JPH06129858A - Vibration gyro - Google Patents

Abstract

PURPOSE:To minimize the absorption of vibrations in the contact surface of a movable body and to detect the angular velocity with high sensitivity when the force of vibrations is very small, by fixing the main body of a vibration gyro in the movable body with a support at the point of the minimum amplitude on the line of extension of the center of axis of a vibrator. CONSTITUTION:The main body 10 of a vibration gyro is fixed in a movable body 29 with a support 23, a fixed way 25 and a rubber cushion 27. However, the fixed point Po for the center of the axis to be fixed to the inner surface of a base 12 makes the node of vibrations of a vibrator 14. Therefore, the amplitude transmitted becomes minimum at the point Pm on the line of extension of the center of axis of the vibrator 14 from the point Po to the outer surface of the base 12 in the outer circumferential surface of the base 12 and a housing 20. Since the main body 10 is fixed in the movable body 29 at the point Pm with the support like a pole, the vibration transmitted can be transferred to an index scale 21 without being reduced, and also since the support 23 is mounted on the fixed way 25 provided in the rubber 27, the absorption of vibrations due to the support 23 can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibrating gyro, and more particularly to an improvement in its holding mechanism.

[0002]

2. Description of the Related Art Conventionally, gyros have been used only for special purposes such as ships and airplanes, but in recent years, they have also been used for navigation systems such as private cars or self-propelled robots that do not require a track. It is like this.
These systems integrate the output of the gyro to determine the azimuth, integrate the moving speed to obtain the moving distance, and grasp the current position based on the azimuth and the moving distance. Will also be accumulated. For this reason, gyros used in these fields are required to have extremely high angular velocity detection functions as well as severe conditions such as small size, low price, and high durability, and development of a gyro that meets these requirements is urgently required. .

As a gyro, those based on various principles have been developed, but a so-called vibration gyro or tuning fork gyro has been drawing attention due to its high angular velocity detection sensitivity and the like (Japanese Patent Publication No. 2-57247). . This vibrating gyro is an application of the phenomenon that when a rotating angular velocity is applied to a vibrating object, the Coriolis force acts in the direction perpendicular to the vibrating object. The displacement amount in the direction orthogonal to the vibration direction of the child is detected, and the azimuth is determined from the displacement amount. A general structure of the vibrating gyroscope is that a bar-shaped vibrator having an outer frame formed of a base and a cylindrical housing having an opening at one end installed in the base, and a rod-shaped vibrator having one end fixed to the inner surface of the base. It is provided. Further, a main scale is installed at the other end of the vibrator, and an index scale is installed in an opening at the other end of the housing so as to be opposed to the main scale. And
A vibration force in a constant direction (X-axis direction) is applied to the vibrator in advance, and the displacement amount in the direction (Y-axis direction) orthogonal to the vibration direction of the vibrator due to the angular velocity of rotation is calculated between the main scale and the index scale. It is obtained from the relative movement amount in the Y-axis direction.

When the vibration gyro configured as described above is installed in a moving body such as an automobile, the outer surface of the base is fixed to the moving body via a vibration isolating member or the like.
The use of the vibration isolating member is to prevent the vibration gyro from being damaged by the vibration of the moving body and to reduce the measurement error of the angular velocity. In order to detect the angular velocity of the vibrating gyro with high sensitivity and high performance, it is effective to increase the amplitude of the vibrator in the Y-axis direction when the rotational angular velocity is applied. Since the amplitude of the vibrator in the Y-axis direction is proportional to the amplitude in the X-axis direction, if the amplitude of the vibrator in the X-axis direction is increased, the amplitude in the Y-axis direction when the rotational angular velocity is applied. Also grows.

Here, in order to increase the amplitude of the vibrator in the X-axis direction, the vibration force applied to the vibrator may be increased.
Considering the size and cost of the vibration gyro, it is desirable to obtain a large amplitude with a small vibration force. In the configuration of the vibrating gyroscope, as described above, one end of the vibrator is fixed to the base, and the other end is provided with the main scale. An outer frame is integrally formed with the base and the housing, and an index scale is installed in the opening of the housing. Therefore, when the vibrator is forcibly vibrated in the X-axis direction, the vibration of the vibrator is transmitted to the index scale via the base and the housing, and the index scale also vibrates in the X-axis direction. In particular, when a vibrating force applying section for forcibly vibrating the vibrator is provided on the inner surface of the housing, the housing receives a reaction force when the vibrating force is applied to the vibrator, and therefore the index scale is provided through the housing. Will vibrate further. Since the vibration of the index scale and the vibration of the vibrator vibrate in opposite phases in the X-axis direction, the relative movement amount between the index scale and the main scale increases, and the same effect as when the amplitude of the vibrator is increased is obtained. Will be obtained.

