JPH11281315A - Reflected light discriminating method and its apparatus, and position detecting apparatus of moving object which uses the reflected light discriminating apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reflected light discriminating method which is accurate, simple and practical. SOLUTION: A reflecting body as a detection object is irradiated with two laser beams (a), (b) different in incidence angle, from semiconductor lasers 11, 13. When reflected lights of the two laser lights (a), (b) are received by passive elements 32, 34, the reflected lights from a retroreflection body 2 are discriminated. By this method, the retroreflection body 2 can be discriminated from other noise (regular reflection bodies 41 such as a window, a metal frame and a pipe). External disturbance noise can be eliminated and erroneous detection due to noise can be prevented in a laser induction system.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflected light discriminating method for discriminating whether or not light is reflected from a retroreflector, an apparatus therefor, and a moving object position detecting device using the reflected light discriminating device. .

[0002]

2. Description of the Related Art Conventionally, there has been known a method of measuring a current position of a moving body using three retroreflectors arranged at predetermined coordinates.

The retroreflector consists of a triangular pyramid prism composed of three flat reflecting surfaces orthogonal to each other as if one corner of a cube was cut off, and the incident light was reflected by the three surfaces. Later, it works to send it back exactly in the direction of incidence. Further, as a retroreflector, a triangular pyramid-shaped prism processed into a sheet shape as if laid out in plural is also used. This sheet-shaped retroreflector is often used in a vertically long state.

A method of measuring the current position of the moving object will be described with reference to FIG. A light beam is emitted from a rotating body that rotates two-dimensionally around a predetermined position of the moving body 1 to scan the entire circumference,
Predetermined three places: point A (X1, Y1), point B (X2,
Y2), and the rotation angle of the rotator when the reflected light from the retroreflector 2 arranged at the point C (X3, Y3)} is input is detected.

In FIG. 5, ψ is the attitude angle of the moving body 1 from the X axis, L12 is the distance between points A and B, and L13 is the points A and C.
The distance between points, Θ1 is the rotation angle when point A is detected,
Θ2 is the rotation angle when point B is detected, Θ3 is the rotation angle when point C is detected, ε1 is the angle of point B from the X axis with point A as the origin, and ε2 is B with point A as the origin. It is the angle between point-C.

The position (Xv, Yv) and attitude angle ψ of the moving body 1 are obtained by the following equations (1) to (10). (For details, see “Systems and Control,” Vol. 29, No. 8, (1985) p. 553.
See ~ 560. ) Xv = X1 + kＱ (Q2−Q1) (1) Yv = Y1−kＰ (P2−P1) (2) ψ = π− { ¹ + tan ⁻¹ } (Yv−Y1) / (Xv−X1) } ... (3) k = 2 (P1 · Q2 -P2 · Q1) / {(P2 -P1) 2 + (Q2 -Q1) 2} ... (4) P1 = L12 · sin (α-ε1) / 2sinα ... (5) Q1 = L12 · cos (α−ε1) / 2 sinα (6) P2 = L13 · sin (α + ε1 + ε2) / 2sinβ (7) Q2 = −L13 · cos (α + ε1 + ε2) / 2sinβ (8) α = Θ1−Θ2 (9) β = Θ1−Θ3 (10) In the above position measurement, the reflected light detected is a retroreflector 2.
It is necessary to identify whether the light is reflected light from the camera or reflected light (noise) from a regular reflector such as a window or a metal pipe. Therefore, the retroreflector 2 is provided as follows and identified. I have. Bar code type arrangement method A plurality of retroreflectors are arranged in a bar code and identified. Barcode pasting method A barcode is pasted on the back and front of the retroreflective body for identification.

[0007]

However, the method of identifying reflected light by the above-described retroreflector has the following problems. Bar code type arrangement method There is a problem that the installation size of the retroreflector becomes large and signal processing becomes complicated. In addition, the angle information necessary for measuring the current position may be inaccurate. Furthermore, when the reflector accidentally exists in the gap between the retroreflectors forming the barcode, the barcode itself is not satisfied, and there is a possibility that an error may occur. Barcode pasting method Because the size of the retroreflector is limited, it becomes impossible to identify the pasted barcode when the distance is long,
There is a fear that the reflected light cannot be identified.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an accurate, simple, and practical reflected light discriminating method and apparatus, and a mobile object position detecting apparatus using the reflected light discriminating apparatus.

