U.S. patent number 6,109,568 [Application Number 09/178,379] was granted by the patent office on 2000-08-29 for control system and method for moving multiple automated vehicles along a monorail.
This patent grant is currently assigned to Innovative Transportation Systems International, Inc.. Invention is credited to Chris Brian Gilbert, Bernd Hillebrecht.
United States Patent |
6,109,568 |
Gilbert , et al. |
August 29, 2000 |
Control system and method for moving multiple automated vehicles
along a monorail
Abstract
The monorail system of the present invention contains a monorail
and a system controller that has a first radio frequency ethernet
communications device. Location markers are attached to the
monorail. A vehicle is positioned to move on the monorail. The
vehicle contains a motor drive system that moves the vehicle on the
monorail. A remote controller is interconnected to the motor drive
system, and the remote controller controls movement of the vehicle
and receives information from the system controller. A reader
connected to the remote controller senses the location markers
attached to the monorail. A second radio frequency ethernet
communications device is provided and is connected to the remote
controller. The radio frequency ethernet communications device
wirelessly communicates with the first radio frequency ethernet
communications device on the system controller to create a wireless
ethernet network containing at least the system controller and the
remote controller. The information from the system controller is
delivered over the wireless ethernet network to the vehicle, and
the information is used to instruct the vehicle in the controlled
movement on the monorail.
Inventors: |
Gilbert; Chris Brian (Aurora,
CO), Hillebrecht; Bernd (Morrison, CO) |
Assignee: |
Innovative Transportation Systems
International, Inc. (Morrison, CO)
|
Family
ID: |
22652321 |
Appl.
No.: |
09/178,379 |
Filed: |
October 23, 1998 |
Current U.S.
Class: |
246/3; 104/88.03;
246/167R; 246/2R; 246/5 |
Current CPC
Class: |
B61L
23/005 (20130101) |
Current International
Class: |
B61L
23/00 (20060101); B61L 027/00 () |
Field of
Search: |
;246/2R,3,5,167R,182R
;340/933,988,989 ;701/1,2,19,20,23,24
;104/88.01,88.02,88.03,88.04,88.05,295,296,300 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
Micron Communications, Inc., Micron 125 kHz Readers, Catalog (no
date). .
Micron Communications, Inc., Small Disk Asset Tag, Catalog (no
date). .
Micron Communications, Inc., Micron 125 kHz External RFID Antenna,
Catalog (no date. .
Sunx Trading Co., Ltd., Obstacle Detection Sensor PX-2 Series,
Instruction Manual, Japan (no date). .
Rockwell Automation Allen-Bradley, Connect to the Future Today with
Allen-Bradley's SLC 5/05TM Processor with Ethernet, Catalog, Nov.
1997, Publication 1747-1.18, USA. .
Symbol Technologies, Inc., Spectrum 24 Wireless LAN, Dec. 1997,
Part No. DJ, USA..
|
Primary Examiner: Le; Mark T.
Attorney, Agent or Firm: Dorr, Carson, Sloan & Birney,
P.C.
Claims
What is claimed is:
1. A monorail system comprising:
a monorail having a plurality of stations thereon;
a source of power on said monorail;
a system controller having a first radio frequency ethernet
communications device; and
at least one vehicle moving on said monorail among said plurality
of stations, said at least one vehicle comprising:
a drive motor connected to said power for moving said vehicle on
said monorail;
a remote controller connected to said drive motor for controlling
said movement of said vehicle, said remote controller further
receiving information from said system controller; and
a second radio frequency ethernet communications device
interconnected to said remote controller, said second radio
frequency ethernet
communications device and said first radio frequency ethernet
communications device of said system controller forming a wireless
ethernet network including at least said system controller and said
remote controller in said at least one vehicle;
a remote device connected to said remote controller, said remote
device configured to perform a predetermined task at one of said
plurality of stations on said monorail before moving on said
monorail to perform another predetermined task at another one of
said plurality of stations,
said information from said system controller delivered over said
wireless ethernet network to said at least one vehicle for
instructing said at least one vehicle in said controlled movement
on said monorail.
