JP2925454B2 - Mobile body guidance device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for guiding an automatic transport vehicle in a moving body, for example, a factory.

[0002]

2. Description of the Related Art Conventionally, there are the following devices for guiding an automatic transport trolley in a factory or the like. Device that uses electromagnetic induction This device embeds electric wires in the floor along the moving path of the transport trolley, guides the transport trolley while detecting the magnetic field change caused by the flow of AC current through the wires. It is. This device uses magnet guidance. In this device, a magnet is arranged on the floor along the moving path of the carrier, and the magnetic field generated by the magnet is detected by a magnetic sensor provided on the carrier, while Is to induce. This device is equipped with a device that can detect the moving distance and moving direction on a transport trolley. Based on information obtained from this device, the current position is calculated, and the traveling direction is determined by the user. Is the method to be determined. Device using guidance by recognition of images, symbols, etc.This device is equipped with a recognition device that recognizes images around the movement route of the transport vehicle or specific symbols, and recognizes images or symbols by this recognition device. This is a method for determining the traveling direction of the transport vehicle.

[0003]

However, according to the above-described guidance device, there is a problem that the use of the carriage cannot be performed when the road surface on which the carriage is moved is made of a magnetic material such as an iron plate.

[0004] Further, according to the above-described guidance device, there is a problem that the accumulated error increases during guidance and the possibility of deviating from the moving route is high. Further, according to the above-mentioned guidance device, there is a disadvantage that a recognition device for recognizing an image, a symbol, or the like mounted on a transport trolley is very expensive.

[0005] Therefore, an object of the present invention is to provide a mobile object guidance device that can solve the above-mentioned problems.

[0006]

In order to solve the above-mentioned problems, a first means of the present invention is to dispose an optical waveguide along a moving path of a moving body and to place a laser beam on one end of the optical waveguide. A light emitter is arranged, and on the moving body side, an ultrasonic emitter that emits ultrasonic waves to the optical waveguide, a light receiving unit that receives laser light emitted from the optical waveguide by an acousto-optic effect by this ultrasonic wave, and from this light receiving unit And a control device for controlling the steering device of the moving object based on the light receiving signal of the moving object.

According to a second aspect of the present invention, in the first aspect, a photodetector is disposed at one end of the optical waveguide, and the laser light is transmitted to a portion of the optical waveguide where the laser light is emitted to the outside. Is a guidance apparatus for a mobile object, which is provided with a measuring device for measuring a round trip time of the moving object.

Further, a third means of the present invention is the above-mentioned first means.
Alternatively, in the second means, the present invention is a moving object guiding device in which optical communication devices are respectively arranged on the moving object side and one end of the optical waveguide.

[0009]

In the above arrangement, when an ultrasonic wave is transmitted to an optical waveguide arranged along the movement path of a moving body, an acousto-optic effect is generated at that portion, and therefore, a laser beam traveling in the optical waveguide is generated. Is diffracted at that portion and emitted to the outside.

The emitted laser light is received by a light receiving section provided on the moving body side, and the light receiving position is detected, and the moving body is moved so that the light receiving position is a predetermined position of the moving body. If controlled, the moving body can be accurately guided along the optical waveguide.

A measuring instrument for measuring the reciprocating time of the laser light is disposed at one end of the optical waveguide, and the laser light is reflected at a portion where the refractive index is changed by the ultrasonic wave to utilize the laser light. The position of the moving body can be detected by calculating the reciprocating time up to the portion where the refractive index changes.

Further, by arranging the optical communication devices on the mobile body side and one end side of the optical waveguide, communication can be performed between the fixed station side and the mobile body side.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In the present embodiment, a case will be described in which, for example, in a factory or the like, a transport trolley (an example of a moving body) that automatically transports a package to a destination via a predetermined moving path is guided.

