JPH0453527Y2 - - Google Patents

Description

[Detailed description of the device] (Industrial field of application) The present device is used for surveying, construction, or processing, and is attached to various types of equipment to determine the size and direction of the tilt angle of the equipment. This invention relates to an inclination sensor for detecting an inclination.

(Prior Art) Conventionally, many tilt sensors have been proposed that photoelectrically detect the tilt angle of equipment using a liquid level or a pendulum. 5 to 7 show one typical example of a conventional tilt sensor. Figure 5 shows the configuration of this tilt sensor. In the figure, 1 is a container whose optical path is made of glass, 2
is a float having a reflective mirror surface on the lower surface, 3 is a translucent liquid that floats the float 2, 4 is a light emitting element, 5 is an aperture,
6 is a light projecting lens, 7 is a light receiving lens, and 8 is a four-part light receiving element. Components other than the float 2 and liquid 3 are fixed to the equipment. In this tilt sensor, the image of the diaphragm 5 is reflected by the reflective surface of the float 2 and formed on the four-divided light-receiving element 8 . When the device is tilted, the float 2 floating in the liquid 3 tilts relatively, and the four-divided light receiving element 8
The image of the aperture 5 moves above, and the tilt is detected. FIG. 6a shows the relationship between the images of the four-part light-receiving element 8 and the aperture 5, and 81 to 84 indicate four light-receiving elements. In the figure, a solid line 51 shows the image of the diaphragm 5 when the device is not tilted. The dashed line shows the position of the image of the diaphragm 5 when the device is tilted. FIG. 7 shows an example of a tilt detection circuit connected to the four-division light-receiving element 8.
In the figure, 11 to 13 indicate addition/subtraction amplifiers, and 14 and 15 indicate dividers. The input signals of the adding/subtracting amplifiers 11 to 13 correspond to the outputs of the light receiving elements 81 to 84. 2
1 and 22 indicate outputs of this detection circuit corresponding to orthogonal inclination angles, respectively. In addition and subtraction amplifiers 11 to 13, + indicates addition and - indicates subtraction.
To explain the operation, from now on, the X-Y coordinates will be taken as shown in FIG. 6b. When the device is tilted in the X direction, the aperture 5
As shown in FIG. 6b, the image moves from the position of the broken line to the position of the solid line, the outputs of the light-receiving elements 81 and 82 increase, and the outputs of the light-receiving elements 83 and 84 decrease. Then, the output of the addition/subtraction amplifier 11 shown in FIG. 7 increases, and a slope output in the X direction is obtained at 21 in FIG. Similarly, when tilting in the Y direction, a tilt output in the Y direction is obtained at 22 in FIG. Further, even when tilting in both the X and Y directions at the same time, the X and Y tilt outputs are obtained at 21 and 22 using the same principle.

These conventional tilt sensors measure the liquid level, which changes as the equipment tilts, and the tilt of the mirror attached to the pendulum.
Photoelectric detection is based on the so-called optical lever principle, but it requires an optical system for light projection and imaging, especially when trying to increase the detection sensitivity by increasing the lever ratio. There was a drawback that the size of the tilt sensor became large.

(Problems to be Solved by the Invention) The purpose of the invention is to improve the above-mentioned drawbacks of the conventional inclination sensor, and to provide a compact inclination sensor with high detection sensitivity using a simple optical system. There is a particular thing.

(Means for Solving the Problems) In order to achieve the first half of the purpose, the inclination angle sensor of the present invention includes a reflecting mirror that is tilted relative to the device due to the inclination, and a light beam is directed to the reflecting mirror surface. It is composed of three or more light receiving elements that are arranged on concentric circles around the center line of the luminous flux from the light emitting element and receive light reflected from the reflecting mirror surface. and,
The outputs of these light-receiving elements are sequentially read out in a fixed period and in a fixed order, and the readout output is filtered in a frequency band corresponding to the above-mentioned period. The configuration is configured to detect the magnitude of the tilt angle and the direction of the tilt from the phase difference.

(Function) When the light emitting element and the light receiving element are arranged as described above, the amplitude of the sine wave output corresponds to the magnitude of the tilt angle, and the phase corresponds to the direction of the tilt, so that these can be detected.

(Example) Next, an example of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing one embodiment of a tilt sensor according to the present invention. This tilt sensor includes a container 1 made of glass, for example, whose lower surface is transparent, a float 2 whose lower surface has a reflective mirror surface,
a translucent liquid 3 sealed in the container 1 and floating the float 2; a light emitting element 4 provided below the container 1 to illuminate the bottom surface of the container 1 and emitting a conical light beam;
Three or more light receivers arranged concentrically around the center line of the luminous flux entering the container 1 from the light emitting element 4 and arranged at equal intervals on concentric circles so as to receive the light reflected by the reflective mirror surface of the float 2. It is composed of an element 9, and the elements other than the float 2 and the liquid 3 are in a fixed relationship with each other and are attached to equipment. FIG. 2 is a drawing showing the relative relationship between the light emitting element 4 and the light receiving element 9. In the case of the figure, eight light receiving elements 91 to 98 are arranged concentrically with the light emitting element 4 at the center, and at equal intervals. .
With this arrangement, the conical light beam emitted from the light emitting element 4 is reflected on the lower surface of the float 2 and enters the light receiving elements 91 to 98. When the float 2 is not inclined relative to the light emitting element 4 and the light receiving element 9, the same amount of light enters each of the light receiving elements 91 to 98. However, when the container 1, the light emitting element 4, and the light receiving elements 9, 91 to 98 are tilted with respect to the horizontal plane, the amount of light incident on each of the light receiving elements 91 to 98 changes depending on the tilt angle and the direction of the tilt.

