JPH1195838A - Automated guided vehicle system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To hold a travelable quantity at an intersection relatively large by giving a chance to travel through an intersection to each automated guided vehicle according to the order of arrival at before the intersection and then giving a chance to travel through the intersection to a next vehicle if the precedent vehicle is enabled to travel through the intersection within a specific time. SOLUTION: An intersection control part 32 accepts a request to travel through each intersection from an automated guided vehicle 10 through an unmanned truck management part 22 and puts requests in a queue according to the arrival order. Then when a precedent vehicle 10 has traveled through an intersection and the lock of the intersection is unlocked, a change to travel through the intersection is given to unmanned trucks in order from the head of the queue. In the queue of the intersection control part 32, respective vehicles 10 are arranged in the arrival order and if a vehicle 10 is not allowed to travel through the intersection within the specific time after reaching the head of the queue, the order of the vehicle 10 in the queue is decreased by, for example, one to give the following vehicle 10 a chance to travel.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic guided vehicle system that travels on the ground, ceiling, and the like, and more particularly, to control of intersections.

[0002]

2. Description of the Related Art An automatic guided vehicle system is used for transporting articles in factories and warehouses. In the automated guided vehicle system, several to several tens of automated guided vehicles are used and run along the track, or run while recognizing the current position on the track by scanning a position recognition pattern with a laser or the like. Let it.

[0003] Generally, there is an intersection in the traveling route of the automatic guided vehicle, and the control system of the automatic guided vehicle searches the automatic guided vehicle that can travel on the intersection by storing the automatic guided vehicle arriving before the intersection in a queue. Then, the vehicle is driven from a vehicle capable of traveling. However, according to such control, the automatic guided vehicle on the main route side having a large traveling amount can generally continuously cross the intersection, and the automatic guided vehicle on the auxiliary route side having a small traveling amount has a long time in front of the intersection. I found that I could wait.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to enable an unmanned guided vehicle on a main route and an unmanned guided vehicle on an auxiliary route to travel fairly at an intersection, and to keep the travelable amount at the intersection relatively high. An additional object of the present invention is to enable the time until a time-up after giving an opportunity to travel at an intersection to be finely controlled according to the situation at each intersection. An additional object of the invention according to claim 3 is to prevent the automatic guided vehicle from being unable to run on an intersection and blocking the intersection.

[0005]

According to a first aspect of the present invention, there is provided a system for driving a number of automatic guided vehicles along a traveling route having an intersection, wherein each automatic guided vehicle has an opportunity to travel at the intersection in accordance with the order of arrival at the intersection. And then, if it is not possible to travel at the intersection within a predetermined time, the next automatic guided vehicle is provided with an opportunity to travel at the intersection.

The invention according to claim 2 is characterized in that the predetermined time is made variable for each intersection.

The invention according to claim 3 is further characterized in that it is possible to detect that the automatic guided vehicle does not become unable to travel on the intersection and to make it possible to travel at the intersection.

[0008]

According to the first aspect of the present invention, each automatic guided vehicle is given an opportunity to travel at an intersection in accordance with the order of arrival at the intersection, and the vehicle can travel at the intersection within a predetermined time after giving this opportunity. If not, give the next unmanned guided vehicle the opportunity to travel at the intersection. According to the present invention, the queue is processed in the order of arrival at the intersection, and even if the driving conditions are not initially established when the opportunity to travel at the intersection is given, the driver waits until the running conditions are satisfied until the time is up, Gives you the opportunity to drive at an intersection. For this reason, it is possible not only to give preferential treatment to the main route where traveling conditions are easy to be prepared but also to give an opportunity to travel fairly to an auxiliary route where traveling conditions at the intersection are difficult to be prepared. Further, after a predetermined time has elapsed after the opportunity to travel at the intersection is given, the opportunity to travel to the next automatic guided vehicle is given, so that the travelable amount at the intersection can be kept relatively high. For this reason, it is possible to eliminate traffic congestion in front of the intersection, to prevent delay in transport on an auxiliary route, and to improve overall transport efficiency.

According to the second aspect of the present invention, the time up to time-up is made variable at each intersection. For example, at an intersection where traffic volume is prioritized, the time up to time-up is reduced, and the traffic volume is small, so that fairness is improved. At intersections where priority can be given, the time until time-up is increased, and detailed measures can be taken for each intersection according to the balance between traffic volume and fairness.

According to the third aspect of the present invention, if there is a possibility that the vehicle may not be able to travel on the intersection and close the intersection, no permission to travel to the intersection is issued, so that the intersection is closed for a long time by the automatic guided vehicle. There is no.