2. The monorail system, as claimed in claim 1, further
comprising:
at least one positioning marker attached to said monorail; and
a reader connected to said remote controller for sensing said at
least one positioning marker as said at least one vehicle moves
on said monorail past said at least one positioning marker.
3. The monorail system, as claimed in claim 1, further
comprising:
at least one radio frequency marker attached to said monorail;
and
a radio frequency receiver attached to said at least one vehicle
for reading said radio frequency marker as said vehicle passes said
radio frequency marker.
4. The monorail system, as claimed in claim 1, further
comprising:
a collision avoidance system having at least one sensor connected
to said remote controller in said at east one vehicle.
5. The monorail system, as claimed in claim 4, wherein said at
least one sensor comprises an infrared sensor.
6. A monorail system comprising:
a monorail having a plurality of stations thereon;
a source of power on said monorail;
a system controller having a first radio frequency ethernet
communications device;
at least one location marker attached to said monorail; and
at least one vehicle moving on said monorail among said plurality
of stations, said at least one vehicle comprising:
a motor drive system connected to said power for moving said
vehicle on said monorail;
a remote controller interconnected to said motor drive system for
controlling movement of said vehicle and for receiving information
from said system controller;
a reader connected to said remote controller for sensing said at
least one location marker attached to said monorail;
a remote device connected to said remote controller, said remote
device configured to perform a predetermined task at one of said
plurality of stations on said monorail when said at least one
location marker is sensed before moving on said monorail to perform
another predetermined task at another one of said plurality of
stations; and
a second radio frequency ethernet communications device connected
to said remote controller, said radio frequency ethernet
communications device wirelessly communicating with said first
radio frequency ethernet communications device on said system
controller to create a wireless ethernet network including at least
said system controller and said remote controller,
said information from said system controller delivered over said
wireless ethernet network to said at least one vehicle for
instructing said at least one vehicle in said controlled movement
on said monorail.
7. The monorail system, as claimed in claim 6, wherein said
location marker comprises a radio frequency transponder.
8. The monorail system, as claimed in claim 7, wherein said radio
frequency transponder comprises a passive radio frequency
transponder.
9. The monorail system, as claimed in claim 7, wherein said radio
frequency transponder comprises an active radio frequency
transponder.
10. The monorail system, as claimed in claim 6, wherein said
location marker comprises:
a device containing information wherein said information includes
an ASCII character string, wherein said ASCII character string
translates into a number.
11. A monorail system comprising:
a monorail having a plurality of stations thereon;
a source of power on said monorail;
a system controller having a first radio frequency ethernet
communications device;
at least one location marker attached to said monorail, said at
least one location marker comprising a radio frequency transponder
including a numeric data string; and
at least one vehicle moving on said monorail among said plurality
of stations, said at least one vehicle comprising:
a motor drive system connected to said power for moving said
vehicle on said monorail;
a remote controller interconnected to said motor drive system for
controlling movement of said vehicle and for receiving information
from said system controller;
a reader connected to said remote controller for sensing said at
least one location marker attached to said monorail, said reader
comprising a tuned antenna;
a remote device connected to said remote controller, said remote
device configured to perform a predetermined task at one of said
plurality of stations on said monorail when said at least one
location marker is sensed before on said monorail to perform
another predetermined task at another one of said plurality of
stations; and
a second radio frequency ethernet communications device connected
to said remote controller, said radio frequency ethernet
communications device wirelessly communicating with said first
radio frequency ethernet communications device on said system
controller to create a wireless ethernet network including at least
said system controller and said remote controller,
said information from said system controller delivered over said
wireless ethernet network to said at least one vehicle for
instructing said at least one vehicle in said controlled movement
on said monorail.
