JPH0784643A - Autonomous intersection control method for automated guided vehicle - Google Patents

Abstract

PURPOSE:To allow each unmanned vehicle to autonomously execute intersection control without using a ground control board and allowing a certain specific unmanned vehicle to wait on an intersection for a long time. CONSTITUTION:Radio equipments capable of simultaneously executing transmission and reception and independently setting up respective frequency bands are loaded on respective unmanned vehicles 7A to 7C and respectively different frequency bands corresponding to the number of inlets of each intersection are allocated to respective intersections 1-1, 1-2. When an unmanned vehicle 7A arrives at the inlet of a certain intersection 1-2 e.g. the vehicle 7A receives the frequecy allocated to the intersection 1-2, and while transmitting frequency with the highest priority out of frequency bands other than bands transmitted from other vehicles 7B, 7C, waits until frequency higher than the one transmitted from the vehicle 7A itself only by one level disappears. When the higher frequency disappears, the vehicle 7A switches its own transmission frequency to the frequency higher only by one level, enters into the intersection at the time of transmitting the frequency with the highest priority order and then stops the transmission of the frequency at the time of leaving the intersection. When priority order of unmanned vehicles is previously determined, the x generation of collision can be prevented even at the time of simultaneous attrival at an intersection.

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 autonomous intersection of an automatic guided vehicle (hereinafter referred to as an unmanned vehicle), which prevents a certain unmanned vehicle from waiting at an intersection for a long time. .

[0002]

2. Description of the Related Art In an unmanned transportation system, it is necessary to perform intersection control so that unmanned vehicles 7 do not collide with each other in an intersection area 1 such as a merging, branching or intersection of guide lines as shown in FIG. Conventionally, as shown in FIG. 5, vehicle detectors 2 and 3 such as sensors and switches are provided at the entrance and exit of the intersection area 1, and signals 4 and 5 from these vehicle detectors 2 and 3 are transmitted to the ground. When the control panel 6 receives the command, it judges whether or not the vehicle can enter the intersection including the priority order, and gives the unmanned vehicle 7 a command 8 to permit or disallow the approach.

[0003]

As described above, in the prior art, complicated control sequence software is required for the ground control panel 6 to manage all the intersection control including the priority order, and the vehicle detector for each intersection. Due to the fact that 2 and 3 are required and the installation work of the vehicle detectors 2 and 3 is required, the cost and man-hours required to implement the intersection control are large. Further, if the priorities are simply fixed and set among the unmanned vehicles, as shown in FIG. 6, when a plurality of unmanned vehicles 7A and 7B are in a standby state at each entrance of a certain intersection area 1, At the time when the preceding unmanned vehicle 7C passed and became able to enter the intersection, the unmanned vehicle 7B with the higher priority was the first to enter, so despite having arrived at the intersection entrance first Unmanned vehicle 7 with lower priority
A may not be able to enter and may have to wait for a long time. As a result, the waiting time at the transport destination becomes long.

Therefore, the present invention provides a method by which an unmanned vehicle can autonomously perform intersection control so that a ground control panel is not necessary and a certain unmanned vehicle does not wait at an intersection for a long time. The purpose is to provide.

[0005]

According to the autonomous intersection control method of the present invention which achieves the above object, it is possible to simultaneously perform transmission and reception to each unmanned vehicle of an unmanned conveyance system, and to set the frequency independently. Equipped with wireless communication equipment, assigned to each intersection the same number as the number of entrances to the intersection and different frequencies, setting priority to each assigned frequency for each intersection, and unmanned vehicles arriving at the intersection At that time, the wireless communication device receives the transmission frequency from the other vehicle, transmits the highest priority frequency out of the frequencies that are not transmitted, and receives the reception of the higher priority frequency. Wait for it to die, and when this reception is over, switch the transmission frequency of your vehicle to a frequency with a higher priority, and your vehicle transmits the highest priority frequency. Enters the intersection point, it is characterized in that to stop transmission when leaving the intersection.

