JPH03180789A - Sensor device for laser light reception - Google Patents

Abstract

PURPOSE:To cover the visual field of 360 deg. with one photodetector (PD) by providing the PD whose light reception face is arranged to face the space between the outside reflection face of an inner cylindrical reflector and the inside reflection face of an outer cylindrical reflector. CONSTITUTION:Slits 41 to 48 through which laser light is transmitted are provided at prescribed intervals on a light reflection face 5B of a cylinder member 3 as the outer cylindrical reflector. Optical paths 7B and 7C out of optical paths 7A to 7C of the laser light made incident on, for example, the slit 42 from a laser lighthouse are emitted to the outside through slits 43 and 47 respectively, but the optical path 7A is repeatedly reflected by light reflection faces 5A and 5B and reaches a light reception face 6A of a PD 6. Since the laser light of the laser lighthouse is turned, several percent of laser light is repeatedly reflected to reach the liquid reception face 6A in the same manner as the optical path 7A. Consequently, the visual field of 360 deg. is covered with one PD 6 because laser light can be received by the light reception face 6A whichever direction the laser light-house exists in to a sensor device. Thus, the cost is reduced and the device is miniaturized, and the degradation in yield and reliability is prevented.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a sensor device for laser light reception, and in particular to a light receiving unit installed on the side of an unmanned moving body in position control of an unmanned moving body using a laser lighthouse. The present invention relates to a laser light receiving sensor device suitable for use as a laser light receiving sensor device.

[Background technology]

Recently, various methods for measuring the position, direction, etc. of unmanned moving objects have been studied in various fields in order to automate the positioning and guidance of unmanned moving objects using laser lighthouses. A position and direction measurement system using such a laser lighthouse can be used, for example, for ships passing through straits or ports, aircraft running or taxiing in airports, mobile work machines in factories and farms, construction work machines, construction work robots, etc. It can be used for monitoring and guidance.

Depending on the purpose of use, a laser lighthouse may be one that rotates two laser beams at a constant angular velocity, or one that rotates two synchronized laser beams in opposite directions at a constant angular velocity so that they are always aligned with respect to a reference line. A device that outputs in a line-symmetrical direction is used.

FIG. 10 shows the configuration of a position measurement system using two laser lighthouses that rotate two synchronized laser beams in opposite directions at a constant angular velocity.

In this figure, laser lighthouses 51 and 52, which are devices on the laser oscillation side, are installed at two reference points, respectively. In addition, these laser lighthouses 51 and 52 are arranged so that the reference lines where the two output laser beams overlap coincide with each other.
In addition, both reference lines are set to match a line L (the length of which is known) connecting the reference points.

On the other hand, a laser light receiving sensor device 54 is installed on the moving body 53 at a height where the laser beam can be received. This sensor device 54 is actually configured with a photodetector that receives laser light, a clock circuit that measures time, an arithmetic circuit that calculates angle and position, and the like.

Here, how to obtain angles and positions in this position measurement system will be explained.

When the rotary table of the laser lighthouse 51, 52 is rotated at a constant speed, a counterclockwise laser beam (CCW) and a clockwise laser beam (CW) that are symmetrical with respect to the reference line are rotated and irradiated. The passage timing of these laser beams (ccw, cw) is detected by a photodetector. If this light reception time interval is measured with a timer circuit, the angle of that point can be determined because the light reception time interval and the angle between the measurement point and the reference line are proportional.

In this way, in the arithmetic circuit, the laser lighthouse 51.52
The angle (θhθ2 shown in FIG. 10) formed between and the reference line is calculated, and the plane position coordinates are instantaneously calculated from this and the known reference line length.

In addition, as a method of measuring the position and orientation of a moving object using a laser lighthouse, a laser light receiving sensor device (light receiving part) is placed at each of three points on the moving object, and the movement is made with respect to a reference point based on so-called trigonometry. There are methods of calculating the distance to the representative point of the moving object and the traveling direction (heading) of the moving object.

In any of the above cases, the light receiving section of the sensor device needs to have a 360° field of view in order to receive the laser beam, no matter what direction the moving body faces.