12. A monorail system comprising:
means for defining a path of movement having a plurality of
stations thereon;
a source of power on said means for defining a path of
movement;
means for controlling said monorail system having a first means for
wirelessly transmitting via an ethernet network;
at least one means for moving along said path of movement among
said plurality of stations, said means for moving comprising:
means for propelling said means for moving on said path of
movement, said means for propelling connected to said power;
means for remotely controlling connected to said means for
propelling, said means for remotely controlling commanding movement
of said means for moving and receiving information from said means
for controlling;
a remote device connected to said means for remotely controlling,
said remote device configured to perform a predetermined task at
one of said plurality of stations before moving to another one of
said plurality of stations to perform another predetermined task;
and
second means for wirelessly communicating interconnected to said
means for remotely controlling, said second means for wirelessly
communicating and said first means for wirelessly communicating
forming a wireless ethernet network including at least said means
for controlling and said means for remotely controlling in said at
least one means for moving,
said information from said means for controlling delivered over
said wireless ethernet network to said means for moving for
instructing said at least one means for moving in said controlled
movement on said path of movement.
13. The monorail system, as claimed in claim 12, further
comprising:
means for demarking zones along said path of movement connected to
said means for remotely controlling.
14. The control system, as claimed in claim 12, further
comprising:
means for sensing a location means connected to said means for
remotely controlling, said location means attached to said monorail
and identifying vehicle movement zones.
15. The control system, as claimed in claim 12, further
comprising:
means for detecting obstacles connected to said means for remotely
controlling; and
means for avoiding a collision with said obstacles connected to
said means for remotely controlling.
16. A method for controlling at least one vehicle along a monorail
having a system controller and having a plurality of stations
thereon, said method comprising the steps of:
assigning a unique ethernet address to said at least one vehicle on
said monorail;
selectively transmitting at least one instruction from said system
controller to said at least one vehicle via a wireless ethernet
network, said transmitted instruction containing said unique
ethernet address;
receiving said selectively transmitted at least one instruction at
said at least one vehicle having said unique ethernet address;
storing said at least one received instruction in memory on said
vehicle having said unique ethernet address; and
performing a predetermined task based on said stored instruction
before moving on said monorail to another of said plurality of
stations to perform another predetermined task.
17. The method, as claimed in claim 16, further comprising the step
of:
transmitting a confirmation command from said at least one vehicle
having said unique ethernet address to said system controller over
said wireless ethernet network, said confirmation command
containing said unique ethernet address.
18. The method, as claimed in claim 16, wherein performing said
stored instruction further comprises the steps of:
sensing a location marker attached to said monorail, said location
marker having a unique location string;
comparing said location string with said at least one instruction
wherein said at least one instruction comprises an instruction set
having a plurality of instructions each instruction having a unique
identifier;
executing a specific instruction from said plurality of
instructions in said instruction set wherein said executed specific
instruction has an identifier correlated to said unique location
string.
19. The method, as claimed in claim 16, further comprising the
steps of:
identifying an obstacle in a movement path of said vehicle; and
avoiding a collision with said obstacle.
20. The method, as claimed in claim 19, wherein avoiding a
collision step further comprises the steps of:
first sensing said obstacle within at least about three meters of
said vehicle;
first instructing said vehicle to move at a first predetermined
velocity;
second sensing said obstacle within at least about one meter of
said vehicle; and
second instructing said vehicle to stop moving.
21. A method for controlling at least one vehicle along a monorail
having a system controller, said method comprising the steps
of:
assigning a unique ethernet address to said at least one vehicle on
said monorail;
selectively transmitting at least one instruction from said system
controller to said at least one vehicle via a wireless ethernet
network, said transmitted instruction containing said unique
ethernet address;
receiving said selectively transmitted at least one instruction at
said at least one vehicle having said unique ethernet address;
storing said at least one received instruction in memory on said
vehicle having said unique ethernet address;
performing said stored instruction, said performing step
comprising:
sensing a location marker attached to said monorail, said location
marker having a unique location string;
comparing said location string with said at least one instruction
wherein said at least one instruction comprises an instruction set
having a plurality of instructions each instruction having a unique
identifier;
executing a specific instruction from said plurality of
instructions in said instruction set wherein said executed specific
instruction has an identifier correlated to said unique location
string; and
transmitting a confirmation command from said at least one vehicle
having said unique ethernet address to said system controller over
said wireless ethernet network, said confirmation command
containing said unique ethernet address;
identifying an obstacle in a movement path of said vehicle; and
avoiding a collision with said obstacle, said avoiding step
comprising:
first sensing said obstacle within at least about three meters of
said vehicle;
first instructing said vehicle to move at a first predetermined
velocity;
second sensing said obstacle within at least about one meter of
said vehicle; and
second instructing said vehicle to stop moving.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to moving multiple
automated vehicles, and, more particularly, to a control system and
method for moving an automated vehicle along an automated
electrified monorail under central control.
