configuration, an electrostatic force that attracts the movable weight acts on each correction portion when a voltage is applied. For example, when the movable weight rotates clockwise (vibrates) due to reciprocating rotational vibration, and the movable weight swings away from each correction part due to the influence of the quadrature phase error, the electrostatic force acts in a direction to attract the movable weight. To do. That is, the quadrature phase error is canceled out by the electrostatic force, and the movable weight vibrates in a reciprocating manner in a plane without causing a shake. Therefore, noise is removed in the detection of the Coriolis force, and the angular velocity can be detected with high accuracy. Further, since the error correction means is composed of a plurality of correction portions arranged in the circumferential direction of the movable weight with the Z axis being an axis orthogonal to the detection axis as a center, each correction portion is not formed long in the radial direction. However, it is possible to sufficiently obtain the overlapping area, that is, the electrostatic force in the circumferential direction, and to suppress the increase in the outer dimensions.

In this case, it is preferable that the plurality of correction portions are arranged line-symmetrically around at least one of the detection axis and an axis orthogonal to the detection axis.

According to the above configuration, the correcting portion is arranged line-symmetrically on the detection axis or on the axis orthogonal to the detection axis, so that the rotational vibration gyro does not increase in the axial direction.

In this case, each correction portion extends in the radial direction from the outer peripheral end of the movable weight, and overlaps the extending piece constituting the movable electrode and the extending piece in the vibration direction of the reciprocating rotational vibration. It is preferable to have a correction electrode on the fixed side arranged in the.

According to the above configuration, when the movable weight rotates clockwise or counterclockwise, the electrostatic force (superimposed area) between the correction electrode to which the voltage is applied and the extended piece changes. That is, in one cycle of the rotating movable weight, the larger the displacement, the larger the overlapping area and the stronger the electrostatic force generated. Thereby, even if the applied voltage is constant, the generated electrostatic force is changed in proportion to the rotational vibration displacement, so that the quadrature phase error is canceled and the error oscillation of the movable weight can be corrected.

In this case, it is preferable that a pair of correction electrodes is provided so as to overlap both sides of the vibration direction of the reciprocating rotational vibration.

According to the above configuration, the tilting of the movable weight is caused to fall forward with respect to the detection axis due to the quadrature phase error (for example, the upper half of the movable weight is tilted downward in the Z-axis direction about the X axis (front falling = backward rising). ) Or rear descending (for example, the lower half of the movable weight is inclined downward in the Z-axis direction around the X axis (rear descending = front ascending)) Can be sucked so as to be located within a predetermined plane.

In this case, the correction electrode is preferably formed in a planar shape in which the area of the overlap portion between the extending piece and the correction electrode changes corresponding to the displacement of the reciprocating rotational vibration.

According to the above configuration, the quadrature phase error can be accurately canceled by the generated electrostatic force only by adjusting the voltage applied to the correction electrode. The planar shape of the correction electrode may be a trapezoid or a triangle.

Similarly, the movable weight is formed with a plurality of openings corresponding to the plurality of correction portions, and each correction portion constitutes an opening and an opening edge portion constituting a movable-side electrode, and an opening portion. It is preferable to have a correction electrode on the fixed side arranged so as to overlap the opening edge portion in the vibration direction of the reciprocating rotational vibration.

According to the above configuration, the opening edge can have the same function as the extended piece. As a result, the area of the movable weight can be reduced compared to the case where the extended piece is provided in the radial direction from the outer peripheral surface of the movable weight, and the air resistance when rotating and reciprocating can be reduced.

Also, the correction electrode is preferably formed in a fan shape that is concentric with the movable weight.

According to the above configuration, since the shape of the outer peripheral edge of the movable weight and the shape of the outer peripheral edge of the correction electrode in the circumferential direction are concentric circles, the quadrature phase error is accurately corrected in proportion to the rotational vibration of the movable weight. be able to.

On the other hand, it is preferable that two orthogonal detection axes are provided and two sets of error correction means provided corresponding to the two detection axes, respectively.

According to the above configuration, since two sets of error correction means are provided corresponding to two orthogonal detection axes, when the movable weight rotates and vibrates, it is tilted with respect to which axis due to a quadrature phase error. However, the movable weight can be attracted so as to be positioned within a predetermined plane so as to cancel out the quadrature phase error. For this reason, noise is removed in detecting the Coriolis force of each axis, and the angular velocity of each axis can be accurately detected.

In this case, it is preferable that a plurality of correction portions constituting the two sets of error correction means are evenly arranged in the circumferential direction of the movable weight. In addition, the plurality of correction units are assigned to any of the detection axes based on the error swing of the movable weight.

According to the above configuration, it is possible to easily manufacture a plurality of correcting portions in the circumferential direction of the movable weight. Also, some of the plurality of correction units are allocated to correct a quadrature error around one detection axis, and the rest are allocated to correct a quadrature error around the other detection axis. By assigning more correction units to detection axes that generate a large amount of quadrature error, correction by electrostatic force can be performed in accordance with the magnitude of the quadrature error around each detection axis.

In this case, a voltage application unit that applies a voltage to the pair of correction electrodes is further provided, and the voltage application unit fixes the voltage applied to one of the pair of correction electrodes to a constant value and varies the voltage applied to the other. The voltage applied to the pair of correction electrodes can be variably adjusted.

According to the above configuration, when the voltage with respect to one correction electrode is fixed, the attractive force due to the electrostatic force can be adjusted by adjusting the other correction electrode. Further, the magnitude of the attractive force can be adjusted by making the voltage applied to each correction electrode variable.

FIG. 1A is a schematic plan view of a uniaxial vibrating gyroscope according to the first embodiment. FIG. 1B is a sectional view taken along the line AA. It is an enlarged plan view around a correction part according to a modification. It is a figure which shows the relationship between the displacement by error rocking | fluctuation, and the electrostatic force which cancels this. It is a circuit block diagram for generating a DC voltage. FIG. 5 is an output waveform diagram of each part in the circuit block diagram of FIG. 4. It is a flowchart of error fluctuation correction by DC voltage. It is a plane schematic diagram of the uniaxial vibrating gyroscope which concerns on 2nd Embodiment. It is a plane schematic diagram of the biaxial vibration gyroscope concerning 2nd Embodiment. It is a plane schematic diagram of the biaxial vibration gyroscope concerning 3rd Embodiment.