For this reason, conventionally, in a system for measuring the position and direction of an unmanned moving object using a laser lighthouse, as shown in FIG.
An omnidirectional light receiving sensor covering a 60° field of view is used.

[Problem to be solved by the invention]

However, in the conventional omnidirectional light-receiving sensor described above, it is necessary to use a large number of photodetectors, which increases manufacturing costs, reduces yield, and reduces reliability.
This method had problems such as an increase in the size of the device.

[Purpose of the invention]

An object of the present invention is to improve the disadvantages of the conventional example and to provide a sensor device for laser light reception that has a 360° field of view by using only one (in some cases, two) photosensors.

(Means for Solving the Problems) The present invention includes a first cylindrical reflector having at least an outer reflecting surface, and at least an inner reflecting surface and having a diameter slightly larger than that of the first cylindrical reflector. The first and second cylindrical reflectors are arranged substantially concentrically and at a predetermined interval. The cylindrical reflector is provided with several slits of a predetermined width that allow laser light to pass therethrough at predetermined intervals along the entire circumferential direction.Furthermore, the first cylindrical reflector and the second cylindrical reflector In between, a light receiving means having a light receiving surface facing the gap between the outer reflective surface of the first cylindrical reflector and the inner reflective surface of the second cylindrical reflector is interposed. The structure is adopted.

This aims to achieve the above-mentioned purpose.

[First Embodiment] Hereinafter, a first embodiment of the present invention will be described based on FIGS. 1 and 2.

The laser light receiving sensor device (hereinafter referred to as "sensor device") 1 of the embodiment shown in FIG. 1 cylindrical member 2 and a second cylindrical member 3 as a second cylindrical reflector formed to have a slightly larger diameter than the first cylindrical member 2.

Of these, the outer surface of the first cylindrical member 2 has an outer reflecting surface (the center part of the first cylindrical member 2) having a constant width (only the part corresponding to the slit 4 shown in the figure) along the entire lateral circumferential direction. A first light reflecting surface 5A is formed as a surface that reflects light outward from the outside. On the other hand, the inner surface of the second cylindrical member 3 has an inner reflective surface (a surface that reflects light toward the center of the second cylindrical member 3) in a portion facing the first light reflective surface 5A. A second light reflecting surface 5B is formed.

Further, in the second light reflecting surface 5B portion of the second cylindrical member 3σ, slits 4° 4 of a predetermined width through which laser light can pass through at predetermined intervals over the entire lateral circumferential direction are provided. are provided at eight equally spaced locations.

A photodetector 6 as a light receiving means is interposed between the first cylindrical member 2 and the second cylindrical member 3 and has a light receiving surface 6A facing the gap between them. (See Figure 1 (1)).

The light receiving surface 6A of the photodetector 6 has first and second light receiving surfaces.
It is arranged in the normal direction of the cylindrical members 2 and 3, and is inserted into and fixed in the notches 2A and 3A provided in the first cylindrical member 2 and the second cylindrical member 3. Said 1st. Second light reflecting surface 5A.

5B is formed by coating with a high reflective material.

The sensor device 1 of the first embodiment configured as described above is as follows:
Actually, it is installed and used on the unmanned moving body 53 shown in FIG. 1O described above. In FIG. 1(2), reference numeral IA indicates a lid member, reference numeral IB indicates a bottom plate portion, and IC indicates a support member.

Here, the operation of this embodiment will be explained based on FIG. 2.

In FIG. 2, reference numerals 7A to 7C indicate optical paths of laser light incident on the slit 4□ from a laser lighthouse (not shown) similar to the conventional laser lighthouses 51 and 52 described above. Among these, code 7B.

7C indicates a case where the light enters the second cylinder 3 but exits to the outside through separate slits 41 and 43, and 7A indicates a case where the light reaches the light receiving surface 6A after being reflected several times. shows the optical path of

Since the laser light from the laser lighthouse is rotating, several percent of the incident laser light is reflected several times and reaches the light receiving surface 6A in the same way as in the optical path 7A.

Therefore, regardless of the orientation of the laser lighthouse with respect to the sensor device 1, the photodetector 6 can receive the laser beam for the above reason, and only 6 photodetectors can cover 3600 fields of view. .

