JPS6010243B2 - Attitude detection device using hologram - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device that detects an attitude angle using a hologram.

There is a conventional "attitude detection device" as a device for detecting the attitude angle of a small-mouth pipe burying machine, a tunnel excavator, etc.

As shown in FIG.
The lens 3 focuses the light and forms an image on the position sensor 4, and the laser beam L' of the detection device 2 responds to changes in the position of the light point P from the center position 4a of the position sensor 4 by changing the attitude angle relative to the laser beam L'. The azimuth angle and pitch angle of the detection device 2 are detected based on the output signal obtained by the detection device 2. However, in the conventional detection device described above, there are severe limitations on the aberration of the condenser lens, and a large lens is required to cover the parallel movement of the device.

Such large scale lenses are technically difficult to produce and are also quite heavy. Moreover, it is extremely expensive. The present invention has been newly developed in view of the above-mentioned points, and has a completely different detection principle from the above-mentioned conventional detection device, uses a hologram instead of a lens, and detects coherent waves emitted from a laser transit, etc. The present invention provides an attitude detection device using a hologram that detects an attitude angle with respect to the laser beam.

The present invention will be described in detail below based on one embodiment of the accompanying drawings.

First, the principle of the present invention will be briefly explained.

As shown in FIG. 2, a pinhole PH is provided at a predetermined position in front of the three-dimensional hologram 6, and this pinhole P generates plane wave laser light LP. When irradiated with . The laser beam L passing through this pinhole PH becomes a spherical wave Ls and is irradiated onto the three-dimensional hologram 5. Note that this three-dimensional hologram 5 is an extremely sensitive photographic film. On the other hand, from the front of this three-dimensional hologram 5, a predetermined attitude angle (azimuth angle 8, pitch angle)
A plane wave laser beam LP is irradiated to expose and print the spherical wave Ls and the plane wave LP at the same time, followed by development processing.
In this way, a hologram is created. Next, when the three-dimensional hologram 5 created as described above is irradiated with a plane wave laser beam LP from the same attitude angle as before (azimuth angle 0, pitch angle) as shown in FIG. The pinhole PH and the plane-symmetrical position P with respect to the hologram 5
It is centered on '.

In other words, the three-dimensional hologram 5 functions in the same way as lenses. In this way, the hologram can be reproduced. In this way, for a laser beam incident at a certain angle, 1
Two light spots (real images) correspond to each other.

Therefore, by disposing a sensor at this light spot position, the angle of incidence can be detected. Therefore, by repeating the above-mentioned hologram creation operation (multiple exposure), it is possible to arbitrarily make many light points correspond to many angles, and a small photocell, etc. can be attached to each of these light spot positions. By disposing a light receiving element of 1, it is possible to detect a change in the angle of incidence of the incident laser light.

The present invention has been made based on the above principle, and in FIG. 4, light receiving elements such as photocells 6 to 9 are arranged at predetermined positions behind the three-dimensional hologram 5. These photocells 6 to 9 are on a plane parallel to the three-dimensional hologram 5, and with respect to the optical axis Lo passing through the center ○ of the three-dimensional hologram 5,
Photocells 6 and 7 are vertically symmetrical, and photocells 8 and 9 are
are placed in symmetrical positions. Of course, Photocell 6
, 7 and between the photocells 8 and 9 are designed based on the size of the stereoscopic hologram 5, the distance from the stereoscopic hologram 5 to these photocells 6 to 9, and the maximum value of the attitude angle to be detected. That's a problem. The three-dimensional hologram 5 is, for example, a square photographic plate. Photocell 6~
9 outputs voltages V6 to V9 according to the intensity of incident light and applies them to arithmetic circuits 10 and 11.

The arithmetic circuit 10 calculates the logarithmic ratio logV6/V of inputs V6 and V7.
7 and outputs the corresponding pitch angle signal V. Arithmetic circuit 1 1 is the logarithmic ratio of inputs V8 and V9 logV8/V
9 and outputs the corresponding azimuth signal V8. Also, the maximum azimuth of the attitude angle to be detected is 8o, and the maximum pitch angle is 8o. shall be. Then, for the three-dimensional hologram 5 (
Pitch angle, azimuth angle) = plane wave L irradiated at (o, 0)
Exposure is performed together with the spherical wave Ls in the manner shown in FIG.

Similarly, (pitch angle, azimuth angle) = (one o, 0), (pitch angle, azimuth angle) = (0, 8).

), (pitch angle, azimuth angle) = (0, -8.

) is exposed together with the spherical wave Ls' so that the plane wave LP irradiated with the photocells 7, 8, and 9 is focused on the positions of the photocells 7, 8, and 9.

After multiple exposures are performed a total of four times in this way, a hologram is created by developing. In this way, the attitude angle detection device 12 is configured. Now, suppose that the plane wave LP is incident on the three-dimensional hologram 5 at a pitch angle of 8 (one eight. At this time, as described above, by appropriately setting the spacing between the photocells 6 to 9, the light from the pitch angle -o<o is focused on the photocells 6 and 7 at a certain ratio. Therefore, the photocells 6 and 7 output characteristic voltages V6 and V7 as shown in FIG. 5a. Similarly, the azimuth angle is -8. <minus 8. The light from the photocells 8, 9 is focused at a certain ratio,
9 outputs voltages V8 and V9 having characteristics as shown in FIG. 6a. Therefore, the ratio logV6/V7, logV8/
If you get V9, you'll get one. <nokunoo, one 8o<minus 8o
The pitch angle and azimuth angle 8 can be determined within the range of . Thus, the arithmetic circuit 10 with the characteristics shown in FIGS. 5b and 6b
, 11, the incident angle of the plane wave LP, that is, the attitude angle (of, 8) of the detection device 12 with respect to the plane wave LP can be detected. As explained above, according to the present invention, it is easy to set the reference beam because it is independent of fluctuations in the intensity of the laser beam and the thickness of the beam, and moreover, it is possible to detect even if the surface of the hologram is dirty. can.

Further, there are advantages such as being able to provide a large-diameter, lightweight device at low cost.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a conventional attitude detection device, FIGS. 2 and 3 are diagrams showing the principle of the present invention, and FIG. 4 is a diagram showing an embodiment of the attitude detection device using a hologram according to the present invention. , and FIGS. 5 and 6 are graphs showing an example of the output signal of the present device. 5...Stereoscopic hologram, 6-9...Photocell, 10-11... Arithmetic circuit, LP...
Plane wave laser light, Ls... Spherical wave laser light. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6

Claims (1)

[Claims] 1 A three-dimensional hologram that has been printed with multiple exposures in advance in order to focus plane wave laser light incident from four directions with a predetermined azimuth angle ±θ_0 and pitch angle ±ψ_0 on two pairs of four points, and a three-dimensional hologram placed at each focusing point. two pairs of light-receiving elements that output signals according to the intensity of light, and a first arithmetic circuit that calculates an azimuth based on the signals of each light-receiving element of the first pair and outputs a corresponding azimuth signal. , a second arithmetic circuit that calculates a pitch angle based on the signal of each light receiving element of the second pair and outputs a corresponding pitch angle signal, and a direction within the range of azimuth angle ±θ_0 and pitch angle ±ψ_0. An attitude detection device using a hologram that detects the angle of incidence of laser light irradiated from the front.