Hereinafter, a rotational vibration gyro according to an embodiment of the present invention (hereinafter referred to as “vibration gyro”) will be described with reference to the accompanying drawings. This vibrating gyroscope is an angular velocity sensor in a MEMS (micro-electro-mechanical system) sensor manufactured by microfabrication technology using silicon or the like as a material, and is driven by reciprocating rotational vibrations in the normal and reverse directions. The thing of embodiment is packaged in about 1 mm square, for example, and is commercialized. In the following, a rotary vibration gyro with a single movable weight will be described. However, the movable weight may be separated into a drive weight and a detection weight. In the plan view, the description will be made with the left-right direction as the “X-axis (Coriolis force detection axis) direction”, the front-rear direction as the “Y-axis direction”, and the penetration direction as the “Z-axis direction”.

FIG. 1A is a schematic plan view of a uniaxial vibrating gyroscope with a drive electrode omitted, and FIG. 1B is a cross-sectional view taken along the line AA.
The vibrating gyroscope 1 includes a plurality of sets of drive electrodes 3 (not shown in FIG. 1A) located on the outermost periphery on the substrate 2 and a flat plate-shaped movable electrode disposed inside the plurality of sets of drive electrodes 3. A total of four torsion support springs 7 (supports) each spanned between the weight 4, the anchor 6 disposed at the center of the movable weight 4, and the anchor 6 and the movable weight 4 in the X-axis direction. Spring), a pair of detection electrodes 9, 9 for detecting the displacement of the movable weight 4, and an error correction means 40a for removing a quadrature error (Quadrature Error) described later. The error correction means 40a includes four correction units 41 to 44 disposed on the outer peripheral portion of the movable weight 4, and a D / A conversion unit (voltage application unit) 77 that applies a DC voltage to the four correction units 41 to 44 ( (See FIG. 4 for details). The vibrating gyroscope 1 includes a sealing member 12 that seals the above-described constituent elements on a substrate 2 (see FIG. 1B).

The movable weight 4 and the four torsion support springs 7 constitute a movable part of the vibrating gyroscope 1 and are supported on the substrate 2 via the anchor 6. This movable part is formed by etching a substrate made of silicon. The fixed detection electrode 32 of the detection electrode 9 is above the movable weight 4 and is supported below the sealing member 12 (details will be described later). The movable weight 4 (the same applies to the torsion support spring 7) is composed of a conductive member, and the movable drive electrode 22 and the movable detection electrode 31 described later are composed of a part of the movable weight 4.

The plurality of drive electrodes 3 are arranged at equal intervals in the circumferential direction on the outer peripheral portion of the movable weight 4. Each drive electrode 3 includes a fixed drive electrode 21 integrally formed on the substrate 2 and a movable drive electrode 22 provided as a part of the movable weight 4 so as to extend radially outward from the outer peripheral end of the movable weight 4. And is composed of. The fixed drive electrode 21 and the movable drive electrode 22 are opposed to each other in the form of comb teeth. When an AC voltage is applied to the fixed drive electrode 21 and the movable drive electrode 22, the movable weight 4 is moved to Z by the electrostatic force generated between the two electrodes. Rotates and vibrates around the axis (around the center of gravity).

As described above, the movable weight 4 is formed of two circular flat plates centered on the Z axis. Needless to say, the movable weight 4 is formed vertically and symmetrically (in the Y-axis direction) with respect to the X-axis (detection axis) serving as the center of vibration due to the Coriolis force.

The anchor 6 is disposed so as to be inserted through a rectangular laterally elongated opening formed at the center position of the movable weight 4 and is erected integrally on the substrate 2 so as to be slightly higher than the movable weight 4. In this case, the anchor 6 is formed in a columnar shape, and the above-described four torsion support springs 7 extend in an S shape on the X axis from both side surfaces thereof. Each torsion support spring 7 spans between the anchor 6 and the edge (opening edge) of the horizontally long opening, and supports the movable weight 4 in a state of being lifted from the substrate 2.

Each torsion support spring 7 functions as a hinge shaft of the movable weight 4 that allows rotation of the movable weight 4 and vibrates by Coriolis force. That is, the torsion support spring 7 functions as a so-called torsion spring. The four torsion support springs 7 are each bent in an S shape, and are arranged symmetrically about the X axis and symmetrical about the Y axis. In this case, the four torsion support springs 7 function “soft” with respect to the vibration around the Z axis of the movable weight 4 and somewhat “rigid” with respect to the oscillation (vibration) around the X axis. That is, the movable weight 4 that has received the Coriolis force has a seesaw whose upper half and lower half in the Y-axis direction are substantially centered on the two torsion support springs 7 and 7 (the X axis that is the detection axis). Vibrate.

The pair of detection electrodes 9 includes a pair of movable detection electrodes 31 and 31 configured by an upper half portion and a lower half portion in the Y-axis direction of the movable weight 4 made of a conductive material, and a pair of movable detection electrodes 31. , 31, and a pair of fixed detection electrodes 32, 32 facing the upper side with a capacitance gap 33 as a minute gap. When the movable weight 4 vibrates (swings) like a seesaw due to the Coriolis force around the X axis, the capacitance between the movable detection electrode 31 and the fixed detection electrode 32 changes, and the angular velocity is detected based on this change. (See FIG. 4). In the present embodiment, if the angular velocity around the Y axis is received while the movable weight 4 is rotating and vibrating, the movable weight 4 is vibrated (oscillated) around the X axis by the generated Coriolis force. Thereby, the electrostatic capacitance of a pair of detection electrodes 9 and 9 changes, and the received angular velocity is detected.

Each of the fixed detection electrodes 32 is formed in a plane shape that is substantially the same shape as the movable detection electrode 31 configured by a half portion of the movable weight 4, and is substantially at the same position in the XY plane with respect to the corresponding movable detection electrode 31. They are arranged in parallel. Each fixed detection electrode 32 is made of polysilicon or the like formed on the sacrificial layer, and is supported by a plurality of electrode support portions (not shown) spaced apart on the substrate 2. That is, the pair of fixed detection electrodes 32 and 32 and the pair of electrode support portions are produced by removing the sacrificial layer by etching or the like. Each fixed detection electrode 32 may be formed on the sealing member 12.

