JPS6171311A - Slant angle sensor - Google Patents

Abstract

PURPOSE:To output the slant angle and direction automatically and highly accurately, by directly projecting light from a light source, or by reflecting the light by using a concave reflecting mirror. CONSTITUTION:A rotary body 21 is supported by an upper part of a capsule and a lower part 12 of the capsule in a freely rotating state by way of a liquid 22. The path of the body 21 is always vertical. In order to reflect the light from an upward light source 23a of a light source 23 downward, a concave reflecting mirror 24 is fixed to the shoulder of the step, which is formed on the inner surface of a spacer 17. The positions of the focal points of the light source 23 and the concave reflecting mirror 24 are determined and fixed, so that either of the reflected light from the concave reflecting mirror 21 and the upward light source 23b or the direct light from a downward light source 23b agrees with the axis of an optical fiber 2, which is attached to the rotary body 21. The projected light from the downward light source 23b directly reaches the inlet port of the optical path of the rotary body. When the light passes the optical fiber 2 and is outputted from a ball lens 4 at a lower part 5 of the rotary body, the light is converged by the lens effect. The focal point is formed on an effective light receiving surface 27 of a two-dimensional position detection element 26.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a tilt angle sensor that detects a two-dimensional tilt angle of a structure or a moving body.

(Background of the Invention) There is a strong desire to constantly measure the angle of inclination of industrial robots, ships, special vehicles for civil engineering work, and the like.

Tilt angle sensors used in such devices include:
Rather than precise measurement accuracy, it is required that stable and reliable display be possible, and that the structure be robust and inexpensive.

Conventional inclination angle measurement devices use a rod with a weight attached to one end that can be rotated freely in one plane around a fulcrum, so that the rod always remains vertical even if the supporting structure is tilted. There are some methods that take advantage of this to display the angle of inclination.

In such a device, the length from the fulcrum to the weight affects the measurement accuracy, and if the device is made smaller, the accuracy is poor and it is easily affected by vibration.

In addition, during measurement, the device is placed on the plane to be measured, and the measurement point is rotated 360 degrees around the maximum angle of elevation or depression, which is read from the reference direction, and at the same time, the inclination angle indicated at that time is read. operation is required,
Improvements to these shortcomings have been strongly desired.

(Object of the Invention) An object of the present invention is to solve the problems of the conventional device and
It is an object of the present invention to provide a tilt angle sensor that is capable of reliable two-dimensional display without requiring WE operations, has a robust structure, and is inexpensive.

(Structure of the Invention) In order to achieve the above object, the inclination angle sensor according to the present invention is provided by attaching the inclination angle sensor main body and a weight, or a float, or a float and a weight, and rotating the inclination angle sensor main body in the above item 1 with a liquid separated. a rotary body that is freely supported and always keeps the path of light passing through the center in a vertical direction; a light source; and a light beam from the light source is focused toward the center of the rotary body, and the tilt angle sensor body is positioned at any tilted position. an optical system that makes light from the light source enter parallel to the light path; and a two-dimensional position detection element that is disposed on the tilt angle sensor body at a position that receives the light that has passed through the light path of the rotating body. , the position calculation circuit calculates the output of the two-dimensional position detection element and outputs the inclination angle of the inclination angle sensor body and the direction of inclination. is configured to read the direction of the

Further, the rotating body may have a top shape made by cutting out a part of a sphere and have an optical path in a portion corresponding to the axis of the top, or the body of the rotating body and the float may be separated and the inside of the body of the rotating body may be By extending the optical path and attaching the float, the main body of the rotating body and the float are combined.

Since the rotating body is filled with liquid in the gap between the rotating body and the capsule, the frictional resistance is extremely small and the rotating body can rotate freely. Because of this, the heavier one always points downwards due to the difference in specific gravity.

Part of the light emitted from the light source is directed to the top of the rotating body, and the other part is reflected by the concave reflector and then applied to the top of the rotating body, changing the positional relationship between the top of the rotating body and the light source. There is always sufficient light.

The light passes straight up and down the optical path of the rotation (7←) and is focused on the extension line of the vertical axis of the lens ball at θ11.1 below the rotating body, so its focus is the light receiving element of the two-dimensional position detection element. If it is on a plane, it is possible to easily detect an accurate inclination angle and direction corresponding to the inclination of the case that fixes the capsule that supports the rotating body.

(Example) Hereinafter, the present invention will be described in more detail with reference to the drawings and the like.

FIG. 1 is a top (cross-sectional) view of an embodiment of the present invention, and FIG. 2 is a perspective view of an example of a rotating body used in the tilt angle sensor of FIG.

