JP2566336B2 - Displacement detection device - Google Patents

Description

The present invention relates to a displacement detection device for detecting a rotation angle, that is, an angular displacement.

[Conventional technology]

Conventionally, a compass, a tilt angle sensor, and other gyro devices have been developed as displacement detection devices for detecting angular displacement. In particular, various methods or mechanisms have been studied for gyro devices such as mechanical gyros and laser gyros.

[Problems to be Solved by the Invention]

However, there is no conventional compass with small size and high precision. Further, in the conventional gyro device, although the accuracy is high, the mechanism and structure are complicated, adjustment is not easy, and the gyro device requires careful handling. Further, the gyro device itself is large in size, difficult to handle, has limited uses, and is very expensive.

In addition, the conventional tilt angle sensor has a complicated mechanism and structure,
Adjustment was not easy.

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

[Means for solving the problem]

In order to achieve the above object, in the displacement detection device according to the present invention, (a) a container rotatable about a predetermined rotation axis set as a reference member whose displacement is to be detected,
(B) It is housed in a container, has one or two or more refraction surfaces between it and a medium that fills the container, and is rotatably provided around the predetermined rotation axis so that it is free from inertial force or external force. Accordingly, it has a movable means for maintaining a constant direction, (c) a light source provided on the container side, and a plurality of light receiving surfaces arranged in a direction perpendicular to the predetermined rotation axis, and from the light source to a light receiving surface via a refracting surface. A light detecting means for detecting incident refracted light, and based on an output from the light detecting means, the movable means rotates relative to the container in response to an inertial force or an external force and deviates from a reference position. When the deviation detecting means for detecting the fact and the deviation direction thereof and (d) the deviation detecting means detect the deviation of the movable means from the reference position, the container is moved in the deviation direction along the predetermined rotation axis. The returning means for rotating, and (e) the relative position between the reference member and the container. It has a structure and a displacement detection means for detecting the position.

According to a preferred embodiment of the displacement detecting device according to the present invention, the displacement detecting means detects the relative displacement between the reference member and the container based on the driving direction and the driving amount of the returning means.

According to another preferred embodiment of the displacement detecting device according to the present invention, the movable means is a transparent liquid having a refractive index different from that of the medium filling the container. The refracting surface is a horizontal surface formed above the liquid.

According to another preferred embodiment of the displacement detecting device according to the present invention, the movable means is a transparent flat plate medium having a refractive index different from that of the medium filling the container. It has a different refractive index from the medium that fills the container. The refracting surfaces are two flat surfaces formed on both sides of the flat medium.

According to another preferred embodiment of the displacement detecting device according to the present invention, the light detecting means is a CCD or a PSD.

[Action]

In the first displacement detecting device according to the present invention, even if the reference member rotates about a predetermined rotation axis, the movable means maintains a constant direction due to inertia or external force. When the reference member rotates and the movable means deviates from the reference position, the refracted light emitted from the light source and incident on the light receiving surface via the refracting surface provided on the movable means shifts to one of the plurality of light receiving surface side by side directions. .
The deviation detecting means detects the occurrence of deviation of the detection position of the refracted light and the deviation direction from the output of the light detecting means. The returning means immediately rotates the container so as to follow the direction in which the movable means is displaced, and returns the relationship between the container and the movable means to the state before the displacement occurs. The displacement detection means detects the relative rotation amount of the container with respect to the reference member, and detects the displacement of the reference member, that is, the displacement detection device itself.

In this case, the positional relationship between the container and the movable means is maintained constant macroscopically, although microscopically repeated vibrations occur near the reference position. Therefore, the container is driven while always canceling the contact resistance between the container supporting the movable means and the movable means in the positive and negative directions, and the error caused by such contact resistance is minimized. Can be suppressed. As a result, the movable member accurately operates according to the inertia.

In a preferred embodiment of the displacement detecting device according to the present invention, the returning means keeps the movable member at the reference position by rotating the container, and the displacement detecting means monitors the driving direction and the driving amount of the returning means. are doing. Therefore, if this driving amount is integrated while considering the driving direction of the returning means, the relative displacement of the container with respect to the reference member can be detected. That is, the displacement of the reference member can be detected.

〔Example〕

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

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

A cylindrical plastic container 4 and a servomotor 2 are housed inside an outer box 1 which is a reference member. The servomotor 2 is fixed to a fixed point 3 provided at one end of the outer case 1. On the other hand, the container 4 is supported on the other end of the outer box 1 by a bearing 6 or the like so as to be rotatable around an axis 5.
Further, the container 4 is connected to the servomotor 2 via a shaft 7, and its rotation is controlled by the servomotor 2.