By the way, in the vibrating gyroscope 1 configured as described above, for example, if the torsion support spring 7 is not etched vertically with high accuracy, a quadrature phase error occurs. That is, if the torsion support spring 7 is etched not in a rectangular cross section but in a parallelogram in cross section, or when the Z axis and the center of gravity of the movable weight 4 do not coincide (incomplete shape), the movable weight 4 is driven. When this occurs, unnecessary vibration (error fluctuation) occurs based on the quadrature phase error. This error oscillation appears in the same cycle as the rotational oscillation (drive) of the movable weight 4 and is 90 ° out of phase with the oscillation (oscillation) due to the Coriolis force, but its amplitude is large, so that the detection sensitivity is improved. affect. Therefore, in the present embodiment, the error correction means 40a is provided as described above in order to eliminate error fluctuation around the X axis (detection axis) that occurs based on the quadrature phase error.

The error correction means 40a has a plurality of (four in the present embodiment) correction portions 41 to 44 disposed outside the movable weight 4 as described above. A DC voltage is applied to each of the correction units 41 to 44 from a D / A conversion unit (voltage application unit) 77 (see FIG. 4). The four correction portions 41 to 44 include an upper left correction portion 41 and an upper right correction portion 42 that function when the upper half portion of the movable weight 4 swings downward in the Z-axis direction (forward downward), A lower left side correction part 43 and a lower right side correction part 44 that function when the lower half swings downward (rearward downward) in the Z-axis direction are provided. The upper left correction unit 41, the upper right correction unit 42, the lower left correction unit 43, and the lower right correction unit 44 are arranged symmetrically about the X axis and symmetrical about the Y axis. ing. In addition, since the thing of embodiment is a structure which removes error fluctuation | variation with the electrostatic force which arises with the applied DC voltage, it is trying to attract | suck the half part of the movable weight 4 (attraction | suction).

The upper left correction portion 41 extends radially outward from the outer peripheral end of the movable weight 4 and extends on both sides in the vibration direction of the reciprocating rotational vibration with respect to the extended piece 41a constituting the movable electrode and the extended piece 41a. A pair of fixed correction electrodes 41b and 41c arranged so as to overlap each other. The extended piece 41a is formed integrally with the movable weight 4, and the pair of correction electrodes 41b and 41c are a plurality of electrode support portions (not shown) arranged on the substrate 2 separately from the fixed detection electrode 32 described above. (See FIG. 1B). When the extending piece 41a moves clockwise (circular movement) by the reciprocating rotational vibration (drive) of the movable weight 4, the overlap area (overlapping area) between the extending piece 41a and the correction electrode 41c is proportionally increased. To increase. Similarly, when the extended piece 41a moves counterclockwise (circular movement), the overlap area (overlapping area) between the extended piece 41a and the correction electrode 41b increases proportionally.

Similarly, the upper right correction portion 42 has an extended piece 42a and a pair of correction electrodes 42b and 42c, and the lower left correction portion 43 has an extended piece 43a and a pair of correction electrodes 43b and 43c. The lower right correcting portion 44 includes an extending piece 44a and a pair of correcting electrodes 44b and 44c.

Although details will be described later, the extension electrodes 41 a, 42 a, 43 a, 44 a and the correction electrodes 41 b, 42 b, 43 b, 44 b and the correction electrodes 41 c, 42 c, 43 c, 44 c are A DC voltage is selectively applied so as to produce a predetermined potential difference between the two. For example, when a DC voltage is applied between the extension piece 41a and the correction electrode 41b so as to generate a predetermined potential difference, an electrostatic force is generated in proportion to the overlapping area of the extension piece 41a and the correction electrode 41b. . In other words, a force that pulls up in the Z-axis direction by electrostatic force acts on the movable-side extending piece 41a against the fixed-side correction electrode 41b. A DC voltage V1 is applied to each of the correction electrodes 41b, 42b, 43b and 44b, and a DC voltage V2 is applied to each of the correction electrodes 41c, 42c, 43c and 44c (see FIG. 4).

When the DC voltage V1 and the DC voltage V2 are set to different voltages and applied to the respective correction electrodes 41b to 44b and 41c to 44c, the attractive force in the Z-axis direction due to the electrostatic force changes due to driving vibration. In order to maximize the change in the attractive force due to the drive vibration, the potential difference between the correction electrode to which one of the DC voltages V1 and V2 is applied and the extending piece on the movable side is maximized, and the other DC voltage is applied. This can be realized by setting the potential difference between the correction electrode to which is applied and the extended side corresponding to the correction electrode to zero. In order to minimize the change in the attractive force due to the drive vibration, the DC voltages V1 and V2 may be set to the same potential. When adjusting the attractive force, either one of the DC voltages V1 and V2 is set to a fixed value and the other is set to a variable value. It is also possible to switch the application electrodes of the DC voltages V1 and V2 (selective application) and switch the direction (polarity) of the change in the attractive force in the Z-axis direction with respect to the driving direction. On the other hand, both values of the DC voltages V1 and V2 may be variable values. In this case, by setting each suction force (variation range) with a different value, it is possible to use the coarse adjustment and the fine adjustment separately, so that the adjustment accuracy can be increased without increasing the circuit scale.

Hereinafter, the correction process when the movable weight 4 to be driven is swung around the X axis due to the quadrature phase error will be described in detail. The selective application of the DC voltage will be described separately for the “first case” and the “second case”. Further, a case where the DC voltage V1 is a fixed value (the same potential as the extending side on the movable side) and the DC voltage V2 is a variable value will be described. As will be described in detail later, the vibration gyro 1 oscillates by error due to imperfections for each product. At that time, the operation is either “first case” or “second case”.

