JPS6233611B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a collision prevention device for unmanned transport vehicles in a system in which a large number of unmanned transport vehicles automatically travel along a travel path set on a road surface to transport goods and the like.

In factories where mass production is carried out through assembly line operations, the parts, materials, etc. needed for the process must be transported from the parts and materials storage area where they are accumulated to where they are needed during the production process. .

In such cases, parts and materials must be transported from one or several locations at most to almost every location during the production process. Although the content is relatively simple, it involves a considerable amount of work, and if it were to be done manually, it would require a large number of people, which is not desirable from the standpoint of labor saving, and would also result in a large increase in product costs.

For this reason, so-called unmanned transport systems have been put into practical use, in which driving guidance means are installed in passages within factories, and unmanned transport vehicles automatically travel along the paths to transport parts.

An example of such an unmanned transportation system is shown in FIGS. 1 to 6 of the drawings.

FIG. 1 is a bottom view of the unmanned carrier. This unmanned carrier 1 has a six-wheel structure, with intermediate wheels 2a and 2b.
are drive wheels, and front wheels 2c, 2d and rear wheels 2e, 2f are steering wheels. Front wheels 2c, 2d and rear wheel 2
The steering mechanisms 3a and 3b of e and 2f are connected by a single steering shaft 5 via rack and pinion mechanisms 4a and 4b. A gear 6 is attached to the steering shaft 5, and a steering angle is transmitted to the gear 6 from a steering motor 7 via a gear 8. That is, by rotating the steering shaft 5 with the steering motor 7,
The front wheels 2c, 2d and the rear wheels 2e, 2f can be given the same steering angle in opposite directions. intermediate shaft 2
The running driving force of the wheels a and 2b is transmitted from a running motor 9 via a gearbox 10 and a running shaft 11. Further, at the front and rear ends of the vehicle body, light receiving element rows 12a and 12b each having a large number of light receiving elements arranged in a horizontal line.
is installed, and its light receiving element rows 12a, 12
Light sources 13 each consisting of a fluorescent lamp are arranged in parallel with b.
a and 13b are installed.

An unmanned carrier with such a configuration is designed to automatically travel along a reflective guiding strip laid on a travel path while detecting it. The traveling control system will be explained with reference to FIGS. 2 to 7.

FIGS. 2A and 2B show the relationship between the light receiving element array 12a, the light source 13a, and the reflection guide zone 14 at the front end of the automatic guided vehicle.

A reflection guide band 14 made of aluminum tape or stainless steel tape with high light reflectivity is pasted on the road surface 15 along the path of the automatic guided vehicle. When the road surface is irradiated with the light source 13a, the reflection induction zone 1
4, strong reflected light can be obtained due to specular reflection.
On the contrary, from the road surface 15, weak reflected light is obtained due to diffuse reflection due to the unevenness of the road surface and, in addition, because the reflectance is smaller than that of the reflection guiding band 14. The amount of reflected light is detected by the light receiving element a1 built into each hood 16.
Receives light at ~a12. This photodetector is made of, for example, CdS.
(Cadmium sulfide) whose resistance value changes depending on the amount of light received. Light receiving elements a1 to a1
In order to convert the amount of reflected light received at step 2 into a binary on/off signal, an appropriate threshold value is provided. Comparing this threshold value with each of the light receiving elements a1 to a12, the light receiving element located on the road surface 15 receives an off signal because the reflected light is weak, and the light receiving element located on the reflection guiding zone 14 receives a strong reflected light, so the light receiving element is turned off. Turns on signal. In this way, the road surface 15 and the reflection guiding zone 14 are identified by processing the intensity of the reflected light from the road surface.

Next, FIG. 3 shows the relationship between the light receiving element and the steering angle.

Opposite steering angles are determined for each of the light receiving elements a1 to a12. The light receiving elements a6 and a7 have the smallest steering angle, and the steering angle increases as the light receiving element approaches the left direction, that is, the light receiving element a1, or the right direction, that is, approaches the light receiving element a12. For example, when the light receiving element a6 is turned on, a steering angle command of 10 degrees to the left is output, and when the light receiving element a10 is turned on, a steering angle command of 40 degrees is output.