[0006]

However, since the conventional vibrating gyro has the outer surface of the base directly fixed to the vibration isolating member or the like, the vibration isolating member serves as a damper to reduce the vibration of the index scale. That is, the vibration of the base transmitted from the vibrator is absorbed by the vibration isolating member and is not transmitted to the index scale. Therefore, there is a problem that the relative movement amount between the main case and the index scale is reduced, and the angular velocity detection sensitivity is reduced. The present invention has been made in view of the above-mentioned problems of the prior art, and an object thereof is to detect angular velocity with high sensitivity even if the vibration of the vibrator is efficiently transmitted to the index scale and the vibration force applied to the vibrator is minute. It is to provide a vibrating gyro capable of

[0007]

In order to achieve the above object, a vibrating gyro according to claim 1 of the present invention is an outer frame comprising a base and a cylindrical housing having an opening at one end installed in the base. A portion, a vibrating means having one end erected and fixed to the inner surface of the base, a vibrating means for applying a vibrating force in the X-axis direction to the vibrating means, and a main scale installed at the other end of the vibrating means. Displacement detecting means for detecting displacement of the vibrating means in the Y-axis direction, the displacement detecting means having an index scale provided in the opening at the other end of the housing and facing the main scale, and the displacement detecting means. And an angular velocity calculating means for calculating an angular velocity from the amount of displacement in the Y-axis direction. In the vibrating gyro, one end is fixed to the outer surface of the base so that the vibrating means has an axis on the same line as the axis of the vibrating means. A post, the other end of the strut is fixed to the surface, the back surface is characterized by comprising a fixed base which is fixed to the moving body via the vibration isolation member.

Further, in the vibrating gyroscope according to a second aspect, the vibrating means is provided in the vibrating means, and the magnet portion is divided into an N pole and an S pole by a plane including an axis of the vibrating means.
An exciting coil, which is wound in a cylindrical shape so as to have an axis coaxial with the axis of the vibrating means, and is arranged such that the inner surface of the central portion of the cylinder is close to the magnet portion, A vibrating force in the X-axis direction is applied to the vibrating means by a magnetic moment between the magnet portion and the exciting coil, which is generated by periodically flowing an exciting current to the exciting coil.

[0009]

In the vibrating gyro according to the first aspect of the present invention, as described above, when the vibrating gyro is fixed to the moving body, the fixed base fixed to the moving body via the vibration isolating member and the base are connected by the columns. It is fixed. The support column is fixed to the outer surface of the base so as to have an axis aligned with the axis of the vibrating means. Here, the vibrator has a cantilever structure in which only one end is fixed to the inner surface of the base, and a node of vibration of the vibrator serves as a fixing point to the inner surface of the base. Therefore,
On the outer peripheral surface of the outer frame part, the amplitude due to the vibration transmitted from the vibrator becomes the minimum, that is, the corresponding point on the outer surface of the base with the fixed point of the vibrator, that is, the outer surface of the base where the extension line of the axis of the vibrator intersects. It becomes the upper point. Since the vibrating gyroscope according to the present invention connects and fixes the vibrating gyro with the moving body by the support only at the point on the outer surface of the base where the amplitude is minimum on the outer peripheral surface of the outer frame portion as described above,
The reduction of the vibration transmitted from the vibrator can be minimized, and the vibration of the vibrator can be efficiently transmitted to the index scale.

Further, since the support column is not directly fixed to the vibration isolating member but is connected to a fixing base provided on the vibration isolating member, vibration absorption by the support column can be further reduced. Further, in the vibrating gyroscope according to the second aspect of the present invention, the vibrating means forcibly vibrates the vibrating means in the X-axis direction at the substantially resonance frequency. When the angular velocity ω is input in this state, the Coriolis force Fc corresponding to the angular velocity ω becomes Y.
It is generated in the axial direction, and the vibrating means also vibrates in the Y-axis direction. Therefore, the Coriolis force F corresponding to the input angular velocity ω
By detecting the displacement in the Y-axis direction generated by c with the displacement detecting means, the angular velocity calculating means can output the input angular velocity ω. As described above, in the vibrating gyroscope according to the present invention, the driving piezoelectric element or the like is not attached to the vibrating means itself, and does not affect the vibration.