<First case>
In the first case, the DC voltage V2 is applied to the correction electrodes 41b, 42b, 43b, and 44b, and the DC voltage V1 is applied to the correction electrodes 41c, 42c, 43c, and 44c. In this state, when the movable weight 4 rotates clockwise (one amplitude of driving) and the lower half of the movable weight 4 tilts downward in the Z-axis direction around the X-axis (rear descending = front ascending), the correction electrode The extended piece 43a overlaps with 43b while being separated in the Z-axis direction, and at the same time, the extended piece 44a is overlapped with the correction electrode 44b while being separated in the Z-axis direction. At this time, since a DC voltage is applied to the correction electrode 43b and the correction electrode 44b, the extended pieces 43a and 44a are attracted (pulled up) to the correction electrodes 43b and 44b by the generated electrostatic force. On the other hand, the extended pieces 41a and 42a are separated from the correction electrodes 41b and 42b and overlap the correction electrodes 41c and 42c to which the DC voltage V1 is applied. Since the DC voltage V1 has the same potential as the extending side on the movable side, the electrostatic force is reduced in the upper half of the movable weight 4. Therefore, the force for pulling up the movable weight 4 becomes stronger on the extended sides 43a and 44a side. In addition, the electrostatic force between the extended pieces 43a and 44a and the correction electrodes 43b and 44b is obtained by the following equation.
F = (1/2) ・ ε ・ (S / (dx) ² ) ・ V ²
= A ・ S ・ V ² (A = ε / 2 (dX) ² )
Thus, the electrostatic force is proportional to S (area) and V ² (square of potential difference).

Subsequently, when the movable weight 4 rotates counterclockwise and the upper half of the movable weight 4 tilts downward in the Z-axis direction about the X axis (front descending = back ascending), the extended piece with respect to the correction electrode 41b At the same time as 41a is superposed while being separated in the Z-axis direction, the extended piece 42a is superposed while being separated from the correction electrode 42b in the Z-axis direction. At this time, since the DC voltage V2 is applied to the correction electrode 41b and the correction electrode 42b, the extended pieces 41a and 42a are attracted (raised) by the correction electrodes 41b and 42b by the generated electrostatic force. On the other hand, the extension pieces 43a and 44a overlap with the correction electrodes 43c and 44c, but a DC voltage V1 is applied to them, and the DC voltage V1 has the same potential as the extension piece on the movable side. The electrostatic force decreases and the attractive force decreases. Therefore, the force for pulling up the movable weight 4 becomes stronger on the extending pieces 41a and 42a side.
In this way, by repeating the above-described operation on the movable weight 4 that oscillates and oscillates, the seesaw-like error swing is canceled, and the movable weight 4 maintains a parallel state with respect to the substrate 2.

<Second case>
In the second case, the DC voltage V2 is applied to the correction electrodes 41c, 42c, 43c, and 44c, and the DC voltage V1 is applied to the correction electrodes 41b, 42b, 43b, and 44b. In this state, when the movable weight 4 rotates clockwise (one amplitude of driving) and the upper half of the movable weight 4 tilts downward in the Z-axis direction about the X-axis (front descending = back ascending), the correction electrode The extended piece 41a overlaps with 41c while being separated in the Z-axis direction, and at the same time, the extended piece 42a is overlapped with the correction electrode 42c while being separated in the Z-axis direction. At this time, since the DC voltage V2 is applied to the correction electrode 41c and the correction electrode 42c, the extended pieces 41a and 42a are attracted (raised) by the correction electrodes 41c and 42c by the generated electrostatic force. On the other hand, with respect to the lower half of the movable weight 4, the extended pieces 43a and 44a overlap with the correction electrodes 43b and 44b, but a DC voltage V1 is applied to them, and the DC voltage V1 is extended on the movable side. Because of the same potential as the installation piece, the electrostatic force is reduced and the attractive force is reduced. Therefore, the force for pulling up the movable weight 4 becomes stronger on the extending pieces 41a and 42a side.

Subsequently, when the movable weight 4 rotates counterclockwise and the lower half of the movable weight 4 tilts downward in the Z-axis direction around the X-axis (rear descending = front ascending), the extended piece with respect to the correction electrode 43c 43a overlaps while being separated in the Z-axis direction, and at the same time, the extended piece 44a is superimposed on the correction electrode 44c while being separated in the Z-axis direction. At this time, since the DC voltage V2 is applied to the correction electrode 43c and the correction electrode 44c, the extended pieces 43a and 44a are attracted (raised) by the correction electrodes 43c and 44c by the generated electrostatic force. On the other hand, in the upper half portion of the movable weight 4 that is in the upward direction, the extension piece 41a and the correction electrode 41b overlap, and the extension piece 42a and the correction electrode 42b overlap. Since the DC voltage V1 is applied and has the same potential as that of the extending piece on the movable side, the electrostatic force is reduced and the attractive force is reduced. Therefore, the force for pulling up the movable weight 4 becomes stronger on the extending pieces 43a and 44a side.
Also in this case, the above operation is repeated on the movable weight 4 that oscillates and rotates, so that the seesaw-like error swing is canceled and the movable weight 4 maintains a parallel state with respect to the substrate 2.

By the way, the correction force for making the upper half and the lower half of the movable weight 4 parallel to the substrate 2 can be obtained by the following equation.
(Correction power when going down)
Fp = A ・ (S + ΔS ・ sin (ωt)) ・ (V2-V0) ² + A ・ (S-ΔS ・ sin (ωt)) ・ (V1-V0) ²
= A ・ [(S + ΔS ・ sin (ωt)) ・ (V ² + 2V ・ ΔV + ΔV ² )
+ (S-ΔS ・ sin (ωt)) ・ (V1 ² -2V ・ V1 ・ V0 + V0 ² )]
= A ・ [V2 ² + V1 ² -2 ・ V0 ・ (V2 + V1) + V0 ² ) + ΔS ・ (V2 ² -V1 ² -2 ・ V0 ・ (V2-V1)) ・
sin (ωt)]
(Correction power when going down)
Fn = A ・ (S-ΔS ・ sin (ωt)) ・ (V2-V0) ² + A ・ (S + ΔS ・ sin (ωt)) ・ (V1-V0) ²
= A ・ [(V2 ² + V1 ² -2 ・ V0 ・ (V2 + V1) + V0 ² ) -ΔS ・ (V2 ² -V1 ² -2 ・ V0 ・ (V2-V1)) ・
sin (ωt)]
As described above, a correction force having a reverse polarity is applied to the upper electrode and the lower electrode in the same cycle as the drive displacement.

