U.S. patent application number 09/863526 was filed with the patent office on 2001-12-06 for travelling vehicle system.
This patent application is currently assigned to Murata Kikai Kabushiki Kaisha. Invention is credited to Sone, Hiroki.
Application Number | 20010049572 09/863526 |
Document ID | / |
Family ID | 18661063 |
Filed Date | 2001-12-06 |
United States Patent
Application |
20010049572 |
Kind Code |
A1 |
Sone, Hiroki |
December 6, 2001 |
Travelling vehicle system
Abstract
A distribution computer 10 and a plurality of controllers
12.about.15 are connected together via a LAN. One of the
controllers acts as a main controller 12 to transmit control from
the distribution controller 10 to the controllers 12.about.15. The
controllers 12.about.15 are duplicated so as to back up one
another, and a main programmable controller 16 monitors the
controllers 12 to 15 to detect defects. Arc nets 19.about.22 are
connected together via an RS232C line to communicate the passage of
a travelling vehicle between themselves. Even with an extended
running path, the present invention hinders a delay in
communication and thus a delay in control, thereby preventing
system down caused by a defect in a controller.
Inventors: |
Sone, Hiroki;
(Kagamigahara-shi, JP) |
Correspondence
Address: |
ARMSTRONG,WESTERMAN, HATTORI,
MCLELAND & NAUGHTON, LLP
1725 K STREET, NW, SUITE 1000
WASHINGTON
DC
20006
US
|
Assignee: |
Murata Kikai Kabushiki
Kaisha
Kyoto-shi
JP
|
Family ID: |
18661063 |
Appl. No.: |
09/863526 |
Filed: |
May 24, 2001 |
Current U.S.
Class: |
701/23 ;
180/167 |
Current CPC
Class: |
G08G 1/04 20130101 |
Class at
Publication: |
701/23 ;
180/167 |
International
Class: |
G05D 001/00 |
Foreign Application Data
Date |
Code |
Application Number |
May 26, 2000 |
JP |
2000-156247 |
Claims
1. A travelling vehicle system comprising a running path for
travelling vehicles which is divided into a plurality of zones and
a plurality of zone controllers for controlling the travelling
vehicles in the corresponding zones, the system being characterized
in that: said plurality of zone controllers are divided into a
plurality of groups, a plurality of group controllers are provided
for controlling the corresponding groups, and each of the group
controllers backs up at least one of the other group
controllers.
2. A travelling vehicle system according to claim 1, characterized
in that communication lines are provided to connect said groups
together without using the group controllers.
3. A travelling vehicle system according to claim 1, characterized
in that one of said group controllers acts as a main controller so
that an upper controller and said plurality of group controllers
communicate with one another via the main controller, and at least
one of the other group controllers is configured to back up the
main controller.
4. A travelling vehicle system according to claim 2, characterized
in that one of said group controllers acts as a main controller so
that an upper controller and said plurality of group controllers
communicate with one another via the main controller, and at least
one of the other group controllers is configured to back up the
main controller.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a travelling vehicle
system, and in particular, to prevention of a delay in control and
system down which may occur when the overall length of a traveling
path for travelling vehicles is increased to obtain a larger-scale
system.
BACKGROUND OF THE INVENTION
[0002] In a travelling vehicle system such as a tracking cart
system, a running path is divided into a plurality of zones and a
zone controller is provided for each zone so as to control a
travelling vehicle that has entered that zone. A system controller
is also provided for controlling these zone controllers, and a
network is used to connect all of these controllers together. The
system controller receives a conveyance instruction from an upper
controller such as a distribution computer for the entire factory
to correspondingly control the zone controllers, and report the
results of conveyance to the distribution computer.
[0003] When the scale of the travelling vehicle system is increased
and the running path for travelling vehicles is extended, a larger
number of zone controllers are required and a delay may occur in
the communication between the system controller and the zone
controllers, thereby wastefully stopping travelling vehicles.
Additionally, as the number of zone controller is increased, the
limit of the capacity of the system controller is reached soon.