However, since the actual reflection guiding band 14 has a certain width, there is a high possibility that the light receiving element turns on at two or more locations, as shown in FIG. (In FIG. 2, two locations a6 and a7 are on.) Therefore, in addition to the circuit that processes the on/off signal, a steering angle extraction circuit that selects one steering angle is required. An example of the circuit is shown in FIG. The outputs of the light receiving elements a1 to a12 are converted into on/off signals by an on/off processing circuit 17. A switch 19 is connected to an extraction circuit 18 that extracts one on-signal from among the on-off signals. Depending on the command of this switch 19, the light receiving element that is turned on at the far left side is extracted, or
Extract the light receiving element that is turned on at the far right. Other light receiving elements are ignored even if they are on. This logic is composed of gate circuits and the like. Thereby, the extracted light receiving element becomes a steering command.

The switch 19 is effective in selecting the branching direction.
When the reflection guiding band 14 branches left and right as shown in FIG. 5, if the switch 19 extracts the light-receiving element a3 that is turned on at the leftmost position, the unmanned carrier will enter the left branch and the most left branch. If the light receiving element a7 that is turned on on the right side is extracted, the unmanned carrier will enter the right branch.

Next, a control circuit for the automatic guided vehicle in response to a steering command will be explained with reference to FIG. Reflected light from the road surface is detected by a light receiving element array 12a, converted into an on/off binary signal by an on/off processing circuit 17, and inputted to a steering angle extraction circuit 18 to select one steering angle. This steering angle is input to the servo circuit 20, and the amplifier circuit 2
1 to drive the steering motor 7. For example, a potentiometer 22 is attached to the steering motor 7 as an angle detector to detect the rotation angle. This rotation angle is fed back to the servo circuit 20, and steering is performed so that the rotation angle matches the steering angle command.

Incidentally, in such a driving system, although it depends on the purpose of use, in many cases, a plurality of unmanned carrier vehicles are introduced on the travel route, and in most cases, they are operated simultaneously. In addition, it is common for many merging points to be formed on the driving route, and therefore there is a considerable possibility that two unmanned vehicles will collide at the merging points.

Therefore, conventionally, a method as shown in FIG. 7, for example, has been adopted to prevent collisions in such cases.

In FIG. 7, 23 and 24 are reflection guiding bands 14.
A detection device for an unmanned carrier installed on the approach road side near a confluence point formed in a travel road by
Reference numerals 5 and 26 denote an unmanned carrier stop command device, which is also installed on the approach road side, and 27 is an unmanned carrier vehicle detection device, which is installed on the exit road side near the merging point.

Here, the detection device 23 is configured to set the stop command device 26 into operation when it detects the presence of the carrier, the detection device 24 is configured to likewise set the stop command device 25, and the detection device 27 It is configured to reset both stop command devices 25, 26 to an inoperative state when it detects the presence of a carrier, and furthermore, stop command devices 25, 26 are configured to It is installed on a running road surface, etc., and if an unmanned carrier approaches it while it is operating, the unmanned carrier will remain stopped and wait, and when the operation is stopped, the unmanned carrier will stop running. Of course, when the stop command devices 25 and 26 are in an inactive state, there will be no effect even if the unmanned carrier approaches there.

Next, the operation will be explained.

Suppose now that two unmanned transport vehicles 1a and 1b are traveling toward this merging point, and the transport vehicle 1a happens to pass by the detection device 23 first.

As a result, the detection device 23 is activated by the stop command device 26.
It sends a signal to the device and sets it to the operating state. Therefore, the transport vehicle 1b that attempts to enter the junction later is immediately stopped by the stop command device 26 which is set in this operating state.

Therefore, only the transport vehicle 1a continues to travel and enters the junction, and eventually passes by the detection device 27. As a result, this detection device 27 sends a signal to the stop command device 26 and resets it to an inactive state, so that the stopped transport vehicle 1b is released and starts traveling, and can enter the junction. become able to.

On the other hand, when the unmanned carrier vehicle 1b approaches the detection device 24 first, the stop command device 25 is set to the operating state, the carrier vehicle 1a is stopped thereon, and the carrier vehicle 1b passes through the junction. Stick detection device 27
You will be forced to wait until you pass by.

Therefore, the method shown in FIG. 7 can prevent collisions of unmanned transport vehicles in unmanned transport systems, but in such conventional methods Since it is necessary to install a large number of detection devices and stop command devices, as well as electrical circuits connecting these devices, the amount of ground-side equipment required is enormous when many merging points are used on a complex driving route. This results in a significant increase in the initial cost and construction period.In addition, the number of parts to be processed on the floor of passageways in factories, etc. becomes stricter, and there is a risk that the usage as a passageway will deteriorate. There were various drawbacks, such as the fact that many facilities were fixed.