As long as the Z axis and the center of gravity of the movable weight 4 do not deviate, the error correction means 40a is omitted from the upper left correction unit 41 and the upper right correction unit 42, or the lower left correction unit 43 and the lower right correction unit 44. May be. Further, in this embodiment, the correction portions 41 and 42 are provided in the upper half portion of the movable weight 4 and the correction portions 43 and 44 are provided in the lower half portion, respectively, but three or more correction portions are provided in each half portion. (However, the three or more correction parts may be symmetrical with respect to the Y axis).
Further, in accordance with the displacement of the reciprocating rotational vibration of the movable weight 4, the correction electrode 41b is adjusted so that the area of the overlapping portion between each extending piece 41a to 44a and each correction electrode 41b to 44b, 41c to 44 changes. The planar shapes of .about.44b and 41c.about.44 may be trapezoids or triangles, for example.

FIG. 2 shows a modification of each correction unit, taking the upper left correction unit 41 as an example. In this modification, the extending piece 41a and the correction electrodes 41b and 41c have a planar shape that curves in a fan shape around the Z axis (the center of gravity of the movable weight 4). Thereby, the overlapping area of the extending piece 41a and the correction electrodes 41b and 41c increases and decreases proportionally (inversely proportional), and the error swing of the movable weight 4 can be corrected accurately.

FIG. 3 shows the displacement of the movable weight 4 in the Z-axis direction (error fluctuation) based on the quadrature phase error and the change in the electrostatic force applied to the movable weight 4 in one amplitude (drive) of the movable weight 4. . In this case, due to the influence of one amplitude (drive) of the movable weight 4, the displacement of the movable weight 4 that becomes the seesaw motion changes proportionally (linearly) around the neutral position. On the other hand, the applied electrostatic force also changes proportionally (linearly) due to the influence of one amplitude (drive) of the movable weight 4. The proportional (linear) change in the electrostatic force is explained by taking the correction unit 41 as an example, and the potential difference between the extension piece 41a and the correction electrode 41b is made constant by the DC voltage applied to the correction electrode 41b. In addition, in one amplitude (drive) of the movable weight 4 (one amplitude (drive) of the movable weight 4), this is achieved by proportionally increasing or decreasing the overlapping area of the extended piece 41a and the correction electrode 41b. Thereby, the quadrature phase error is canceled out by the electrostatic force, and the movable weight 4 to be driven maintains a state parallel to the substrate 2 (no error fluctuation).

Next, a correction method for canceling the error fluctuation based on the quadrature error will be described with reference to FIGS. As described above, the movable weight 4 is reciprocally rotated (driven) around the Z axis by applying an AC voltage to the drive electrode. That is, it reciprocates clockwise and counterclockwise as shown (for example, FIG. 1 a) at the drive resonance frequency of the movable weight 4. Although omitted in FIG. 1A, the drive electrodes 3 (actually provided in a plurality in the circumferential direction of the movable weight 4) are comb-shaped movable drive electrodes 22 formed integrally with the movable weight 4. A pair of comb-like fixed drive electrodes 21 provided so as to mesh with the movable drive electrode 22, and one fixed drive electrode 21 is adjacent to the forward drive direction (clockwise) with respect to the movable drive electrode 22, The other fixed drive electrode 21 is disposed so as to be adjacent in the backward movement direction (counterclockwise).

Then, an AC voltage is applied to one fixed drive electrode 21 and the other fixed drive electrode 21 with a phase difference of 180 ° (see “drive signal” in FIG. 5a), whereby the movable weight 4 is reciprocally rotated (driven). Let In the “drive signal” in FIG. 5, the drive signal to one fixed drive electrode (forward movement side) is represented by “SOP”, and the drive signal to the other fixed drive electrode (return movement side) is represented by “SON”. Yes. Due to this drive signal (application of an alternating voltage), the actual movable weight 4 rotates back and forth with a phase delay of 90 ° (see “drive vibration” in FIG. 5b). In this case, the forward monitor signal is represented by “MONP” and the backward monitor signal is represented by “MONN”. In the embodiment, the vibration (seesaw motion) due to the Coriolis force appears at substantially the same frequency as the drive resonance frequency and is 90 ° out of phase with the drive vibration of the movable weight 4 ("angular velocity signal" in FIG. 5c). reference). In this case, in FIG. 4, the vibration (swing) corresponding to the detection electrode 9a is represented by “SELP”, and the vibration (swing) corresponding to the detection electrode 9b is represented by “SELN”.

On the other hand, since the quadrature phase error is mainly based on the shape failure of the support spring 7, the vibration (swing) detected by the pair of detection electrodes 9, 9 is movable at the same frequency as the drive resonance frequency. It appears in the same phase as the driving vibration of the weight 4 (see “Quadrature Error Signal” in FIG. 5d). In this case, in FIG. 4, the quadrature phase error signal corresponding to the detection electrode 9a is represented by “Qselp”, and the quadrature phase error signal corresponding to the detection electrode 9b is represented by “Qseln”. In this embodiment, in order to correct the movable weight 4 that vibrates (seesaw motion) due to the quadrature phase error so as to be parallel to the substrate 2, half of the amplitude of the “quadrature phase error signal” is extracted by synchronous detection (FIG. 5e “ The correction value is determined based on the amplitude value from which the noise has been removed by the LPF (low-pass filter) 74 of the filter unit described later (see “quadrature phase error signal after synchronous detection”) (FIG. 5f). (Refer to “DC voltage as a correction signal”).

As described above, the circuit for generating this correction signal corrects the vibration (tilt) in FIG. 1a with respect to the vibration (tilt) in which the movable weight 4 moves forward (backward upward) when moving forward and backwards (forward) when returning. DC voltage ("V2" in FIG. 4) applied to the correction electrodes 41c and 42c on the right side of the portions 41 and 42 and the correction electrodes 43c and 44c on the right side of the correction portions 43 and 44, and the movable weight 4 Correction electrodes 41b and 42b and correction portions 43 and 44 on the left side of the correction portions 41 and 42 in FIG. 1a with respect to vibration (tilt) that moves forward (backward downward) during movement and backward upward (forward downward) during backward movement. DC voltage (FIG. 5f) composed of a DC voltage (“V1” in FIG. 4) applied to the correction electrodes 43b and 44b on the left side of FIG. In FIG. 5f, the former DC voltage is represented by “DCP” and the latter DC voltage is represented by “DCN”. Since it is assumed that the vibration (seesaw motion) form due to the quadrature phase error varies depending on the product, finally, “V1” and “V2” are correctly switched and applied to the corresponding correction electrode. (Refer to FIG. 5g “post-correction signal”). Further, the quadrature phase error with respect to the Y axis is also canceled by the signal processing described above.