When additional system controllers are then installed and assigned
with different running paths obtained by dividing the original
running path, if any of the system controllers becomes defective,
the travelling vehicle system is shut down.
[0004] It is a basic object of the present invention to prevent,
despite an extended running path, a delay in the communication
between zone controllers and a system controller as well as the
system-down of a travelling vehicle system.
[0005] It is an additional object of the present invention to
enable the communication between adjacent group zone controllers
without using any system controller in order to prevent a delay in
control.
[0006] It is an additional object of the present invention to
reduce communication burdens on an upper controller such as a
distribution computer.
SUMMARY OF THE INVENTION
[0007] The present invention provides a travelling vehicle system
comprising a running path for travelling vehicles which is divided
into a plurality of zones and a plurality of zone controllers for
controlling the travelling vehicles in the corresponding zones, the
system being characterized in that the plurality of zone
controllers are divided into a plurality of groups, a plurality of
group controllers are provided for controlling the corresponding
groups, and each of the group controllers backs up at least one of
the other group controllers.
[0008] Preferably, communication lines are provided to connect the
groups together without using the group controllers.
[0009] Preferably, one of the group controllers acts as a main
controller so that an upper controller and the plurality of group
controllers communicate with one another via the main controller,
and at least one of the other group controllers is configured to
back up the main controller.
[0010] According to the present invention, even if the running path
for travelling vehicles is extended and the number of zone
controllers is increased, since the zone controllers are divided
into the plurality of groups, which are assigned to the different
group controllers, the amount of time required for the
communication between the zone controllers and the group
controllers can be reduced to prevent a delay in control caused by
a delay in communication.
[0011] Furthermore, in the present invention, the plurality of
group controllers back up one another, so that the system-down of
the travelling vehicle system can be prevented even if any of the
group controllers is shut down. Thus, in a factory, if a travelling
vehicle system is used for a basic conveyance system or the like
which is used for inter-process conveyance, a larger-scale reliable
travelling vehicle system is obtained.
[0012] Furthermore, the communication lines are provided to connect
the groups together without using the group controllers. This
communication lines are auxiliary and different from lines for
connecting the zone controllers and the group controllers together.
Thus, the entry of a travelling vehicle into the adjacent group or
the like can be processed through the communication between the
zone controllers without using the group controllers, thereby
preventing a decrease in the speed of the communication between the
zone controllers which may occur at the boundary between the
groups.
[0013] Moreover, one of the group controllers acts as the main
controller to allow the group controllers and the upper controller
to communicate with one another. Thus, the upper controller needs
to communicate only with the main controller as in the prior art.
Additionally, since one of the group controllers backs up the main
controller, the travelling vehicle system is not shut down even if
the main controller is shut down.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a layout of a travelling vehicle system of an
embodiment of the present invention.
[0015] FIG. 2 is a view showing the configuration of a control
system in the embodiment.
[0016] FIG. 3 is a view showing the relationship between the
components of the control system in the embodiment.
[0017] FIG. 4 is a view showing the configuration of a control
system in a variation of the present invention.
[0018] FIG. 5 is a view showing the relationship between the
components of the control system in the embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0019] FIGS. 1 to 3 shows an embodiment of the present invention.
In these figures, 2 is a travelling vehicle system as a whole, 4 is
a track, and 6 is a linear travelling vehicle. A linear motor (a
primary conductor) may be provided on the ground (track) or on the
travelling vehicle body. Instead of the linear travelling vehicle
6, another tracking cart or a travelling vehicle that runs without
using any track may be used.
[0020] 8 is a LAN, and 10 is a distribution computer for
controlling the entire distribution of products in a semiconductor
factory, a liquid-crystal factory, or the like, and the
distribution computer 10 corresponds to an upper controller for the
travelling vehicle system 2. 12 is a main controller, and
13.about.15 are subcontrollers. The controllers 12.about.15
actually have the same configuration. The controllers 12.about.15
are an example of plural group controllers, and the main controller
12 communicates with the distribution computer 10, and the
subcontroller 13 backs up the main controller 12. The subcontroller
14 backs up the subcontroller 13, the subcontroller 15 backs up the
subcontroller 14, and the main controller 12 backs up the
subcontroller 15. In this manner, the controllers 12.about.15 each
back up the adjacent controller.
