JP3136782B2 - Autonomous guided vehicle intersection control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling an intersection of an automatic guided vehicle, which is devised so as to prevent a collision at the intersection.

[0002]

2. Description of the Related Art In a factory or the like, a large number of automatic guided vehicles are traveling, and the traveling paths may intersect or merge. In an automatic guided vehicle system having an intersection or a junction, it is necessary to perform control so as to prevent the automatic guided vehicles from colliding with each other at an intersection or the like. Conventional collision prevention control methods include a ground station management method and an autonomous control method.

Here, an example of a ground station management system will be described.
In this system, each intersection is provided with an entrance detecting device for detecting that an automatic guided vehicle has entered. Then, when the entry detection device detects that one automatic guided vehicle has entered the intersection area, the ground station turns to the automatic guided vehicle,
Send an entry permission signal. The automatic guided vehicle that has received the entry permission signal continues to travel and passes through the intersection. If the entry detection device detects that two automatic guided vehicles have entered the intersection area through another travel path, the ground station sends an entry permission signal to one of the automatic guided vehicles and Send an entry prohibition signal to the automatic guided vehicle. The automatic guided vehicle that has received the entry permission signal continues to travel and passes through the intersection. The unmanned guided vehicle that has received the entry prohibition signal stops temporarily before the intersection, and after one of the unmanned guided vehicles has passed through the intersection, receives an advance permission signal and proceeds toward the intersection.

Next, an example of the autonomous control system will be described. In this method, the automatic guided vehicle stops temporarily before the intersection and transmits a detection wave (light or ultrasonic wave) to a predetermined range in the left-right direction. When it is detected that there is no other automatic guided vehicle within a predetermined range in the left-right direction, the vehicle advances toward the intersection. When detecting that there is another unmanned guided vehicle in a predetermined range in the left-right direction,
It stops as it is, and the detected unmanned guided vehicle travels toward the intersection after passing through the intersection.

[0005]

However, the above prior art has the following problems. That is, in the ground station management method, an approach detection device is required for each intersection, and the cost increases in proportion to the number of intersections. In addition, the autonomous control system uses optical sensors and ultrasonic sensors to output detection waves, but these sensors have directivity, so if there is an obstacle such as a wall around the intersection, the blind spot will This may cause a collision without detecting the presence of another automatic guided vehicle.

The present invention has been made in view of the above-mentioned prior art, and provides a control method for reliably and easily preventing a collision at an intersection.

[0007]

SUMMARY OF THE INVENTION The present invention for solving the above-mentioned problems is to provide a specific frequency when an automatic guided vehicle reaches an entrance of an intersection.
Detects whether there are a number of optical signals
Emits an optical signal with a lower frequency range than the detected optical signal.
When the vehicle stops while the optical signal is not detected from the beginning
Emits the highest frequency light signal and heads for the intersection
Higher than the light signal that was emitted when the vehicle was stopped
If the optical signal in the frequency range disappears, do not change the frequency
Continue toward the intersection while continuing to emit the light signal,
Stop generating light signals when you reach the exit
You. The present invention also relates to an automatic guided vehicle reaching an entrance of an intersection.
Stop once, and enter the intersection number and the vehicle
A radio signal that contains the assigned AGV number as information
Signal and stop at the intersection entrance
Continue to stop when signal is received, but answer signal
When you don't receive the traffic, go to the intersection and drive at the intersection
The inside is assigned to the intersection number indicating the intersection and the vehicle
A wireless signal containing the automated guided vehicle number as information
Include the same intersection number as the intersection number transmitted with
When a wireless signal is received, an answer signal is sent and the intersection
When it reaches the mouth, it sends a radio signal with the automatic guided vehicle number set to zero
Stop at the entrance of the intersection because the answer signal was received
Radio signal with an automatic guided vehicle number of zero
It is characterized by proceeding to the intersection when received.

[0008]

According to the present invention, an optical signal or a radio signal is used to detect whether or not there is another vehicle in an intersection, to proceed to the intersection when there is no other vehicle, and to indicate that the vehicle is in the intersection while traveling at the intersection. emits a signal, stop the generation of the signal If you get the intersection.

[0009]

Embodiments of the present invention will be described below in detail.

(First Embodiment) First, a first embodiment will be described. FIG. 1 shows an automatic guided vehicle 1 used in the first embodiment. The automatic guided vehicle 1 includes a traveling control device 2, a sound wave signal generator 3, a speaker 4, a microphone 5, a sound wave sorting device 6, and a marker detection sensor 7. When receiving the signal generation command from the traveling control device 2, the sound wave signal generator 3 outputs a sound wave signal Eo which is an electric signal having a specific frequency and a specific rhythm. The speaker 4 receives the sound wave signal Eo and emits a sound wave S which is a sound in an audio frequency range having a specific frequency and a specific rhythm. The microphone 5 receives the sound and outputs a sound wave signal Ei. The sound wave sorter 6 sorts the sound wave signal Ei and determines whether the sound received by the microphone 5 is noise or a sound wave S emitted from the automatic guided vehicle 1. And sends the result of the determination to the travel control device 2. The marker detection sensor 7 detects an incoming marker and an outgoing marker (described later). The traveling control device 2 performs control for avoiding a collision at an intersection, as described later.