[0006]

[Operation] When an unmanned vehicle arrives at the entrance of a certain intersection, the frequency assigned to the intersection is received, the frequency not transmitted from other vehicles is searched, and the frequency having the highest priority is transmitted. To do. The priority of unmanned vehicles can be known from the transmission frequency. While transmitting this, wait until the reception of one higher priority frequency is gone, and when it disappears, it is judged that the priority of the own vehicle has increased by 1 and the transmission frequency of the own vehicle is increased by one. Switch to the frequency of. When the number of allocated frequencies is 3 or more, the above-described transmission switching is repeated until the reception of the frequency of the higher priority is completely lost. When the transmission frequency of your vehicle becomes the highest priority frequency at the intersection, the priority of your vehicle is the highest, so enter the intersection while transmitting that frequency, and send it when you leave the intersection. Stop. From the above,
Waiting unmanned vehicles are getting higher priority, so
Without waiting for a certain unmanned vehicle at the intersection for a long time,
The unmanned vehicle itself can control the intersection.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An autonomous intersection control method according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an unmanned conveyance system to which the autonomous intersection control method of the present invention is applied. In FIG. 1, each unmanned vehicle 7A, 7B is provided with an autonomous intersection control device 11A, 11B including a wireless communication device (hereinafter referred to as a wireless device) 9 and a control device 10. In FIG. 1, reference numeral 1 is an intersection area, 9A is a priority order setting device, 12 is a traveling road, 13 is a transmission signal of the unmanned vehicle 7A, 14 is a transmission signal of the unmanned vehicle 7B, and 15 is a mark.
Reference numeral 16 represents a mark detector.

FIG. 2 shows an example of driving routes and frequency allocation. In the traveling route illustrated in FIG. 2, there are two intersection areas 1-1 and 1-2, and one of the intersection areas 1-
1 has N = 2, that is, two entrances, and the other intersection area 1-2 has N = 3, that is, three entrances. Therefore, in the example of FIG. 2, the first and second frequencies aHz and bHz are assigned to one intersection area 1-1, and the first frequency aHz is given priority over the second frequency bHz. Is high. Also, in the other intersection area 1-2,
2nd, 3rd and 3 frequencies cHz, dHz and eHz are assigned, the first frequency cHz has priority over the second frequency dHz, and the second frequency dHz has priority over the third frequency eHz. The rank is high. The frequencies aHz to eHz are all different from each other.

The radio 9 can simultaneously perform transmission and reception, and can independently set the frequencies aHz to eHz assigned to all the intersection areas 1-1 and 1-2. When an unmanned vehicle equipped with it arrives at the entrance of a certain intersection area, the radio 9 receives the frequency assigned to the intersection and searches for a frequency that is not transmitted from another vehicle, and the highest priority is given to them. While transmitting the higher frequency, the frequency of one higher priority is monitored, and when it disappears, the transmission frequency of the own vehicle is switched to the frequency of one higher priority than before. The wireless device 9 repeats the above operation until the transmission frequency switches to the highest frequency at the intersection. The control device 10 stops or waits until the radio 9 of the own vehicle transmits the highest priority frequency among the frequencies assigned to the intersection, and at the same time transmits the highest priority frequency. Let your vehicle enter the intersection area and exit.
The radio 9 continuously transmits the frequency with the highest priority while the vehicle is traveling through the intersection, and stops the transmission when the vehicle exits the intersection.

Any means can be used to determine whether the unmanned vehicle has arrived at the intersection entrance, which intersection it is, and whether the unmanned vehicle has exited the intersection. Good, for example, as shown in FIG. 1, a mark detector 16 detects a mark 15 such as a magnet or an iron plate as a command plate installed at an entrance or an exit of the intersection area 1 and the like. This can be achieved by counting the total number.