The rotating body in Fig. 2 has a top shape with a part of the sphere cut out, and has a central part 1 of the rotating body shaped like a drum body, and an optical fiber 2.
The rotating body is composed of an upper part 3 of the rotating body that supports the rotating body, and a lower part 5 of the rotating body in which the pole lens 4 is embedded, and the entire rotating body is finished in a shape inscribed in a highly spherical spherical surface.

The central portion 1 of the rotating body is made of a material with a very light specific gravity, such as a foamed plastic material, and the lower part 5 of the rotating body is made of a material that is very heavy, such as lead or brass.

In this way, the lower part of the rotating body is heavy, and when it is in the liquid and can rotate freely, its vertical position is always determined along the vertical line. To help adjust the relationship, there are adjustment screws 6 at several locations slightly below the center of the rotating body. ...6 is provided.

The specific gravity of the entire rotating body can be finely adjusted by the size of the adjusting screw 6 used, and the optical fiber 2 can be adjusted by adjusting the screwing depth.
The center axis of the rotating body passing through the center of the pole lens can be finely adjusted so that it coincides with the vertical line.

Depending on the material of each part of the rotating body, if changes over time are expected due to the liquid placed between the rotating body and the capsule, it is necessary to cover the entire rotating body with a film, such as by spraying a resin.

In order to reduce the frictional resistance of rotation, the relationship between the specific gravity of the liquid inserted between the rotating body and the capsule and the specific gravity of the entire rotating body is such that (specific gravity of the rotating body) ≧ (specific gravity of the liquid) holds. , adjust the specific gravity of the rotating body and create it.

FIG. 3 shows an example of a capsule for determining the position of a rotating body. Each component is a plastic molded product, and the material is selected to allow the light source wavelength to easily pass through.

Furthermore, the light source wavelength range! In the case of a material with a relatively large amount of 2 or a high refractive index, it is preferable to mold it as shown in FIG. In the figure, a rotating body is inserted into the gap 13 created between the capsule upper part 11 and the capsule lower part 12 and assembled. Silicone oil, alcohol, or the like is injected between the rotating body and the capsule through the liquid injection port 14. In the figure, 15 is an air vent hole for releasing the air in the gap 13 during hydraulic operation, and 16 is an air vent hole on the lower surface of the capsule upper part 11 to prevent light from leaking from other than the light path in the rotating body. It is a fully curved vapor deposition surface or metal foil made on the contacting part.

17 is a spacer for maintaining an appropriate distance between the concave reflector and the light source at an appropriate position;
Gold BMM for reflection inside the spacer on the step ring
Make side 18. Holes 19 provided at multiple locations on the spacer
is for fixing the light source through a thin rod that holds it.

FIG. 1 shows an example of an inclination angle sensor main body according to an embodiment of the present invention.

The rotating body 21 is rotatably supported by the capsule upper part 11 and the capsule lower part 12 with a liquid 22 in between, and the path of light is always vertical. The light sources 23, which are arranged vertically and back to back, are supported by thin beams 20 that are inserted and fixed into holes 19 provided in the spacer 17, and are installed at appropriate positions from the capsule.

In order to reflect the upward light 'fM 23a of the light source 23 downward through the hole, the concave reflecting mirror 24 is fixed so that the periphery of the concave surface is pressed against the shoulder of the step provided on the inner surface of the spacer 17. In this case, for any posture of the rotating body when the sensor is in use, either the reflected light from the upward light source 23a reflected by the concave reflector 24, or the direct light from the downward light source 23b, which is another light source of the light source 23, The positions of the light source and the focal point of the concave reflecting mirror are determined and fixed so as to coincide with the axis of the optical fiber 2 attached to the rotating body.

25 is a mount base for fixing the capsule and spacer. The mount base and spacer are black to prevent reflection of visible and infrared light.

Of the light from the light sources installed in this way, the downward light source 23
If the mount base placed on the structure to be measured is vertical or close to relative vertical as shown in FIG. When exiting from the ball lens 4 in the lower part 5 of the rotating body, it is focused by the lens effect and the two-dimensional position detection element 26
The light is focused on the effective light-receiving surface 27 of.

Furthermore, if the structure of the light emitted from the upward light source 23a is greatly tilted and the mount base is also tilted by θ1 degree as shown in FIG. Light source 2 reaching the entrance of the optical path and pointing downward
As in the case of the light emitted from 3b, the two-dimensional position detection element 26
The light is focused on the effective light-receiving surface 270 of .

The performance as a tilt angle sensor is determined by the resolution of the position detection element.

In this embodiment, 51300 manufactured by Hamamatsu Potonics Co., Ltd. is used as the two-dimensional position detection element 26.

