JP2006195859A - Guided vehicle system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a guided vehicle system by which traffic congestion conditions of traveling paths are appropriately understood and an overhead traveling vehicle can select an efficient traveling path. <P>SOLUTION: When blocking requests to a specific area are accepted from the overhead traveling vehicle, each zone controller adds them to queuing, gives blocking permission to a overhead traveling vehicle at the head of the queuing and when the traveling is completed, releases blocking. A time average is calculated using the number of overhead traveling vehicles in the queuing as an index indicating the traffic congestion circumstances of the specific area and announced from the controller to the overhead traveling vehicles. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a transport vehicle system such as an overhead traveling vehicle or an automatic guided vehicle, and more particularly to avoiding a traffic jam on a travel route.

  A transport vehicle such as an overhead traveling vehicle or an automatic guided vehicle stores a route map in which an average travel time between points on a route is entered in a travel route map. When the conveyance command is assigned, the shortest travel route is selected from the route map to travel. The systems using overhead traveling vehicles and automatic guided vehicles have increased in size. For example, the number of overhead traveling vehicles per system exceeds 100, and interbay routes that are routes between bays, intrabay routes that are routes within bays, and Are mixed. When the travel route becomes longer, it becomes important to select an appropriate travel route while avoiding traffic congestion.

Patent Document 1 proposes to solve this problem by causing the controller to periodically report the current position from each automatic guided vehicle and grasping the position of each automatic guided vehicle by the controller. And if the position of the automatic guided vehicle can be grasped, the traffic jam situation can be estimated from the density. However, in this method, it is necessary to grasp the position of all automatic guided vehicles with a controller.
JP-A-11-212463

A basic problem of the present invention is to make it possible to accurately grasp a traffic jam situation of a transport vehicle system.
An additional problem in the invention of claim 2 is to make it possible to accurately obtain the traffic jam situation within the range of existing system control signals and communication.
An additional problem in the invention of claim 3 is that it is possible to provide more reliable data on traffic jam conditions when selecting the travel route of the transport vehicle.

  The transport vehicle system of the present invention is a system in which a transport vehicle travels under the control of a controller along a travel route having an intersection, and the number of transport vehicles waiting in a specific area on the entry side to the intersection. It is characterized in that a traffic jam calculation means for obtaining the vehicle is provided, and the travel route of the transport vehicle is selected according to the obtained number.

  Preferably, the traffic jam calculation means obtains the number of vehicles waiting on the basis of the number of transport vehicles that have requested permission to travel to an intersection and the number of transport vehicles that have passed the intersection and requested cancellation of travel permission.

  Preferably, in the traffic jam calculation means, the traffic jam calculation means obtains an average of the number of transport vehicles waiting in the specific area per predetermined time.

  In this invention, the traffic jam situation is grasped from the number of transport vehicles waiting in a specific area on the approach side (upstream side) of the intersection. The specific area is a place where traffic congestion is likely to occur, and if it is determined which specific area is congested, the travel route can be accurately selected. For this reason, it is not always necessary to grasp the positions of all the transport vehicles, and the traffic jam situation can be grasped accurately.

  The specific area is an area where exclusive control (blocking control) is originally required, and the transport vehicle requests the controller permission to travel before passing the intersection from the specific area, and requests the release of the travel permission after the travel is completed. There are many systems. Therefore, if we focus on the number of transport vehicles that have requested permission to travel to the intersection and the number of transport vehicles that have passed the intersection and requested cancellation of travel permission, the information necessary for exclusive control must be used. You can count the actual number of traffic jams. This eliminates the need for additional resources or additional communication.

  The traffic situation in a specific area varies in an instant, and if you select a travel route corresponding to the instantaneous value of the traffic situation, the traffic area will become the next quietest area, instead of a bypass. Certain areas may then become crowded and the system may not be stable. Therefore, when the travel route of the transport vehicle is determined based on the time average of the traffic jam condition in the specific area, the optimum travel route can be selected as a whole while suppressing fluctuations in the traffic jam situation.