[0009]

In order to achieve the above object, the invention according to claim 1 irradiates a light beam to a reflector to be detected, and the reflected light is reflected from a retroreflector. A reflected light identification method for identifying whether or not
A plurality of light beams having different angles are applied to the reflector to be detected, and when at least two or more reflected lights of the plurality of light beams are received, reflected light from the retroreflector is used using effective light reception. Is recognized.

According to the above method, when a plurality of light beams having different angles are radiated to the reflector to be detected, and if the reflector to be detected is a retroreflector, at least two reflected light beams are reflected. The light returns along the irradiated optical path, and the reflected light of these light rays is received. On the other hand, if the reflector to be detected is a specular reflector, the reflected light of one ray returns along the illuminated optical path, while the reflected light of another ray follows the illuminated optical path. Never return. Therefore, when reflected light of at least two or more light rays is received, it is recognized as reflected light from the retroreflector.

According to a second aspect of the present invention, there is provided a reflected light discriminating apparatus for irradiating a light beam on a reflector to be detected and discriminating whether or not the reflected light is a reflected light from a retroreflector. A light irradiating unit that irradiates a plurality of light beams having different angles to the reflector to be detected, a light detecting unit that detects reflected light of the plurality of light beams, and a light detecting unit that detects the reflected light of the plurality of light beams. When at least two or more reflected lights are received, a recognizing means for recognizing the reflected light from the retroreflector using effective light reception is provided.

According to the above configuration, when a plurality of light beams having different angles are irradiated on the reflector to be detected, if the reflector to be detected is a retroreflector, at least two reflected light beams are reflected. The light returns along the illuminated light path, and reflected light of these light beams is received. On the other hand, if the reflector to be detected is a specular reflector, the reflected light of one ray returns along the illuminated optical path, while the reflected light of another ray follows the illuminated optical path. Never return. Therefore, when at least two reflected lights of the plurality of light beams irradiated by the light irradiation means are received by the light detection means, the recognition means recognizes the reflected light from the retroreflector.

According to a third aspect of the present invention, there is provided an apparatus for detecting a position of a moving body which moves within a predetermined area, wherein a plurality of retroreflectors are provided at predetermined positions of the area, and
Light irradiating means for irradiating a plurality of light beams having different angles over the entire circumference while rotating, light detecting means for detecting reflected light of the plurality of light rays, and an angle for detecting a rotation angle of the light irradiating means Detecting means; and recognizing means for recognizing as reflected light from the retroreflector using effective light reception when at least two or more reflected lights of the plurality of light beams are received by the light detecting means; By means, when it is recognized as reflected light from the retroreflector, the rotation angle of the light irradiation means detected by the angle detection means is stored, and the current position of the moving body is determined by the stored rotation angles. It is characterized in that a measuring means for measuring is provided.

According to the above arrangement, when at least two or more reflected lights are detected by the light detecting means, the reflected light is recognized as reflected light from the retroreflector by using effective light reception, and the light irradiation detected by the angle detecting means is detected. By storing the rotation angle of the means, the arrangement angle of each retroreflector about the center of rotation of the light irradiation means is detected, and the current position of the moving body is determined from the position of each retroreflector about these moving bodies. Is measured.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. It is assumed that three retroreflectors are arranged around the moving body as in FIG.

FIG. 1 is a configuration diagram of a main part of a moving body equipped with guidance equipment for implementing a reflected light identification method according to an embodiment of the present invention. The movable body 1 such as a forklift is provided with a laser beam generating means for generating a laser beam, a rotating mirror means for irradiating the laser beam over the entire circumference in a plane, and a laser beam reflected from the reflector as guidance equipment. And a position detecting means of the moving body 1 are provided.

As shown in FIG. 1, the laser beam generating means is installed at a slight angle from the vertical direction with a first semiconductor laser 11 and a drive circuit 12 for irradiating the laser beam vertically upward. A second semiconductor laser 13 for irradiating a laser beam to a point where the laser beam of the first semiconductor laser 11 irradiates the reflecting mirror to be irradiated, and a driving circuit 14 for the second semiconductor laser 13.