As explained above, according to the first embodiment, a 360° field of view can be covered with only six photodetectors, making it possible to reduce manufacturing costs and prevent a decline in yield and reliability. This has the advantage that the device can be made smaller.

Note that if the photodetector 6 has one large light-receiving surface, it can be used to detect the presence or absence of light reception. For example, it can be used as a level meter (height meter).

In addition, when the sensor device 1 of the above embodiment is used outdoors under direct sunlight, the projected light signal (projected light signal) that is reflected and received by the surface of the cylindrical member is separated from the disturbance light. Methods such as increasing the power to improve the S/N ratio, excluding light with wavelengths other than laser light using an optical filter, using a modulated light source to perform differential detection processing between when the light is turned on and when the light is turned off, or the pulse transfer differential method, etc. It is desirable to perform another signal processing method to accurately receive the relevant laser light.

Furthermore, the second cylindrical member 3 has a structure in which eight plate members each having an arc-shaped cross section are provided, and ring-shaped fixing members are provided at the upper and lower edges of these plate members to integrally fix them. Good too.

[Second Embodiment] Next, a second embodiment of the present invention will be described based on FIG. 3.

Here, the same reference numerals are used for the same components as in the first embodiment described above.

In this embodiment, the first cylindrical member 2 as the first cylindrical reflector and the second cylindrical member 3 as the second cylindrical reflector in the first embodiment described above have their respective inner diameter sides and outer diameters. It is characterized by having reflective surfaces on both sides.

That is, these cylindrical reflectors 2.3, as shown in FIG. is mirror-finished, and as a result, in addition to the second light-reflecting surface 5B as an inner reflective surface and the first light-reflecting surface 5A as an outer reflective surface, another inner reflective surface 5C and an outer reflective surface 5D are formed as shown in the figure. each formed.

The other configurations are the same as those of the first embodiment described above.

Even with this configuration, in addition to having the same functions and effects as the first embodiment, there is no need for coating for forming a reflective surface, which facilitates manufacturing and allows for reduction in size and weight.

Note that in the second embodiment, the first. The second cylindrical reflector is formed of a single piece of metal material having reflective surfaces on both the inner and outer diameter sides, but one of the second cylindrical reflectors is on the inner and outer diameter sides. It may be formed from a single piece of metal material having a reflective surface on one side, and the other may be constructed in the same manner as in the first embodiment. Alternatively, either one or both of the first and second cylindrical reflectors,
It is also possible to form a reflective surface by coating a light reflecting material on both the inner and outer sides of a cylindrical member.

[Third Embodiment] Next, a third embodiment of the present invention will be described based on FIG. 4.

Here, the same reference numerals are used for the same constituent members as in the first embodiment described above.

The sensor device 11 of this embodiment has a light receiving surface 6A of the photodetector 6 in the sensor device 1 of the first embodiment described above.
The feature is that a reflecting mirror 8 is placed on the back side of the part.

The other configurations are the same as in the first embodiment.

Even in this case, the same effect as in the first embodiment is obtained.

In addition to this effect, the light traveling toward the reflecting mirror 8 is reflected by the reflecting mirror 8 and directed toward the photodetector 6, which increases the proportion of light that reaches the light receiving surface 6A, making the laser beam more reliable. This makes it possible to receive light.

In this embodiment as well, one or both of the cylindrical reflectors may be formed of a single piece of metal material, as shown in the second embodiment.

[Fourth Embodiment] Next, a fourth embodiment of the present invention will be described based on FIG. 5.

Here, the same reference numerals are used for the same components as in the first embodiment described above.

The sensor device 21 of this embodiment includes a first cylindrical member 2 as a first cylindrical reflector and a cylindrical member 3 as a second cylindrical reflector in the sensor device 1 of the first embodiment described above. It is characterized in that the width dimensions of the notches 2A and 3A are approximately doubled, and a photodetector 9 as another light receiving means is arranged on the back side of the light receiving surface 6A of the photodetector 6 so that the light receiving surface 9A is back to back. The other configurations are the same as in the first embodiment.

