JP2786727B2 - Displacement detector - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a displacement detection device for detecting a rotation angle, that is, an angular displacement.

[Conventional technology]

Conventionally, compass and other gyro devices have been developed as displacement detection devices for detecting angular displacement. Especially for gyro devices such as mechanical gyro and laser gyro,
Various schemes or mechanisms are under consideration.

[Problems to be solved by the invention]

However, there has been no conventional compass of small size and high precision. Further, in the conventional gyro apparatus, although the accuracy is high, the mechanism and structure are complicated, adjustment and the like are not easy, and attention is required for handling. Further, the gyro apparatus itself is large, difficult to handle, has a limited use, and is very expensive.

In view of the above circumstances, an object of the present invention is to provide a displacement detection device having a very simple structure, small size and light weight, and high accuracy.

[Means for solving the problem]

In order to achieve the above object, the displacement detecting device according to the present invention comprises: (a) supported by a displacement detected member whose displacement is to be detected; X not parallel to three rotating axes
Support means rotatable about an axis, a Y axis and a Z axis;
(B) a movable member rotatably supported around x-axis, y-axis, and z-axis, which are set in the support means and are parallel to three rotation axes which are not intersected and are not in the same plane; c) when the movable member is rotated relative to the support means in accordance with the inertial force and deviates from the reference position of the support means, the occurrence of the deviation and each of the x-axis, y-axis and z-axis And (d) when the displacement detecting means detects the displacement of the movable member from the reference position, the supporting means is used to detect the displacement of the movable member about the X, Y, and Z axes. Return means for rotating the support means in the same direction as the displacement direction of the movable member with respect to the x-axis, y-axis, and z-axis; and (e) relative movement between the displacement detection member and the container. Displacement detecting means for detecting displacement about each of the X, Y and Z axes And, it has a configuration with a.

In a preferred embodiment of the displacement detection device according to the present invention, the support means is a container whose inside is reduced in pressure. A movable member is accommodated in the interior space of the container.

In another embodiment of the displacement detection device according to the present invention, the movable member and a liquid having substantially the same specific gravity as this,
It is to be accommodated in the internal space of the support means.

[Action]

In the displacement detection device according to the present invention, the movable member maintains a fixed direction due to inertia even when the displacement detection member and the support member rotate around any one of the X axis, the Y axis, and the Z axis. . For example, when the displacement detection member rotates and the movable member is displaced from its reference position, the displacement detection means generates the displacement and the displacement direction for each of the x-axis, y-axis, and z-axis provided on the support member. And detect. Here, the reference position means that the movable member has a predetermined positional relationship with respect to the container, and this positional relationship can be arbitrarily set in advance.
However, this positional relationship cannot be changed during the operation of the displacement detection device. When it is detected that the movable member has deviated from the reference position, the return means includes an x-axis of the movable member,
The support member is rotated around any one of the X, Y, and Z axes in accordance with the directions of displacement with respect to each of the y axis and the z axis. In this case, the return means rotates the support means so as to follow the direction in which the movable member has shifted. Therefore, the relationship between the container and the movable member returns to the state before the occurrence of the displacement, that is, the state of the reference position. The displacement detecting means is
The amount of rotation of the support means relative to the displacement detection member is X
The displacement is detected for the axis, the Y axis, and the Z axis, and the displacement of the displacement detection member, that is, the displacement detection device itself is detected.

Note that the positional relationship between the support member and the movable member is maintained macroscopically constant, although the vibration is repeated microscopically near the reference position. Therefore, the container is driven while always canceling the contact resistance between the support member and the movable member in the positive and negative directions, and errors caused by such contact resistance can be minimized. it can.

In a preferred embodiment of the displacement detection device according to the present invention, since the inside of the container serving as the support means is depressurized, even if the movable member rotates with respect to the container or the outside, the resistance received by the movable member is extremely small. . Therefore, the movable member accurately maintains its state according to the inertia. Note that the displacement detection device itself may be housed in the depressurized container without using the depressurized container as the supporting means. In this case, similarly, the resistance applied to the movable member is extremely small.