With this configuration, the first semiconductor laser 11 irradiates the first laser beam a vertically upward through a half mirror to be described later, and the second semiconductor laser 13 obliquely vertically raises the second laser beam through the half mirror. The laser beam b is applied. The second laser beam b is applied to a point of the reflecting mirror where the first laser beam is applied.

The rotating mirror means comprises a vertical cylindrical conduit 17 serving as a path for the laser beams a and b,
Is connected below the center, and a cylindrical body 19 mounted on a ring-shaped bearing 18 and laser beams a and b guided from the conduit 17 and arranged in the cylindrical body 19 at an inclination of 45 degrees are connected to each other. A reflecting mirror 21 for reflecting and guiding to a window 20 provided on the side surface of the cylindrical body 19, and a first pulley fitted around the conduit 17 to rotate the conduit 17
22, a DC motor 23 and a drive circuit 24 thereof, a second pulley 25 directly connected to a rotation shaft of the DC motor 23,
Belt that transmits the torque of pulley 25 to first pulley 22
It consists of 26.

With this configuration, the DC motor 23
When driven by 24, the rotational force of the DC motor 23 is transmitted to the conduit 17 via the second pulley 25, the belt 26, and the first pulley 22, and the conduit 17 rotates. The laser beams a and b which have been rotated and applied to the inside of the conduit 17 are applied to the entire periphery of the moving body 1 around the center position of the conduit 19 due to the rotation of the reflection mirror 21.

Light irradiation means is formed by the laser beam generating means and the rotating mirror means. The light detecting means includes a half mirror 31 disposed above the semiconductor lasers 11 and 13 so as to face the reflection mirror 21 at an inclination of 45 degrees. The half mirror 31 reflects the light from the first semiconductor laser 11. First laser beam a returned along the emitted optical path
Light receiving element 32 for receiving the reflected light of the
And the second semiconductor laser reflected by the half mirror 31
It comprises a second light receiving element 34 for receiving the reflected light of the second laser beam b returning along the optical path emitted from 13 and an amplifier 35 thereof.

With this configuration, the reflected light of the first laser beam a and the reflected light of the second laser beam b guided through the reflecting mirror 21 are respectively reflected by the half mirror 31 to be connected to the first light receiving element 32 and the first light receiving element 32. The light is incident on the second light receiving element 34, and the light receiving signals of the first light receiving element 32 and the second light receiving element 34 are amplified by the amplifiers 33 and 35, respectively.

The position detecting means is connected to the conduit 17 and detects an angle of rotation of the conduit 17.
A mirror rotation angle detector 39 for adding a pulse signal output from the encoder 38 to measure a rotation angle (irradiation angle of a laser beam) の of the reflection mirror 21 that makes the traveling direction of the moving body 1 0 °; And an arithmetic processing unit 40.

The arithmetic processing unit 40 includes a mirror rotation angle detector 32
Of the mirror rotation angle Θ output from the first light receiving element 32 amplified by the amplifiers 33 and 35, respectively.
And the light receiving signal of the second light receiving element 34
It is determined whether or not the reflected light detected by (1) is reflected light from the retroreflector 2 or reflected light from a regular reflector such as a window or a metal pipe. When it is recognized that there is, the mirror rotation angle Θ is stored for each detection signal, that is, the angle from the traveling direction of the retroreflector 2 is stored, and the current position is measured from these angles. The position detecting means serves as both the recognizing means and the measuring means.

A method of identifying reflected light in the arithmetic processing unit 40 will be described in detail. The method of measuring the current position is the same as the conventional method, and the description is omitted. First, when the direction of the reflection mirror 21 matches the direction of the arrangement of the semiconductor lasers 11 and 13, the laser beams a and b are emitted in the vertical direction as shown in FIG.