An object of the present invention is to provide a collision prevention device that can reliably prevent collisions of unmanned guided vehicles at merging points without requiring almost any additional ground equipment, while eliminating the drawbacks of the prior art described above. It is in.

In order to achieve this objective, the present invention uses radio waves to propagate a stop control signal between an unmanned guided vehicle that entered a confluence point first and an unmanned guided vehicle that subsequently attempted to enter a confluence point later. The vehicle is characterized by a structure in which most of the equipment for preventing collisions can be installed on the unmanned carrier.

Hereinafter, the present invention will be explained in detail based on the drawings.

FIG. 8 shows an embodiment of the travel path according to the present invention applied to the unmanned transportation system shown in FIGS. 1 to 6, in which the travel paths from the A side and the B side merge as the C side travel path. The confluence point 0 is reached by the guidance zone 14.
is formed, and two unmanned carrier vehicles 1a and 1b are placed there.
This shows the state in which the vehicle has been running.

In the figure, reference numerals 28, 29, and 30 are reflective tapes made by pasting thin strips of aluminum or stainless steel having a predetermined length on the road surface and having a high light reflectance.

Here, the tape 28 serves as an object to be detected for detecting that the transport vehicle 1a entering the confluence point 0 from the A side has reached the vicinity of the confluence point 0. A tape 29 is provided at a predetermined length on the right side at right angles to the guide band 14, and a tape 29 is also provided in the same manner as the tape 28 for the object to be detected with respect to the transport vehicle 1b from the B side. Transport vehicle 1a merged onto C side and traveled
Alternatively, it serves as a detected object for detecting that the object 1b is a predetermined distance away from the confluence point 0, and is provided on the left side in the direction of travel in the same way as the tapes 28 and 29.

Therefore, the portion of these tapes 28, 29, and 30 that is formed to include the confluence point 0 becomes the collision section.

9A and 9B show that one of the reflective tapes 28 or 29, for example tape 28, is covered with a carrier, for example 1a.
has just reached the state where the light from the light source 13a is reflected by this tape 28 and the light receiving element array 1
The light enters five light-receiving elements a ₁ to _{a 5} in 2a at the same time to detect that the carrier vehicle 1a has entered the collision zone.

FIG. 10 shows an embodiment of an unmanned guided vehicle equipped with a collision prevention device according to the present invention, including a light source 13a, a light receiving element array 12a, an on/off processing circuit 17, a steering angle extraction circuit 18, a servo circuit 20, an amplifier circuit 21, The structure and operation of the steering mechanism for automatic travel, which includes the steering motor 7 and the potentiometer 22, are as described in FIGS. 1 to 6.

In the figure, 31 specifies the destination of the unmanned carrier,
A setting circuit 32 is a setting circuit 31 for controlling the vehicle to follow a predetermined travel route and reach the destination.
33 is a drive circuit, 34 is a travel motor, 35 is a collision prevention circuit, 36 is a signal processing circuit, and 37 is a radio wave transmitter,
38 is a radio wave receiver.

Next, the operation will be explained.

When the unmanned carrier vehicle starts traveling, the travel control circuit 32 and the on/off processing circuit 17 are controlled by the output from the setting circuit 31, and the vehicle travels toward the destination.
As explained in FIGS. 1 to 6, the steering motor 7 is controlled so that the vehicle automatically travels along the reflective guidance zone 14 installed on the road surface 15.

At this time, the traveling control circuit 32 is also supplied with a signal from the on/off processing circuit 17, and when the signal from the processing circuit 17 disappears, the rotation of the traveling motor 34 is immediately stopped. This prevents the unmanned carrier from running out of control even if it deviates from the guide zone 14.

Now, the signal from the on/off processing circuit 17 is also supplied to the signal processing circuit 36 provided in the collision prevention circuit 35, and the light receiving element array 12a detects the reflective tape 28 or 29 provided on the approach road side of the collision section. , when signals are simultaneously obtained from all of the light-receiving elements _A1 to _A5 , the transmitter 37 is activated to start transmitting radio waves for collision prevention, and at the same time, the receiver, which is normally in the receiving operation state, is activated. 38 to be inactive.