Therefore, extremely accurate angular velocity detection can be performed. Further, since the vibrating means is provided with a cylindrical exciting coil having an axis coaxial with the axis of the vibrating means, when an exciting current is passed through the cylindrical exciting coil, the exciting coil becomes parallel to the axis of the vibrating means. A magnetic field is generated. Then, a magnetic force is generated between the magnet portion provided in the vibrating means and the exciting coil by the magnetic field, and the vibrating means is vibrated by the magnetic moment based on the magnetic force. Further, since the magnet portion and the inner surface of the central portion of the cylindrical excitation coil are arranged close to each other, the vibrating means can be excited even if the exciting current flowing through the excitation coil is small, and the excitation coil can be miniaturized. be able to.
Further, by disposing the vibrating means and the axis of the exciting coil on the same axis, it is possible to improve the assembling accuracy.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a vibrating gyroscope according to one embodiment of the present invention. FIG. 1A is a side sectional view and FIG. 1B is a front sectional view. Vibration gyro body 10 shown in FIG.
Is a base 12, a vibrator 14 as an oscillating means erected on the inner surface of the base 12, a vibrating means 16 for vibrating the vibrator 14, and a displacement detecting means 1 including a photoelectric encoder.
8 and. A cylindrical housing 20 is installed on the base 12, and the displacement detecting means 18 is supported at the upper end of the housing 20. The vibrator 14 is formed in a round bar shape, and the resonance frequencies in the X direction and the Y direction are substantially the same. A main scale 22 is provided on the upper end of the vibrator 14.

The vibrating means 16 includes a magnet plate 24 formed in a donut shape and an exciting coil 26 which is wound in a cylindrical shape so as to have a shaft center coaxial with the shaft center of the vibrator 14.
And have. Then, the donut-shaped magnet plate 24
Has its central hole fitted to the tip side of the vibrator 14. Further, the cylindrical excitation coil 26 is arranged such that the inner surface of the central portion thereof is close to the outer periphery of the donut-shaped magnet plate 24, and is wound around a coil bobbin 28 fixed to the inner wall of the housing 20. Further, the oscillator 14
The magnet plate 24 fitted in is divided into an N pole and an S pole by the Y axis passing through the axis of the vibrator 14 as shown in FIG. 2 which is a plan sectional view of the magnet plate 24.

The vibrating gyro body 10 according to this embodiment is constructed as described above, and then the vibrating gyro body 1 is constructed.
A holding mechanism for a moving body such as an automobile, which is 0, will be described.
As shown in the figure, the vibrating gyro main body 10 includes a support 2
3, fixed to the moving body 29 by a fixed base 25 and a vibration-proof rubber 27. The column 23 is formed in a rod shape, and one end of the column 23 is fixed to the outer surface of the base 12 so that the axis of the column 23 is aligned with the axis of the vibrator 14. Further, the other end of the column 23 is connected and fixed to a fixed table 25, and the fixed table 25 is a rubber vibration isolator.
It is fixed to the moving body 29 via 7.

The above is the schematic structure of the holding mechanism according to the present embodiment. Next, referring to FIGS. 3 and 4, the vibrating means 1 of the present embodiment is described.
6 and the angular velocity detection mechanism will be described. First, when the excitation coil 26 shown in FIG. 3 is excited at a predetermined cycle (see FIG.
(A), a magnetic field is generated parallel to the axis of the exciting coil 26, that is, the axis of the vibrator 14. The direction of the pole of the magnetic field is determined by the direction of the current flowing through the exciting coil 26. That is, when a current is passed in the forward direction from the winding start side to the winding end side of the excitation coil 26 shown in FIG. 3, an N pole is generated on the upper side and a S pole is generated on the lower side of the excitation coil 26 in the figure. On the contrary, when a current is passed in the opposite direction from the winding end side to the winding start side of the excitation coil 26, an S pole is generated on the upper side of the excitation coil 26 and an N pole is generated on the lower side. Then, as shown in FIG.
4, when the north pole is located on the right side and the south pole is located on the left side, when a forward current is applied to the excitation coil 26, as described above, the north pole is on the upper side and the south pole is on the lower side. As a result, the force is pulled upward on the left side of the magnet plate 24, which is the S pole, and conversely, the force is pushed down on the right side, which is the N pole. When a current in the opposite direction is applied to the excitation coil 26, the poles of the magnetic field generated are opposite to each other as described above, so that the force is pushed down to the left side, which is the S pole of the magnet plate 24, A force that is pulled upward is generated on the right side, which is the N pole.

For this reason, the force generated in the magnet plate 24 in the upward direction is + Fm, and the force in the downward direction is −Fm, and the center point of the donut-shaped width of the magnet portion 24 from the axial center of the vibrator 14. Let l be the distance to
Receives a bending moment of M = 2Fml (M: bending moment). Therefore, FIG.
As shown in (A), in synchronization with the vibration wave in the resonance state of the vibrator 14, the excitation coil 26 shown in FIG. 3 is wound in the forward direction from the winding start side to the winding end side, and then from the winding end side. The vibrator 14 is vibrated by the bending moment, which is generated by alternately passing a current to the excitation coil 26 in the opposite direction to the start side (FIG. 4 (B)).