Inside the container 4, water 8 as a movable means is stored. Since the amount of water 8 is about half the volume of the container, the container 4 is filled with water up to the position of its rotation axis.

A light source 12 that emits infrared light is provided on the upper side surface of the container 4 as a light source. Further, on the lower side of the side surface of the container 4, a light detector 14 is provided as a light detecting means so as to face the light source 12.

FIG. 2 illustrates the positional relationship between the container 4 and the water 8 inside when the displacement detecting device of FIG. 1 is in an operating state.

As shown in FIG. 2A, when the water 8 is at the reference position with respect to the container 4, the horizontal plane which is the refracting surface and the line connecting the centers of the light source 12 and the photodetector 14 are orthogonal to each other. Therefore, the infrared light emitted from the light source 12 is incident on the boundary point between the pair of light receiving surfaces 14a and 14b of the photodetector 14. Therefore, the amounts of light detected by the light receiving surfaces 14a and 14b are almost equal. From this state, for example, when the container 4 rotates counterclockwise, the water 8 shifts clockwise from the reference position in FIG. 2 (a). As a result, as shown in FIG. 2B, the amount of light reaching the light receiving surface 14a from the light source 12 increases, and the light receiving surface 14b increases.
The amount of light that reaches is reduced. Similarly, when the container 4 rotates clockwise, the amount of light reaching the light receiving surface 14a from the light source 12 decreases, and the amount of light reaching the light receiving surface 14b increases. As will be described in detail below, these light source 12 and light-receiving surface 14a, 1
By using 4b, it is possible to detect the displacement of the water 8 as the movable means from the reference position and the displacement direction.

FIG. 3 shows a circuit configuration of the control circuit 16 and the like shown in FIG.

The LED 12a corresponding to the light source 12 is supplied with power from the control circuit 16 and generates infrared light. Further, the photodiodes 15a, 15b corresponding to the light receiving surfaces 14a, 14b respond to infrared light from the light source,
Generate voltage or current. The control circuit 16 is adjusted so that the output voltage at point A becomes zero when the amounts of light incident on the photodiodes 15a and 15b become substantially equal. That is,
When the outputs from both photodiodes are unbalanced, the servo motor 2 is driven to rotate the container 4. The rotation direction of the container 4 in this case is a direction in which the unbalance of the outputs from both photodiodes is canceled. As a result, 8
Even if is displaced with respect to the container 4, the positional relationship between the water 8 and the container 4 is immediately returned to the original state (state of the reference position) by the control circuit 16 and the servomotor 2.

The rotation angle of the container 4 is indirectly detected from the rotation amount of the servo motor 2 by a rotary encoder 18 attached to the servo motor 2 and displayed on an angle indicator 17. In this case, the rotary encoder 18 serves as displacement detecting means.

 The operation of the displacement detector of FIG. 1 will be described below.

The illustrated displacement detection device is attached to an object on which the displacement detection device is to be mounted, such as a vehicle or other device that requires detection of angular displacement from vertical.

Consider a case where an object equipped with a displacement detection device rotates and the displacement detection device rotates about an arbitrary axis parallel to the axes 5 and 7. In this case, since the rotation of the container 4 is controlled only by the servomotor 2, the container 4 is not
It does not rotate with respect to each other and the positional relationship between the container 4 and the outer case 1 does not change. On the other hand, the water 8 maintains its original orientation or position due to its inertia. Since the air in the container is also an inertial body, the water 8 does not receive the resistance of the air. As a result, the water 8 rotates relatively to the container 4 and the outer box 1. Assuming that water 8 was in the reference position beforehand, water 8
Will deviate from the reference position.

As shown in FIG. 2, the rotation of the water 8 is caused by the photodetector.
Monitored by 14. The control circuit 16 has two light-receiving surfaces 14
The servo motor 2 is rotated based on the differential output of the light detection outputs from a and 14b.

Specifically, when the output difference from the photodetector 14 exceeds a predetermined value, it is determined that the water 8 has deviated from the reference position, and depending on whether the output difference is positive or negative, the water 8 deviates from the reference position. Can be determined. According to this result, the control circuit 16 drives the servomotor 2 to rotate the container 4 in the direction in which the water 8 is displaced. When the output difference from the photodetector becomes equal to or smaller than a predetermined value, the control circuit 16 stops the servomotor 2 and stops the rotation of the container 4. As a result, the water 8 returns to the reference position with respect to the container 4.