2. Statement of the Problem
Conventional automated electrified monorail (AEM) systems,
typically, contain a monorail, a number of vehicles that move along
the monorail and control electronics that control the movement of
the vehicles along the monorail. The monorail is an industry
standard rail having an I-type cross section. In most applications,
the monorail is installed overhead on a beam or suspended from the
ceiling. This overhead configuration allows the vehicles to move
along the monorail and perform tasks without being impeded by
obstacles located at the floor level.
The vehicles contain a suspension system that connects the vehicle
to the monorail. The suspension system contains wheels that contact
and move along the monorail. Typically, an electric motor is
attached to the wheels to propel the vehicle along the monorail.
The electrical power for the motor is provided by a number of
bus-bar-type power conductors that are hardwired and physically
attached along the perimeter of the monorail. Typically, electrical
power is provided by four power conductors (three-phase power and a
ground wire). The motor contains electrical connectors that provide
electrical contact to the power conductors as the vehicle travels
along the monorail.
The conventional AEM system has electronic control equipment that
is used to instruct the vehicle to move along the monorail. The
control equipment usually contains a number of bus-bar-type control
conductors that are hardwired and physically attached along the
perimeter of the monorail with the power conductors. Typically,
conventional AEM systems require about eight to twelve conductors
for controlling and powering the vehicles. A predetermined number
of the control conductors are used to control the movement and
speed of the vehicle while the other conductors may be used to
control the vehicle while performing a variety of other functions.
At a first end, the control conductors are connected to a system
controller that determines the voltage that is to be applied to the
control conductors. Along the length of the monorail, the control
conductors make contact with the vehicle electronics which contain
electrical connectors that electrically contact the control
conductors as the vehicle moves along the monorail.
In these systems, the vehicle control electronics are typically
hardwired on the vehicle. The control electronics provide vehicle
control by interpreting the voltage applied to the control
conductors. This interpreted voltage is translated into an applied
motor voltage. Accordingly, the electric motor moves the wheels
corresponding to this applied motor voltage.
When the vehicles are required to change speeds, for example around
curves or known obstacles, these conventional AEM systems require
physical cuts in the control conductors, thereby providing movement
zones having a specific voltage. Such movement zones are created by
physically cutting the control conductors into separate
electrically isolated sections. Each section becomes a movement
zone and must be separately connected to the system controller
which controls the voltage applied to the conductors in the
zone.
Installation of conventional AEM systems is typically expensive and
labor intensive because these systems require eight to twelve
conductors including control and power conductors to be manually
installed and routed along the perimeter of the monorail. In
addition to the installation expenses, the creation of movement
zones on the monorail also are labor intensive and expensive
requiring manually cutting and electrically isolating the section
conductors at specified locations along the monorail and connecting
each separate section to the system controller. After installation,
modification of the AEM system, particularly moving the movement
zones from one location to another, is difficult because the
hardwired conductors must each be disconnected from the system
controller and reconnected at the new location. However, if the
size of the monorail is changed, all the control conductors must be
removed and reinstalled since these conductors have been physically
cut to create the movement zones.
Additionally, aside from moving the monorail, relocation of the
movement zones on an existing monorail presents a variety of
problems. Since the control conductors have been physically cut to
create movement zones, any relocation of these zones on an existing
monorail requires removal of the old conductors and installation of
new conductors. In addition, the new conductors must be physically
cut and electrically isolated to create the movement zones newly
desired location. The modification and installation of the
conventional AEM systems can become even more expensive if the AEM
system is installed or modified in an enclosed structure that has
many obstacles to restrict the movement of the installation
workers. Furthermore, this modification is expensive due to the
high cost of the materials (wires, cables and cable trays) and due
to the labor time that is required to make the modification.
