JPS60316A - Inclination detector - Google Patents

Abstract

PURPOSE:To obtain an inclination detector having high accuracy and high vibration resisting property by detecting laser light which is made incident to the surface of liquid at an incident angle corresponding to the inclination of a subject, refracted and transmitted. CONSTITUTION:When a car is inclined from a horizontal position by an angle theta, laser light is made incident to the oil surface at the same angle theta of incidence. The light is refracted by a refractive angle theta' at the border surface of oil. The light transmitted through the oil 3 is refracted moreover at the oil border surface to which a concave lens effect is applied by the curved bottom of a vessel 2 when passing through the bottom of the vessel 2 and then made incident to a position separated from the center 0 of a detecting element 9 by DELTAl. The distance DELTAl is calculated from the shown formula ( I ) and the angle theta of inclination is obtained from the displacement DELTAl.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an inclination detection device that is attached to an object to be inspected and detects the inclination of the object.

For example, if this type of device is installed on a vehicle, it will be possible to obtain appropriate gear selection information when driving on a slope, a warning of insufficient tire pressure, or a rollover prevention warning, and it is also possible to warn of theft of a tire while the vehicle is parked. .

By the way, as the above-mentioned inclination detection device, there is a conventional mechanical type which detects the inclination by changing the angle of a pendulum, but it has a problem that it is susceptible to vibration. In addition, there are devices in which the inclination is detected by conducting between the contacts due to the change in the level of the conductive liquid that accompanies the inclination, but there is a limit to the number of contacts that can be installed, and minute changes in inclination are Cannot be detected.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, it is an object of the present invention to provide a highly accurate tilt detection device that has excellent resistance to vibrations and the like and is capable of detecting minute changes in tilt.

That is, the inclination detection device of the present invention includes a container filled with a liquid and made of a laser beam-transmitting material, a light emitting means for emitting a laser beam from above the container toward the surface of the liquid, and a light emitting device that refracts a laser beam in the liquid. A light receiving means for receiving transmitted laser light is provided integrally with the test object, and a signal processing means is provided for processing the output signal of the light receiving means to determine the inclination of the test object.

Hereinafter, the structure and operation of the present invention will be explained together with reference to the illustrated embodiments.

In FIG. 1, a case 1 provided in a vehicle is provided with a container 2 made of transparent resin such as acrylic, and the container 2 is filled with silicone oil 3. The container 2 has a cylindrical shape, and its bottom surface is formed into an upwardly convex curved surface, and is supported and fixed within the case 1 by a reed and a support stand 4. A laser diode 6 is connected to the center of the upper surface of the container 2 through a condensing lens 5.
is the provision. Laser diode 6 has key switch 7
Power is supplied from the battery 8 through the.

The support base 4 is provided with a light incident position detecting element 9 serving as a laser light receiving means at the center thereof. As shown in FIG. 2, the detection element 9 has a semiconductor film formed in a square shape at the center of a circular substrate to serve as a light receiving surface 9a, and emits an output signal according to the incident position of the laser beam, as will be described later. After the output signal is processed by a signal processing circuit 10, it is input to a display 11 to display the inclination angle of the vehicle.

That is, when the vehicle is in a horizontal state, as shown by the arrow in FIG.
-Y line intersection).

As shown in FIG. 3, when the vehicle is tilted at an angle θ with respect to the horizontal position, the laser beam is incident on the oil surface, which remains horizontal, at an incident angle of θ. At this time, the light is refracted at a refraction angle θ' at the oil interface where the refractive index changes. Oi/
When the light transmitted through I/3 passes through the bottom of container 2,
The light is further refracted at the oil boundary surface, which is given a concave lens effect by the curved bottom of the container, and enters the detection element 9 at a position distant from the center O by Δl.

The displacement Δl when there is no concave lens effect is given by the following equation (a), where L is the distance from the point of incidence of the laser beam on the oil surface to the center of the detection element 9.

Δ, 5=L @ jan(θ-θ')・Song...listen(a
) Also, if the refractive index of tV3 is n, then the relationship is: Substituting equation (to) into equation (a), we can find the displacement Δl and the inclination angle θ. In this embodiment, due to the concave lens effect of O/L/3, the above displacement △
l is enlarged, thereby improving the resolution of the inclination angle θ.

Here, FIG. 4 shows a circuit example of the signal processing circuit 1o. The processing circuit 1o calculates the incident position of the laser beam incident on the light receiving surface 9a based on the output signal of the incident position detection element 9.
In the figure, 10a, 10'b, 100. xocl,10e,1
0f,, 10g.

10h, xoi, :LOj, 10, 1op is an operational amplifier (for example, MA'i'14Q manufactured by Fairchild)
), lom, and Ion are dividers (for example, ICL8o13 manufactured by Intersil).

The “-” terminal of the operational amplifier loa, lo, b is the detection element 9
The current output terminals 1 and 2 are connected to the operational amplifier 10.
0. The “-” terminal of IOd is the current output terminal 0 of the detection element 9.
1, connected to oj.

And each operational amplifier xoa used in the active area ~
The rJ terminal voltage of loa is equal to the "+" terminal voltage, therefore the "-" terminal voltage of the operational amplifier loa110b is the ground voltage, and that of the operational amplifier 100% l0ct is a negative voltage -Vs.

In this state +a, the light incident position detection element 9 has an operational amplifier xo
a, xob output resistor 101a;

Currents X1 and X3 respectively flow through 101b, and a resistor 101Q flows into the output of the operational amplifier 100% lod.
, mol(i), Ryuryuko Y1 and Kou Y1 flow out respectively.

Therefore, each op amp loa, 101).