FIG. 3 is a block diagram showing an example of a tilt detection circuit of this tilt sensor connected to the light receiving elements 91 to 98. In FIG. 3, 91 to 98 are light receiving elements, 4 is a light emitting element, 31 is a sequential selection circuit, and 32
is a bandpass filter and amplifier circuit, 33 is a rectifier circuit, 34
is a phase comparison circuit, 35 is a reference oscillation circuit, and 36 is a phase comparison circuit.
APC and light emitting element drive circuit. Figure 4 shows
FIG. 4 is a waveform diagram showing the output of each part in FIG. 3; The outputs of the light-receiving elements 91 to 98 are sequentially selected at regular intervals by the sequential selection circuit 31 in synchronization with the output of the reference oscillation circuit 35, and are sequentially output at regular intervals.
The situation is shown in Figure 4A. In the figure, T indicates the period of the sequential selection circuit 31. In FIG. 4A, the envelope connecting the peaks of the outputs 91 to 98 of the light receiving elements 91 to 98 corresponds to the magnitude and direction of the tilt of the tilt sensor, and has a sine wave shape as shown by the broken line in the figure. . The output of the sequential selection circuit 31 is set to a frequency of 1/
Bandpass filter and amplifier circuit 3 that passes only the band near T
When bandpass filtering is performed with 2, the envelope portion is output. This is shown in Figure 4B. In the figure, A indicates amplitude. The output of the bandpass filter and amplifier circuit 32 (FIG. 4b) has an amplitude A corresponding to the magnitude of the tilt angle and a phase angle corresponding to the direction of the tilt. for example,
As the tilt angle of the tilt angle sensor increases, the amplitude A increases correspondingly. Further, when the direction of the inclination changes, the phase changes with respect to the reference point of repeated reading. To be more specific, in Figure 4A, the output 93 is the maximum and the output 97 is the minimum, but when tilted in the opposite direction, the output 93 is the minimum and the output 97 is the maximum, and the phase is 180 ° It shifts.
The output of the bandpass filter and amplification circuit 32 is converted into a rectifier circuit 33.
When rectified by
Get 1. This situation is shown in Figure 4C. In the figure, k ₀
is a constant. On the other hand, the bandpass filter and amplification circuit 32
The output from the phase comparison circuit 34 is output from the reference oscillation circuit
The phase is compared with a reference signal of period T obtained from
a signal 42 corresponding to a phase angle corresponding to the direction of tilt;
Output. This situation is shown in FIG. 4D. In the figure,
Reference numeral 51 indicates a reference signal from the reference oscillation circuit 35, 52 indicates the output of the bandpass filter and amplifier circuit 32, and Δ indicates the phase difference between the two.

As is clear from the above description, according to the present invention, the magnitude of the tilt angle and the direction of tilt can be detected simultaneously by using a simple optical system, and the tilt sensor can be miniaturized.

Note that in the above description, the circuit that obtains the final outputs 41 and 42 as analog values has been described.
Even in this case, various modifications are possible. moreover,
Various modifications are possible to match the input conditions of the subsequent processing system. For example, a circuit that performs digital processing to output a digital value is also possible.

(Effects of the invention) According to the invention, the magnitude of the tilt angle and the direction of the tilt can be detected simultaneously with high sensitivity using a simple optical system, and the tilt sensor can be configured in a small size.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the configuration of one embodiment of the tilt sensor of the present invention, FIG. 2 is a plan view showing the relative relationship between the light emitting element and the light receiving element, and FIG. 3 is a block diagram of the tilt detection circuit. Fig. 4 is a waveform diagram of the output signals of each part in Fig. 3, Fig. 5 is a schematic diagram showing the configuration of a conventional tilt sensor, and Fig. 6 shows the relationship between the image of the light receiving element and the aperture in Fig. 5. The explanatory diagram shown in FIG. 7 is a block diagram of the tilt detection circuit of FIG. 5. 1... Container, 2... Float, 3... Liquid, 4...
Light emitting element, 9, 91-98... Light receiving element, 31...
... sequential selection circuit, 32 ... bandpass filter and amplification circuit, 33 ... rectification circuit, 34 ... phase comparison circuit,
35...Reference oscillation circuit, 36...APC and light emitting element drive circuit, 41...Output corresponding to the magnitude of the tilt angle, 42...Output corresponding to the direction of tilt.

Claims (1)

[Scope of utility model registration request] A reflecting mirror that is inclined relative to the device due to the inclination, a light emitting element that emits a luminous flux toward the reflecting mirror surface, and a light emitting element arranged on a concentric circle around the center line of the luminous flux from the light emitting element and said It consists of three or more light-receiving elements that receive light reflected from a reflecting mirror surface, and the outputs of these light-receiving elements are sequentially read out at a certain period and in a certain order, and the read output is filtered in a frequency band corresponding to the above-mentioned period. A tilt sensor characterized in that the magnitude and direction of the tilt angle are detected from the amplitude of the obtained sine wave output and the relative phase difference between the sine wave output and the reference oscillator output.