Even in this case, in addition to obtaining the same effect as in the first embodiment, the light receiving surface 6A of the two photodetectors 6.9,
9A are back-to-back, it is possible to receive the light that has a shorter path after entering the second cylinder 3 among the light that reaches the light receiving surfaces 6A and 9A. . Therefore, attenuation of the received laser light due to the number of reflections can be suppressed, and the S/N ratio between the projected light and the disturbance light can be increased, thereby improving the light reception accuracy.

In this embodiment as well, one or both of the cylindrical reflectors may be formed of a single piece of metal material, as shown in the second embodiment.

[Fifth Embodiment] Next, a fifth embodiment of the present invention will be described based on FIG. 6.

In this embodiment, a pair of sensor devices 1 of the first embodiment described above are provided, and these are mounted on a moving body (not shown) at a predetermined interval so that the respective photodetectors 6 are located on opposite sides.

In this way, it is possible to complement each other's fields of view and improve the overall light reception efficiency, and furthermore, an optical filter that transmits only light of different wavelengths can be placed in front of the light reception surface 6A of each photodetector 6. This makes it possible to receive light of different wavelengths.

In this embodiment as well, any or all of the cylindrical reflectors constituting the sensor device 1 may be formed of a single piece of metal material, as shown in the second embodiment.

[Sixth Embodiment] Next, a sixth embodiment of the present invention will be described based on FIG. 7.

Here, the same reference numerals are used for the same components as in the first embodiment described above.

The sensor device 31 of this embodiment is the first cylindrical member 2. In place of the second cylindrical member 3, an inner cylindrical member 12 with a regular octagonal cross section as a first cylindrical reflector and an outer cylindrical member 13 with a regular octagonal cross section as a second cylindrical reflector are provided. It is characterized by the fact that

In this case, slits 14, 14, . . . are provided at each corner of the outer cylindrical member 13.

The other configurations are the same as in the first embodiment.

When a laser beam hits a corner of the inner cylindrical member 12, it is thought that it will be diffusely reflected, but since the laser beam output from the laser lighthouse is rotating, a few percent of the light will be reflected on the light receiving surface 6A of the photodetector 6. Since it is considered that , the same effect as in the first embodiment can be obtained in this case as well.

In this embodiment, a case where a cylindrical member having a regular octagonal cross section is used is exemplified, but it is also possible to use a cylindrical member having a regular 10, 2, 16, etc. shape.

Furthermore, in this embodiment, the first. Although the case in which the cross-sectional shapes of the second cylindrical reflectors are both regular polygons is particularly illustrated, in addition to this,
Only one of them may have a regular polygonal cross section, and the other may be constructed using a cylindrical member.

Furthermore, in this embodiment as well, one or both of the cylindrical reflectors may be formed of a single piece of metal material, as shown in the second embodiment.

In addition, in the first to sixth embodiments described above, the slit 4.14 was opened. It is desirable to configure the system to prevent the intrusion of

[Seventh Embodiment] Next, a seventh embodiment of the present invention will be described based on FIG. 8.

In the sensor device 41 of this embodiment, the second cylindrical member 3 in the first embodiment described above is made of a transparent material such as glass or acrylic resin.

The inner circumferential surface of the second cylindrical member 3, except for the slit 4 portion, is coated with a coating that highly reflects light to form a second reflective surface 5B.

The other configurations are the same as in the first embodiment.

Even with this configuration, in addition to having the same functions and effects as the first embodiment, there is an advantage that manufacturing becomes easier because there is no need to provide an opening as the slit 4.

In addition, in this embodiment, a case is illustrated in which a coating that highly reflects light is applied to the inner peripheral surface of the second cylindrical member 3, but a coating that highly reflects light may be applied to the outer peripheral surface. .

Furthermore, in the above first to seventh embodiments, the first
The cylindrical reflector is formed of a transparent member, and a coating that highly reflects light is applied to the outer or inner surface of the transparent member to form an outer reflective surface (a surface that highly reflects light toward the outside). You may do so.

[Eighth Embodiment] Next, an eighth embodiment of the present invention will be described based on FIG. 9.