  In the following, an optimum embodiment for carrying out the present invention will be shown.

  1 to 7 show an embodiment and its modifications. In these drawings, 2 is an overhead traveling vehicle system, 4 is a traveling route, and 6 is a LAN. The overhead traveling vehicle system 2 is divided and controlled by a plurality of zone controllers ZCU1 to ZCU9, and the entire overhead traveling vehicle system is controlled by the system controller 10. A plurality of overhead traveling vehicles 12 travel along the travel route 4 and convey articles between load ports provided in a processing device, a stocker, or the like. In the case of simply referring to the controller, the system controller 10 and the zone controllers ZCU1 to ZCU9 are collectively referred to. The traveling route of the overhead traveling vehicle 12 may be determined autonomously or on the controller side. Furthermore, a conveyance command is assigned to the overhead traveling vehicle 12 from the system controller 10 via the zone controllers ZCU1 to ZCU9.

  Instead of the overhead traveling vehicle, an automatic guided vehicle or a tracked carriage may be used, and the type of the overhead traveling vehicle 12 is arbitrary. The overhead traveling vehicle system 2 is a large-scale system that combines an article transport route (intra-bay route) in a process and an article transport route (inter-bay route) between processes. The travel route 4 includes both an intrabay route and an interbay route, but FIG. 1 shows the interbay route as a center. This is because the travel route is limited within the intrabay route, and the importance of selecting the travel route is lower than that of the interbay route. It is assumed that the overhead traveling vehicle 12 consistently conveys articles from the intrabay route load port via the interbay route to the destination intrabay route load port.

  Reference numeral 14 denotes a specific area, which is provided at an intersection such as a branching part or a merging part of the travel route 4. In the embodiment, the range of the specific area 14 is from the upstream side of the intersection to the position where the exclusive control is no longer necessary after passing through the intersection, but the method of determining the range of the specific area 14 is arbitrary. Further, when the overhead traveling vehicle 12 enters the specific area 14 from the upstream side of the intersection, the overhead traveling vehicle 12 outputs an entry permission request (also called a blocking request or a travel permission request) to the intersection to the zone controller. At this time, for example, if the vehicle is going straight, the entry permission is requested to a part necessary for straight traveling in the specific area 14, and if it is a branch, permission to enter the part necessary for traveling diverging is requested. Request. Thus, since the part which requires entry permission is different between straight travel and branching, whether the branching or straight traveling is determined from the approach permission request at the branching part. The specific area 14 or the like is divided into a plurality of portions in units of points, and the point for requesting permission for entry is designated in the request for permission to enter. The overhead traveling vehicle that has requested entry permission waits in a specific area until entry is permitted, and if permitted, passes the intersection and requests cancellation of entry permission after passing. When the specific area 14 is a merging section, the overhead traveling vehicle 12 that has entered this section outputs a blocking request to the merging section (request for permission to enter the merging section) to the zone controller and waits until the merging permission is given. Then, when it has passed through the junction, it requests blocking cancellation.

  In addition to this, the specific area 14 may include a section where it is difficult to avoid a collision with the front sensor of the overhead traveling vehicle 12, a vicinity of the load port, and a narrow path section, such as a curve section of the travel route 4. However, the load port and the cul-de-sac section are mostly located on the intra bay route, and even if the traffic conditions on the intra bay route are grasped, it is often not useful for selecting the travel route of the overhead traveling vehicle 12. This is limited to intra-route routes where the route is a simple round route or one with a shortcut of 1 or 2 added to the round route. Even if traffic conditions can be grasped, the destination load port is specified. This is because the degree of freedom in selecting a travel route is poor. Most of the traffic on the intrabay route is upstream of the intersection, and this portion is designated as a specific area 14. If traffic congestion can be grasped in a specific area consisting of bifurcations and junctions, interbay routes generally have many bypasses, and the main route is more complicated than a simple orbit, so the optimal travel route Can be selected. For this reason, in the embodiment, the traffic jam situation in the specific area 14 is grasped. In addition to the specific area 14, it is also possible to grasp traffic conditions such as a curve section, a load port, or a dead end section.