FIG. 4 shows a circuit configuration for performing the correction by the DC voltage described above. This correction accurately detects (detects) quadrature phase error and generates a DC voltage that cancels out of quadrature phase error, so that the vibratory gyroscope 1 is movable without applying any angular velocity (no Coriolis force is generated). The weight 4 is driven. The movable weight 4 is driven by a drive circuit (not shown), and the above “drive signal” is applied to the drive electrode. Further, in this drive circuit, the drive of the movable weight 4 is monitored to obtain the above “drive vibration”.

The “quadrature phase error signal” input from the pair of detection electrodes 9 and 9 to the CV converter 71 is converted into a change in voltage by the change in capacitance, and is output to the synchronous detector 72 after amplification. The synchronous detection unit 72 detects the “quadrature phase error signal” while synchronizing with the drive monitor signal (“drive vibration”) of the drive circuit input from the synchronization signal switching unit 73, and performs the above-described “quadrature phase error signal synchronization”. A signal “after detection” is obtained. From this signal, noise is removed by the LPF 74 of the filter unit, and the signal is output to the measurement unit 75. In the measurement of the Coriolis force, the synchronization signal switching unit 73 switches the drive monitor signal to the above “drive signal” to achieve synchronization.

In the measurement unit 75, the arithmetic processing is performed by the above-described mathematical formula for obtaining the correction force at the time of forward and rearward descending, and the correction voltage applied to the correction units 41 to 44 is determined. This voltage is output to the SPI unit 76 as a digital value, and the SPI unit 76 converts the serial signal into a parallel signal. Then, the D / A converter 77 converts the digital value into an analog value (DC voltage) and outputs it. The two “DC voltages” are switched by the subsequent correction switching unit 78, and the correction voltage “V1” or “V2” is applied. The actual one is adjusted by repeating the above routine work (details will be described later).

FIG. 6 is a flowchart of the correction using the DC voltage described above. As described above, first, the above-mentioned “drive signal” is applied to the drive electrode 3 to drive the movable weight 4 (see S1). Next, the synchronous signal switching unit 73 is switched to the drive monitor signal, and synchronous detection of the “quadrature phase error signal” is performed (see S2). In addition, the correction switching part 78 is in the state switched to any one correction electrode (refer S3). Subsequently, the signal of “quadrature phase error signal after synchronous detection” is output to the measurement unit 75 (see S4). In the measurement unit 75, the measurement voltage Vo that becomes the signal of “quadrature phase error signal after synchronous detection” and the reference The voltage Vref is compared (see S5). Here, if Vo-Vref is zero or substantially zero (“YES”), it is determined that appropriate quadrature phase error correction has been performed, and correction by DC voltage is terminated (see S6).

On the other hand, if Vo−Vref≈0 is not satisfied (NO), it is determined whether or not Vo−Vref> 0 (see S7). If “YES”, the correction voltage is adjusted again (see S8). A later correction voltage is applied (see S9) and measurement is performed. Here, if the switching of the correction voltage “V1” or “V2” to the correction electrode by the correction switching unit 78 is wrong (the setting in S3 is wrong), the determination is “NO”. In such a case, after the switching operation of the correction switching unit 78 is performed (see S10), the correction voltage is applied (see S9), and then the process returns to S4.

In this way, the quadrature phase error generated by the movable weight 4 is canceled by the electrostatic force, and the movable weight 4 to be driven is maintained in a state parallel to the substrate 2 (no error fluctuation). Therefore, the quadrature phase error based on the imperfection of the shape is removed, and the detection accuracy of the Coriolis force can be greatly improved.

FIG. 7 is a schematic plan view of a uniaxial vibrating gyroscope showing a second embodiment (drive electrodes are omitted). As shown in the figure, the vibration gyro 1A of the second embodiment is similar to the first embodiment in that the movable weight 4 is connected to the substrate via four torsion support springs 7 extending from the anchor 6 in the X-axis direction. Released on 2. In the vibration gyro 1A, four openings 65 are formed in the peripheral portion of the movable weight 4, and four (plural) correction portions 61 to 64 around the opening 65 are configured. Also in this case, the error correction means 40a includes an upper left correction portion 61 and an upper right correction portion 62 located in the upper half of the movable weight 4, and a lower left correction portion 63 and a lower right correction portion 64 located in the lower half. The upper left correction unit 61, the upper right correction unit 62, the lower left correction unit 63, and the lower right correction unit 64 are arranged symmetrically about the X axis and centered on the Y axis. Are arranged in line symmetry.

The upper left correction portion 61 faces the opening 65 formed on the surface of the movable weight 4 and the pair of opening edges 61a and 61a constituting the opening 65 in the vibration direction of the reciprocating vibration. The correction electrodes 61b and 61c are fixedly arranged so as to overlap. The other correction parts 62 to 64 have the same structure. The opening edge portions 61a, 62a, 63a, and 64a constitute a fixed-side electrode.

Also in this case, when the movable weight 4 is reciprocatingly oscillated, the opening edge portions 61a to 64a and the corresponding correction electrodes 61b to 64b or the correction electrodes 61c to 64c are overlapped to cause an electrostatic force to act on the movable weight 4. . The inclination of the movable weight 4 is corrected by the electrostatic force, and the movable weight 4 to be driven maintains a parallel state with respect to the substrate 2.

Instead of providing an extended piece at the outer end of the movable weight 4, a plurality of correction portions 61 to 64 are formed around the opening 65 of the movable weight 4, thereby making it possible to make a right angle without increasing the outer dimension of the movable weight 4. The error fluctuation due to the phase error can be corrected, and the angular velocity can be accurately detected.