Further, when the light receiving element array 12a reaches the reflective tape 30 provided on the exit side of the collision section and signals are obtained from the light receiving elements _a6 to _a10 at the same time, the signal processing circuit 36 remains in operation until then. The transmitter 37 that was in the inactive state is switched to the inactive state to stop transmitting radio waves, and after a predetermined period of time, the receiver 38 that was in the inactive state is returned to the receivable state to maintain a steady state. control.

This receiver 38 generates a signal P at its output while the collision prevention radio wave is being received, and when the traveling control circuit 32 receives this signal P, the traveling control circuit 32 immediately rotates the traveling motor 34. The transport vehicle is configured to stop and not run while the signal P is present.

Now, as shown in Fig. 8, suppose that two unmanned guided vehicles 1a and 1b are traveling almost simultaneously toward merging point 0, and if they continue to do so, there is a possibility of a collision near merging point 0. .

Then, by chance, the transport vehicle 1b reaches the top of the reflective tape 29 first, and as a result, signals are simultaneously generated from the light receiving elements a ₁ to _{a 5} of the light receiving element array 13a of the transport vehicle 1b and sent to the signal processing circuit 36. Suppose that it is supplied.

As a result, the transmitter 37 of the unmanned carrier 1b is activated and emits radio waves for collision prevention. It goes without saying that the receiver 38 is rendered inactive at the same time.

On the other hand, since the unmanned carrier 1a has not yet reached the reflective tape 28, it is in a steady operating state in which it can receive radio waves from the receiver 38 in its anti-collision circuit 35.

Therefore, the radio waves from the transmitter 37 of the unmanned guided vehicle 1b are immediately received by the receiver 38 of the unmanned guided vehicle 1a, and the signal P is supplied to the traveling control circuit 32 of the unmanned guided vehicle 1a. The unmanned guided vehicle 1a is stopped almost at the same time as the unmanned guided vehicle 1b, which had approached the confluence point 0 earlier, reaches the reflective tape 29. Meanwhile, the unmanned carrier vehicle 1b continues to travel, enters the collision zone, passes through the confluence point 0, enters the C-side travel path, and eventually reaches the reflective tape 30. Then, signals appear simultaneously from the light-receiving elements a ₆ to _{a 10} of the unmanned carrier vehicle 1b, the signal processing circuit 36 is activated, and the transmitter 37 is switched to the inactive state as already explained. As a result, the radio waves sent to the unmanned guided vehicle 1a, which was stopped outside the collision zone, disappear, and the unmanned guided vehicle 1a starts traveling again and enters the merging point 0. The unmanned carrier vehicles 1b and 1a sequentially travel through the confluence point 0 without causing a collision. At this time, the unmanned guided vehicle 1a that has entered the collision zone also detects the reflective tape 28 and sends out radio waves, and performs a collision prevention operation against the other unmanned guided vehicle that is approaching the merging point 0 later. Needless to say, this operation continues until the reflective tape 30 is detected. In this way, the unmanned carrier vehicles 1b and 1a, which have passed through the merging points one after another and entered the running path on the C side, are exposed to the reflective tape 3.
After a predetermined period of time has passed after detecting 0, each receiver 3
8 is switched to a steady state in which it can receive radio waves, and prepares for the next collision prevention operation.

The above is about the case where the unmanned guided vehicle 1b approaches the confluence point 0 before 1a, but on the other hand, if the unmanned guided vehicle 1a approaches before 1b, then the unmanned guided vehicle 1b will It is stopped outside the collision zone and is kept on standby until the preceding unmanned carrier vehicle 1a reaches the reflective tape 30 and finishes passing through the collision zone.

As described above, according to the present embodiment, collision prevention operation can be achieved simply by installing the reflective tapes 28, 29, and 30 on the road surface 15, and the purpose of collision prevention can be achieved with almost no ground equipment required. be able to.

FIG. 11 shows the signal processing circuit 36 in the present invention.
In one embodiment, 39 and 40 are 5-input AND circuits, 41 and 42 are set-reset flip-flops (hereinafter simply referred to as FF), and 43 is a delay circuit.

Here, the input of the AND circuit 39 includes a light receiving element.
Signals a ₁ ′ to a ₅ ′ from _{a 1} to _{a 5} are input to the AND circuit 40, and signals a 6 ′ to a 6 ′ to a 5 from light receiving elements a ₆ to a ₁₂ are input to the AND circuit 40.
a ₁₂ ' are supplied respectively, and the delay circuit 43 is provided to return the receiver 38 to the normal reception operation state after a predetermined time has elapsed after the unmanned carrier passes over the reflective tape 30. This prevents the preceding unmanned guided vehicle, which has already passed through the collision zone, from being stopped by radio waves from the unmanned guided vehicle that subsequently entered the collision zone.