In an actual displacement detection device, generally, it continuously rotates in an arbitrary direction. Therefore, it is desirable that the container 4 also smoothly and accurately rotate so as to cancel this rotation. For that purpose, it is desirable to operate the servo motor 2 even if the output difference from the photodetector 14 is small. Further, it is desirable that the rotation of the servo motor 2 be smooth and that the response be good.

FIG. 4 and FIG. 5 explain the configuration of the second embodiment of the first displacement detecting device according to the present invention.

The configuration of the second embodiment is almost the same as the configuration of the first embodiment. The same parts are designated by the same reference numerals as those in FIG. 1 and their explanations are omitted.

Unlike the first embodiment, a flat plate-shaped movable plate 28 that is movable means is housed inside the container 4 together with air 38.
The movable plate 28 is made of a transparent glass plate and is rotatably supported by shafts 25 and 27 about the same rotation axis as the container. In this case, the movable plate 28 is an inertial body and maintains a constant direction due to its inertia even if the container 8 rotates.
Further, infrared light from the light source 12 is refracted by the upper and lower two surfaces of the movable plate 28 and enters the photodetector 14.

FIG. 5 shows the case where the container 4 is rotated counterclockwise from the reference position. Since the movable plate 28 maintains a constant direction with respect to the outside world, the movable plate 28 rotates relative to the container 4. Therefore, the infrared light beam 22 from the light source 12 has its optical path changed by the glass movable plate 28, and
It is incident on the light receiving surface 14a on the left side of 14. Although not shown, when the container 4 is rotated in the clockwise direction, the infrared light beam 22 from the light source 12 has its optical path changed by the glass movable plate 28, so that the light receiving surface 14b on the right side of the photodetector 14 is changed. Incident on. If the differential output from each of the light receiving surfaces 14a and 14b is detected, the rotation of the movable plate 28 and the rotation direction thereof can be detected. Servo motor 2 with the same control circuit as in FIG.
Is driven, even if the movable plate 28 is displaced with respect to the container 4, the positional relationship between the movable plate 28 and the container 4 is immediately returned to the original state (state of the reference position). The rotation angle of the container 4 (that is, the rotation displacement of the displacement detection device itself) is detected by a rotary encoder 18 attached to the servomotor 2 and displayed on a degree indicator.

6 and 7 illustrate the configuration of the third embodiment of the first displacement detection device according to the present invention.

The configuration of the third embodiment is also similar to that of the first and second embodiments. The same parts are designated by the same reference numerals as those in FIG. 1 and their explanations are omitted.

Unlike the second embodiment, the inside of the vacuum container 4 that houses the movable plate 28 made of glass is depressurized. Therefore, the movable plate
Even when the plate 28 rotates relative to the container, the movable plate 28 does not receive a minute resistance from air or the like.

FIG. 7 shows the case where the container 4 is rotated counterclockwise from the reference position. Also in this case, the infrared light beam 22 from the light source 12 has its optical path changed by the glass movable plate 28, as in FIG.
Incident on. Although not shown, when the container 4 is rotated clockwise, the infrared light beam 22 from the light source 12 is incident on the light receiving surface 14b on the right side of the photodetector 14. If the differential output from each light receiving surface 14a, 14b is detected, the movable plate 28
Can be detected and its rotation direction can be detected. If the servomotor 2 is driven by the control circuit of FIG. 3, the movable plate 28 is always kept in a constant state with respect to the container 4. The rotation angle of the container 4 is detected by a rotary encoder 18 attached to the servomotor 2 and displayed on a degree indicator.

FIGS. 8 to 11 explain one embodiment of the third displacement detecting device according to the present invention.

FIG. 8 is a diagram showing the configuration of the embodiment. A liquid 8 which is a movable means is stored in the container 24. container
A light source 32 is provided on the top of 24, and light from this light source 32 enters a photodetector 34 provided on the bottom of the container 2. 9 is a side view of the container of FIG. Light source 32
It consists of an LED 32a and a lens 32b. The infrared light from the LED 32a becomes a focused beam 22 by the lens 32b, is refracted on the liquid surface, then travels through the liquid and is focused on the photodetector 34. The photodetector 34 is a photoelectric detection device having light-receiving surfaces arranged in a matrix in the x-axis and y-axis directions of FIG.
Etc. can be used.

FIGS. 10 and 11 explain the operation and principle of the displacement detector of FIG.