[0011]

1 to 5 show an embodiment. FIG. 1 shows a traveling route 2 of the automatic guided vehicle in the embodiment. The traveling route 2 is provided on a track or a trackless route in a factory, a warehouse, or the like, is divided into points (not shown) for each predetermined section, and 4 to 9 are intersections provided on the traveling route 2. An intersection is a point where the flow of the automatic guided vehicle 10 from two routes crosses, and is used separately from a mere branch where one route is divided into two. Automatic guided vehicle 10 is, for example, several to one.
Approximately 00 vehicles are arranged on the traveling route 2, a plurality of stations 12 shown in FIG. 2 are arranged along the traveling route 2, and the automatic guided vehicle 10 transports articles between these stations.

FIG. 2 schematically shows a situation at an intersection. Assume that there are intersections A and B on the left and right main routes in the figure, and there is an auxiliary route that joins the main route from the bottom to the upper right of the figure so as to cross these intersections. Since the station 10 is located at a point next to the intersection A, it is assumed that the intersection A is in a state where it is easily blocked. Assuming that the six automatic guided vehicles 10-1 to 10-6 arrive in the order of the branch numbers in such a situation, the processing of the intersection in the embodiment will be described below.

FIG. 3 shows a control system of the automatic guided vehicle system. The system is managed by a system computer 20, and an automatic guided vehicle management unit 22 communicates with the automatic guided vehicle 10 by wire or wireless communication. Each automated guided vehicle 1
0 requests the automatic guided vehicle management unit 22 for permission to travel to a point to be traveled or an intersection, and reports the execution status of the transport command and the like. The automatic guided vehicle management unit 22 assigns a transport command to each of the automatic guided vehicles 10, and permits traveling in response to a traveling permission request from the automatic guided vehicle 10. Then, the automatic guided vehicle 10 travels to the next point or intersection upon receiving the travel permission.

Reference numeral 24 denotes a bus in the system computer 20 which receives a transfer command from a higher-level computer or a control terminal (not shown) and reports the transfer result to the external input / output 2.
6, an allocating unit 28 for allocating and executing a transfer command to the automatic guided vehicle 10 and the like are connected. Reference numeral 30 denotes a route table management unit that stores the required travel time between the stations along the travel route 2 in, for example, a graph format, and searches for an unmanned transport vehicle that can execute the transport command in the shortest time. And the allocation unit 28
Assigns a transfer command to an unmanned guided vehicle that can execute the transfer command in the shortest time and executes the command.

Reference numeral 32 denotes an intersection control unit which is a central concept of the present invention. The intersection control unit 32 receives a travel permission request from the automatic guided vehicle 10 via the automatic guided vehicle management unit 22 for each of the intersections 4 to 9, and receives these requests on a first-come-first-serve basis. Put in the queue in order. Then, when the preceding unmanned guided vehicle finishes traveling at the intersection and the intersection is unlocked, the automatic guided vehicle 10 is given an opportunity to travel through the intersection sequentially from the head of the queue. After that, a predetermined time is waited. During this time, if the intersection can travel or the vehicle can travel from the beginning, the automatic guided vehicle 10 is permitted to travel and travel one by one.

The meaning that an intersection can travel means that at least the target intersection itself can travel, but in the present embodiment, the automatic guided vehicle does not stop on the intersection to block the intersection. Define more strictly. First, FIG.
When the two intersections A and B are adjacent to each other as described above, it is meaningless for the AGV 10-2 that is going to cross them, even if only the first intersection B can travel, and the next intersection A also travels. Must be possible. Therefore, when trying to cross a continuous intersection, all of these intersections must be able to travel.

The automatic guided vehicle 1 is located at the next point of the intersection.
If 0 cannot enter, the automatic guided vehicle 10 will stop in the intersection. Therefore, when the automatic guided vehicle 10 crosses the intersection, the condition that the vehicle can travel to the next point after the intersection is also added. This condition is added to the condition that if the intersections are continuous, the vehicle can travel at all the continuous intersections. For the automatic guided vehicle 10-2 in FIG. The condition is that the point can run.

Each automatic guided vehicle is arranged in the queue of the intersection control unit 32 on a first-come-first-served basis, and passes through the intersection in the first-come-first-served basis in principle. However, if the automatic guided vehicle is not given permission to run at the intersection within a predetermined time after reaching the head of the queue, the rank of the automatic guided vehicle in the queue is moved down by one, for example, and the next automatic guided vehicle is moved down. After giving the transport vehicle an opportunity to travel, it is given an opportunity to cross the intersection again. The degree of lowering the rank in the queue of an unmanned guided vehicle whose time has increased due to a lack of permission to travel at an intersection within a predetermined time may be determined as appropriate.

The time until the time-up is variable for each intersection. For example, at an intersection with heavy traffic, this time is shortened.
It is preferable to lengthen this time at an intersection with a small traffic volume. Further, the time until the time-up may be changed depending on the direction of crossing the intersection. For example, in the case of FIG. If the time until time-up is relatively long in the left-right direction crossing only the intersection, the traffic in the left-right direction on the main route diagram will be given priority and the traffic in the vertical direction on the auxiliary route diagram will be sacrificed to some extent . Conversely, if the time from the bottom to the top of the figure is increased and the time in the left and right directions is shortened, an auxiliary route that tends to be congested in front of the intersection can be preferentially provided. In this way, the longer the time until the time-up, the more fairly each route can be handled, and the shorter the time until the time-up, the more vehicles per hour can be increased. Further, if the time until the time-up is made variable for each intersection or is changed depending on the direction across the intersection, it is possible to balance the fairness and the increase in the travelable amount.