Also, in conventional AEM systems, the control electronics use
discrete signals which limit the amount of data that is capable of
being transmitted over the control conductors. Accordingly, to
increase the amount of data that can be transmitted, the
conventional AEM systems require that additional control conductors
be added to the monorail. These additional conductors also require
labor intensive and expensive installation and modification.
Another problem with conventional AEM systems is found in the
hard-wired vehicle control electronics. Since the vehicle control
electronics are hardwired to the vehicle, the AEM system must be
shut down or the vehicle must be removed from the monorail to
reprogram the control electronics. Reprogramming is typically
accomplished by physically changing the hard-wired electronics or
by changing the program located in memory in a vehicle controller.
In either case, the vehicle must be physically stopped
for the change to occur.
Finally, conventional AEM systems are equipped with collision
devices containing proximity sensors that are located on an arm
extending from the vehicle. These proximity sensors prevent the
vehicles from colliding during movement on the monorail. These
conventional collision devices have a detection range that is
limited to the length of the arm on which the proximity sensor is
positioned.
Therefore, a need exists for an AEM system that is easier and less
expensive to install than present systems, and an AEM system that
is readily adaptable to change and modification. In addition, a
need exists for an AEM system that allows for uncomplicated
physical relocation or modification of the movement zones. A need
exists for an AEM system that communicates significantly more data
that conventional systems. Also, there is a need for an AEM system
that allows for vehicle program changes that do not require the
entire AEM system to be shut down or vehicles to be removed from
the monorail. Finally, a need exists for a vehicle having a
collision avoidance system where the detection range is not
dependent upon the length of a sensor arm.
SUMMARY OF THE INVENTION
1. Solution to the Problem.
The problems mentioned above and other problems are solved by the
present invention. The present invention provides a monorail system
that is less expensive and easier to install than present systems
because the present invention does not require the installation of
separate and costly control conductors. The present invention
provides a novel movement zone that eliminates the expense
associated with physically cutting the control conductors into
movement zones and therefore allows the movement zones to be easily
relocated. The present invention also provides an AEM system that
can be physically moved or modified easier than existing monorail
systems which have control conductors and the problems associated
with the control conductors. In addition, the present invention
provides a system where the programming of the vehicle control
electronics can be changed without shutting down the AEM system or
removing the vehicles from the monorail.
Further, the present invention provides an AEM system that does not
severely limit the amount of data that can be transmitted to the
vehicles. The present invention also provides a novel AEM system
that uses vehicles equipped with collision avoidance devices to
avoid collisions with other vehicles or objects positioned on the
monorail and objects that are not positioned on the monorail.
Further, the collision avoidance system of the present invention
has a programmable detection range. Finally, the AEM system of the
present invention processes significantly more data between the
central controller and the vehicle.