100% lod output is “-” terminal voltage and resistance 101a
, 1oll), mole, and 1oad, and current-voltage conversion is performed.

By the way, in this embodiment, 51300 manufactured by Hamamatsu Photonics Co., Ltd. is used as the detection cable 9. This detection element 9
In this case, when the laser beam is incident on the point indicated by P in FIG.

y), the coordinate values x, y and the electric current worker X! , engineering x,
・Work Yl・Work Y There is the following relationship with x.

The above coordinate values X1y are respectively in the X-axis direction (x in the figure).
− By calculating the coordinate value x1y from the above equation) and (e), the inclination angle of the vehicle in the two-dimensional direction can be determined.

Here, the feedback resistors 101a, 1o1b, and molc of the operational amplifiers 1Oa to 1Od.

If the resistance value of 101d is R, then the operational amplifiers 10a, 1
ob's output voltages Vx, , VXg and current line Xl.

It has a proportional relationship with X2 as shown in the following equations (f) and (2).

VxI = Engineering xt ・R... Song...
■V, x, = Engineering x, eR・・・・・・・・・・・・
...(2) (There is an illusory proportional relationship.

Vy, = R engineering Y1 song...song...'I
's = ” 工 Ys ... song ...... (i
lThe above voltages VXl and VXx are applied to the operational amplifier 10θ which constitutes an inverting amplifier, and the operational amplifier 10f which constitutes a differential amplifier.
The signal is then input to the divider 10m and then processed by the divider 10m.

And the output Dx of the buffer amplifier lok is becomes.

Moreover, the voltages VY0 and VYt are the operational amplifier 10e,
Operational amplifier 101.1oj with the same configuration as xof
is input to , and then processed by the divider Ion,
The buffer amplifier 1oe outputs it as an output Dy.

The output Dy becomes.

The above outputs Dx and Dy are equal to the coordinate value X1y shown in the above equation) and (e), therefore, in the display device 11 (see Figure 1) into which the output DxSDy is input, the value of each output Dx and Dy is equal to the coordinate value X1y in the JJX axis direction. Then, the tilt angle of the vehicle in the y-axis direction is calculated and displayed.

As described above, according to the inclination detection device of the present invention, as the vehicle to be inspected inclines, the incident angle of the laser beam incident on the oil surface changes, and the laser beam is transmitted and refracted and received. By detecting the incident position of the laser beam incident on the incident position detection element, which is the means, it is possible to accurately know the inclination angle of the vehicle.

According to the present invention, it is possible to simultaneously measure inclination angles in two-dimensional directions, so inclination in any direction can be accurately detected. Also, since there are no mechanically moving parts, it has excellent vibration resistance. Furthermore, V with an extremely narrow luminous flux
- Since the laser light is used, the angle of inclination can be detected with extremely high accuracy.

Since the silicone oil filled in the container has a high refractive index, the laser beam is effectively refracted. Moreover, since the above-mentioned oils have the same refractive index and different viscosities, it is possible to easily adjust the responsiveness of the device by using different oils depending on the application. Therefore, depending on the application, low viscosity water, alcohol/L/or various high viscosity oils and fats may of course be used in addition to silicone oil.

When using liquids with different refractive indexes, by adjusting the amount filled in the container and changing the height of the liquid level, the laser beam entry position can be kept constant regardless of the refractive index of the liquid. , and no readjustment of the processing circuit is required.

Incidentally, as shown in FIG. 5, the same concave lens effect as in the above embodiment can be obtained even if the bottom surface of the container 2 is made thick and the upper surface thereof is curved downward in a concave shape. In this case, the refractive index nl of the container 2 is larger than the refractive index n2 of the liquid 3 in the container. For example, water (nl ==
1.33), quartz glass (ni-i: 1.46) is used for the container 2.

A CCD sensor, a photodiode array, etc. may be used in place of the above entry position detection element, and if the purpose is to issue an alarm at a predetermined angle of inclination, a photodiode may be provided at a position corresponding to the above angle. Just leave it there.

As described above, the inclination detection device of the present invention has a structure in which the light receiving means receives the laser light that is incident on the liquid surface at an incident angle corresponding to the inclination of the object and is refracted and transmitted, and has good accuracy. This realizes an inclination detection device with excellent vibration resistance, making it suitable for use in vehicles and the like.

[Brief explanation of the drawing]

Fig. 1 is a device configuration diagram including a cross section of the entire detection section, Fig. 2 is a plan view of the entry position detection element, Fig. 3 is a sectional view of the entire detection part when the object is tilted, and Fig. 4 is a signal A circuit diagram of the processing circuit, and FIG. 5 is a sectional view of the entire detection section showing another embodiment. 2... Container 3... Liquid 6...
... Light emitting means 9 ... Light receiving means 10 ...
・Signal processing circuit

Claims (4)

[Claims] (1) A container made of a laser beam transparent material filled with a liquid, a light emitting means for emitting laser light from above the container toward the surface of the liquid, and receiving the laser light that is refracted and transmitted through the liquid. What is claimed is: 1. An inclination detection device, characterized in that a light receiving means is provided integrally with a test object, and a signal processing means is provided for processing an output signal of the light receiving means to determine the inclination of the test object. (2) A patent claim in which the light receiving means is a two-dimensional light incident position detecting element that is arranged in a planar manner on the bottom surface of the container and emits an output signal according to the incident coordinate position of the laser beam that has been refracted and transmitted through the liquid. The inclination detection device according to item 1. (3) The inclination detection device according to claim 1, wherein the container has a thin bottom surface and is curved upwardly in a convex manner. (4) The inclination detection device according to claim 1, wherein the container has a thick bottom surface and an upper surface curved downward in a concave shape.