As shown in FIG. 2A, when the reflecting mirror 21 for irradiating the laser beam faces the retroreflector 2,
The retroreflector 2 functions to send the incident light beam back exactly in the incident direction, so that both the light receiving elements 32 and 34 detect the light. On the other hand, as shown in FIG. 2B, the reflection mirror 21 for irradiating the laser beam is
, The regular reflector 41 functions to reflect light rays at the same exit angle with respect to the incident angle and the perpendicular, so that the first
The light receiving element 32 detects light, and the second light receiving element 34 does not detect light.

Then, the cylindrical body 19 rotates and the reflecting mirror 21
Is different from the direction of the arrangement of the semiconductor lasers 11 and 13 by 90 degrees, the laser beams a and b are emitted in the left-right direction as shown in FIG.

In this case, similarly, when the reflecting mirror 21 for irradiating the laser beam faces the retroreflector 2, both the light receiving elements 32 and 34 detect light, and the reflecting mirror 21 for irradiating the laser beam is When facing the regular reflector 41, the first light receiving element 32 detects light, and the second light receiving element 34 does not detect light.

Therefore, the arithmetic processing unit 40 includes the amplifiers 33 and 35
When the light receiving signal of the first light receiving element 32 is inputted through the, it is confirmed whether the light receiving signal of the second light receiving element 34 is inputted,
When the input of the light receiving signal of the second light receiving element 34 is confirmed, it is recognized that the reflected light of the retroreflector 2 is detected.

With the configuration of the above-mentioned guidance equipment, laser beams a and b are irradiated from the moving body 1 over the entire circumference of the moving body 1,
When the light receiving signal of the first light receiving element 32 is input, it is confirmed whether the light receiving signal of the second light receiving element 34 is input, and when the input of the light receiving signal of the second light receiving element 34 is confirmed, the retroreflector 2 Is detected, and the mirror rotation angle Θ detected by the rotation angle detector 31 at this time is stored, so that the arrangement angle of each of the retroreflectors 2 around the moving body 1 is determined. Is detected, and the current position of the moving body 1 is measured from the positions of the respective retroreflectors 2 around the moving body 1. The moving body 1 moves along a preset route based on the measured current position.

As described above, the retroreflector 2 and other noises (the regular reflector 41 such as a window, a metal frame, and a pipe) can be distinguished, so that disturbance noise can be removed and erroneous position detection due to the noise can be prevented. In addition, by combining with the guidance method, accurate, accurate, and safe guidance can be performed without the influence of the reflection noise. In addition, noise can be removed in hardware, and the load of signal processing on the arithmetic processing unit 40 can be reduced.

In this embodiment, two laser beams a and b are used. However, as shown in FIG.
13 is provided with a third semiconductor laser 13 'at a position of 90 degrees, a light receiving element for the third semiconductor laser 13' is provided, and three laser beams are used to determine whether the reflector is a retroreflector. Can be detected. At this time, the combination of the semiconductor laser and the light receiving element used for recognition can be determined based on the direction of the window 20 provided on the side surface of the cylinder 19 that can be detected by the rotation angle detector 39.

In FIG. 4, the retroreflector 2 as viewed from the moving body 1
When the specular reflector 41 exists near the "left and right" of
In order to avoid accidentally detecting both reflected lights, a set of semiconductor lasers and light receiving elements that are aligned in accordance with the direction of the window 20 is used (actually, the Each time the direction changes by 90 degrees, the combination of the semiconductor laser and the light receiving element is changed). In FIG. 4A, when the semiconductor lasers 11 and 13 whose alignment is aligned with the direction of the window 20 are used, and when the direction of the window 20 is at a position rotated by 90 degrees, as shown in FIG. In addition, the semiconductor laser whose orientation matches the direction of the window 20
I use 11 and 13 '. As described above, when the arrangement is in accordance with the direction of the window 20, that is, when the direction of the reflection mirror 21 is in agreement with the arrangement of the semiconductor lasers, the light is emitted in the vertical direction as shown in FIG. A laser beam is used. Therefore, when viewed from the moving body 1, the retroreflector 2
When the specular reflector 41 is present near the left and right of the image, it is possible to avoid accidentally detecting both reflected lights.

When the specular reflector 41 is located near the “up and down” of the retroreflector 2 as viewed from the moving body 1, in order to avoid accidentally detecting both reflected lights,
A set of a semiconductor laser and a light receiving element whose arrangement differs by 90 degrees depending on the direction of the window 20 may be used.