As described above, the vibrator 14 is vibrated by passing a current through the exciting coil 26, the excitation cycle is further adjusted, and the vibrator 14 is vibrated in the X-axis direction at a substantially resonance frequency f. Then, for example, a known angular velocity ω _a is input to the vibrator 14 that is forcedly vibrated, and the output waveform of the excitation coil is compared with the waveform of the amplitude in the Y-axis direction generated by the Coriolis force, and the resonance frequency f or The output of the excitation coil is finely adjusted so that the vibration speed V _x has a constant value (FIG. 4 (C)). On the other hand, when an unknown angular velocity ω is input, a Coriolis force Fc corresponding to the angular velocity ω is generated in the Y-axis direction (FIG. 4 (D)). As described above, the resonance frequency f of the vibrator 14 is the same in both the X-axis and Y-axis directions, so the vibrator also vibrates in the Y-axis direction.

As a result, the Coriolis force, that is, the angular velocity ω can be detected by measuring the amplitude of the vibration in the Y-axis direction. Next, the operation of the holding mechanism when the vibrator 14 is vibrated by the vibrating means 16 will be described. Here, the angular velocity is detected by vibrating the oscillator 14 in the X-axis direction as described above and generating the angular velocity when the angular velocity is input.
Since the angular velocity is detected by measuring the amplitude of vibration in the Y-axis direction of the
The detection sensitivity is improved by increasing the amplitude in the Y-axis direction. Since the amplitude in the Y-axis direction is proportional to the amplitude in the X-axis direction, increasing the amplitude of vibration of the vibrator 14 in the X-axis direction also increases the amplitude in the Y-axis direction when the angular velocity is input. .

On the other hand, the amplitude of the vibrator 14 in the Y-axis direction is detected by the displacement detecting means 18. The displacement detecting means 18, which will be described in detail later, detects the relative movement amount between the main scale 22 provided at the upper end of the vibrator 14 and the index scale 21 provided so as to face the main scale 22. is there. Therefore, if the relative movement amount of the main scale 22 and the index scale 21 in the X-axis direction is increased, the relative movement amount in the Y-axis direction when the angular velocity is input is also increased, and detection can be performed with high sensitivity. And
When the vibrator 14 is vibrating in the X-axis direction by the vibrating means 16, the vibration is transmitted to the base 12 to which the vibrator 14 is fixed, and further transmitted to the index scale 21 via the housing 20. The index scale 21 also vibrates in the X-axis direction in the opposite phase to the vibration of the vibrator 14. Therefore, if the vibration of the vibrator 14 is efficiently transmitted to the index scale 21, the relative movement amount of the main scale 22 and the index scale 21 in the X-axis direction becomes large even when the amplitude of the vibrator 14 is small, and the vibration is increased. The same effect as when the amplitude of the child 14 is increased is obtained, the amplitude in the Y-axis direction is increased when the angular velocity is input, and the angular velocity can be detected with high sensitivity.

However, when fixing the vibrating gyro body 10 to the moving body 29, the base 12 and the housing 2 are fixed.
Since the movable body 29 on the fixed surface in contact with the outer peripheral surface of 0 acts as a damper, the vibration transmitted from the vibrator 14 to the base 12 and the housing 20 is absorbed and reduced. Particularly, a moving body such as an automobile is violently vibrated, and the moving body 2
Since the vibrating gyro main body 10 is attached to the moving body 29 via a vibration damping member or the like in order to reduce the influence of the vibration of the 9 itself, the vibration of the index scale 21 is large.
Is almost not transmitted to. Therefore, in the vibration gyro according to the present embodiment, the vibration of the vibrator 14 is efficiently transmitted to the index scale 21 by fixing the vibration gyro main body 10 to the moving body 29 by the holding mechanism described above.

That is, the vibrating gyro main body 1 is designed so that the absorption of vibrations on the fixed surface which is in contact with the outer peripheral surface is minimized.
0 is fixed to the moving body 29. In FIG. 1, the node of vibration of the vibrator 14 is the fixed point Po on the inner surface of the base 12 at the axis of the vibrator 14. Therefore, the minimum value of the amplitude of the vibration transmitted on the outer peripheral surfaces of the base 12 and the housing 20 is theoretically a point Pm on the extension line of the axial center of the vibrator 14 from the point Po to the outer surface of the base 12. Then, it was confirmed in the experiment. It was also confirmed by experiments that the maximum amplitude of the vibration transmitted on the outer peripheral surfaces of the base 12 and the housing 20 is the ridge Ps at the upper end of the outer peripheral surfaces. Therefore, fixing the vibrating gyro body 10 to the moving body 29 at the point Pm that is the farthest from the maximum amplitude Ps and has the minimum amplitude minimizes the reduction of the vibration transmitted from the vibrator 14. Therefore, the vibration can be efficiently transmitted to the index scale 21.

In this embodiment, as described above, the vibrating gyro body 10 is fixed to the moving body 29 only at the point Pm by the rod-like support 23, so that the vibration transmitted from the vibrator 14 is transmitted. Can be transmitted to the index scale 21 without decreasing. In addition, since the support column 23 is not directly fixed to the anti-vibration rubber 27 provided on the moving body 29 but is attached to the fixed base 25 provided on the anti-vibration rubber 27, the absorption of vibration by the support column 23 is further reduced. It becomes possible. In addition, the vibration of the vibrator 14 can be more efficiently performed by the index scale 2
1, the base 12 and the housing 2 for transmission to
0 and the member used for the displacement detecting means 18 is preferably a homogeneous material having good vibration transmission efficiency, such as brass, bronze, aluminum, or iron.

