JPH0570844B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides a light for guiding and information sensing of an automatic guided vehicle that detects the position of a light reflective tape laid on the floor and provides a traveling control signal to the automatic guided vehicle. This invention relates to a reflective tape reading device.

Conventional technology Conventionally, this type of reading device detects the difference in the amount of retroreflective light between the light reflecting tape with retroreflectivity and the floor surface, which is laid on the floor along the guide course of the automatic guided vehicle. The device is configured to detect a location. The reading device uses a fluorescent lamp as a light source. Then, fluorescent lights are attached to the front and rear of the automatic guided vehicle in the direction of the axle to illuminate the downward direction, and multiple photodetectors are arranged parallel to the fluorescent lights to detect reflected light on the automatic guided vehicle. A configuration is adopted. In other words, the relative positional relationship between the automatic guided vehicle and the light-reflecting tape is recognized by detecting the position of the multiple photodetectors that received and received the reflected light, and the vehicle can move straight or turn, etc. This is used as the standard for travel control signals.

Problems to be Solved by the Invention However, when lighting the fluorescent lamp, it is necessary to provide a device for increasing the low voltage of the battery in the power supply section, and there is a drawback that the power consumption is large.

Furthermore, this type of reading device lacks reliability in detecting light reflective tape because it is easily affected by aging, tilting, and ambient light of the light reflective tape. have the disadvantage of being unusable or unreliable.

Therefore, in order to detect coaxial light, a method has also been proposed in which the irradiated light and the reflected light are separated using a beam splitter. However, in this method, it is necessary to adjust the angle of the beam splitter in order to align the two optical axes of the light emitting section and the photodetecting section. As a result, the beam splitter mounting structure becomes complicated.
Another drawback is that it is difficult to reduce the size and weight of the reading device.

The present invention was devised in view of the above circumstances, and is an automatic guided vehicle that has low power consumption, high detection accuracy of light reflective tape, high reliability, simple structure, and easy alignment of the optical axis. The object of the present invention is to provide a reading device for light reflective tape for guidance and information detection.

Means for Solving the Problems A light reflective tape reading device for guiding and information sensing of an automatic guided vehicle according to the present invention reads light reflective tapes at the front and rear parts of the automatic guided vehicle and along the axle direction thereof. A plurality of devices are arranged to detect the position of the light-reflecting tape based on the difference in the amount of retroreflection between the light-reflecting tape laid on the floor along the guidance course and the floor. In the control device that provides a travel control signal to the light reflecting tape, the reading device for each of the light reflecting tapes includes a semiconductor light emitting element as a light source, and guides the irradiated light from the semiconductor light emitting element to the light reflecting tape and detects retroreflection reflected from the light reflecting tape. An optical fiber cable that guides light to a photodetector, and is provided in an outer frame having an opening to form an image of the irradiated light on the surface of a light reflective tape and to focus the retroreflected light on the end face of the fiber cable. It is equipped with a lens system and a photodetector that receives retroreflected light through the lens system and an optical fiber cable, and the optical fiber cable has a plurality of randomly arranged projections having an appropriate diameter. Optical fiber core wires for light and reflected light are bundled into one, and the lens system is arranged so as to irradiate the irradiated light obliquely onto the light reflective tape. There is.

Embodiment FIG. 1 is an explanatory diagram schematically showing the configuration of an automatic guided vehicle equipped with a light reflective tape reading device (hereinafter simply referred to as "reading device") for automatic guided vehicle guidance and information detection according to the present invention. It is. In the figure, 101 is an automatic guided vehicle, and a light reflective tape 10 with retroreflectivity is laid on the floor along the travel route.
2 is detected and the vehicle starts running.

The light reflective tape 10 is placed on the front and rear parts of the automatic guided vehicle 101 and along the axle direction thereof.
A plurality of reading devices 103 and 104 are each arranged as means for detecting 2. 10
5 is a steering wheel, 106 is a drive wheel, and 107 and 108 are information light reflective tapes. The information light reflective tape 107 is made of the same material as the guide light reflective tape 102, has a predetermined length and a predetermined width, and is provided on the floor at a predetermined distance from the guide light reflector tape 102. A two-dimensional barcode is attached to the surface. In addition, information light reflective tape 10
8 is similar to the information light reflective tape 107 except that the surface is not displayed. The combination of the barcode and non-display is set in advance, and the reading devices 103 and 104 detect this combination to transmit information such as the destination, vehicle speed, branching direction, etc. of the automatic guided vehicle to the automatic guided vehicle 101. It's becoming like that.