FIG. 2 shows an example of an intersection, where the road R1 and the road R2 intersect to form an intersection. An entry marker Mi is set at a position in front of the intersection on the traveling paths R1 and R2, and an exit marker Mo is set at a position outside the intersection. 1A and 1B are automatic guided vehicles, which have the same configuration as that shown in FIG. 8 is an obstacle.

The control at the intersection will now be described with reference to FIG. (1) The traveling control device 2 of the automatic guided vehicle 1 knows that the vehicle has entered the intersection area by the marker detection sensor 7 detecting the entering marker Mi, and temporarily stops the vehicle (step 1). (2) At this time, the sound wave signal Ei output from the microphone 5 is selected by the sound wave separation device 6 to determine whether or not another automatic guided vehicle 1 is within the intersection (step 2). (3) When there is no other vehicle, a sound wave S is transmitted (step 3). (4) Check the possibility of simultaneous transmission (step 4). (5) When there are simultaneous calls, a predetermined priority is determined (step 5). If the priority is low, the self-sound is stopped (step 6) and the process waits until other sounds stop, and the priority is high. If a sound wave S is emitted, the vehicle advances and enters an intersection. (6) After the intersection, the marker M is output by the marker detection sensor 7.
When o is detected (step 7), transmission of the sound wave is stopped (step 8).

Since the above control is performed, in the example of FIG. 2, when the automatic guided vehicle 1A travels at the intersection while emitting the sound wave S, the automatic guided vehicle 1B is stopped at the intersection entrance.
After the automatic guided vehicle 1A detects the outgoing marker Mo after passing the intersection and stops transmitting the sound wave S, the automatic guided vehicle 1B now proceeds to the intersection while emitting the sound wave S. Thus, collision at an intersection can be prevented.

Moreover, since the sound wave S has a lower directivity than light and ultrasonic waves, even if there is an obstacle 8 near the intersection, the sound wave S emitted from another vehicle can be received, and the blind spot can be eliminated without blind spots. The nature increases. Further, since the sound wave S has a specific frequency and a specific rhythm, detection of another vehicle is not disturbed even if there is noise.

(Second Embodiment) Next, a second embodiment will be described. In the second embodiment, an automatic guided vehicle 1 having the same configuration as that shown in FIG.
Have different frequencies. The operation of the second embodiment is as shown in FIG. 4. Only steps 5 and 6 are different from those of the first embodiment, and the other steps are the same as those of the first embodiment. That is, when simultaneous transmission is performed in step 5, the self-sound is stopped when the frequency of the sound wave of the own vehicle is lower than the frequency of the sound wave of the other vehicle based on the frequency set individually for each vehicle (step 6). When the frequency of the own sound wave is high, the sound wave S is emitted while traveling to enter the intersection. In other steps, the same operation as in the first embodiment is performed to prevent collision at an intersection.

In the second embodiment, when two AGVs simultaneously reach the position before the intersection, the priority of the frequency is used to determine which one has priority. To determine the automatic guided vehicle that will travel through the intersection.

(Third Embodiment) Next, a third embodiment will be described. As shown in FIGS. 5 and 6, the automatic guided vehicle 20 used in the third embodiment includes a travel control device 21 and a light control device 22.
, A marker detection sensor 23 and optical sensors 24a, 24b,
24c and 24d are provided. Optical sensors 24a, 24
b, 24c and 24d are installed at the four corners of the automatic guided vehicle 20 and have a light projecting function and a light receiving function.
As shown by A1, A2, A3, and A4, the sensor has a wide detection area and a wide directivity. These optical sensors 24a, 24
4b, 24c, and 24d output a high-frequency (level 1) optical signal P1, a medium-frequency (level 2) optical signal P2, and a low-frequency (level 3) optical signal P3 in response to a command from the light control device 22. I do. Also, the optical sensors 24a, 24b, 24c, 24
d is a high-frequency electric signal E1 when receiving the level 1 optical signal P1, an intermediate-frequency electric signal E2 when receiving the level 2 optical signal P2, and a low-frequency electric signal when receiving the level 3 optical signal P3. E3 is sent to the light control device 22. Further, the marker detection sensor 23 detects an incoming marker and an outgoing marker. The traveling control device 21 performs control for avoiding a collision at an intersection, as described later.