  2 and 3 show the calculation of the traffic jam in the zone controller ZCU. The traffic jam may be calculated by the system controller 10 instead of the zone controller. A queue 21 is provided for each specific area 14 to be subjected to blocking control, and the overhead traveling vehicle 12a that has entered the specific area is allowed to enter the branch or junction of the specific area as a blocking request to the zone controller. Request. At this time, the overhead traveling vehicle 12a notifies the zone controller of its own ID, for example, the number of the car and the type of branching or straight traveling. The blocking permission part 22 permits blocking to the top overhead traveling vehicle of the queue 21 and permits entry to the branching part or the joining part. When the overhead traveling vehicle 12b permitted to block finishes traveling in the branching section and the merging section, the overhead traveling vehicle 12b is assumed to have traveled, and a blocking release request is input to the zone controller. It is deleted and blocking is allowed for the next overhead traveling vehicle.

  The above process is schematically shown in FIG. From the number of overhead traveling vehicles in the queue 21, the number of vehicles waiting in a specific area can be grasped. The data required to determine the number of units waiting is a blocking permission request or a blocking release request, which are originally necessary for controlling the specific area 14 and do not require additional communication or resources.

  The traffic jam calculation unit 23 obtains the number of traffic jams from the number of overhead traveling vehicles waiting in the queue 21. Preferably, the number of traffic jams is calculated as a time average of, for example, about 5 minutes to 10 minutes, and if necessary, the current number of standby units, the number of standby units in the past about 5 minutes to 10 minutes, and the past 1 hour to 1 day. Output multiple traffic information such as the number of standby units in the long-term average. In the flow rate calculation unit 24, the number of overhead traveling vehicles that have passed through the branching unit and the merging unit, or the number of vehicles that are waiting in a specific area and are about to pass through the branching unit and the merging unit is obtained as the flow rate. In the case of the junction, there is only one type of traveling direction, so there is only one type of flow rate. The data of the flow rate calculation unit 24 can be used as a prediction value as to whether or not the downstream side of each specific area will be congested in the future.

  The number of standby vehicles in the specific area determined by the traffic jam calculation unit 23 and the number of overhead traveling vehicles that have traveled in the specific area determined by the flow rate calculation unit 24 are input to the system controller 10. The totaling unit 26 totals these data for all the specific areas, and notifies the zone controllers ZCU1 to 9 of the traffic jam for each specific area from the announcement unit 27 via the LAN 6. Then, each zone controller broadcasts the traffic congestion situation over the entire travel route 4 to the overhead traveling vehicle 12 under its control.

  FIG. 4 shows the processing on the overhead traveling vehicle 12 side, the route map 41 describes a travel route map, and describes the position of a specific area, the position of a load port, the position of a cover alley section, and the like. The distance and the average travel time are described. The overhead traveling vehicle receives from the zone controller the degree of traffic jam (traffic jam situation) and the traffic jam prediction in each specific area, and updates the route map 41. The degree of traffic jam may be expressed, for example, as it is as the number of overhead traveling vehicles standing by in a specific area, or converted into an appropriate rank such as A to C. The flow rate of each specific area, in other words, the number of units that have passed through the junction, the number of branches that have passed to the branch side, and the number of units that have passed straight ahead, to what extent this route is used, It can be used to predict whether congestion will occur. The overhead traveling vehicle periodically writes these data in the route map 41.

  When an overhead traveling vehicle enters a specific area, it outputs a request for permission to enter the specific area, that is, a blocking permission request, to the zone controller. Then, a blocking cancel request (blocking release request) is output to the zone controller. The announcement receiving unit 44 receives the broadcast from the zone controller and writes the degree of traffic jam and the traffic jam prediction in the route map 41. The route determination unit 45 determines a travel route when a conveyance command is assigned from the zone controller. In the determination of the travel route, for example, the average travel time of the route map is corrected in accordance with the degree of traffic jam or traffic jam prediction, and the route that has the shortest travel time from the current location to the destination is selected. The travel route may be determined by the zone controller, the system controller 10 or the like.