Next, the vibration control means for controlling the vibration of the vibrator 14 in the X-axis direction will be described. As described above, when the angular velocity ω is applied, the vibrator 14 draws a locus as shown in FIG. On the other hand, the angular velocity ω is the velocity V in the Y-axis direction.
It is proportional to y (maximum velocity point = point where Y-axis amplitude becomes zero). Since Vy is also proportional to Vx (velocity in the X-axis direction), if Vx is controlled to be constant, the angular velocity ω will be proportional to only the change in Vy. Here, the distance X from the origin of the vibrator 14 and the velocity Vx are each expressed by the following equation 1.

[0024]

X = Px · sin2πf · t Vx = dX / dt = 2πf · Px · cos2πf · t Px: maximum amplitude, f: frequency, t: time. From the above formula 1, the maximum speed is cos2πf · t = 1 or −
When 1, Vx = 2πf · Px. Here, it is necessary to vibrate the vibrator 14 at its resonance frequency f and control so that the amplitude Px is always constant. Therefore, in this embodiment, a self-excitation control mechanism is adopted, and a vibration wave detection means 30 and an excitation control means 32 are provided as shown in FIG. 6, and the photoelectric encoder 1 is used as the vibration wave detection means 30.
8, an X-axis encoder 18a, an X-axis preamplifier 34, a phase shifter 36 as an excitation control means 32, an automatic control gain circuit (AGC) 38, and an amplifier 40. Then, the X-axis encoder 18a detects the vibration state of the vibrator 14 in the X direction, and outputs the output of the X-axis encoder 18a to the X-axis.
The signal is amplified by the axis preamplifier 34, shifted to an appropriate phase by the phase shifter 36, and input to the amplifier 40 in order to obtain the synchronization and the required size for vibrating the vibrator 14. The output of the X-axis preamplifier 34 is also input to the AGC 38, which detects the amplitude of this sine wave and instructs the amplifier 40 the gain necessary for vibrating the vibrator 14.

Then, the amplifier 40 has a desired excitation gain,
In addition, the vibrating means 1 is synchronized with the resonance state of the vibrator 14.
Excitation control is performed on 6. Further, the angular velocity calculation means 50 according to the present embodiment uses the Y-axis displacement amount obtained from the Y-axis displacement detection means 52. The Y-axis displacement detecting means 52 according to this embodiment includes the Y-axis encoder 18b of the photoelectric encoder 18 and the Y-axis preamplifier 54. Then, the signal of the Y-direction amplitude detected by the Y-axis encoder 18b is amplified by the Y-axis preamplifier 54 and then input to the angular velocity calculation means 50. Here, since the angular velocity ω is proportional to the amplitude in the Y direction, the multiplication value becomes the angular velocity ω by appropriately adjusting and multiplying the coefficient A in the angular velocity calculation means 50. Further, in the present embodiment, the output of the AGC 38 is input to the angular velocity calculation means 50 as the coefficient A for correction, so that more accurate angular velocity output can be performed. If the integration is further performed by the integration calculator, the angle output can be obtained.

As described above, according to the vibrating gyroscope of the present embodiment, the amplitude of the vibrator 14 can be controlled to be constant in synchronization with the resonance state of the vibrator 14. Further, in this embodiment, the vibration control and the angular velocity calculation are performed based on the analog data from the photoelectric encoder 18, so that the circuit configuration can be simplified. In the present invention, since the angular velocity ω is obtained by measuring the amplitude in the Y-axis direction as described above, even if a low frequency disturbance is superposed as shown in FIG. Next, the displacement detecting means 18 according to the present invention will be described with reference to FIGS. FIG. 8 is a vertical cross-sectional view showing the basic structure of a photoelectric encoder according to an embodiment of the present invention, and FIG. 9 shows I-I shown in FIG.
A cross-sectional view along the line is shown. In the figure, the main scale 22 of the photoelectric encoder 18 is a moving member 5.
6 and the index scale 21 is provided on the moving member 58. Then, the relative movement amount of the moving members 56 and 58 is detected. One light emitting element 60 and four light receiving elements 62a, 62b, ... 62d are arranged on the upper surface of the index scale 21 in FIG. The lead wires of the light emitting element 60 and each light receiving element 62 are fixed to the printed board 64.