As described above, when the regular reflector 41 is located near the retroreflector 2, the effective light reception is used according to the position (selection of the combination of the semiconductor laser and the light receiving element to be used). Or by turning off a combination of a semiconductor laser and a light receiving element that is not used), and noise (a window, a metal frame, a pipe, or the like) can be further removed, and the identification accuracy can be improved.

It is needless to say that the number of rays to be irradiated is not limited to three but can be increased by changing the angle.

[0037]

As described above, according to the present invention, the reflector to be detected is irradiated with a plurality of light beams having different angles, and it is determined whether at least two or more reflected lights of the plurality of light beams have been received. By confirming, it is possible to recognize whether or not the light is reflected from the retroreflector, so that other noise (window,
Metal frames, pipes, etc.) can be removed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a moving object equipped with guidance equipment for implementing a reflected light identification method according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of the reflected light identification method.

FIG. 3 is an explanatory diagram of the reflected light identification method.

FIG. 4 is an explanatory diagram of guidance equipment for realizing a reflected light identification method according to another embodiment.

FIG. 5 is an explanatory diagram of position measurement by a laser guiding facility.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Moving body 2 Retroreflector 11, 13, 13 'Semiconductor laser 17 Conduit 19 Cylindrical body 20 Window 21 Reflection mirror 22, 25 Pulley 23 DC motor 26 Belt 31 Half mirror 32, 34 Light receiving element 38 Encoder 39 Rotation angle detector 40 Arithmetic processing unit a First laser beam b Second laser beam A, B, C Installation position of retroreflector

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Yoichiro Nakamura 1-7-89 Minami Kohoku, Suminoe-ku, Osaka-shi, Osaka Inside Hitachi Zosen Corporation (72) Inventor Yoshihiro Igaki Minami-Kohoku, Suminoe-ku, Osaka-shi, Osaka 1-7-89 Inside Hitachi Zosen Corporation (72) Inventor Hirotoshi Shimoda 1-7-89 Minami Kohoku, Suminoe-ku, Osaka City, Osaka Prefecture Inside Hitachi Zosen Corporation (72) Inventor Kazunari Daiyoshi Nishi-ku, Osaka City, Osaka Prefecture (15) Inventor Hisatoshi Narazaki 1-15-10, Kyomachibori, Nishi-ku, Osaka-shi, Osaka, Japan

Claims (3)

[Claims] 1. A reflected light discriminating method for irradiating a light beam on a reflector to be detected and identifying whether or not the reflected light is a reflected light from a retroreflector, wherein the reflector to be detected is provided. Irradiating a plurality of light beams having different angles to each other, and when at least two or more reflected light beams of the plurality of light beams are received, recognizes the reflected light from the retroreflective body using effective light reception. A reflected light identification method. 2. A reflected light discriminating device for irradiating a light beam to a reflector to be detected and identifying whether or not the reflected light is a reflected light from a retroreflector, wherein the reflector to be detected is provided. Light irradiating means for irradiating a plurality of light rays having different angles with respect to light; light detecting means for detecting reflected light of the plurality of light rays; and at least two or more reflected lights of the plurality of light rays are received by the light detecting means. A reflected light identifying device that recognizes the reflected light from the retroreflector by using the effective light reception when the reflected light is detected. 3. A position detecting device for a moving body moving in a predetermined area, wherein a plurality of retroreflectors are provided at predetermined positions in the area, and the moving body is rotated over the entire circumference while rotating. Light irradiating means for irradiating a plurality of light beams having different angles, light detecting means for detecting reflected light of the plurality of light rays, angle detecting means for detecting a rotation angle of the light irradiating means, and the light detecting means When at least two or more reflected lights of the plurality of light beams are received, a recognition unit that recognizes that the reflected light is a reflection light from the retroreflective body using effective light reception; When it is recognized that the reflected light is the reflected light, the rotation angle of the light irradiation means detected by the angle detection means is stored, and the measurement means for measuring the current position of the moving object is provided based on the stored rotation angles. Features Device for detecting a position of a moving body that.