FIG. 9 shows the container 24 rotated clockwise about the y-axis. Therefore, the liquid 8 is rotating relative to the container 24 in the counterclockwise direction. When the container 24 is inclined by the angle θ ₁ , the incident angle of the focused beam 22 incident on the liquid surface is also the angle θ ₁ . Further, the refraction angle θ ₂ on the liquid surface follows Snell's law sin θ ₁ = n × sin θ ₂ . Further, the position where the refracted condensed beam 22 is detected by the photodetector 34 is in a direction perpendicular to the y-axis (in this case, coincides with the x-axis direction) as compared with the case where the inclination θ ₁ is zero. Is displaced by the shift amount l. Therefore, the shift amount 1 is given by the following equation.

l = d × tan (θ ₁ −θ ₂ ) However, since the relationship between θ ₁ and θ ₂ is given by Snell's law, θ ₂ = sin ⁻¹ (sin θ ₁ / n). Here, assuming that the incident point is always at the center of the cross section of the container, the distance d from the incident point to the detection surface of the photodetector 34 is constant when the incident angle θ ₁ is within the range of a predetermined inclination. To be kept. FIG. 11 shows the relationship between the inclination θ _{1 of the} liquid surface and the deviation amount ₁ of the detection position. However, n = 1.5,
d = 10 mm. Since the deviation amount 1 and the inclination θ ₁ have a one-to-one correspondence, the inclination of the liquid, that is, the container can be obtained from the deviation amount l.

The above is the detection of the inclination around the y-axis, but the detection of the inclination around the x-axis is also possible. Further, even when the rotations about the x-axis and the y-axis are combined, the rotations about the respective axes can be similarly detected. This is explained by the fact that the components related to the respective axes of rotation of the liquid surface correspond to the respective deviation amounts in the direction perpendicular to the respective axes, and the respective components and deviation amounts are independent variables. That is, the rotation around the x-axis is converted into the shift amount in the y-axis direction, and the rotation around the y-axis is converted into the shift amount in the x-axis direction.

Note that such conversion can be instantaneously performed by a computing device such as a microcomputer. Therefore, if the shift amount of the detection position detected by the photodetector 34 is converted into the rotation angle around the x-axis and the y-axis at any time, the container 24
That is, the inclination of the displacement detecting device can be detected at any time.

Here, considering that the higher the refractive index of the liquid 8 is, the smaller the refraction angle θ ₂ is, the higher the refractive index of the liquid 8 is, the better the sensitivity of the displacement detecting device is. Further, if the viscosity is high, it becomes strong against vibration, but if it is too high, the responsiveness of the displacement detecting device is deteriorated. Liquids that meet such specifications include, for example, immersion oil for immersion objective lenses.

Although the liquid surface is used as the refracting surface, a flat plate-shaped high refractive index medium may be used. For example, assume that a movable plate having a thickness d and a refractive index n is movably provided around the x axis. When the tilt of the movable plate is θ ₁ and the incident angle of the focused beam is θ ₁ , the shift amount l of the focused beam is given by l = a × d × sin θ ₁ . The variable a is Given in.

Alternatively, a prism-shaped movable plate may be used instead of the flat plate. In this case, the formula regarding the deflection angle of the prism is used.

The present invention is not limited to the above embodiment, but various modifications can be made.

For example, in the embodiment shown in FIGS.
The light detecting means 14 is composed of a CCD, a PSD, etc. having three or more light receiving surfaces arranged one-dimensionally and therefore light receiving elements.
The light receiving position of 22 may be detected. When the light receiving position can be detected, the rotation amounts of the containers 4 and 14 can also be calculated, so that the rotation amount of the servo motor 2 can be determined according to the calculated rotation amount.

In the embodiment shown in FIGS. 4 and 6, it is desirable that the rotary shafts 25, 27 of the movable plate 28 be provided slightly above the center of the movable plate 28. In this case, the center of gravity of the movable plate 8 is the rotary shaft 25,
Since it is set lower than 27, the movable plate 28 is kept in a constant state by gravity regardless of whether or not the displacement detection device is in an operating state. If the movable plate 28 is kept in a constant state under the gravitational field as described above, the initial setting of the position of the movable plate 28 after the displacement detecting device is stopped becomes simple, and the angular displacement is detected. Accuracy is improved.

Further, a liquid such as water may be stored inside the container 4. By using a liquid, the difference in refractive index on the refractive surface of the movable plate 28 is reduced, but the load on the shafts 22, 27 is reduced. Therefore, the movable plate 28 accurately maintains the fixed direction according to its inertia. In this case, in order to reduce the contact resistance between the container 4 and water, a coating such as Teflon may be applied. Further, a buffer composed of a hollow tube may be provided inside the side surface of the container 4. Since this buffer expands and contracts according to the pressure of the liquid in the container, it can absorb the volume change of water due to the temperature change and can prevent the generation of bubbles.