The sensor device 51 of the embodiment shown in FIG. 9 includes a cylindrical member 22 as a cylindrical member made of a transparent material such as glass or acrylic resin with a predetermined thickness.

The inner surface of this cylindrical member 22 is provided with an outer light reflecting surface (a surface that reflects light toward the outside) 2 having a constant width over the entire inner circumferential direction.
5A is formed. Further, an inner light reflecting surface (a surface that reflects light inward) 25B is formed on the outer surface of the cylindrical member 22 that faces the outer light reflecting surface 25A. Furthermore, slits 4.4 of a predetermined width through which laser light can pass are provided at eight equal intervals over the entire periphery of the inner light reflecting surface 25B.

A photodetector 6 as a light receiving means is provided so as to penetrate through the outside and inside of this cylindrical member 22.

Here, the outer reflective surface 25A is formed by coating the inner surface of the cylindrical member 22 with a highly reflective material. Also,
The inner reflective surface 25B is formed by coating the outer surface of the cylindrical member 22 with a highly reflective material, and at this time, this is done so that only the portions of the slits 4.4... are not coated. .

Further, the photodetector 6 is provided on the cylindrical member so that its light receiving surface 6A is arranged in the normal direction of the cylindrical member 22, and the light receiving surface 6A is located between the outer reflective surface 25A and the inner reflective surface 25B. It is inserted into and fixed in the cutout 22A.

The other configurations are the same as in the first embodiment.

Even with this structure, it has the same functions and effects as the first embodiment described above, and since it does not have a double structure like the above-mentioned embodiments, the structure is very simple and manufacturing is easy. This has the advantage of being easier.

In addition, in the first to eighth embodiments described above, all sensor devices are fixed type, but this eliminates the need for a motor, a drive mechanism, etc., which is a drive source for one rotation. In addition to simplifying the configuration and reducing costs, it is a fixed type in order to prevent vibrations and maintain high light reception accuracy, and it is also possible to use the sensor device itself by rotating it once. be. Furthermore, in the case of a fixed type, there are no sliding parts, so it is excellent in terms of durability.

[Effects of the Invention] Since the present invention is configured and functions as described above, according to this, after the rotating laser light output from the laser lighthouse enters the second cylindrical reflector through the slit, several percent of the laser light is The light is reflected several times by the outer reflective surface of the first cylindrical reflector and the inner reflective surface of the second cylindrical reflector, and reaches the light receiving surface of the light receiving means. Therefore, no matter what direction the laser lighthouse is located with respect to the sensor device, the light receiving means can receive the laser beam, and only one light receiving means is required.
This will cover a 360° field of view.

Therefore, since a 360° field of view can be covered with only one light receiving means, manufacturing costs can be significantly reduced, and the device can be made smaller and lighter, providing an unprecedented and excellent laser light receiving sensor device. can do.

[Brief explanation of drawings]

FIG. 1 (1) is a partially omitted cross-sectional view showing the first embodiment of the present invention, FIG. 1 (2) is a schematic perspective view showing the first embodiment, and FIG. 2 is a partially omitted cross-sectional view showing the first embodiment of the present invention. 3(1) is a schematic perspective view showing the second embodiment of the present invention, FIG. 3(2) is a schematic cross-sectional view of FIG. 2(2), and FIG. 4 is a schematic perspective view showing the second embodiment of the present invention. FIG. 5 is a partially omitted cross-sectional view showing the fourth embodiment of the present invention, and FIG. 6 is a partially omitted explanation showing the fifth embodiment. 7 is a partially omitted cross-sectional view showing the sixth embodiment, FIG. 8 is a partially omitted cross-sectional view showing the seventh embodiment, and FIG. 9 is a partially omitted cross-sectional view showing the eighth embodiment. The omitted cross-sectional views and FIGS. 10 and 11 are explanatory diagrams showing a conventional example. 1... Sensor device, 2... First cylindrical member as a first cylindrical reflector, 3... Second cylindrical member as a second cylindrical reflector. Cylindrical member 4... Slit, 5A... First light reflecting surface as an outer reflecting surface, 5B... Second light reflecting surface as an inner reflecting surface , 5C...Inner reflective surface, 5D...
・Outer reflective surface, 6... Photodetector as light receiving means, 6A... Light receiving surface, 8...
Reflector, 9... Photodetector as light receiving means, 9A... Light receiving surface, 11... Sensor device, 12... First cylindrical reflector an inner cylindrical member as a second cylindrical reflector, 13... an outer cylindrical member as a second cylindrical reflector, 14... a slit, 21...
... Sensor device, 22 ... Cylindrical member as a cylindrical member, 25A ... Outer reflective surface, 25B.
...Inner reflective surface, 31, 41.51...
sensor device.