[0021] The controllers 12.about.15 each control a plurality of zone
controllers 18 via arc nets 19.about.22 constituting an information
network. At the boundaries between the arc nets 19.about.22, the
zone controllers 18, 18 are normally connected together via RS232C
lines 24. The RS232C lines 24 are used to allow one of the zone
controllers 18, 18 to directly notify the other that the linear
travelling vehicle 6 has entered the area of the adjacent arc net.
The controllers 12.about.15 are each connected to the two arc nets
and normally control only one of the groups of zone controllers 18,
while controlling both groups of zone controllers 18 during
backup.
[0022] The distribution computer 10 and the controllers 12.about.15
are connected together through the LAN 8 (information communication
network) such as Ethernet, which operates at a high speed and has a
large capacity. The main controller 12 communicates with the
distribution computer 10, and this communication is intercepted by
the subcontroller 13 for backup. The controllers 12.about.15 are
each connected to the two arc nets and are each configured so as to
control both the right and left arc nets (groups), and the arc nets
are connected together via the RS232C line 24 at their boundary.
Main programmable controllers 16 are each connected to a
corresponding one of the arc nets 19.about.22 to check the
communication from the controllers 12.about.15 or the like to the
arc nets 19.about.22 in order to always monitor the controllers 12
to 15.
[0023] FIG. 3 shows how a signal is transmitted from the
distribution computer 10 to the zone controller 18. The main
controller 12 intervenes in the communication between the
controllers 13.about.15 and the distribution computer 10. The
distribution computer 10 transmits a conveyance instruction to the
main controller 12 and receives the results of conveyance from the
main controller 12. The backup subcontroller 13 intercepts the
communication between the distribution computer 10 and the main
controller 12, and the communication between the main controller 12
and the subcontrollers 13.about.15 and the like. The subcontroller
13 thus has management data for the conveyance system similar to
those held by the main controller 12, so as to back up the main
controller 12. In this embodiment, only one subcontroller 13 is
assigned to the backup of the main controller 12, but all the
subcontrollers 13.about.15 may back up the main controller 12.
[0024] In FIG. 3, the controllers 12, 13 are each shown separately
in a block for controlling the entire conveyance system and in a
block for controlling the zone controller 18, but these are the
separate blocks in the same controller. The main programmable
controller 16 always monitors the state of each of the controllers
12.about.15, and if any of the controllers 12.about.15 becomes
defective, the main programmable controller 16 instructs the
adjacent controller to perform a backup operation. Thus, whichever
controller becomes defective, another controller may back up this
defective controller to prevent system-down. The above adjacent
controller intercepts the communication between the controller to
back up and the distribution computer 10 via the LAN 8, and also
intercepts the communication between the controller to back up and
the zone controllers or the like via the arc net. Thus, when the
main programmable controller 16 instructs backup, the adjacent
controller can immediately control the arc net.
[0025] Further, since each controller controls only a limited
number of zone controllers, almost no delay occurs in the
communication between the controller and the zone controller.
[0026] Furthermore, the zone controllers 18, 18 can directly
communicate with each other at the boundary between the arc nets
19.about.22 via the RS232C line 24, thereby preventing a delay in
communication caused by the intervention of the controllers
12.about.15.
[0027] FIGS. 4 and 5 show a variation of the present invention.
[0028] In this variation, the same reference numerals as those in
FIGS. 1.about.3 denote the same components, that is, this variation
is similar to the embodiment in FIGS. 1.about.3 except for the
points indicated below. In the variation, a backup switch 30 is
used to connect the adjacent arc nets 19.about.22 together for
backup, and if any of the controllers is shut down, the backup
switch 30 is closed to connect the adjacent arc nets together for
backup. Then, the main controller 12 is backed up, for example, by
the subcontroller 13 for duplication and each controller is
similarly backed up by the adjacent controller for duplication. If
any of the controllers becomes defective, the backup switch 30 is
closed to allow one corresponding controller to control the two
groups for backup.
* * * * *