Next, a second embodiment of the present invention will be described with reference to a schematic plan view of the biaxial vibrating gyroscope of FIG. Note that the drive electrodes are not shown in FIG. 8 as in FIG.
Similar to the first embodiment (FIG. 1A), the biaxial vibrating gyroscope 11 of the second embodiment has a drive electrode and a movable weight 4 and is disposed inside the movable weight 4. A pair of X-axis divided detection weights 5a, 5a and a pair of Y-axis divided detection weights 5b, 5b, an anchor 6 disposed at the center position of the movable weight 4, and an anchor 6 A pair of X-axis weight support springs 7a, 7a and an anchor 6 spanned between the X-axis split detection weights 5a, 5a and a pair of spans spanned between the Y-axis split detection weights 5b, 5b. Y-axis weight support springs 7b, 7b, a pair of X-axis weight connection springs 13a, 13b for connecting the movable weight 4 and the respective X-axis divided detection weights 5a, 5a, and the movable weight 4 and the respective Y-axis divided detection weights 5b, A pair of Y-axis weight coupling springs 13b, 13b that couple 5b and a pair of vibrating X-axis A pair of X-axis detection electrodes for detecting the displacement of the detection weights 5a, 5a and a pair of Y-axis detection electrodes (both not shown) for detecting the displacement of the vibrating pair of X-axis divided detection weights 5b, 5b ing. The biaxial vibrating gyroscope 11 includes an X axis error correcting means 40b for removing error fluctuations around the X axis (detection axis) generated based on the quadrature error, and a Y axis generated based on the quadrature error. Y-axis error correction means 40c for removing error fluctuation around the (detection axis).

The connection form of the pair of X-axis weight support springs 7a and 7a and the pair of Y-axis weight support springs 7b and 7b and the anchor 6 is such that the movable part mainly composed of the movable weight 4 and the detection weight 5 is the X-axis and the Y-axis. And it is comprised so that it may become symmetrical about a Z-axis. That is, with respect to the Z axis, the center of gravity of the vibration gyro 11 (movable part) overlaps with the axes of the X and Y support springs 7a and 7b and the anchor 6, and the vibration gyro 11 (movable part) with respect to the XY plane. ) Is placed so that the center position of the Thereby, it becomes difficult to receive the influence of accelerations, such as gravity, for example, and the freedom degree of installation can also be improved.

The pair of X-axis divided detection weights 5a and 5a and the pair of Y-axis divided detection weights 5b and 5b are formed in exactly the same flat fan shape having an angle of 90 °, and are arranged at a pitch of 90 °. When the rotationally oscillating drive weight 4 receives an angular velocity about the X axis, the pair of X axis divided detection weights 5a and 5a are centered on the pair of X axis weight support springs 7a and 7a together with the drive weight 4 due to the generated Coriolis force. Each vibrates. Similarly, when the rotationally oscillating drive weight 4 receives an angular velocity around the Y axis, the pair of Y axis divided detection weights 5b and 5b together with the drive weight 4 is generated by the generated Coriolis force and the pair of Y axis weight support springs 7b and 7b. Vibrate around each other.

The pair of X-axis weight connection springs 13a and 13a and the pair of Y-axis weight connection springs 13b and 13b have exactly the same form, and are formed in a narrow cross-sectional rectangle, respectively, and the drive weight 4 is subjected to rotational vibration. The Coriolis force received by the driving weight 4 is absorbed and transmitted to the detection weight 5. That is, the rotation vibration of the drive weight 4 is not transmitted to the detection weight 5 by the pair of X-axis weight connection springs 13 a and 13 a and the pair of Y-axis weight connection springs 13 b and 13 b, but vibration due to the Coriolis force is transmitted to the detection weight 5. It has come to be. As a result, the pair of X-axis split detection weights 5A and 5A and the pair of Y-axis split detection weights 5B and 5B vibrate by Coriolis force without being affected by the rotational vibration of the drive weight 4.

The pair of X-axis detection electrodes has a pair of movable detection electrodes constituted by a pair of X-axis divided detection weights 5a and 5a and a small gap (however, larger than the amplitude of the detection weight 5) with respect to the pair of movable detection electrodes. And a pair of fan-shaped fixed detection electrodes facing each other (both not shown). Similarly, the pair of Y-axis detection electrodes includes a pair of movable detection electrodes constituted by a pair of Y-axis divided detection weights 5b and 5b, and a pair of fan-like surfaces facing each other with a minute gap with respect to the pair of movable detection electrodes. And a fixed detection electrode. When the X-axis divided detection weights 5a and 5a or the Y-axis divided detection weights 5b and 5b vibrate due to the Coriolis force, the capacitance between the respective movable detection electrodes and the fixed detection electrodes changes, and based on this change, a desired value is obtained. Is detected.

The error correction means 40b around the X axis is the same as the error correction means 40a of the first embodiment, and is constituted by correction parts 41 to 44, and the error correction means 40c around the Y axis is constituted by correction parts 45 to 48. Has been. Although the detailed description will be given to the first embodiment, the X axis error correcting means 40b includes an upper left correcting portion 41, an upper right correcting portion 42, a lower left correcting portion 43, and A lower right correction unit 44 is provided. Further, the Y axis around error correction means 40c includes a right upper correction unit 45, a right lower correction unit 46, a left upper correction unit 47, and a left lower correction unit 48 which are provided symmetrically with respect to the X axis. The correction portions 45 to 48 are provided with extension pieces 45a to 48a and correction electrodes 45b and 45c, 46b and 46c, 47b and 47c, 48b and 48c corresponding to the extension pieces 45a to 48a, and D / An A conversion unit (voltage application unit) (see FIG. 4) is connected.

When the error fluctuation occurs due to the quadrature phase error with respect to the X axis, the error correcting means 40b around the X axis operates as described with reference to FIG. That is, when the movable weight 4 reciprocates and the upper half or the lower half of the movable weight 4 tilts around the X axis, the correcting portions 41 to 44 operate in the same manner as in FIG. .

Hereinafter, a correction process when the drive weight 4 swings around the Y axis due to a quadrature error will be described. In this case as well, two vibration modes (downwardly to the right or downward to the left with respect to the Y axis) are provided as described above. When the correction process around the Y axis is performed, a voltage is always applied to the correction electrodes 45b to 48c.

When the movable weight 4 rotates in the forward direction (clockwise) and the left half of the movable weight 4 is tilted to the left in the Z-axis direction around the Y axis (left down = upper right), the extension pieces 47a and 48a A DC voltage is applied to the superimposed correction electrodes 47b and 48b, and the extending pieces 47a and 48a are attracted to the correction electrodes 47b and 48b. The movable weight 4 is attracted only by the electrostatic force of the correction electrodes 47b and 48b.