When the detection limit is expressed as a distance on the light receiving surface, it is 6 μm.

Therefore, the distance from the center of the ball to the light receiving surface is
Then, the slope θ around 1 becomes θ=tan-' (0,006/X) and χ=12
Since θ=0.028° in mm, the angle reading accuracy is calculated to be 0.028°.

The output of the two-dimensional position detection element having such performance is calculated by an analog calculator, and the tilt angle and direction can be displayed in analog or digital form using the output.

FIG. 6 shows a system diagram of the electrical configuration in an embodiment of the present invention.

In the figure, the two-dimensional position detection element 26 of the tilt angle sensor 31
After the output is processed by an analog calculator 32, it is converted by an AD converter 33 and displayed on a display 34 for digital display.

Operating power is supplied from the power supply unit 35 to the tilt angle sensor, analog computing unit, AD converter, and display, respectively.

Power supply unit ACIO (DC-D for IV or from in-vehicle storage battery)
Any DC type that obtains the required DC voltage with a C converter may be used.

FIG. 7 is a diagram showing still another embodiment of the tilt angle sensor according to the present invention.

In the figure, parts that are the same or have the same function as those in FIG. 1 are denoted by the same reference numerals, so their explanation will be omitted, and only the parts that are different from the embodiment in FIG. 1 will be explained.

The rotating body separates an inverted conical float 8 from a highly spherical rotating body 7, extends an optical fiber 2 forming an optical path passing through the float 8, guides it into the rotating body, and carries the optical fiber 2. A float 8 having a light specific gravity is connected to a rotating body 7 having a heavy specific gravity, and a ball lens 4 is built in near the lower part of the rotating body 7.

The cavity formed between the capsule upper part 11 and the capsule 12 and filled with liquid is not spherical as in the case of FIG. 1, and the surface where the upper capsule forms the cavity includes a part of a relatively large spherical surface. The gap in the lower capsule is formed so that it fits with the small spherical body 7 of the rotating body through a thin liquid surface, so that the body 7 of the rotating body can freely rotate.

Therefore, the center of rotation of the rotating body coincides with the center point of the sphere of the rotating body 7, and the float 8 freely moves along the upwardly directed hemispherical part inside the upper part of the capsule.

The thickness 8 is made of a material with a very light specific gravity, whereas the main body 7 of the rotating body is made of a metal with a heavy specific gravity, so the light that passes through the interior of the rotating body is always directed from above along the vertical line. The downward passage is similar to that in FIG.

The upward light source 23a of the light source 23 or the downward light source 23
Light emitted from b passes through an optical fiber that penetrates the float 8 and is tipped by the ball lens 4 to the two-dimensional position detection element 2.
The light is focused on the effective light receiving surface 27 of No.6.

By making the main body of the rotating body into a small sphere and separating the floats, the specific gravity of the rotating body can be adjusted by the second
This can be done relatively easily without the need for an adjustment screw as shown in the figure, and alignment of the light path with the center of gravity of the rotating body leads to improved sensor performance, which also makes this adjustment easier.

Furthermore, the swing angle of the rotating body corresponding to θ1 in FIG. 5 can be swung over a wider range in the embodiment shown in FIG. 7 than in the embodiment shown in FIG. It is approximately determined by the effective light-receiving area of the position detection element, and the distance from the rotation center of the rotating body to the light-receiving surface is defined as X =
6 mm, the As light receiving area of 51300 manufactured by Hamamatsu Photonics Co., Ltd. used in the example is 13×13 mm, so that a measurable inclination angle of ±47.2° is obtained.

FIG. 9 is an enlarged sectional view of a second embodiment of the tilt angle sensor according to the present invention.

In this embodiment, the light from the light source 40 is focused by focusing lenses 41a and 41b toward the center of the rotating body. The focusing lenses 41a and 41b are fixed by a lens frame 42.

In this embodiment, the front part of the inclination angle sensor is ``tJ'' longer than in the previous embodiment, but one light source is sufficient.

(Modifications) Various modifications can be made to the embodiments described in detail above within the scope of the present invention.

As an example, FIG. 8 shows a modification of the rotating body.

Figures (A) to (D) are modified examples of the rotating body used in the embodiment shown in Figure 1, and (E) +' (F) are modified examples of the rotating body used in the embodiment shown in Figure 7. This is an example.

Figure (A) shows the center part 1 of the rotating body divided into two parts, upper and lower.The light shielding property remains the same, but the area where the rotating body and the capsule face each other via the liquid is reduced, and the response when the slope changes is made faster. There is.

For the same purpose, the width of the strip facing the capsule in the central portion 1 is made thinner in Figure (B).

