JP2900556B2 - Automatic guided vehicle collision prevention device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Industrial Field of the Invention The present invention relates to an automatic guided vehicle used for making a production line FA, etc., and in particular, an intersection, a junction, a junction, etc. on a traveling route. The present invention relates to a device for preventing automatic guided vehicles from colliding with each other.

B. Summary of the Invention In order to prevent collisions between the automatic guided vehicles, each automatic guided vehicle is provided with a light projecting means and a light receiving means for each vehicle body corner, and as a coded light unique to the own vehicle different from other vehicles, a fixed Each vehicle emits the same number of light pulses as the car number of the own vehicle to notify the other vehicle of approach, and identifies the other vehicle by receiving the coded light to control the standby and progress of the own vehicle. . This eliminates the need for a ground station for collision prevention. Also, since the light emitted by the own vehicle and the light emitted by the other vehicle have different numbers of pulses per fixed period, even if the detection sensitivity area is widened, the light emitted by the own vehicle is reflected by ground equipment etc. , It is possible to detect the approach of another vehicle with a small number of light emitting and receiving devices without a dead zone.

C. Conventional technology With the adoption of FA and FMS in factories, systems have been developed that enable automatic transfer of production lines between processes using automated guided vehicles.

FIG. 4 shows a layout of a transportation operation route in which a plurality of, for example, four automatic guided vehicles 1 operate in parallel between a plurality of processes, and a traveling route using a light reflecting tape on the floor surface or a guide line under the floor. The automatic guided vehicle 1 detects 2 and travels.
FIG. 5 shows an appearance of the automatic guided vehicle 1.

When the automatic guided vehicle 1 travels, a traveling route 2
Since there are intersections, junctions, and junctions, it is necessary to take measures to prevent the automatic guided vehicles 1 from colliding with each other at these points.

An example of a conventional collision prevention method will be described with reference to FIG.
In this example, the two guide lines 4 and 5 intersect at the intersection 3, the guide line 5 is set as the priority traveling route, and a sensor 8 such as a reed switch or a photoelectric tube is installed in front of the intersection 3 to perform unmanned operation. Detects passage of the carrier 1A. A switch 7 is provided between the other induction wire 4 and the induction electromagnetic wave oscillator 6. Then, the ground station 10 outputs a detection signal 11 of the automatic guided vehicle 1A from the sensor 8.
In response to this, a standby command 12 is issued and the switch 7 is turned off. As a result, no guided electromagnetic wave is emitted from the guide wire 4, and the traveling automatic guided vehicle 1B stops. Alternatively, the photoelectric tube 9 is installed in front of the intersection 3 in place of the switch 7, and upon receiving the detection signal 11 from the sensor 8, the ground station 10 issues a standby command 13 and emits a stop signal light from the photoelectric tube 9. Upon receiving this light, the automatic guided vehicle 1B stops.

D. Problems to be Solved by the Invention However, in the above-described conventional technology, control by the ground station 10 is indispensable, and the whole unmanned transport system becomes complicated.

Therefore, as an autonomous intersection control system in which the unmanned guided vehicle itself detects the other vehicle and performs control such as stopping and proceeding, a system in which each vehicle emits light and uses its reflection is considered.

However, in autonomous intersection control using reflected light,
In particular, when proceeding to a junction (junction) where the vehicle crosses obliquely, a dead zone of the optical sensor easily occurs, and there is a risk of collision. Eliminating this dead zone requires multiple optical sensors in every direction, which is expensive and has limitations. Or,
It is conceivable to widen the detection sensitivity area of the optical sensor to eliminate the dead zone. However, in this case, erroneous detection is caused by reflected light from the ground equipment, and normal operation may be hindered.

An object of the present invention is to provide an automatic guided vehicle collision prevention device that solves the above-mentioned problems.

E. Means for Solving the Problems The collision preventing device for an automatic guided vehicle according to the present invention includes a setting device for setting a car number of the own vehicle, a frequency divider for a clock signal, and setting for the setting device for each fixed period. A frequency divider that outputs the same number of pulses as the car number that has been set, and a plurality of light emitting units that are installed at each corner of the vehicle body and emit light pulses according to the pulses output by the frequency divider, A plurality of light receiving means installed at each corner of the vehicle body and outputting a pulse according to the received pulse light; and a plurality of light receiving means connected to each of the light receiving means and counting the number of output pulses of the corresponding light receiving means at the constant period. From a plurality of counters, the count value of each of the counters and the car number set in the setting unit, the light source of the pulsed light received by each of the light receiving means identifies the other vehicle or the own vehicle as the source automatic guided vehicle, Based on the result of the identification, the standby and the progress of the own vehicle are controlled. A control device, or the control device recognizes an approaching direction of another vehicle from the count value of each counter, and based on the recognition result of the approach direction and the count value of each counter. Further, the present invention is characterized in that the standby and progress of the own vehicle are controlled in accordance with a predetermined priority.

F. Action Each unmanned guided vehicle has its own encoded light,
It emits the same number of light pulses as the car number at regular intervals to notify other vehicles of approaching, and does not detect the reflected light of the light emitted by the own vehicle, but instead emits the same number of light pulses as the other vehicles By detecting an eigennumber of pulsed lights, it is possible to detect the approach between each other and stand by to avoid collision.