Although not specifically explained in the case of FIGS. 8 to 10 above, in the present invention, the operation of generating the signal P by the transmitter 37 and receiver 38 of the collision prevention circuit 35 is performed during the collision period. It needs to be enabled only when there is an unmanned carrier nearby, so the transmission output of the transmitter 37 and the receiver 3
Needless to say, it is necessary to appropriately determine the sensitivity of 8 and limit the operating range as described above.

The operation of the embodiment shown in FIG. 11 is as follows.

When the unmanned carrier vehicle reaches the top of the reflective tape 28 or 29 and the signals a ₁ ′ to a ₅ ′ appear simultaneously from the light receiving elements a ₁ to a ₅ , the match condition of the AND circuit 39 is satisfied, so the signal is output from the output of the AND circuit 39 . is generated. Since the output signal of the AND circuit 39 is applied to the set input of the FF 41, the FF 41 is set, a signal appears at its output, the transmitter 37 is activated, and the emission of radio waves is started. At the same time, the output of the AND circuit 39 is given to the reset input of the FF 42, so
FF 42 is reset, there is no signal at its output, and receiver 38 is rendered inactive.

Next, when the unmanned carrier vehicle reaches the top of the reflective tape 30, the signals _a6 '~ from the light receiving elements _a6 ~ _a10
a ₁₀ ' is simultaneously applied to the input of the AND circuit 40,
Since the input condition is satisfied, the output signal is supplied to the reset input of FF 41, and FF 41 is reset and its output becomes 0. As a result, the transmitter 37 becomes inactive and stops transmitting radio waves. At the same time, the output of the AND circuit 40 is delayed for a predetermined time by the delay circuit 43 and is supplied to the set input of the FF 42, so that the FF 42 is set after a predetermined time has elapsed since the signal appears at the output of the AND circuit 40, and the signal is not received. The machine 38 is put back into operation.

Therefore, the signal processing circuit 3 shown in FIG.
6, the object of the collision prevention device according to the embodiment explained in FIGS. 8 to 10 can be achieved.

FIG. 12 shows another embodiment of the signal processing circuit 36 used in the collision prevention device according to the present invention, in which the AND circuit 40 and FF4 in the embodiment shown in FIG.
1, 42, and a delay circuit 43, timer circuits 44, 45 and an inverting circuit 46 are provided instead.

The configuration of this example is simplified by focusing on the fact that the speeds of all unmanned guided vehicles are almost the same, and therefore the time from when they enter the collision zone to when they exit from it can be considered almost constant. A signal indicating that the vehicle has exited the collision zone is obtained from a timer circuit. Therefore,
The reflective tape 30 shown in FIG. 8 does not need to be provided.

Reflective tape 28 when the unmanned carrier reaches the collision zone
Alternatively, signals a ₁ ′ to a ₅ ′ according to 29 appear simultaneously,
When AND circuit 39 generates an output signal, this signal starts timer circuits 44 and 45.
These timer circuits 44 and 45 are of a type that, when started by an input signal, continues to generate a signal for a predetermined period _of time. The configuration is such that the relationship τ ₁ <τ ₂ is satisfied between the duration time width τ ₂ of the output signal, and the value of the time width τ ₁ is determined by the value of the time width τ 1 in FIG. Alternatively, the time from passing through 29 until reaching the reflective tape 30, that is, the unmanned carrier 1a
Alternatively, 1b is set to be equal to the time required to pass through the collision zone.

Since the transmitter 37 is operated by the output of the timer circuit 44, the transmitter 37 transmits radio waves only while the timer circuit 44 is generating the output, that is, only when the unmanned vehicle is within the collision zone. will be done.

Further, since the receiver 38 is operated with the output obtained by inverting the output of the timer circuit 45 by the inverting circuit 46, only while the output from the timer circuit 45 is being generated, that is, when the unmanned carrier is within the collision zone, Further, the vehicle is in an inactive state only from the time the vehicle leaves the area until the vehicle has traveled for a predetermined period of time, and is in an active state at other times.

Therefore, the embodiment shown in FIG. 12 can also constitute the collision prevention device according to the present invention in the same way as the embodiment shown in FIG. 11, and there is no need to provide the reflective tape 30. Moreover, the effect of simplifying the circuit configuration can be obtained.