In FIG. 1, reference numeral 1 denotes a guiding device for a transport vehicle 2, for example, an optical fiber (optical waveguide) 3 disposed along a moving path A of the transport vehicle 2 in a loop shape, and one end of the optical fiber 3. A laser light projector 4 and a light receiver 5 disposed in the moving part 2, an ultrasonic transmitter 6 and a light beam position detecting sensor (an example of a light receiving part, more specifically, a one-dimensional light position Sensor 7) and a light transmitter 4 provided on the fixed station side corresponding to one end of the optical fiber 3.
Measuring device 8 for measuring the time until the reflected laser light of the emitted laser light is received and fixed-side optical communication device 9
And a mobile optical communication device 10 provided on the mobile body 2 side.

As shown in FIG. 2, the ultrasonic transmitter 6 emits an ultrasonic wave B to the optical fiber 3 to generate an acousto-optic effect in the core 3a. For example, when the ultrasonic wave B is emitted, the refractive index changes in a stripe shape in the core portion 3a, and the laser light C is diffracted like the laser light C '. In addition, since the angle formed between the core portion wall surface (waveguide inner surface) 3b and the laser beam C 'exceeds the critical angle, the core portion 3
The laser light propagating inside a is emitted out of the optical fiber 3.

Therefore, if the steering device (not shown) of the carriage 2 is controlled so as to detect the laser beam C 'emitted from the optical fiber 3, the carriage 2 can be guided along the movement path A. Can be.

As shown in FIGS. 3 and 4, the light ray position detecting sensor 7 has a light receiving plate 11 mounted on the side of the carriage 2 in a direction perpendicular to the moving path A, and It comprises a plurality of photodiodes 12 arranged in a line on the left and right, and a detection circuit section 13 for detecting the light receiving position based on the light receiving signals obtained from the photodiodes 12.

Although not shown, the detection circuit 1
A control device (not shown) for controlling a steering device (not shown) of the transport vehicle 2 based on the light receiving position obtained in 3 is provided.

Therefore, in the above configuration, when the cargo is transported to a predetermined place in the factory, a laser beam is emitted from the projector 4 into the optical fiber 3, and the transport trolley 2 travels on the optical fiber 3, In the carrier 2, ultrasonic waves are transmitted from the ultrasonic transmitter 6 toward the optical fiber 3.

Then, the core 3a of the optical fiber 3 becomes
The laser beam C is distorted by the ultrasonic wave, the refractive index of this portion changes in a striped shape, and the angle of the laser beam C with respect to the wall surface 3b of the core portion 3a at this portion exceeds the critical angle. It will be emitted outside.

The emitted laser light C 'is received by the light beam position detecting sensor 7. Then, when the light receiving position of the laser light C 'is obtained, a signal for driving the steering device is output from the control device so that the light receiving position is located at the center of the light beam position detection sensor 7. That is,
The carrier 2 is always guided to move on the movement path A by the laser light C ′ emitted from the optical fiber 3.

The laser light C emitted from one end is
Is reflected at the portion where the refractive index distribution is generated, so that the reflected laser light C ″ is received by the light receiver 5 and the round trip time is detected by the measuring device 8. , The distance to the carrier 2 can be determined by an arithmetic unit (not shown).
That is, the position of the transport vehicle 2 can be known in real time.

Further, since the ultrasonic waves are always emitted from the carrier 2, the laser beam C can be emitted and incident on the portion of the optical fiber 3 where the refractive index has changed. Bidirectional communication can be performed between the device 9 and the optical communication device 10 on the moving side of the carrier 2. That is, if the laser light from the mobile optical communication device 10 is incident on the optical fiber 3 at an angle smaller than the critical angle, the laser light propagates through the optical fiber 3 and reaches the fixed optical communication device 9.

The laser beam for communication may be a laser beam for guidance, or a laser beam dedicated to communication different from the laser beam for guidance. As described above, unlike the magnetic guidance and the guidance based on the recognition of images and symbols, which are described in the conventional example, it is possible to freely communicate between the fixed station side and the carrier 2 via the laser beam. it can.

Here, the light beam position detecting sensor 7 will be described with reference to FIGS. That is, in order to detect a deviation from the center of the moving route of the transporting vehicle 2, the light beam position detecting sensor 7 is, for example, ten by right and left (of course, the number is not limited to ten, The number can be appropriately increased or decreased according to the light receiving range.)
The photodiodes 12A and 12B are provided, and a difference between both signals from the left and right photodiodes 12A and 12B is taken into consideration.