G. Embodiment An embodiment of the present invention will be described with reference to FIGS.

Each automatic guided vehicle has a control device 15 using a CPU (Central Processing Unit) as shown in FIG. 1, a frequency divider 16 using a program counter, a variable setting device 17 for encoding, and # The anti-collision device 20 includes a total of four light emitting / receiving devices 18 from 1 to # 4 and a total of four counters 19 from # 1 to # 4.

As shown in FIG. 2, the four light emitting and receiving devices 18 are provided at four corners of the body of the automatic guided vehicle 1 respectively.

The variable setter 17 sets the car number of the own vehicle as a condition for encoding.

The frequency divider 16 receives the clock signal 21 from the control device 15, and according to the car number of the own vehicle set by the variable setting device 17,
The clock signal 21 is encoded by performing frequency division such that the same number of pulses as the car number is output per fixed period, and the encoded pulse signal 22 is applied to the driver 23 of the light emitter / receiver 18 at each corner. This driver 23 is a pulse signal 22
, The light 25 is projected from the phototube 24 with a pulse corresponding to the output pulse of the frequency divider 16.

FIG. 3 shows an example of the encoding. When n automatic guided vehicles are operating from the first car to the nth car, the i-th car (i = 1 to
For n), encoding is performed such that i optical pulses 26 are output in bursts every fixed period a. Therefore, the variable setting device 17 uses the 4-bit switch 27 to set the numerical value "i" in binary in the case of the i-th car.

On the other hand, the emitter / receiver 18 at each corner has a photoelectric tube 28 as a light receiving element and a buffer 29 thereof.
Is converted into an electric pulse signal 31 and given to the corresponding counter 19.

Each counter 19 counts the input pulse signal 31 at a constant period a, and gives the counting result 32 to the control device 15.

A car judgment unit by software processing in the control device 15
33, it is determined from the counting result 32 from each counter 19 which emitter / receiver 18 has received the encoded light 30 from which car. Then, a comparison is made with the encoded information 34 of the own vehicle set by the variable setting device 17, and if it is not light from the own vehicle, the control device
Reference numeral 15 denotes a motor driving device (not shown) for assuming that another vehicle has approached, so that if the own vehicle is a priority vehicle, the vehicle continues to advance, and if the other vehicle is a priority vehicle, the own vehicle stops or decelerates for standby. Control.

In addition, as a standby method, a straight traveling vehicle is prioritized, and a specific priority traveling route is determined in advance in the control device 15 in a case where the vehicle is orthogonal to the vehicle, or a specific vehicle is set as a priority vehicle as a priority vehicle.
You may decide in advance within 15 or even prioritize each car. Further, the projection of the coded light 25 may be performed at all times, or may be performed only when approaching an intersection, a junction, or a branch point.

In particular, in the present embodiment, the control device 15 has four
It has a function of recognizing the approach direction of the automatic guided vehicle based on which and which car received the light from which car, and judges the progress and standby according to the priority set in advance, and the motor drive device I try to control.

It should be noted that the optical signal encoding circuit is not limited to the one described in the embodiment.

H. Effects of the Invention According to the present invention, a ground station is not required, and furthermore, a unique coded light is emitted for each unmanned guided vehicle to notify other vehicles of approach, so that errors due to reflected light from ground equipment and the like are caused. Detection can be avoided with code recognition. Therefore, since there is no problem even if the detection sensitivity area is widened, it is possible to reduce the number of light emitting and receiving devices. In particular, in the present invention, the same number of light pulses as the car number of the own vehicle is emitted at regular intervals, the received pulse light is counted at regular intervals, and the light source unmanned carrier is another vehicle or the own vehicle. Therefore, both the light encoding and the identification of the other vehicle from the own vehicle are simpler than those of other encoding methods. In addition, by recognizing the approaching direction of another vehicle and controlling standby and progress of the own vehicle in accordance with a predetermined priority, collision prevention is more effectively performed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a plan view showing an example of arrangement of light emitting and receiving devices, FIG. 3 is a diagram showing an example of encoding, and FIG. FIG. 5 is a view showing an example of a layout, FIG. 5 is an external view of an automatic guided vehicle, and FIG. 6 is a view showing a conventional technique. In the drawing, 1 is an automatic guided vehicle, 2 is a traveling route, 15 is a control device, 16 is a frequency divider, 17 is a variable setting device, 18 is a light emitter / receiver, 19 is a counter, 20 is a collision prevention device, and 33 is a car. It is a determination unit.

Claims (2)

(57) [Claims] A setter for setting a car number of the own vehicle; a frequency divider for dividing a clock signal and outputting the same number of pulses as the car number set in the setter at regular intervals. A plurality of light projecting means installed at each corner of the vehicle body and projecting an optical pulse in response to a pulse output from the frequency divider; and A plurality of light receiving means for outputting a pulse; a plurality of counters connected to each of the light receiving means for counting the number of output pulses of the corresponding light receiving means for each of the predetermined periods; and a count value of each of the counters and the setting device. From the set car number, a control device that identifies whether the unmanned guided vehicle that emits the pulsed light received by each of the light receiving units is another vehicle or own vehicle, and controls the standby and progress of the own vehicle based on the identification result. Collision of an automatic guided vehicle characterized by having Stop apparatus. 2. The control device according to claim 1, wherein the control device recognizes the approach direction of another vehicle from the count value of each counter, and based on the recognition result of the approach direction and the count value of each counter.
An apparatus for preventing collision of an automatic guided vehicle, wherein the standby and the advance of the vehicle are controlled in accordance with a predetermined priority.