FIG. 2 is an explanatory diagram showing the configuration of a reading device 103 provided at the front of an automatic guided vehicle according to an embodiment of the present invention. The reading device 103 includes a semiconductor light emitting device 111 such as a light emitting diode as a light source, an optical fiber cable 112, a lens system 113, and a photodetector 114.

The optical fiber cable 112 connects the light emitting diode 1
The light emitted from the light reflecting tape 102 is guided toward the light reflecting tape 102, and the retroreflected light from the light reflecting tape 102 is guided to the detector 114. Lens system 11
3 is a retroreflector that irradiates the light emitted from the light emitting diode 111 guided by the optical fiber cable 112 obliquely onto the light reflective tape 102 to form an image on the surface, and is reflected from the surface of the light reflective tape 102. Light 117 to optical fiber cable 11
The image is formed on the end face of 2.

A photodetector 114 converts the retroreflected light 117 reflected by the light reflective tape 102 into a lens system 113,
Light is received via an optical fiber cable 112. For example, a photodiode or the like is used for this photodetector 114.

The lens system 113 is provided in an outer frame 115 having an opening on the lower surface, and the opening is provided with a dustproof glass or a dustproof and disturbance light removing glass filter 1.
16 is attached.

On the other hand, a reading device 104 provided at the rear of the automatic guided vehicle is configured similarly to the reading device 103 described above.

Light emitted from the light emitting diode 111 passes through the fiber cable 112, is focused by the lens system 113, and forms an image on the light reflective tape 102. The retroreflected light 117 retroreflected by the light reflective tape 102 is collected by the lens system 113 and further enters the photodetector 114 via the optical fiber cable 112. At this time, the regularly reflected light 118 does not return to the lens system 113. That is, by setting the incident angle α of the light emitted from the light emitting diode 111 onto the light reflecting tape 102 to an appropriate angle other than zero, the specularly reflected light 118
, only the components of the retroreflected light 117 can be selectively detected. and light reflective tape 10
2 is tilted, the retroreflected light 117 is focused by the lens system 113, so it does not deviate from the photodetector 114.If the floor surface has a high reflectance and the specularly reflected light 118 is strong, Even if the tape is based on the light-reflecting tape 102, it will not be mistakenly detected as the light-reflecting tape 102.

Figure 3 shows the optical fiber cable 1 inside the outer frame 115.
12 is a cross-sectional view showing the arrangement of the light-receiving optical fiber core through which the retroreflected light passes and the light-projecting optical fiber core through which the irradiation light passes at the end face of No. 12. FIG.

As shown in the figure, the optical fiber cable 112 includes light-emitting and light-receiving optical fibers each having an appropriate diameter, and a plurality of each of them arranged in a disorderly manner and bundled into one. There is. One end of the light emitting and light receiving optical fibers is connected to one light emitting diode 111 and one photodetector 114, respectively, and the other end is connected to a lens system 113.
are optically connected to each other.

The optical fiber cable 112 having the above-mentioned configuration is
It has the following characteristics. That is, the retroreflected light 117 shown in FIG. 2 actually enters from the surface of the light reflective tape 102 and is reflected by a non-illustrated retroreflector provided inside. Therefore, the retroreflected light 117 is not on the same axis as the irradiated light,
It is retroreflected parallel to the irradiated light from a position shifted from the irradiated light. Further, if the light reflecting tape 102 is inclined, etc., the above-mentioned deviation becomes large. Therefore, if one optical fiber is connected for each of light emission and light reception, depending on the amount of deviation, the retroreflected light 1
07 will not be transmitted to the light receiving side. but,
According to this configuration, the optical fiber cores are arranged in a disorderly manner even if the deviation occurs in any direction.
The retroreflected light 107 is connected to one of the optical fibers. Therefore, the retroreflected light 107 is reliably transmitted to the light receiving side.