In all of the above, the unmanned transportation system includes the reflection guide zone 14, the light source 13a, and a large number of light receiving elements _a1 to
This is an example of a system using an optical guidance method using a light-receiving element array 12a consisting of ₁₀ light-receiving element arrays 12a, which is provided in a conventional automated guided vehicle as a detection means for a collision prevention device.
Since the light source 13a and the on/off processing circuit 17 can be used together, the structure is simple and the cost is low. However, it goes without saying that the present invention is also applicable to systems other than optical guidance systems. An embodiment of the present invention in such a system is shown in FIG.

In the figure, 47a and 47b are collision zone entry detectors consisting of a light source and a light receiving element, 48a and 48b
Reference numerals 49 and 50 indicate a collision section passing detector, numerals 49 and 50 indicate a light reflecting plate serving as a detected object, and reference numeral 51 indicates a light reflecting plate provided on the exit road side of the collision section.

FIG. 14 shows an embodiment of an unmanned guided vehicle equipped with a collision prevention device used in the embodiment shown in FIG. (Or,
47b) and 48a (or 48b). Therefore, in FIG.
9 or 50, the detector 47a (or 47b) generates a signal to activate the transmitter 37 and start transmitting radio waves, and at the same time deactivates the receiver 38. Then, when the unmanned carrier vehicle 1a or 1b passes the confluence point 0 and reaches in front of the light reflecting plate 51, the detector 48a (or 48b) generates a signal, puts the transmitter 37 into an inoperable state, and a predetermined period of time has elapsed. It later operates to return receiver 38 to an operational state. Other operations are the same as those of the embodiment shown in FIG.

Therefore, the signal processing circuit 36 in this embodiment
The configuration may be the same as that in FIG. 11, and the output of the AND circuit 39 in FIG. 11 is replaced by the detector 47a.
(or 47b), and AND circuit 40
The output of the detector 48a (or 48b) may be used instead of the output of the detector 48a (or 48b).

Similarly, it is also possible to apply to the embodiment of FIG. 12, in which case the AND circuit 39 of FIG.
The output of the detector 47a (or 47b) may be supplied to the inputs of the timer circuits 44 and 45 instead of the output of the detector 48a (or 47b).
8b) and the light reflecting plate 51 are unnecessary.

FIG. 15 shows another embodiment of the signal processing circuit 36.

This embodiment is particularly suitable as the signal processing circuit 36 in the embodiment shown in FIG.
b), 48a (or 48b) closes the contact 52 when it detects the reflector 49 (or 50), and the detector 48
a (or 48b) is configured to open the contact 53 when the reflective plate 51 is detected.

In the figure, 54 is an electromagnetic relay, 55 to 57 are its contacts, 58 is a slow operation speed recovery type delay relay,
59 is its contact point.

An unmanned carrier, for example 1a, enters the collision zone,
When the detector 47a detects the reflector 49, the contact 52
closes for a short time. The relay 54 then operates in the following path.

[+Power supply → Relay 54 → Contact 53 → Contact 52 →
- Power supply] Since the contact 57 is closed by the operation of the relay 54, power is supplied to the transmitter 37, and a collision prevention radio wave is emitted. At the same time, the contact 56 opens (this contact 56 is a normally closed contact), so the relay 58 that was operating up until then is immediately restored, and its contact 59 is opened to turn on the power to the receiver 38 that was also operating up until then. Turn it off and make it inoperable.

After that, even if the unmanned carrier 1a passes in front of the reflector 49 and the contact 52 of the detector 47a opens, the contact 55 is closed at this time, so the relay 54
is self-retained and remains operational on the next path.

[+Power supply → Relay 54 → Contact 53 → Contact 55 →
- Power Supply] Eventually, when the carrier 1a passes through the confluence point 0 and arrives in front of the reflecting plate 51, the detector 48a is activated and its contact 53 is opened. Thereupon, the relay 54 recovers and opens the contact 57, turns off the power to the transmitter 37 and puts it in an inoperable state, and opens the contact 55 forming the self-holding circuit to prepare for the next operation.

At the same time, the normally closed contact 56 is closed and current flows through the relay 58, but since this relay 58 is of a slow operating speed recovery type, the relay 54 is restored and the contact 56
Even if the receiver 38 is closed, it does not operate immediately, but operates only after a predetermined period of time has passed, and closes the contact 59 to return the receiver 38 to the operating state.