In another embodiment of the displacement detecting device according to the present invention, not only a movable member but also a liquid having substantially the same specific gravity as the movable member is accommodated in the internal space of the support means.
For this reason, it is possible to reduce a load applied to a bearing or the like that supports the movable member so that the movable member can rotate around the x-axis, the y-axis, and the z-axis. That is, when the movable member moves according to its inertia, the resistance received from the support member is extremely small.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 illustrates the configuration of a displacement detection device according to a first embodiment of the present invention.

A first inner box is provided inside the outer box 1 which is a displacement detection member.
11 are housed. The first inner box 11 is formed by a servo motor 2 and a bearing 5 fixed to the outer box
The first inner box 11 is rotatably supported about an axis, and the rotation of the first inner box 11 is controlled by a driving servomotor 2 and a coupling 3 for transmitting the power. The relative rotation angle of the first inner box 11 is detected by a rotation encoder 4 attached to the servo motor 2. Similarly, a second inner box 21 is accommodated inside the first inner box 11. The second inner box 21 is rotatably supported around the Y axis by a servomotor 12 and a bearing 15 fixed to the first inner box 11. Is controlled by a servomotor 12 and a coupling 13 that transmits the power of the servomotor. The relative rotation angle of the second inner box 21 is detected by the rotation encoder 14 attached to the servo motor 12. Further, inside the second inner box 21, a plastic container 6 as a support means is accommodated.
The container 6 is rotatably supported around the Z-axis by a servo motor 22 and a bearing 25 fixed to the second inner box 21. The rotation of the container 6 is controlled by the servo motor 22 and the coupling 23. Is controlled by The relative rotation angle of the container is detected by a rotation encoder 24 attached to the servomotor 22.

That is, the container 6 housed most inside can rotate around three rotation axes (X axis, Y axis, and Z axis), and the amount of rotation around each axis is , 14, and 24.

2 and 3 show details of the container 6 of FIG.

Inside the container 6, a float 7 of a disk lock, which is a movable member, is housed. This float 7 is supported at the center of its disk by bearings 16 and 26,
, Three orthogonal rotation axes (x-axis, y-axis and z-axis)
(Axis). The appearance of the float 7 and the container at this time is shown in FIG. 3 as a side view.
The inside of the container 4 is filled with water, and the specific gravity of the float 7 is slightly larger than that of water. Therefore, the frictional resistance between the float 7 and the shaft 26 is extremely small.

A first light source for generating infrared light is provided on the upper end face of the container 6.
31 and the first photodetector 32 are provided to face each other.
These are a set of sensors that detect the rotation of the float 7 about the x-axis from the change in the amount of light reflected from the mirror 17 on the float 7. Similarly, a second light source 33 and a second light detector 34 are provided on the upper end surface of the container 6 so as to face each other. These also constitute a set of sensors for detecting the rotation of the float 7 about the y-axis. In addition, container 6
A pair of third light sources 35a and 35b are provided on the upper end surface of the light source. Third light detectors 36a and 36b are provided on the lower end surface of the container 6 so as to face the two light sources. One light source 35a and one light detector 36a are photocouplers. Similarly, the other light source 35b and the other light detector 36b are also photocouplers. The light transmitting part 7a and the light transmitting part 7b provided by dividing the float 7 into two parts function as an interrupter. Therefore, the light sources 35a and 35b and the photodetectors 36a and 36b are used as a set of
Rotation about the z-axis is detected.

FIGS. 4 and 5 specifically illustrate a method of detecting the rotation of the float 7. FIG.

FIG. 4 is a diagram showing a side surface of the container, similarly to FIG. 3, and is a diagram for explaining detection of rotation of the float 7 around the x-axis.

FIG. 4 (a) shows the positional relationship between the container 6 and the float 7 when the float 7 is at the reference position.
When the float 7 is in this state, the infrared light beam from the first light source 31 is incident on the mirror 17 on the float 7 and the reflected light is spot-like incident on an area centered on the center of the first light detector. I do. The first light detector 32 has two light receiving surfaces arranged in the y-axis direction (the left-right direction in the drawing). When the amount of light incident on the first light detector 32 is substantially the same, that is, when the reference position shown in FIG. Is determined not to lean around.