FIG. 4 is a block diagram schematically showing the circuit configuration of the reading device according to the present invention. That is, the light emitting diode 111 is intermittently driven by a drive circuit 122 to which the output of an oscillation circuit 121 is applied. The resulting pulsed light is reflected by the light reflecting tape 102, enters the photodetector 114, and is amplified by the amplifier 123. The amplified output is passed through a filter 124 to an A/D converter 125.
is input. The digitally converted electrical signal is input to a control circuit 126 mounted on the automatic guided vehicle, and this control circuit 126 steers the steering wheels 105 based on the input signal. The oscillation circuit 121 in the above is the light emitting diode 1
By pulse-modulating the irradiated light from the photodetector 114 and detecting it in synchronization with the detection input signal from the photodetector 114, it is possible to further prevent noise detection due to specularly reflected light and disturbance light. In some cases, it may be omitted.

Further, the barcode attached to the information light reflective tape 107 is detected by the photodetector 114 as described above, and is input to a microcomputer (not shown) for arithmetic processing, and the barcode is determined based on the output. It is based on the directive.

In addition, in the non-display light reflective tape 103, the non-display light reflective tape 108 is detected by the photodetector 114.
By counting the number of detections of , the information given for each count is detected. Either of the information light reflective tape 107 and the non-display reflective tape 108 can be adopted as appropriate.

Therefore, in the present invention, an optical fiber cable is used to guide an automatic guided vehicle and read a light reflective tape for information detection, and a coaxial light emitting and receiving optical system is realized, and the diameter of each optical fiber core wire is large. For the purpose of increasing the amount of light, a plurality of optical fibers are bundled together to form a single optical fiber cable, which has a simple structure and allows easy alignment of the optical axis.

Effects of the Invention The automatic guided vehicle guidance and information detection light reflective tape reading device according to the present invention uses a coaxial light emitting and light receiving optical system using an optical fiber cable in which fine optical fiber core wires of an appropriate diameter are bundled. Since the structure is simple and the optical axis can be easily aligned, reliability can be improved and the range of applicable floor surfaces can be expanded.

Furthermore, since the present invention uses a semiconductor light emitting element as a light source, the power consumption required for irradiation is extremely low, and the battery can be made smaller and have a longer lifespan. Further, by using a control method in which the semiconductor light emitting element is pulse-driven, the effect of making it easier to distinguish it from ambient light was obtained.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram schematically showing the configuration of an automatic guided vehicle equipped with an embodiment of the light reflective tape reading device according to the present invention, and FIG. 2 is an explanatory diagram schematically showing the configuration of the light reflective tape reading device. 3 is a cross-sectional view of the optical fiber cable end face within the outer frame of the light reflective tape reader, and FIG. 4 is a block diagram schematically showing the circuit configuration of the embodiment shown in FIG. 1. 101...Automated guided vehicle, 102...Light reflective tape, 103,104...Light reflective tape reading device, 107,108...Light reflective tape for information, 1
11... Light emitting diode, 112... Optical fiber cable, 113... Lens system, 114... Photodetector.

Claims (1)

[Claims] 1 A plurality of light reflective tape reading devices are arranged at the front and rear of the automated guided vehicle along the axle direction, and light reflective tape with retroreflectivity is laid on the floor along the guidance course. In the control device that detects the position of the light reflective tape based on the difference in the amount of retroreflection between the tape and the floor surface and provides a travel control signal to the automatic guided vehicle, the reading device for each of the light reflective tapes uses a semiconductor light emitting element as a light source. an optical fiber cable that guides the irradiated light from the semiconductor light emitting element to the light reflective tape and guides the retroreflected light reflected from the light reflective tape to the photodetector; It is equipped with a lens system that forms an image on the surface of the light reflective tape and focuses the retroreflected light onto a single surface of the fiber cable, and a photodetector that receives the retroreflected light via the lens system and the optical fiber cable. The optical fiber cable is formed by bundling a plurality of randomly arranged optical fiber core wires for light projection and reflected light, each having an appropriate diameter, and the optical fiber cable is formed by bundling together a plurality of optical fiber core wires for projecting and reflecting light, each having an appropriate diameter and arranged in a disorderly manner. A light reflective tape reading device for guiding an automatic guided vehicle and detecting information, characterized in that the irradiation light is arranged so as to irradiate the light reflective tape obliquely.