Therefore, the signal processing circuit according to the embodiment shown in FIG. 15 can sufficiently achieve the purpose of preventing collisions of unmanned guided vehicles, and has a simple structure because the electromagnetic relay is the main component. Therefore, reliable operation can be expected, and a highly reliable collision prevention device can be obtained.

As explained above, according to the present invention, there is no need for a large number of detection devices and stop command devices, etc., which were installed in aisles and the like to prevent collisions in unmanned transportation systems, as in the prior art. There is no need for an enormous amount of equipment, and it is possible to provide a low-cost and highly reliable collision prevention device that eliminates all the drawbacks of the prior art.

[Brief explanation of the drawing]

Fig. 1 is a bottom view showing an example of an optically guided unmanned guided vehicle, Fig. 2 (a) and (b) are a plan view and a side view of the relationship between the light receiving element and the reflective guide band of the optically guided unmanned guided vehicle, and Fig. 3 is a bottom view showing an example of an optically guided unmanned guided vehicle. A graph showing the relationship between the operation of the light-receiving element and the steering angle of an optically guided unmanned guided vehicle. Figure 4 is a block diagram of the steering angle extraction circuit. Figure 5 is the steering angle extraction effect when the reflective guidance band is branched. FIG. 6 is a block diagram showing a control system of an optically guided unmanned carrier vehicle in response to a steering command, and FIG. 7 is a conceptual diagram showing a conventional example of a collision prevention device for an unmanned carrier vehicle in an unmanned transportation system. FIG. 8 is a conceptual diagram of an embodiment showing the running path of the unmanned guided vehicle according to the present invention, and FIGS. 10 is a block diagram showing a control system of an unmanned guided vehicle to which a collision prevention device according to an embodiment of the present invention is applied, and FIG.
Figure 12 is a block diagram showing one embodiment of a signal processing circuit used in a collision prevention circuit, Figure 12 is a block diagram showing another embodiment, and Figure 13 is for an unmanned transportation system other than the optical guidance system. Conceptual diagram showing an example of a running path when the present invention is applied, 1st
FIG. 4 is a block diagram showing an embodiment of the control system of the unmanned guided vehicle used in the embodiment of FIG. 13.
FIG. 15 is a circuit diagram showing another embodiment of the signal processing circuit. 1a, 1b...Unmanned carrier, 12a...Light receiving element, 13a...Light source, 14...Reflection guiding band, 2
8, 29, 30...Reflective tape, 31...Setting circuit, 32...Travel control circuit, 33...Drive circuit,
34...Travel motor, 35...Collision prevention circuit,
36...Signal processing circuit, 37...Radio wave transmitter, 3
8... Radio receiver, 39, 40... AND circuit,
41, 42... Flip-flop, 43... Delay circuit, 44, 45... Time limit circuit, 46... Inverting circuit, 47a, 47b, 48a, 48b... Detector, 49, 50, 51... Light reflecting plate, 52...Contact of detector 47a, 53...Contact of detector 48a, 54...Electromagnetic relay, 55-57...Contact of relay 54, 58...Slow operation speed recovery type delay relay, 59...Relay 58 contact point.

Claims (1)

[Scope of Claims] 1. A vehicle comprising: a travel route having travel guidance means installed on the road surface and having at least one merging section; and a plurality of unmanned carriers that simultaneously travel automatically along the travel route. In the unmanned transportation system, a first detection means is provided with a detected object located near the approach road side of the merging section, and detects that the detected object has entered the merging section by the presence of the detected object; a second detection means for detecting that the self has escaped from the merging portion; and a radio wave transmission operation is started by the detection signal from the first detection means; and by the detection operation from the second detection means. a transmitting means for stopping a radio wave sending operation; and a transmitting means that is normally in a radio wave receiving operation state and enters a receiving operation stop state when a detection signal is given from the first detecting means, and detecting from the second detecting means. All of the plurality of unmanned guided vehicles are provided with a receiving means that returns to a receiving operation state in response to a signal, and a traveling control means that stops the traveling of the unmanned guided vehicle in response to an output signal of the receiving means, A collision prevention device for an unmanned transport vehicle, characterized in that it is configured to prevent two or more unmanned transport vehicles from entering a portion at the same time. 2. A collision prevention device for an unmanned guided vehicle according to claim 1, wherein the second detection means comprises a timer whose trigger input is a detection signal from the first detection means.