FIG. 4 (b) shows the case where the float 7 has rotated counterclockwise around the x-axis. In this case, the container 6 is actually
Rotates clockwise with respect to the outside world. When the float 7 is tilted in this manner, the mirror of the infrared light beam from the first light source 31
The angle of incidence on 17 is reduced, and the reflected light is incident on the left side of the first photodetector 32 as shown. Therefore, the amount of light detected on the left light receiving surface increases, and the amount of light detected on the right light receiving surface decreases. By measuring the differential output of these detected light amounts, in the case of FIG.
Is tilted counterclockwise around the x-axis.

The detection of the rotation around the x-axis has been described above, but the operation around the y-axis is also the same. However, the first
The second light source 33 and the second light detector 34 which are orthogonal to the light source 31 and the first light detector 32 will be used.
In this case, the second light source 33 and the second light detector 34, which are a set of sensors, are used to detect the rotation and the direction of the mirror 27, that is, the movable member 7 around the y axis.

FIG. 5 illustrates an operation related to rotation about the z-axis.

FIG. 5A is a plan view of the container 6 and shows the positional relationship between the container 6 and the float 7 when the float 7 is at the reference position. When the float 7 is in this state, the infrared light beams from the third light sources 35a and 35b detected by the third light detectors 36a and 36b respectively
It is about half of the maximum when blocked by 7b. In this case, the amounts of light incident on the respective third light detectors 36a and 36b are equal, and it is determined that the float 7 is not tilted around the z-axis.

FIG. 5 (b) shows the case where the float 7 has rotated counterclockwise around the z-axis. In this case, the container 7 is actually
Rotates clockwise with respect to the outside world. When the float 7 rotates in this manner, most of the infrared light beam from the third light source 35a passes through the light transmitting portion 7a of the float 7 and reaches the third light detector 36a. On the other hand, most of the infrared light beam from the third light source 35b is blocked by the light shielding portion 7b of the float 7 and does not reach the third light detector 36b. Therefore, the amount of light detected by the left light source 35a increases, and the right light source 35b
Reduces the amount of light detected. By measuring the differential output of these detected light amounts, in the case of FIG. 5B, it is determined that the float 7 has rotated counterclockwise around the z-axis.

FIG. 6 shows a circuit configuration of the light source 31, the light detector 32 and its control circuit shown in FIGS. 3 to 5.

The first light source 31 including an LED or the like is supplied with power from the control circuit and generates infrared light. The first light detector 32 generates a voltage or a current in response to infrared light from a light source. The point when the amount of light incident on both light detectors 32 is almost equal
Since the circuit is adjusted so that the output voltage at A1 becomes zero, if the differential outputs from both photodetectors are unbalanced, a positive or negative output is generated at point A1. Depending on whether the output at point A1 is positive or negative, float 7
The rotation direction about the x-axis can be determined.

The second light source 33 and the second light detector 34 are controlled by a similar circuit. Also in this case, if the differential outputs from both photodetectors 34 are unbalanced, a positive or negative output is generated at point A2. Depending on the positive or negative output generated at point A2,
The direction of rotation of the float 7 about the y-axis can be determined.

In addition, the third light sources 35a and 35b and the second light detectors 36a and 36a
6b is controlled by a similar circuit. Also in this case, when the differential outputs from the two photodetectors 36a and 36b become unbalanced, a positive or negative output is generated at the point A3.

The output signals at points A1, A2 and A3 are detected by the conversion circuit 8. The detected signal is processed by this conversion circuit and converted into an output for driving each of the servomotors 2, 12, 22. For example, as shown in FIG. 4 (b), when the float 7 rotates around the x-axis and an output is generated at the point A1, the servomotor 2 rotates to move the container 6 counterclockwise around the X-axis. Rotate. When the output at the point A1 becomes zero, the rotation of the servomotor 2 is stopped. The float 7 has returned to its original reference position. When the float 7 rotates around the y-axis or the z-axis, an output similarly occurs at points A2 and A3, the container 6 rotates around the Y-axis or the Z-axis, respectively, and the float 7 returns to the reference position. .