A specific control example will be described with reference to FIG. First, as shown in steps S1 to S5, when the unmanned vehicle arrives at the intersection area, it is determined whether or not the frequency having the highest priority among the frequencies assigned to the intersection is transmitted from another vehicle, If it has not been transmitted, it proceeds through the intersection while transmitting that frequency, and stops transmission when it exits the intersection. If it is confirmed in step S2 that the frequency with the highest priority is transmitted from another vehicle,
As shown in steps S6, S7 and S8, it is determined whether or not one frequency having a lower priority is transmitted from another vehicle,
By repeating this, the frequency having the highest priority is searched for among the frequencies that have not been transmitted. Next, step S9-
As shown in S12, while transmitting the previously searched frequency, it is judged whether or not the frequency from another vehicle having a higher priority than that has disappeared, and if it disappears, the transmission frequency of the own vehicle is maintained until now. Switch to a frequency one higher than. This switching process is repeated until the host vehicle transmits the frequency with the highest priority. When the frequency of the highest priority is reached, as in steps S3 to S5, the transmission is started while proceeding to the intersection, and the transmission is stopped at the time of leaving the intersection.

By the way, as a countermeasure against a rare case where a plurality of unmanned vehicles arrive at the entrances of a certain intersection at the same time, as shown in FIG.
By setting A, the priority order between the unmanned vehicles is set in advance, and when no frequency is received from other vehicles, the unmanned vehicle with the highest priority order is the highest priority frequency, 1 The frequency according to the priority is transmitted, such as the frequency with the lower priority and the frequency with the lower priority. This can prevent a collision in the case of simultaneous arrival.

[0013]

According to the present invention, when an unmanned vehicle arrives at the entrance of a certain intersection, it receives the frequency assigned to the intersection and has the highest priority among the frequencies not transmitted from other vehicles. While transmitting the frequency, it waits until the frequency of the priority higher than this one disappears, and when it disappears, the transmission frequency of the own vehicle is switched to the frequency with the higher priority one, and thus the highest priority. Autonomous intersection control is performed in which the intersection is entered when the frequency is transmitted and the transmission is stopped when the frequency is exited. Therefore, it is not necessary to install the conventional ground control panel for intersection control, its management sequence software, the vehicle detector, and these ground side devices. In addition, because the priority increases in sequence while unmanned vehicles are on standby, even if multiple unmanned vehicles are in standby at the entrance to the intersection, the vehicle will wait from the earliest when the intersection becomes available. The unmanned vehicle that you were doing can be the first to enter, and no particular unmanned vehicle will wait long at the intersection.

[Brief description of drawings]

FIG. 1 is a diagram showing an unmanned transportation system to which the present invention is applied.

FIG. 2 is a diagram showing a traveling layout and an example of frequency allocation at intersections.

FIG. 3 is a diagram showing a control flow.

FIG. 4 is a diagram showing an example of an intersection.

FIG. 5 is a diagram showing a conventional example.

FIG. 6 is a diagram showing an example of long-time standby that occurs when priority is fixed.

[Explanation of symbols]

 1 Intersection Area 7A, 7B, 7C Unmanned Vehicle 9 Radio Equipment (Wireless Communication Device) 9A Priority Setting Device 10 Control Device 11A, 11B Autonomous Intersection Control Device 15 Mark 16 Mark Detector

Claims (1)

[Claims] 1. An unmanned vehicle of an unmanned transportation system is equipped with a wireless communication device capable of simultaneously transmitting and receiving and independently setting a frequency, and each intersection is provided with the number of entrances of the intersection. Assigning the same number and different frequencies, setting the priority for each assigned frequency to each intersection, receiving a transmission frequency from another vehicle by the wireless communication device when the unmanned vehicle arrives at the entrance of the intersection, While transmitting the highest priority frequency out of the frequencies that have not been transmitted, wait until the reception of the higher priority frequency is cut off, and when this reception is cut off, the transmission frequency of your vehicle Is switched to a frequency with one priority higher, and the vehicle enters the intersection when the frequency of the highest priority is transmitted, and stops transmission when the vehicle exits the intersection. Control method for autonomous intersection of automated guided vehicle.