Subsequently, when the movable weight 4 rotates in the backward movement direction (counterclockwise) and the right half of the movable weight 4 tilts to the right in the Z-axis direction around the Y axis (right downward = left upward), the extended piece A DC voltage is applied to the correction electrodes 45b and 46b superimposed on the 45a and the extension piece 46a, and the extension pieces 45a and 46a are attracted to the correction electrodes 45b and 46b. That is, the movable weight 4 is attracted only by the correction electrodes 45b and 46b.
By repeating the above-described operation on the movable weight 4 that rotates and vibrates, the seesaw-like error swing is canceled, and the movable weight 4 maintains a parallel state with respect to the substrate 2.

When the movable weight 4 rotates in the forward direction (clockwise) and the right half of the movable weight 4 is tilted to the right in the Z direction around the Y axis (right downward = left upward), and in the backward direction (counterclockwise) When the left half of the movable weight 4 is tilted to the left in the Z direction (left-down = up-right), the electrostatic force between each extended piece and the corresponding correction electrode is also the same as described above. Thus, the movable weight 4 is sucked.

As described above, the biaxial rotational vibration gyro is provided with the correcting portions 45 to 48 with respect to the X axis not only with respect to the Y axis but also with respect to the X axis. As a whole, since eight correction parts (4 × 2 sets) are provided in the circumferential direction of the drive weight 4, not only the quadrature phase error centered on the X axis but also the quadrature phase error centered on the Y axis Can be canceled out, and the angular velocities of the two axes can be detected with high accuracy. In this embodiment, eight sets of correction portions are provided symmetrically with respect to each axis, but of course, more than that may be provided. As shown in the figure, the correction portions 41 to 48 are provided uniformly in the circumferential direction of the movable weight 4, but the intervals between the correction portions 41 to 48 need not be equal.

FIG. 9 is a schematic plan view showing a modification of the biaxial vibrating gyroscope shown in FIG. In the vibrating gyroscope 11A, correction portions 51a to 51t are provided over the entire circumference of the movable weight 4. Each of the correction portions 51a to 51t has an extending piece and a pair of correction electrodes (not shown) as described above.
In the vibration gyro 11A having such a configuration, according to the difference in intensity between the quadrature phase error (error fluctuation) centered on the X axis and the quadrature phase error (error fluctuation) centered on the Y axis, The correction parts 51a to 51t are divided into those for the X axis and those for the Y axis. In this way, if the number of correction parts to which a DC voltage is applied is assigned corresponding to the magnitude of the X / Y quadrature phase error, the quadrature phase error of each of the two axes can be corrected appropriately. Can do. As described above, when the correcting portions 51a to 51t are provided over the entire circumference of the movable weight 4, the correcting portion may not be used as necessary.

1,1A, 11,11A Vibration gyro, 2, substrate, 3 drive electrode, 4 movable weight, 6 anchor, 7 support spring, 9 detection electrode, 40a error correction means, 40b X axis error correction means, 40c Y axis error correction Means, 41-48 correction part, 41a-48a extension piece, 41b-48c correction electrode, 51a-51t correction part, 61-64 correction part, 61a-64a opening edge, 61b-64c correction electrode, 65 opening part, 77 D / A converter

Claims (12)

1. While the movable weight released on the substrate is reciprocally rotated through the drive electrode,
   A rotational vibration gyro that detects a displacement of the movable weight swinging around a detection axis by a Coriolis force via a detection electrode;
   An error correction means for correcting an error swing of the movable weight caused by the reciprocating rotation vibration without applying an angular velocity by applying an electrostatic force to the movable weight;
   The error correction means includes
   A voltage for generating the electrostatic force is applied,
   At least one half of the movable weight defined by the detection axis has a plurality of correction portions arranged in the circumferential direction of the movable weight with an axis orthogonal to the detection axis as a center. Rotating vibration gyro.
2. The rotational vibration gyroscope according to claim 1, wherein the plurality of correcting portions are arranged line-symmetrically around at least one of the detection axis and an axis orthogonal to the detection axis.
3. Each of the correction units is
   An extending piece extending in a radial direction from an outer peripheral end of the movable weight, and constituting an electrode on the movable side;
   The rotary vibration gyro according to claim 1, further comprising a fixed correction electrode arranged so as to overlap the extending piece in a vibration direction of the reciprocating rotational vibration.
4. 4. The rotational vibration gyro according to claim 3, wherein a pair of the correction electrodes are disposed so as to overlap both sides of the vibration direction of the reciprocating rotational vibration.
5. The said correction electrode is formed in the planar shape from which the area of the overlap part of the said extension piece and the said correction electrode changes according to the displacement of the said reciprocation rotational vibration. The rotational vibration gyro described.
6. The movable weight has a plurality of openings corresponding to the plurality of correction portions,
   Each of the correction units is
   An opening edge that constitutes the opening and constitutes the movable electrode; and
   The fixed electrode on the fixed side facing the opening and disposed so as to overlap with the opening edge in the vibration direction of the reciprocating rotational vibration. The rotational vibration gyro described.
7. The rotational vibration gyroscope according to claim 3 or 6, wherein the correction electrode is formed in a fan shape concentric with the movable weight.
8. Including two orthogonal detection axes,
   2. The rotary vibration gyro according to claim 1, further comprising two sets of the error correction means provided corresponding to the two detection axes.
9. 9. The rotary vibration gyro according to claim 8, wherein a plurality of correction portions constituting the two sets of error correction means are arranged uniformly in a circumferential direction of the movable weight.
10. 10. The rotational vibration gyro according to claim 9, wherein the plurality of correcting portions are assigned to any one of the detection shafts based on an error swing of the movable weight.
11. The apparatus further comprises a voltage application unit that applies a voltage to the pair of correction electrodes, and the voltage application unit fixes a voltage applied to one of the pair of correction electrodes to a constant value and varies a voltage applied to the other. The rotary vibration gyro according to claim 4, wherein the rotational vibration gyro is adjustable.
12. The voltage application unit that applies a voltage to the pair of correction electrodes, and the voltage application unit is capable of variably adjusting the voltages applied to the pair of correction electrodes. Rotating vibration gyro.

Images