The above has described the case where the X, Y, and Z axes are parallel to the x, y, and z axes, respectively. However, in actual operation, these axes are not kept in a fixed relation except for the Z axis and the z axis. Specifically, in FIG.
Is rotated about 45 degrees around the Y axis, the X axis also rotates 45 degrees with it, so that the angle between the X axis and the x axis is 45 degrees, and they are not parallel. As described above, in the actual operation, when the rotation of the outer case 1 around the X axis, the Y axis, and the Z axis is integrated, the rotation around the x axis, the y axis, and the z axis is converted to the X axis, the Y axis. And a rotation around the Z axis. The conversion circuit 8 also performs such an operation.

The amount of rotation of each of the servomotors 2, 12, 22 is detected by the rotary encoders 4, 14, 24 and displayed on the angle display 9. Data on the rotational displacement displayed on the angle display 9 is fed back to the conversion circuit 8.

Hereinafter, the operation of the displacement detection device of FIG. 1 will be briefly described.

The illustrated displacement detection device is attached to an object on which the displacement detection device is to be mounted, for example, a vehicle or the like, which is required to detect angular displacement from vertical.

Consider a case where an object on which the displacement detection device is mounted rotates and the displacement detection device rotates around an arbitrary axis parallel to, for example, the x-axis. In this case, since the rotation of the container 6 is controlled only by the servomotor 2, the container 6 does not rotate with the outer box 1, and the positional relationship between the container 6 and the outer box 1 does not change. On the other hand, the float 7 maintains its original orientation or position due to its inertia. As a result, the float 7 rotates relative to the container 6 and the outer box 1. Assuming that the float 7 is at the reference position in advance, the float 7 is shifted from the reference position.

For example, if the float 7 in FIG. 2 rotates clockwise around the x-axis as viewed from the right side of the drawing (in reality,
This means that the outer box 1 and the container 6 have rotated counterclockwise. 6), the amount of light detected by the light detector 32 becomes unbalanced, and an output of a predetermined value or more is generated at a point A1 of the control circuit in FIG. The conversion circuit 8 drives the servo motors 2, 12, and 22 based on the differential output to rotate the container 6 in a direction in which the float 7 is shifted (in this case, clockwise as viewed from the right side in FIG. 2). When the output difference from the light detector 32 becomes equal to or less than a predetermined value, the conversion circuit 8 stops the servomotors 2, 12, and 22 and stops the rotation of the container 6. As a result, the float 7 becomes the container 6
To the reference position again.

The above operation is for the case where the float 7 rotates around the x-axis, but the same holds for the case where the float 7 rotates around the y-axis or the z-axis. Will be maintained. Here, since the rotation amount of the container 6 is monitored by the rotation encoders 4, 14, and 24, the rotation amount of the entire displacement detection device, that is, the angular displacement can be detected.

An actual displacement detection device generally rotates continuously in an arbitrary direction. Therefore, it is desirable that the container 6 also rotates smoothly and accurately so as to cancel the rotation. For this purpose, it is desirable to operate the servomotor even if the output difference from the optical detector is slight. Further, it is desirable that the rotation of the servomotor be smooth and the response be good.

7 and 8 are views for explaining a displacement detecting device according to a second embodiment of the present invention. Note that the same reference numerals are given to portions common to the displacement detection device of the first embodiment.

In the case of the second embodiment, unlike the case of the first embodiment, the pressure inside the container 6 is reduced. The configuration of the other parts is the first
The configuration is completely the same as that of the embodiment. In this case, the resistance from the liquid added to the float 7 is eliminated by the reduced pressure in the container 6. The float 7 is supported only on the container 6 by a bearing or the like. However, since the resistance force from the bearing acting on the float 7 does not change macroscopically the positional relationship between the container 6 and the float 7, the float 7 moves in the positive and negative directions. Work to offset. Therefore, an error in displacement detection can be minimized. Further, if the bearing is formed by utilizing magnetic levitation or the like, the resistance can be further reduced.