2. Summary
The monorail system of the present invention contains a monorail
and a system controller that has a first radio frequency ethernet
communications device. Location markers are attached to the
monorail to define movement zones and areas where specific tasks,
are performed. A vehicle is positioned on the monorail under the
control of a motor drive system that moves the vehicle on the
monorail. A remote controller is interconnected to the motor drive
system, and the remote controller controls movement of the vehicle
based on the delivery of high speed information received from the
system controller. A reader connected to the remote controller
senses each location marker attached to the monorail as the vehicle
moves on the monorail. A second radio frequency ethernet
communications device is provided and is connected to the remote
controller. The radio frequency ethernet communications device
wirelessly communicates with the first radio frequency ethernet
communications device on the system controller to create a wireless
ethernet network containing at least the system controller and the
remote controller. The information from the system controller is
delivered over the wireless ethernet network to the vehicle, and
the information is used to instruct the vehicle in the controlled
movement on the monorail.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of one embodiment illustrating the
automated electrified monorail system of the present invention;
FIG. 2 is a perspective view of another embodiment of the automated
electrified monorail system of the present invention;
FIG. 3 is a block diagram view of a vehicle in the automated
electrified monorail system of the present invention;
FIG. 4 is a block diagram of the radio-frequency ethernet local
access network in the automated electrified monorail system of the
present invention;
FIG. 5 is a functional flow chart representation of a location
marker sensing method used by a vehicle of the present
invention;
FIG. 6 is a functional flow chart representation of a collision
avoidance method used by a vehicle of the present invention;
FIG. 7 is a top view of the automated electrified monorail system
illustrating collision avoidance, obstacle avoidance, movement
zones and other features of the present invention;
FIG. 8 is a perspective view illustrating the arrangement of the
vehicle of the present invention with the monorail;
FIG. 9 sets forth the data sequence that is useful in accordance
with the present invention;
FIG. 10a illustrates a top view of the collision avoidance system
of the present invention having a multiple detection lobe sensor;
and
FIG. 10b illustrates a top view of the collision avoidance system
of the present invention having multiple sensors.
DETAILED DESCRIPTION OF THE INVENTION
1. Overview
In one embodiment, as generally illustrated in FIG. 1, the
automated electrified monorail (AEM) system 100, generally,
contains a monorail 30, a vehicle 10 and a system controller 20.
Only a portion of the monorail 30 is shown. A feature of the
present invention is that the movement of a vehicle 10 is
controlled through a wireless radio-frequency (RF) ethernet network
which contains the system controller 20 and the remote controller
70. It should be appreciated that any number of vehicles 10 may be
positioned to move on the monorail 30 during normal operation. The
use of a wireless RF ethernet network permits high speed data
communication between the vehicle 10 and the system controller 20.
The wireless RF ethernet network 150 also allows program changes in
the remote controller 70 to occur at anytime during operation of
the AEM system 100.
Another feature of the present invention is that location markers
80 are used to define movement zones 190 in FIG. 1 and 710-750
shown in FIG. 7 along the monorail 30. The location markers 80 are
attached to the monorail 30 and are easily moved to modify or
change the location of the movement zones.
In another embodiment, as shown in FIG. 2, the AEM system 100
contains a cellular network 200 that comprises a number of cells
210, 212, 214, 216, 218, 220, 222 and 224. Each cell contains an
access point 202 that is connected to an ethernet backbone 206
through lines 204. The ethernet backbone 206 is connected to an
ethernet hub 208 that is connected to the system controller 20. The
cells are set out to completely cover the vehicle 10 no matter
where it is traveling on the monorail 30 such that the vehicle 10
will always be in radio contact with at least one of the access
points 202. It should be noted that the cells set out in FIG. 2 are
drawn for illustration and that the cell coverage boundaries need
not be hexagonally shaped, can overlap and/or a single cell can
cover the entire AEM system 100. The transmission protocol between
the remote controller 70 and the access points 202 is typically an
industry standard protocol, e.g., IEEE 802.11 wireless transmission
standard.
In summary, the AEM system 100 of the present invention does not
require the use of a number of costly bus-bar-type control
conductors that are physically installed along the perimeter of the
monorail 30 that provide limited bandwidth between the vehicle 10
and the system controller 20. Rather the system controller 20 is
remotely located at any suitable location and delivers high speed
data at greater bandwidth to the vehicle 10 through the air so that
not only is the high cost of the conventional bus-bar-type control
conductors avoided but greater speed and greater bandwidth is
obtained. In addition, the present invention can be installed in
locations where conventional AEM systems could not be installed due
to spatial constraints. The AEM system 100 is not limited to the
physical layout of the monorail 30 nor to the environment the
monorail 30 is located in. Furthermore, while one vehicle 10 is
illustrated in FIG. 1, it is to be expressly understood that many
different conventionally available vehicles can be modified to
conform to the teachings contained herein.