That is, the light receiving position detecting circuit section 13
Ten right photodiodes 12A (P₁ ~ P_TenNote
) And their amplification
Rate K ₁ ~ K_TenAre set to increase in proportion to
Right-side current-voltage conversion amplifier 21 (21A)
Add the amplified voltage obtained by the current-voltage conversion amplifier 21A
The right amplified voltage adding circuit 22 (22A)
Left photodiode 12B (Q₁ ~ Q_TenIndicated by the symbol
), And its amplification factor K₁ ~
K_Ten(Same value as the amplification factor on the right)
Current-voltage conversion increase set to increase
Width meter 21 (21B) and each current-voltage conversion amplifier 2
A left-side amplified voltage addition circuit for adding the amplified voltage obtained in 1B
Path 22 (22B), these amplified voltage adding circuits 22A,
Subtraction circuit for subtracting output voltages added at 22B from each other
23 and the photodiodes 12A on the right side
Is converted into a voltage with a constant amplification factor k.
First, a reference voltage is obtained by adding all these light quantity voltages.
The right reference voltage adding circuit 24 (24A) and each of the above left
Constant amplification of the amount of light received by photodiode 12B
Is converted into a voltage by the ratio k and these light amount voltages
Left side reference voltage addition circuit
24 (24B), these two reference voltage adding circuits 24A,
Light amount voltage addition for adding the reference light amount voltage obtained in 24B
Circuit 25 and the light amount obtained by this light amount voltage adding circuit 25
The output voltage obtained by the subtraction circuit 23 is divided by the voltage
A division circuit 26 and a division signal obtained by the division circuit 26
It consists of a detection circuit 27 that detects the light receiving position based on the value.
Have been.

Next, the operation of the position detecting circuit section 13 will be described. For example, when a laser beam is incident on the right side of the light receiving plate 11, a current corresponding to the amount of received light is generated in some photodiodes 12A on the right side [the graph of FIG. The output signal at the point b) is output according to the position of the photodiode 12A, and the amplified voltage signal amplified at the predetermined amplification factor K _k is output [the graph of FIG. Signal))].

Next, after the amplified voltage signals amplified at the respective predetermined amplification factors K _k are added by the amplified voltage adding circuit 22A [The graph of FIG. 7 shows the relationship between the light receiving position and the added voltage (c 8 shows a graph in the case where a laser beam enters the left photodiode 12B], which is input to the subtraction circuit 23 and is obtained from the photodiodes 12A and 12B on both sides. [The graph of FIG. 10 shows the relationship between the light receiving position and the subtracted voltage (shows the output signal at point d). FIG. 9 shows the case where the light amount is strong. And a weak case].

On the other hand, each reference voltage adding circuit 24A, 24B
Are added by the light amount voltage adding circuit 25 to obtain a light amount voltage. [The graph of FIG. 10 shows the relationship between the current based on the received light amount and the added voltage (the output signal at point e is Shown)].

Then, this light amount voltage is input to a division circuit 26, where the output voltage from the subtraction circuit 23 is divided by the light amount voltage to obtain a position signal. (Indicating an output signal at point f)], a position signal is output. The position signal represents a distance s from the centers of the photodiodes 12A and 12B arranged on the left and right as shown in FIG.

By providing the detection circuit section 13,
By simply providing a plurality of photodiodes 12A and 12B in parallel, for example, a light receiving position of a laser beam can be accurately detected with a simple configuration.

In the above description, the photodiode is divided into left and right, and more specifically, the case where the light is incident on the right photodiode is described. For example, when the light is incident on both the left and right photodiodes,
The subtraction circuit described above functions.

In the above description, the amplified voltage obtained by adding the amplified voltages obtained from the right and left photodiodes is subtracted from each other to determine the position from the center. The positions of the photodiodes may be determined based on one end without dividing the photodiodes into left and right.

In this case, the amplification factor is set to a value that increases sequentially from one end to the other end. In this case, after adding the amplification voltages obtained from the right and left photodiodes, respectively, Procedures such as subtraction from each other can be omitted.