  5 to 7 show algorithms used in the embodiment. In the algorithm of FIG. 5, a request for entering a cart into a specific area is recorded in a queue, and a passing report from the cart that has passed through the specific area is counted to correct the queue. Then, for every fixed time of about 5 minutes to 10 minutes, the average number of overhead traveling vehicles on standby and the flow rate during this period are calculated. These are broadcast to overhead vehicles as traffic information and traffic prediction.

  FIG. 6 is an example in which a sensor is provided in a specific area to check the presence or absence of an overhead traveling vehicle located at a branching part or a joining part. The number of overhead traveling vehicles that require passage through the branching section and the merging section is counted in a queue, and the number of overhead traveling vehicles that have passed through the branching section and the merging section is counted by a sensor. For this reason, a blocking release request is unnecessary, but a sensor is required at the intersection. Then, the time average of the number of units waiting is obtained every fixed time, and the flow rate of the carriage during this period is obtained. In the case of a branching portion, two flow rates on the branching side and the straight traveling side are obtained, and in the case of a junction portion, there is one type of flow rate. The other points are similar to the algorithm of FIG.

  FIG. 7 shows a data flow between the overhead traveling vehicle, the zone controller, and the system controller. The overhead traveling vehicle requests permission to enter a specific area (blocking area), and based on this data, the zone controller grasps the traffic jam situation and inputs traffic jam information in each area to the system controller 10. The system controller 10 collects these data and announces traffic information. The overhead traveling vehicle 12 searches for a travel route based on the traffic jam information.

In the embodiment, the following effects can be obtained.
(1) By using communication for blocking control in a specific area, it is possible to obtain the number of overhead traveling vehicles that are on standby and the flow rate of overhead traveling vehicles.
(2) Congestion information can be obtained by paying attention to branching and merging parts that are particularly important when selecting a travel route on an interbay route. For this reason, the travel route in the interbay route can be selected accurately.
(3) Since the time average can be obtained instead of the instantaneous value of the number of units waiting, the system will not be confused depending on the momentary traffic situation.

The top view which shows typically the layout of the overhead traveling vehicle system of an Example The block diagram which shows the evaluation of the traffic jam situation with each zone controller in the execution example Zone controller queue model diagram Block diagram of control system related to selection of travel route in overhead traveling vehicle The flowchart which shows the congestion avoidance algorithm of an Example Flowchart showing the congestion avoidance algorithm in the modified example Model diagram showing the flow of data related to congestion avoidance in the example

Explanation of symbols

2 Overhead traveling vehicle system 4 Traveling route 6 LAN
ZCU 1 to 9 Zone controller 10 System controller 12 Overhead vehicle 14 Specific area 21 Queue 22 Blocking permission unit 23 Traffic congestion calculation unit 24 Flow rate calculation unit 26 Totaling unit 27 Announcement unit 41 Route map 42 Blocking request unit 43 Blocking cancellation request unit 44 Announcement Receiver 45 Route determination unit

Claims (3)

In the system in which the transport vehicle travels under the control of the controller along the travel route with the intersection,
Conveying vehicle characterized in that it is provided with a traffic jam calculation means for determining the number of transport vehicles waiting in a specific area on the approaching side to the intersection, and the travel route of the transport vehicle is selected according to the determined number of transport vehicles. system. In the traffic jam calculation means, the number of vehicles on standby is obtained from the number of transport vehicles that have requested permission to travel to the intersection and the number of transport vehicles that have passed the intersection and requested release of travel permission. The carrier system according to claim 1, characterized in that The transport vehicle system according to claim 1 or 2, wherein the traffic jam calculation means calculates an average of the number of transport vehicles waiting in the specific area per predetermined time.

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