Claims (13)

[Claims] (1) A first cylindrical reflector having at least an outer reflective surface, and a second cylindrical reflector having at least an inner reflective surface and having a slightly larger diameter than the first cylindrical reflector. the first and second cylindrical reflectors are arranged substantially concentrically and at a predetermined interval, and the second cylindrical reflector is provided with a laser beam at a predetermined interval over the entire lateral circumferential direction. Several slits of a predetermined width through which light can pass are provided, and between the first cylindrical reflector and the second cylindrical reflector, an outer reflective surface of the first cylindrical reflector and a second cylindrical reflector are provided. 1. A sensor device for laser light reception, characterized in that a light receiving means is interposed, the light receiving surface of which faces the gap between the inner reflective surface of the cylindrical reflector and the inner reflective surface of the cylindrical reflector. (2) A claim characterized in that at least one of the first and second cylindrical reflectors is formed of a cylindrical reflector having reflective surfaces on both inner and outer diameter sides. Item 1. The laser light receiving sensor device according to item 1. (3) Claim characterized in that the first cylindrical reflector comprises a cylindrical member and an outer reflective surface having a constant width extending over the entire lateral circumferential direction on the outer surface of the cylindrical member. 1. The laser light receiving sensor device according to 1. (4) Claim characterized in that the second cylindrical reflector comprises a cylindrical member and an inner reflective surface having a constant width extending over the entire lateral circumferential direction on the inner surface of the cylindrical member. 1. The laser light receiving sensor device according to 1. (5) The laser light receiving sensor device according to claim 1, wherein at least one of the first and second cylindrical reflectors is formed in a cylindrical shape. (6) The laser light receiving sensor device according to claim 1, wherein the light receiving surface of the light receiving means is arranged along the radiation direction when viewed from the center of both the cylindrical reflectors. (7) The laser light receiving sensor device according to claim 1, further comprising a reflecting mirror provided on the back side of the light receiving surface of the light receiving means. (8) The sensor device for laser light reception according to claim 1, further comprising another light receiving means, the light receiving surfaces of which are arranged back to back on the back side of the light receiving surface of the light receiving means. (9) Claim 1, wherein the cross-sectional shapes of the first and second cylindrical reflectors are both formed into a regular polygonal shape.
The sensor device for laser light reception described above. (10) The laser light receiving sensor device according to claim 1, wherein the light receiving surface of the light receiving means is subdivided in the axial direction of the cylindrical reflector. (11) The second cylindrical reflector is formed of a transparent member, and a coating that highly reflects light is applied to the inner or outer surface of the transparent member except for the slit portion. The laser light receiving sensor device according to claim 1. (12) The first cylindrical reflector is formed of a transparent member, and the inner or outer surface of the transparent member is coated with a coating that highly reflects light of a constant width over the entire circumferential direction. The laser light receiving sensor device according to claim 1, characterized in that: (13) A cylindrical member made of a transparent member with a predetermined thickness is provided, and an outer light reflecting surface with a constant width extending over the entire lateral circumferential direction is formed on the inner surface of the cylindrical member, and the outer light of the cylindrical member is An inner light-reflecting surface is formed on a portion of the outer surface facing the reflective surface, and slits of a predetermined width through which laser light can pass are provided at predetermined intervals in the entire circumferential direction of the inner light-reflecting surface portion at several locations, A sensor for laser light reception, characterized in that a light receiving means is provided so as to penetrate through the outside and inside of the cylindrical member, and the light receiving surface of the light receiving means is disposed between the inner reflective surface and the outer reflective surface. Device.