In the above embodiment, the guidance device 1 is provided with a two-way communication function. However, in some cases, only the function of transmitting information from the fixed station to the carrier 2 is provided. You may do it. Of course, in this case, the configuration of the communication device is simplified. In some cases, the communication function can be omitted from the guidance device 1.

Further, in the above-described embodiment, the light emitting device and the light receiving device are separately arranged at one end of the optical fiber. However, the light receiving device actually reflects the laser light emitted from the light emitting device. The one configured to separate and detect the reflected laser light returned in front of the projector is used. That is, a light projector and a light receiver that are integrally provided are used.

Further, in the above-described embodiment, a case has been described in which the present invention is applied to a transport trolley for transporting loads in a factory as an example of a moving body.
The present invention can also be applied to the case of guiding various moving objects such as a work vehicle on a highway, a work vehicle in port facilities, airport facilities, and the like.

[0038]

As described above, according to the structure of the present invention, the ultrasonic wave is transmitted to the optical waveguide arranged along the moving path of the moving body, and the refractive index of the portion is changed, so that the fringe distribution of the refractive index is changed. The laser light is emitted from the optical waveguide by making the light source, and the light receiving unit for receiving the emitted laser light is provided on the moving body side, so that the moving body can be moved along the moving path with a relatively simple configuration and accurately. Can be guided along.

A measuring device for measuring the round trip time of the laser light is arranged at one end of the optical waveguide, and the laser light is reflected at a portion where the refractive index is changed by the ultrasonic wave to make the refraction. The position of the moving body can be detected by calculating the round trip time of the laser beam up to the portion where the rate changes.

Further, by arranging the optical communication devices on the mobile body side and one end side of the optical waveguide, communication can be performed between the fixed station side and the mobile body side.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a schematic configuration of a moving object guiding device according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a state inside the optical fiber at the time of guiding in the embodiment.

FIG. 3 is a front view of a main part of the light beam position detection sensor in the embodiment.

FIG. 4 is a block diagram showing a schematic configuration of a light ray position detection sensor in the embodiment.

FIG. 5 is a graph showing a signal state in the middle of the detection circuit unit in the embodiment.

FIG. 6 is a graph showing a signal state in the middle of the detection circuit unit in the embodiment.

FIG. 7 is a graph showing a signal state in the middle of the detection circuit unit in the embodiment.

FIG. 8 is a graph showing a signal state in the middle of the detection circuit unit in the embodiment.

FIG. 9 is a graph showing a signal state in the middle of the detection circuit unit in the embodiment.

FIG. 10 is a graph showing a signal state in the middle of the detection circuit unit in the embodiment.

FIG. 11 is a graph showing a signal state in the middle of the detection circuit unit in the embodiment.

FIG. 12 is a schematic diagram specifically showing a position signal output from a detection circuit unit in the embodiment.

[Explanation of symbols]

 A moving path 1 guidance device 2 carrier 3 optical fiber 4 light emitter 5 light receiver 6 ultrasonic transmitter 7 ray position detection sensor 8 measuring device 9 fixed side optical communication device 10 moving side optical communication device

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-30914 (JP, A) JP-A-60-243707 (JP, A) JP-A-4-35675 (JP, A) JP-A 55- 69898 (JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) G05D 1/02 JICST file (JOIS)

Claims (3)

(57) [Claims] An optical waveguide is arranged along a moving path of a moving body, a light projector is arranged on one end side of the optical waveguide, and an ultrasonic wave for emitting ultrasonic waves to the optical waveguide is arranged on the moving body side. A transmitter and a light receiving unit for receiving light emitted from the optical waveguide by the acousto-optic effect of the ultrasonic wave, and a control device for controlling a steering device of the moving body based on a light receiving signal from the light receiving unit are provided. Mobile body guidance device. 2. A light receiving device is provided at one end of an optical waveguide, and a measuring device is provided for measuring a round trip time of light to a position where light in the optical waveguide is emitted to the outside. The mobile device guidance device according to any one of the preceding claims. 3. An apparatus for guiding a mobile object according to claim 1, wherein an optical communication device is arranged on the side of the mobile object and at one end of the optical waveguide.