The main scale 22 is formed with a striped grating 68 shown in FIG. 10, and the striped grating 68 is
A transparent surface 70 is provided in the center, and a square V-shaped chromium vapor-deposited reflection surface 72 and a transparent surface 70, which are formed from two sets of parallel lines that are parallel to the X-axis direction and the Y-axis direction, are provided outward from the transparent surface 70.
And are alternately and repeatedly formed. Further, one transparent surface 70 of the square shape and one reflective surface 72 adjacent to the outside of the transparent surface 70 are set as one pattern, and the pitches P _{1 to} P _{n of the} one pattern are formed to be the same. further,
As shown in FIG. 11, the area of the square-shaped reflecting surface 72 monotonically increases from the inner side to the outer side. Therefore, the proportion of the reflecting surface 72 in the pitch P _{1 to} P _n of the one pattern is also from the inner side. It is increasing at a constant rate toward the outside (from P ₁ to P _n ).

On the other hand, the index scale 21 is shown in FIG.
As shown in FIG. 2, it is made of a glass plate on which a chromium vapor deposition surface is formed, and at the corresponding positions of the light emitting element 60 on the chromium vapor deposition surface, the emission slits 74a and 74b parallel to the Y axis and the emission slit 74c parallel to the X axis. , 74d are provided.
Further, the light receiving elements 62a, ... 62 on the chromium vapor deposition surface
The output slits 74 corresponding to the respective positions of d
Outside of the entrance slits 76a, 76b, 76c, 7
6d is formed. Therefore, the light L emitted from the light emitting element 60 is, for example, the emission slit 74 serving as a secondary light source.
The light is emitted through a, and the striped grating 68 of the main scale 22 is
Among these, the light is partially reflected in the stripe shape of the transmission surface 70a and the reflection surface 72a parallel to the Y-axis direction, and is received by the light receiving element 60a via the entrance slit 76a. That is, the main scale 2
Of the light radiated on the second striped grating 68, the light radiated on the transparent surface 70 is not reflected, but only the light radiated on the reflective surface 72 is reflected and travels toward the incident slit 76a.

As described above, the striped grating 68 has one pattern pitch P ₁ of the transparent surface 70 and the reflective surface 72.
Since the proportion of the reflection surface 72 in P _n increases from the inner side to the outer side at a constant rate, the reflected light increases as the position irradiated by the light L goes to the outer side of the striped grating 68. The amount of light received by the light receiving element 60 also increases. That is, the position of the main scale 22 in the X direction is set to the light receiving element 62a.
Since it is reflected in the amount of received light, the displacement of the main scale 22 in the X direction can be grasped by detecting the change in the amount of received light. The light receiving element 62a,
The output of 62b is a voltage output differentially amplified by the circuit shown in FIG. That light receiving elements 62a, 62b respectively consists of a phototransistor, the current output I _a phototransistor 62a is output as a voltage change by the current-voltage conversion amplifier 84 consisting of an operational amplifier 80 and the semi-fixed resistor 82 connected in parallel It Also, the current output I of the phototransistor 62b
_b is output as a voltage change by the current / voltage conversion amplifier 86 having the same configuration. Since the current outputs I _a and I _b of the phototransistors 62a and 62b have opposite phases as shown in FIG. 14, the differential amplifier 34 including the resistor 88 and the operation amplifier 90 connected in parallel is used.
By differentially amplifying with, a voltage output V _out as shown in FIG. 15 can be obtained.

Similarly, with respect to the displacement in the Y-axis direction, the transparent surface 70b and the reflective surface 72b parallel to the X-axis direction of the striped grating 68, the exit slits 74c and 74d, the entrance slits 76c and 76d, and the light-receiving slits are received. The elements 62c and 62d act,
It is possible to detect the displacement of the main scale 22 in the Y-axis direction with excellent linearity. here,
The detection sensitivity of the displacement amount of the main scale 22 in the X-axis and Y-axis directions and the detectable displacement range are the pitch width of one pattern of the transparent surface 70 and the reflective surface 72 of the striped grating 68, and the square shape. It changes depending on the amount of increase in the area of the reflective surface 72 from the inside to the outside. Tables 1 and 2 show examples in which the pitch width of the one pattern is changed.

[0031]

[Table 1] ──────────────────────────────────── P ₁ P ₂ P ₃ ...・ ・ ・ ・ ・ ・ P _n-2 P _n-1 P _n ────────────────────────────────── ──Reflecting surface line width (μm) 2 4 6 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 46 48 50 ────────────────────────── ─────────── Transparent surface line width (μm) 48 46 44 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 42 20 ───────────────── ──────────────────── Reflection surface ratio (%) 4 8 12 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 92 96 100 ──────── ─────────────────────────────

[Table 2] ──────────────────────────────────── P ₁ P ₂ P ₃ ...・ ・ ・ ・ ・ ・ P _n-2 P _n-1 P _n ────────────────────────────────── ──Reflecting surface line width (μm) 2 4 6 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 96 98 100 ────────────────────────── ─────────── Transparent surface line width (μm) 98 96 94 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 4 20 ───────────────── ──────────────────── Ratio of reflective surface (%) 2 4 6 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ 92 96 100 ──────── ─────────────────────────────