FIG. 7 shows an example of a traveling path, where R1,
R2 is a traveling road, Mi is an entry marker, Mo is an exit marker, 20
A and 20B are automatic guided vehicles.

The control at the intersection will now be described with reference to FIG. (1) The traveling control device 21 of the automatic guided vehicle 20 knows that the vehicle has entered the intersection area by the marker detection sensor 23 detecting the entering marker Mi, and temporarily stops the vehicle (step 1). (2) It is determined whether another vehicle is at the intersection based on the presence or absence of light reception (step 2). (3) When no light signal from another vehicle is received, the vehicle travels while emitting a level 1 light signal from the light sensors 24a, 24b, 24c, 24d (step 3). (4) When the marker detection sensor 23 detects the outgoing marker Mo after passing through the intersection (step 4), the output of the optical signal of level 1 is stopped (step 5). (5) When it is determined in step 2 that light is emitted from another vehicle, it is determined whether or not the level of the received optical signal is level 3 (step 6). Wait (step 7). (6) If it is determined in step 6 that the light emitted from the other vehicle is not level 3, it is determined whether the level of the received optical signal is level 2 (step 8). The optical signal P3 of the level 3 is output to wait / stop (step 9). (7) If it is determined in step 8 that the light from the other vehicle is not at level 2, it is determined whether the level of the received optical signal is at level 1 (step 10). The optical signal P2 of level 2 is output to wait and stop (step 11). (8) If it is determined in step 10 that the light projection level from the other vehicle is not level 1, the process proceeds to step 3 and proceeds while outputting the level 1 optical signal P1 from the own vehicle.

As described above, the present embodiment uses a plurality of optical sensors 24a, 24b, 24c and 24d having a wide directivity angle, so that the blind spot is reduced, and the presence or absence of light emission from another vehicle is detected. Collisions at intersections can be prevented. Furthermore, since the priority order to enter the intersection is determined by the level of the optical signal, even if multiple automatic guided vehicles are waiting, if there is an intersection, the one arriving first may cancel the standby and enter. it can. Therefore, traffic control at the intersection can be performed smoothly.

In the third embodiment, the optical sensors 24a,
The arrangement of 24b, 24c and 24d may be the arrangement shown in FIG. 9 in addition to the arrangement shown in FIG.

(Fourth Embodiment) Next, a fourth embodiment will be described. As shown in FIG. 10, the automatic guided vehicle 30 used in the fourth embodiment includes a travel control device 31, a wireless control device 32, a wireless data transmission / reception device 33, and a marker detection sensor. The wireless data transmission / reception device 33 transmits and receives the wireless data D according to a command from the wireless control device 32. As shown in FIG. 11, the wireless control device 32 has an intersection number and an automatic guided vehicle (AGV) number as matrix data. The marker detection sensor 34 detects an incoming marker Mi and an outgoing marker Mo (see FIG. 12). Travel control device 3
Reference numeral 1 controls steering and traveling for traveling.

The following control processing is performed by the traveling device 31 and the wireless control device 32. (1) When the entering marker Mi is detected, the vehicle is once stopped, and the wireless data D including the intersection number (C number) entering from now on and the unmanned vehicle number (AGV number) assigned to the own vehicle are paired.
Send as (2) During traveling at the intersection, the wireless data D including the intersection number (C-NO) and the unmanned vehicle number (AGV-NO) is transmitted. Then, when the wireless data D including the same C-NO as the C-NO being transmitted is received during the passage of the intersection, an answer signal is transmitted. (3) Stop once at the entrance of the intersection, C-NO and AGV
After transmitting the wireless data D paired with -NO, the vehicle stays stopped when an answer signal is received from another vehicle, but enters an intersection when no answer signal is received. (4) After completely crossing the intersection and detecting the marker Mo,
The wireless data D with the AGV-NO set to zero is transmitted. (5) When the wireless data D whose AGV-NO becomes zero is received, the vehicle proceeds to the intersection.

Here, the collision avoiding operation at the intersection will be specifically described with reference to FIG. In FIG. 12, the traveling path R
The intersection number at which 1 and R2 intersect is 3 (C = NO3)
And the automatic guided vehicle number of the automatic guided vehicle 30A is 1 (AGV =
NO1), and the unmanned vehicle number of the automatic guided vehicle 30B is 2
(AGV = NO2), Mi is an incoming marker, and Mo is an outgoing marker. D1 is wireless data output by the automatic guided vehicle 30A, and D2 is wireless data output by the automatic guided vehicle 30B.

As shown in FIG. 12A, the automatic guided vehicle 3
0A stops once when the entering marker Mi is detected,
Wireless data D containing C = NO3, AGV = NO1
Send 1 In this case, there is no answer because there is no other vehicle at the intersection, and the automatic guided vehicle 30A enters the intersection at the intersection.