The present invention is not limited to the above embodiment, and various modifications are possible.

For example, a liquid other than water can be used as the liquid contained in the container 6. However, needless to say, a liquid having a low viscosity is desirable. Further, in actual use, it is desirable to use a liquid that is transparent to the light of the light source, has a low melting point, and a large specific gravity.

Further, the inner space of the container may be substantially spherical. Here, that the interior space of the container is substantially spherical means that even if the container is rotated around an arbitrary rotation axis passing through the center of the container, almost no turbulence occurs in the fluid contained in the container. It means shape. By minimizing the turbulence generated in the fluid in the container, the error of displacement detection can be reduced. In this case, the moment of inertia of the movable member may be reduced, and its shape may be non-rotationally symmetric around any of the x-axis, y-axis, and z-axis orthogonal to each other at the center of the internal space. In this case, the fluid maintains a constant direction due to its inertia even when the container rotates around the above-mentioned arbitrary rotation axis. Also, since the movable member also rotates with the fluid due to its own inertia and the action from the fluid,
It will maintain a certain direction in the outside world. That is,
Displacement can be detected by detecting the movement of the fluid in the container indirectly from the movement of the movable member and rotating the container accordingly.

Further, the inner wall of the container 6 may be coated with Teflon or the like to reduce the contact resistance between the container 6 and the liquid in the container.

Further, a buffer made of a hollow tube may be provided on the inner surface of the container 6. Since such a buffer expands and contracts in accordance with the pressure of the liquid in the container, it can absorb a change in volume of water due to a change in temperature and can prevent the generation of bubbles.

Further, as the light emitting means, a light source such as an LD other than the LED may be used. Although infrared light is used as signal light so as not to receive outside light in the visible region as noise, it goes without saying that signal light of various wavelengths can be used. Further, a combination of an ultrasonic wave transmission source and a receiver may be used as the deviation detecting means. Further, a magnetic / electrostatic position detecting device may be provided on the float 7 and the container 6, and this may be used as a deviation detecting means.

Further, in the case of this embodiment, three sets of rotation sensors for the x-axis, the y-axis, and the z-axis each detect the differential output of a photodetector including a pair of photodetectors. A set of rotation sensors may be constituted by a photodetector comprising a section. In this case, the float 7 and the container 6
When is within the range of the predetermined positional relationship, an optical signal from the light source to the optical detector is blocked. For example, if the point at which the intermittent switching of the optical signal switches is set as the reference position,
Except for this switching point, the float 7 has deviated from the reference position. Further, the direction in which the detected optical signal is shifted from the reference position is determined by the state of the intermittent light signal.

Further, the amount of rotation of the container 6 with respect to the outer box 1 may be measured by a resistor. For example, there is a method of increasing or decreasing the variable resistance value of the resistor according to the rotation amount and direction of the servo motor 2. By monitoring the resistance value of the resistor, the drive amount and direction of the servo motor 2 can be detected. Further, the rotation amount of the container 6 can be measured.

Further, as shown in FIG. 2, a magnetic needle 17 can be provided on the float 7. The float 7 keeps a constant state with respect to the gravitational field and a constant state with respect to the terrestrial magnetism field by its own weight. Therefore, the float 7 receives a force that always maintains a constant direction in the directions of the three axes. Therefore, even if the displacement detection device rotates after the displacement detection device stops operating, the float 7 is always kept in a fixed direction, so that the absolute value of the displacement can be easily detected. In addition, during normal operation, errors due to accumulation of action from the liquid in the container can be reduced.

〔The invention's effect〕

As described above, according to the present invention, it is possible to provide a displacement detection device which can detect displacement in any direction, has a very simple structure, is small and lightweight, and has high accuracy. Can be.