FIG. 4 shows the processing of an intersection taking the processing of FIG. 2 as an example. FIG. 5 shows the control algorithm. When the automatic guided vehicles 10-1 to 10-6 arrive before each intersection, they are accommodated in a queue on a first-come, first-served basis. Intersections A and B
Are continuous in the vertical direction in FIG. 2 and are linked,
For example, one common queue is used. Then, the head of the queue is called, and here, the automatic guided vehicle 10-1 is called, and the intersection A is allowed to travel, so that travel permission is given. Here, the intersection can be traveled means that the intersection A to be traveled and the next point can travel, and when the next point is an intersection, it can travel continuously up to the first non-intersection point. It is. In addition, the detection method itself that the automatic guided vehicle can travel without blocking
Optional.

When the traveling permission of the intersection A is given to the automatic guided vehicle 10-1, the automatic guided vehicle 10-2 reaches the head of the queue. The automatic guided vehicle 10-1 stops at the station 12 next to the intersection A, so that it takes time for the intersection A to be able to travel, during which time allocated to the next automatic guided vehicle 10-2 is time. Up. That is, the automatic guided vehicle 10
If traveling permission is not given within a predetermined time after -2 reaches the head of the queue, the rank of the automatic guided vehicle 10-2 in the queue is reduced by 1, for example. Due to the time-up of the automatic guided vehicle 10-2, the next automatic guided vehicle 10-3 is called, and since the intersection B can travel, the vehicle travels, and the automatic guided vehicle 10-2 whose rank is lowered by 1 is called again, and the time is up. By now, the intersections A and B can travel, so cross the intersections A and B. Thereafter, the automatic guided vehicles 10-4 and 10-
5 crosses different intersections A and B, so that traveling permission can be given at the same time. That is, even if the automatic guided vehicle 10-4 crosses the intersection B, the points required for the automatic guided vehicle 10-5 to cross the intersection A and the intersection are not locked. Can be. Then, if the traveling permission of the intersection B is given to the automatic guided vehicle 10-6,
The processing for the group of automatic guided vehicles 10-1 to 10-6 can be completed.

In this embodiment, an unmanned guided vehicle that cannot travel at an intersection is waited for a time until time-up, and if the vehicle cannot be traveled during this time, the rank is lowered. Therefore, an opportunity to fairly cross an intersection is provided even for an auxiliary route having difficult traveling conditions, and it is possible to prevent the automatic guided vehicle traveling on the auxiliary route from waiting for a long time before the intersection.
In addition, the queue processing is performed on a first-come-first-served basis, and the main route priority processing is not performed. Further, the time-up gives the next automatic guided vehicle a chance to travel, so that the travelable amount at the intersection can be kept relatively high.

The time up to the time-up is variable for each intersection, and it is possible to appropriately balance traffic priority and fairness priority. In addition, since the travel permission is issued on the condition that the automatic guided vehicle does not stop on the intersection, the automatic guided vehicle does not run on the intersection and does not block the intersection. Although specific examples have been described in the embodiments, the present invention is not limited to these.

[Brief description of the drawings]

FIG. 1 is a diagram showing a traveling route of an automatic guided vehicle system according to an embodiment.

FIG. 2 is a diagram showing a situation of an intersection in the automatic guided vehicle system of the embodiment.

FIG. 3 is a diagram illustrating a control system of the automatic guided vehicle system according to the embodiment;

FIG. 4 is a diagram showing a control situation of an intersection in the embodiment.

FIG. 5 is a flowchart illustrating intersection control in the embodiment.

[Explanation of symbols]

 2 traveling route 4-9 intersection 10 automatic guided vehicle 12 station 20 system computer 22 automatic guided vehicle management unit 24 bus 26 external input / output 28 allocation unit 30 route table management unit 32 intersection control unit

Claims (3)

[Claims] 1. A system for traveling a number of automatic guided vehicles along a traveling route having an intersection, wherein each automatic guided vehicle is given an opportunity to travel at the intersection in accordance with the order of arrival before the intersection, and thereafter, within a predetermined time An automatic guided vehicle system characterized by providing an unmanned guided vehicle with an opportunity to travel at an intersection when it is not possible to travel at the intersection. 2. The automatic guided vehicle system according to claim 1, wherein the predetermined time is variable for each intersection. 3. The automatic guided vehicle system according to claim 1, wherein it is detected that the automatic guided vehicle does not become unable to travel on the intersection, and the automatic guided vehicle is allowed to travel on the intersection.