As shown in FIG. 12B, the automatic guided vehicle 3
OA transmits radio data D1 containing C = NO3 and AGV = 1 while traveling at an intersection. On the other hand, when the automatic guided vehicle 30B detects the entering marker Mi, it stops temporarily and transmits wireless data D2 containing C = NO3 and AGV = NO2. In this case, the automatic guided vehicle 30A transmits an answer signal because the intersection number (C) of the wireless data D1 and the intersection number (C) of the wireless data D2 are both the same as C = NO3. The automatic guided vehicle 30B receives the answer signal and continues the stopped state.

As shown in FIG. 12C, the automatic guided vehicle 3
When 0A completely passes through the intersection and detects the exit marker Mo, the automatic guided vehicle 30A outputs C = NO3, AGV = N
The wireless data D1 having the content of O0 is output. The automatic guided vehicle 30A detects that the AGV number in the wireless data D1 has changed from NO1 to NO0, and proceeds toward the intersection.

As shown in FIG. 12D, the automatic guided vehicle 30
B transmits radio data D2 containing C = NO3 and AGV = 2 while traveling at the intersection.

When the two AGVs arrive at the entrance of the intersection at the same time, the one with the larger AGV number can enter the intersection preferentially.

As described above, in the fourth embodiment, since signal transmission is performed wirelessly between the automatic guided vehicles, no ground station is required, and collision avoidance can be performed autonomously. Also, when a plurality of automatic guided vehicles arrive at an intersection at the same time, the priority order is determined by the number assigned to each automatic guided vehicle in advance, so that traffic control at the intersection can be performed efficiently.

[0031]

According to the present invention, the blind spot at an intersection can be reduced and a collision at an intersection can be prevented without using a ground station, as described in detail with the above embodiments.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an automatic guided vehicle according to a first embodiment.

FIG. 2 is a plan view showing an intersection state in the first embodiment.

FIG. 3 is a flowchart showing the operation of the first embodiment.

FIG. 4 is a flowchart showing the operation of the second embodiment.

FIG. 5 is a configuration diagram illustrating an automatic guided vehicle according to a third embodiment.

FIG. 6 is a plan view showing an automatic guided vehicle according to a third embodiment.

FIG. 7 is a plan view showing an intersection state in the third embodiment.

FIG. 8 is a flowchart showing the operation of the third embodiment.

FIG. 9 is a plan view showing a modification of the third embodiment.

FIG. 10 is a configuration diagram showing a fourth embodiment.

FIG. 11 is an explanatory diagram showing a data matrix in the fourth embodiment.

FIG. 12 is an explanatory diagram showing an operation in the fourth embodiment.

[Explanation of symbols]

 1,20,30 Automated guided vehicle 2,21,31 Travel control device 3 Sound wave signal generator 4 Speaker 5 Microphone 6 Sound wave separation device 7,23,34 Marker detection sensor 22 Light control device 24a, 24b, 24c, 24d Optical sensor 32 wireless control device 33 wireless data transmitting / receiving device

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-73303 (JP, A) JP-A-64-78307 (JP, A) JP-A-60-89214 (JP, A) JP-A-4- 112212 (JP, A) JP-A-63-305409 (JP, A) JP-A-64-78306 (JP, A) JP-A-62-254211 (JP, A) JP-A-62-192808 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G05D 1/02

Claims (2)

(57) [Claims] 1. When the automatic guided vehicle reaches the entrance of the intersection,
Detects whether there is an optical signal of a specific frequency, and
When there is an optical signal in a lower frequency range than the detected optical signal
Stop while emitting a signal, and the optical signal
At the intersection while emitting an optical signal with the highest frequency.
From the light signal that was emitted while traveling
If the optical signal in the high frequency range disappears, change the frequency.
Continue toward the intersection while continuing to emit light signals,
Stop emitting light signals when you reach the exit of the intersection.
Intersection control method for automatic guided vehicles. 2. When the automatic guided vehicle reaches the entrance of the intersection,
Stop at the end and assign the intersection number and the vehicle
A radio signal that contains the assigned automated guided vehicle number as information
An answer signal is generated with a stop at the intersection entrance
Stop signal is received, but an answer signal is received.
If you do not trust, enter the intersection and while driving at the intersection
The intersection number indicating the intersection and the
Generates a radio signal that contains the human carrier number as information.
Radio that contains the same intersection number as the one that is transmitting to
When a signal is received, an answer signal is sent, and at the intersection exit
When it reaches, it sends a radio signal with the automatic guided vehicle number set to zero,
I stopped at the entrance of the intersection because I received an answer signal
While receiving a radio signal with the automatic guided vehicle number set to zero
Unmanned transport characterized by traveling to an intersection
Car intersection control method.