In the striped grating 68 of Table 1, the pitch width of the one pattern is 50 μm, and the width of the chromium line forming the reflecting surface 72 is increased from the inner side to the outer side by 2 μm per pitch. Therefore, the number of pitches from the pitch P _{1 to} P _n is 25, and the total length from the pitch P _{1 to} P _n is 1250 μm (1.25 mm). In the striped grating 68 in Table 2, the pitch width of the one pattern is 100 μm, and the width of the chromium line forming the reflecting surface 72 is increased from the inner side to the outer side by 2 μm per pitch.
Therefore, the number of pitches from pitch P _{1 to} P _n is 50,
The total length from pitch P _{1 to} P _n is 5000 μm
(5 mm).

In the example of Table 1, the pitch width is 1 compared to the example of Table 2.
Since the amount of increase in the chromium line width per pitch is the same as the example in Table 2, the increase in the ratio of the reflective surface 72 in one pitch from the inside to the outside is shown in the example in Table 2. Compared with the above, the example in Table 1 is larger. Therefore, at the same displacement amount, as the pitch width of one pattern is shortened as in the example of Table 1, the reflectance changes abruptly, so that the detection sensitivity is improved. In Tables 1 and 2, the pitch width of one pattern was changed, but the change in the reflectance also becomes large even if the amount of increase in the width of the chromium line forming the reflecting surface 72 per pitch is increased. The detection sensitivity is improved. That is, the pitches P _{1 to} P _n determined by the pitch width of one pattern and the amount of increase (= the number of pitches) per pitch of the reflecting surface 72.
The shorter the total length up to, the greater the change in reflectance and the higher the detection sensitivity. Therefore, Table 1 and Table 2
In the above example, the ratio of the total lengths of the pitches P _{1 to} P _n is 1.25 mm: 5 mm = 1: 4, and the pitch width is 50 μm as compared with the example of Table 2 in which the pitch width is 100 μm.
In the example of Table 1, the detection sensitivity of about 4 times can be obtained.

On the other hand, if the total length from the pitches P _{1 to} P _n is lengthened, the detection sensitivity will decrease, but naturally the displacement detection possible position range (-P _X to + shown in FIG. 15).
P _X ) becomes wider. That is, the position range in which the displacement of the main scale 22 can be detected is the transparent surface 70 and the reflective surface 72.
The total length from the pitches P _{1 to} P _n is 1.2 because the area corresponds to the striped grating 68 formed by
Compared to the striped grating 68 of Table 1 which is 5 mm, the pitch P ₁ ~
The striped grating 68 in Table 2 having a total length up to P _n of 5 mm has a main scale 2 in the position range of 4 times.
It is possible to detect the displacement of 2.

As described above, the pitch width of the striped grating 68 and the increase amount per pitch of the reflecting surface 72 are adjusted,
By designing the total length from the pitches P _{1 to} P _n to an appropriate value, a wide dynamic range can be obtained, and high sensitivity is achieved in the position range corresponding to the amount of relative movement of the main scale 22. The displacement can be detected with high accuracy. In addition, the photoelectric encoder 18 according to the present embodiment measures the voltage value due to the change in the light amount via the striped grating 68 and detects the displacement of the main scale 22 from the analog signal of the voltage value. It is possible to obtain a photoelectric encoder that is simple, small, and inexpensive.
In the present embodiment, the area of the reflecting surface 72 is monotonically increased from the inner side to the outer side to form the striped grating 68,
It is also possible to monotonically decrease the area from the inside to the outside.

Further, in this embodiment, the pitch width of one pattern consisting of the transparent surface 70 and the reflecting surface 72 is the same,
Although the area of the reflecting surface 72 is monotonically increased from the inner side to the outer side, the pitch width does not necessarily have to be the same. For example, when the pitch width is widened from the inner side to the outer side, reflection in one pitch Ratio of surface 72 (reflection surface 72
It is sufficient to increase the area of the reflecting surface 72 in one pitch so that the reflectance (due to) increases at a constant rate. Further, in the above embodiment, the shape of the magnet plate is a donut shape,
As shown in FIG. 16 (A), the shape of the cross section of the magnet plate is a square shape having a hole at the center for fitting the transducer, the octagonal shape shown in FIG. 16 (B), or the same figure (C). It is also possible to have a cross shape shown in. Further, as shown in FIG. 7C, it is possible to use only both ends 124a and 124b of the magnet plate as magnets. The magnet plate is required to have the same resonance frequency in the X-axis direction and the Y-axis direction, that is, to have the same dynamic balance.