In Figure (C), the central part 1 of the rotating body and the upper part 3 of the rotating body are integrally made of a material with a light specific gravity, and are formed into a hemispherical shape.

In Figure (D), the central portion 1 of the rotating body is formed of a highly light-shielding disc, and the upper rotating body 3 and lower rotating body 5 are separated to form a spherical shape.

Figure (E) shows a float 8 separated from the main body 7 of the rotating body in a spherical shape, and Figure (F) shows a similarly separated float 8 in a cylindrical shape formed by a part of a spherical surface with the upper surface facing upward. This is what I did.

Various other deformations are possible for the rotating body, but it is sufficient to select an appropriate one by taking into consideration the specific gravity, hardness, workability, etc. of the material, and it can quickly respond to changes in the inclination of the structure and can be made smoothly and freely. It is sufficient if the structure is such that it can move and quickly come to rest at a position where the optical path always coincides with the vertical line.

Furthermore, various modifications of the structure of the capsule can be considered in order to satisfy the above-mentioned operation of the rotary body in accordance with various deformations of the rotary body, and although not particularly described, it is preferable to select one that is familiar to Irk.

(Advantageous Effects of the Invention) As explained above, according to the present invention, by reflecting the light emitted from the light source directly or using a concave reflecting mirror, a rotating body that is freely rotatable and through which light always passes in the vertical direction. By efficiently applying light to the rotating body and inputting the output of the two-dimensional detection element that receives the light that has passed through the rotating body into a computing unit, an accurate and highly accurate inclination angle and direction are automatically output.

[Brief explanation of the drawing]

FIG. 1 is an enlarged sectional view of a first embodiment of a tilt angle sensor according to the present invention. FIG. 2 is an enlarged perspective view showing an example of a rotating body used in the embodiment shown in FIG. 3 is a plan view and a front (l-folded plane) view of a capsule rotatably supporting the rotating body of FIG. 2. FIG. FIG. 4 is a sectional view showing another example of the capsule. FIG. 5 is an enlarged cross-sectional view of the main part when the inclination angle sensor of FIG. 1 is tilted by 01 degrees. FIG. 6 is a system diagram showing the electrical configuration of an embodiment according to the present invention. FIG. 7 is a sectional view showing still another embodiment. FIG. 8 is an enlarged perspective view showing another modification of the rotating body. FIG. 9 is an enlarged sectional view of a second embodiment of the tilt angle sensor according to the present invention. 1... Central part of rotating body 2... Optical fiber 3...
- Upper part of the rotating body 4... Ball lens 5 -... Lower part of the rotating body 7... Main body of the rotating body 8... Float of the rotating body 11... Upper part of the capsule 12... Lower part of the capsule 23...・Light source 24... Concave reflecting mirror 26...
・Two-dimensional position detection element 27...Effective light receiving surface of two-dimensional position detection element 32...Analog computing unit 40...Light source 412.41b...Focusing lens 42...Lens frame Patent applicant Opto Kogyo Agent Co., Ltd. Patent Attorney Jusai Inoro 1 Figure/176 Figure/l-7th 10th 8th Country O 9 Figure

Claims (5)

[Claims] (1) A rotary body that is equipped with a tilt angle sensor body and a weight, a float, or a float and a weight, is rotatably supported by the tilt angle sensor body with a liquid separated, and always keeps the path of light passing through the center in the vertical direction. a light source; and an optical system that focuses the light beam from the light source toward the center of the rotating body and makes the light from the light source enter parallel to the light path at an arbitrary tilt position of the tilt angle sensor body. a two-dimensional position detecting element disposed on the tilt angle sensor body at a position that receives the light passing through the light path of the rotating body; and calculating the output of the two-dimensional position detecting element to determine the tilt of the tilt angle sensor body. A tilt angle sensor configured to read the tilt angle and direction of a tilt angle sensor body based on the results of calculations performed by a position calculation circuit that outputs the angle and direction of tilt. (2) The optical system is a concave reflecting mirror, and reflects light emitted toward the concave mirror from a light source placed between the reflecting mirror and the rotating body toward the center of the rotating body. An inclination angle sensor according to claim 1. (3) The tilt angle sensor according to claim 1, wherein the optical system is a focusing lens that focuses light from the light source toward the center of the rotating body. (4) The tilt angle sensor according to claim 1, wherein the rotating body has a top shape made by cutting out a part of a sphere, and has an optical path in a portion corresponding to the axis of the top. (5) The body of rotation is configured to separate the body of the body of rotation and the float, and extend the optical path inside the body of the body of rotation to pass through the interior of the body of the body of rotation, thereby combining the body of the body of rotation and the float. An inclination angle sensor according to range 1.