Further, as the light source, various light sources such as LD other than LED may be used. Further, as the signal light, infrared light is used so as not to receive external light in the visible region as noise, but it goes without saying that signal light of various wavelengths can be used.

Further, the rotation of the container 4 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 low antibody 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 servomotor 2 can be detected, and the rotation amount of the container 4 can be measured.

Further, in the embodiment shown in FIGS. 1 and 8, the containers 4 and 34 may contain two or more kinds of liquids which are not mixed with each other and have different refractive indexes. In this case, the boundary surface of each liquid becomes a refracting surface.

〔The invention's effect〕

As described above, according to the first, second and third displacement detecting devices of the present invention, a highly accurate displacement detecting device having an extremely simple structure, small size and light weight is provided. be able to.

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 returning means.

[Brief description of drawings]

1 is a diagram showing a configuration of a first embodiment of a first displacement detecting device according to the present invention, FIG. 2 is a diagram showing an arrangement of a container and water of the displacement detecting device of FIG. 1, and FIG. FIG. 4 is a diagram showing a circuit configuration of a control circuit and the like of the displacement detection device of FIG. 1, FIG. 4 is a diagram showing a configuration of a second embodiment of the first displacement detection device according to the present invention, and FIG. Is a diagram showing the arrangement of the container and the movable plate of the displacement detection device of FIG. 4, FIG. 6 is a diagram showing the configuration of the third embodiment of the first displacement detection device according to the present invention, and FIG. FIG. 6 is a view showing the arrangement of the container and the movable plate of the displacement detection device of FIG. 6, FIG. 8 is a view showing the configuration of an embodiment of the third displacement detection device according to the present invention, and FIG. 9 is FIG. Showing the arrangement of the container and the movable plate of the displacement detection device of FIG.
FIG. 10 is a diagram showing the state of the liquid when the displacement detecting device of FIG. 8 is inclined, and FIG. 11 is a diagram showing the relationship between the inclination of the container and the deviation amount. 4, 14, 24 ... container, 8, 28 ... movable means, 12, 14, 32, 34 ... deviation detection means, 2, 16 ... return means, 18 ... displacement detection means.

Front page continuation (72) Inventor Yuji Kobayashi 1 1126 Ichinomachi, Hamamatsu City, Shizuoka Prefecture 1126 Hamamatsu Photonics Co., Ltd. (72) Inventor Katsukichi Fujita 1 1126 Ichinomachi, Hamamatsu City Shizuoka Prefecture 1 Hamamatsu Photonics Co., Ltd. (56 ) References JP-A-60-316 (JP, A) Actually developed 59-162611 (JP, U)

Claims (5)

(57) [Claims] 1. 1 or 2 between a container rotatable about a predetermined rotation axis set as a reference member whose displacement is to be detected, and a medium contained in the container and filling the container. Movable means having the above refraction surface, rotatably provided around the predetermined rotation axis, and maintaining a constant direction according to an inertial force or an external force; a light source provided on the container side; A plurality of light receiving surfaces that are arranged in a direction perpendicular to the rotation axis of the light source, and a light detecting means that detects refracted light that enters the light receiving surface through the refraction surface from the light source, and an output from the light detection means. On the basis of the above, the movable means rotates relative to the container in response to an inertial force or an external force and is displaced from a reference position and a displacement detecting means for detecting the displacement direction, and the displacement detecting means is The displacement of the movable means from the reference position was detected. In this case, there is provided return means for rotating the container in the displacement direction along the predetermined rotation axis, and displacement detecting means for detecting relative displacement between the reference member and the container. Displacement detection device. 2. The displacement detecting device according to claim 1, wherein the displacement detecting device detects a relative displacement between the reference member and the container based on a driving direction and a driving amount of the returning device. Detection device. 3. The movable means is a transparent liquid having a refractive index different from that of a medium filling the container, and the refraction surface is a horizontal plane formed at the interface of the liquid with the medium. The displacement detection device according to claim 1. 4. The movable means is a transparent flat plate medium having a refractive index different from that of a medium filling the container, and the refraction surfaces are two flat surfaces formed on both sides of the flat plate medium. The displacement detection device according to claim 1, wherein: 5. The displacement detecting apparatus according to claim 1, wherein the light detecting means is a CCD or a PSD.