Further, according to the displacement detecting device of the preferred embodiment, the angular displacement can be easily detected based on the driving direction and the driving amount of the return means.

Further, according to the displacement detecting device of the preferred embodiment, the use of three sets of optical sensors makes it possible to easily determine that the movable member has shifted from the reference position and the direction in which the movable member has shifted from the reference position.

[Brief description of the drawings]

FIG. 1 is a diagram showing the configuration of a first embodiment of a displacement detecting device according to the present invention, FIG. 2 is a perspective view showing the arrangement of a container and a float of the displacement detecting device of FIG. 1, and FIG. FIG. 4 is a side view showing the arrangement of the container and the float of the displacement detecting device of FIG. 1, FIG. 4 is a view for explaining the detection of the tilt of the float of FIG. 2 around the x-axis, and FIG. FIG. 6 is a view for explaining rotation detection of the float around the z-axis, FIG. 6 is a diagram showing a configuration of a circuit for driving the displacement detection device of FIG. 1, and FIG. 7 is a second embodiment of the displacement detection device. FIG. 8 is a perspective view showing an arrangement of a container and a float of the displacement detecting device of FIG. 2, 12, 22 ... return means, 4, 14, 24 ... displacement detection means, 6 ... support means, 7 ... movable members, 31, 32, 33, 3
4, 35, 36 ... shift detection means.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yuji Kobayashi 1126, Nomachi, Ichinomachi, Hamamatsu City, Shizuoka Prefecture Inside (72) Inventor Katsuyoshi Fujita 1126, Nomachi, Ichinomachi, Hamamatsu City, Shizuoka Prefecture Hamamatsu Photonics Co., Ltd. (56) References JP-A-63-63913 (JP, A) JP-A-63-30712 (JP, A) JP-A-1-217208 (JP, A) Japanese Utility Model Laid-Open No. 63-23608 (JP, U) JK 38-4411, JP, Y1 (58) Fields investigated (Int. Cl. ⁶ , DB name) G01B 21/22-21/26 G01C 9/00-9/36 G01C 19/00-19 / 54

Claims (5)

(57) [Claims] An X-axis and a Y-axis which are supported by a displacement detection member whose displacement is to be detected, and which are parallel to three rotation axes intersecting each other and not in the same plane, which are set in the displacement detection member. And support means rotatable about the Z axis, and rotation about x, y, and z axes parallel to three rotation axes intersecting each other and not in the same plane set in the support means. A movable member that is freely supported, and that when the movable member rotates relative to the support means and deviates from a reference position of the pointing means, the displacement occurs; and the x-axis and the y-axis. And a shift detecting unit for detecting a shift direction with respect to each of the z-axis and a shift detecting unit for detecting the shift direction from the reference position of the movable member. Rotation about the axis relative to the displacement detected member. Returning means for rotating the supporting means in the same direction as the direction of displacement of the movable member with respect to the x-axis, y-axis, and z-axis; and relative displacement between the displacement detection member and the supporting means, A displacement detection device, comprising: displacement detection means for detecting around each of an X axis, a Y axis, and a Z axis. 2. The displacement detecting device according to claim 1, wherein said support means is a container whose inside is decompressed, and said movable member is accommodated in an internal space thereof. 3. The displacement detecting device according to claim 1, wherein said support means contains said movable member and a liquid having a specific gravity substantially equal to said movable member in an internal space thereof. . 4. The return means comprises:
Three sets of driving means for rotating about the axis, the Y axis, and the Z axis, respectively, wherein the displacement detecting means is configured to move the displacement detection member and the support based on a driving direction and a driving amount of the three sets of driving means. 4. The displacement detecting device according to claim 1, wherein a relative displacement with respect to the means is detected. 5. The apparatus according to claim 1, wherein said shift detecting means is configured to determine a shift direction of said movable member about said x-axis and said movable member when said movable member rotates relative to said support means and shifts from a reference position. 5. A sensor according to claim 1, further comprising three sets of sensors for optically detecting a shift direction around the y-axis and a shift direction around the z-axis of the movable member. The displacement detection device according to claim 1.