Further, in the above embodiment, the N of the magnet plate is
The pole and the S pole are divided by the Y-axis passing through the axis of the vibrator, and the exciting coil is excited to excite the vibrator by the bending moment generated between the magnet plate and the exciting coil.
As shown in FIG. 17, the N-pole and the S-pole of the magnet plate are divided by the Y-axis passing through the axis of the oscillator and the horizontal line passing through the center of the magnet plate so that the contacting portions are different poles, and the excitation coil is It is also possible to vibrate the vibrator by the magnetic force generated by the excitation, that is, the attraction between the magnet plate and the excitation coil in the X-axis direction, and the repulsive force. Further, although the vibrating means is provided on the tip side of the vibrator in the above-mentioned embodiment, it may be provided on the fixed side of the vibrator as shown in FIG.

[0038]

As described above, according to the vibrating gyroscope of the present invention, on the outer peripheral surface of the outer frame portion to which the vibration of the vibrating means is transmitted, on the extension line of the shaft core of the vibrating means having the smallest amplitude. Since the support is fixed to the moving body only at the points, it is possible to minimize the absorption of vibration at the contact surface of the vibrating gyro with the moving body and efficiently transmit the vibration of the vibrating means to the index scale. Further, in the vibrating gyroscope according to the second aspect of the present invention, the vibrator is vibrated in a non-contact manner, so that it is possible to perform extremely accurate angular velocity detection with a simple configuration. Further, since the magnet portion and the exciting coil are provided close to each other and the vibrator is excited by the magnetic moment of the magnet portion generated by flowing the exciting current through the exciting coil, a small exciting current is applied to the exciting coil. The vibrator can be excited by simply passing it through, and the excitation coil can be made extremely small. Further, since the axis of the exciting coil is coaxial with the axis of the vibrator, the assembly can be performed with high accuracy and easily.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a schematic configuration of a vibrating gyroscope according to an embodiment of the present invention.

FIG. 2 is a plan sectional view of a magnet plate of the vibration gyro shown in FIG.

[Fig. 3]

[Fig. 4]

5 is an explanatory diagram of a vibrating unit and an angular velocity measuring principle of the vibrating gyro shown in FIG.

6 is an explanatory diagram of a vibration control unit and an angular velocity calculation unit of the vibration gyro shown in FIG.

7 is an explanatory diagram of the influence of low-frequency disturbance on the vibration gyro shown in FIG.

8 is an explanatory diagram of a schematic configuration of a photoelectric encoder used in the vibration gyro shown in FIG.

9 is an explanatory diagram of an arrangement of light emitting elements and light receiving elements of the photoelectric encoder shown in FIG.

10 is an explanatory diagram of a striped grating formed on a main scale of the photoelectric encoder shown in FIG.

11 is an explanatory diagram of an area change according to a position of a reflecting surface of the striped grating shown in FIG.

12 is an explanatory diagram of an index scale of the photoelectric encoder shown in FIG.

FIG. 13 is a configuration explanatory diagram of a differential amplifier circuit of a signal from the light receiving element of the photoelectric encoder shown in FIG.

FIG. 14

FIG. 15 is an explanatory diagram of a signal processing state by the circuit shown in FIG.

FIG. 16 is an explanatory diagram of a shape example of a magnet plate.

FIG. 17 is an explanatory diagram of a division example of a magnet plate.

FIG. 18 is an explanatory diagram of an example of the installation position of the vibrating means.

[Explanation of symbols]

 10 ... Vibration gyro main body 12 ... Base 14 ... Oscillator 20 ... Housing 21 ... Index scale 22 ... Main scale 23 ... Strut 25 ... Fixed base 27 ... Anti-vibration rubber 29 ... Moving body

Claims (2)

[Claims] 1. An outer frame part comprising a base and a cylindrical housing having an opening at one end installed in the base, a vibrating means having one end standing upright on the inner surface of the base, and an X-axis attached to the vibrating means. A vibrating means for applying a vibrating force in a direction, a main scale installed at the other end of the vibrating means, and an index scale provided in the opening at the other end of the housing and arranged to face the main scale. A vibration gyro having: a displacement detecting means for detecting a displacement of the vibrating means in the Y-axis direction; and an angular velocity calculating means for calculating an angular velocity from a displacement amount of the displacement detecting means in the Y-axis direction. A pillar whose one end is fixed to the outer surface of the base so as to have an axis centered on the same line as the axis of the vibrating means, and the other end of the pillar is fixed to the front surface and the back surface to the moving body via a vibration isolating member. Fixed A vibrating gyro, which is equipped with a fixed base. 2. The vibrating gyroscope according to claim 1, wherein the vibrating means is provided in the vibrating means, and the magnet portion is divided into an N pole and an S pole by a plane including an axis of the vibrating means, and the vibration. An excitation coil which is wound in a cylindrical shape so as to have a shaft center coaxial with the shaft center of the means, and which is arranged so that the inner surface of the cylindrical center part is close to the magnet part; A vibrating gyro, wherein a vibrating force in the X-axis direction is applied to the vibrating means by a magnetic moment between a magnet portion and an exciting coil that is generated by periodically flowing an exciting current to the coil.