2. The Automated Electrified Monorail (AEM) System 100 of the
Present Invention
In FIG. 1, one embodiment of the automated electrified monorail
(AEM) system 100 contains a monorail 30, a vehicle 10 and a system
controller 20. In the embodiment shown, the monorail 30 is mounted
in an overhead configuration on beams 120. However, the monorail 30
could be mounted in a top, side, interior, exterior or underneath
configuration with respect to the beams 120. In a preferred
embodiment, the monorail 30 is an industry standard aluminum rail
having an I-type cross-sectional profile. At the largest dimension,
the I-type beam may have a cross section of 180 millimeters by 60
millimeters or a cross section of 240 millimeters by 80
millimeters. This dimension allows the monorail to nominally
support up to 1200 kilograms. However, additional structural
support may be added to the AEM system 100 to increase the weight
limits of the monorail 30. It should be appreciated that the
monorail 30 may be any suitable geometric cross-section, and of
sufficient structure or material that is capable of supporting the
vehicle 10 as herein described.
The vehicle 10 contains a drive motor 50 that is attached to wheels
90 which propel the vehicle 10 along the monorail 30. In a
preferred embodiment, the motor 50 is attached to one wheel 90 to
drive the vehicle 10 on the monorail. In addition to the wheels 90,
guide wheels 810 (FIG. 8) may be positioned on the vehicle 10 so
that the guide wheels 810 assist in contacting the sides 820 of the
monorail 30, especially, during movement along curved portions of
the monorail 30. Generally, the vehicle 10 contains an electrical
connector 140 that engages power conductors 130 as the vehicle 10
moves along the monorail 30. The electrical connector 140 is
connected to a power control panel 142 that, typically, contains
electrical disconnect electronics, fuses and a transformer. The
power control panel 142, then, supplies power to the motor 50 and
the remote controller 70.
A reader 60 is also contained in the vehicle 10 for reading
location markers 80 to determine the location of movement zones 190
in FIG. 1 and 710-750 in FIG. 7 as will be explained later.
A remote controller 70 is contained in the vehicle 10 and is
connected to the motor 50, the reader 60 and a remote RF ethernet
transceiver 40. In a preferred embodiment, the remote controller 70
is an ethernet-capable controller. The remote controller 70,
through the remote RF ethernet transceiver 40, is wirelessly
connected to the system controller 20 through an ethernet access
point 110. Therefore, as shown in FIG. 4, a wireless ethernet local
access network (LAN) system 440 (also called a wireless RF ethernet
network) is created containing the system controller 20 and the
remote controller 70a, 70b and 70c. Also shown in FIG. 4, more than
one remote controller 70a, 70b and 70c, and hence more than one
vehicle 10 can be positioned on the monorail 30. As such, each
remote controller 70a, 70b and 70c having remote RF ethernet
transceivers 40a, 40b and 40c can be connected to the system
controller 20 through the ethernet access point 110 and, thus, the
wireless ethernet LAN system 440 can contain the system controller
20 connected to a plurality of remote controllers 70a, 70b and
70c.
The AEM system 100 of the present invention is conventionally
electrified by power lines 130 having, typically, three phase 480
volts AC power lines and a ground wire. The power lines 130 are
conventionally hardwired along the perimeter of the monorail 30 and
may be commercially purchased (e.g., Vahle U10 bus bar). It should
be noted that any type of power line carrying any suitable voltage
may be used. However, in a preferred embodiment, the power line 130
provides intrinsic safety precautions and meets all UL/CSA safety
standards.
Power is provided to the vehicle 10 from the power line 130 through
contact 140 that is a commercially available sliding contact brush
(compatible with the Vahle U10 bus bar). However any other contact
having similar quality can be used. In addition to the fuses
located in the power control panel 142, the contact 140 can be
fused for overvoltage protection.
In summary, the present invention is not limited to a specific
monorail design, to one type of vehicle configuration or to how
power is delivered to the vehicle 10 and the components contained
therein.
a. Motors and Remote Devices
In a preferred embodiment, as shown in FIG. 8, the vehicle 10
contains a drive motor 50 that is connected to one wheel 90 to move
the vehicle 10 on the monorail 30. In another embodiment, the
vehicle 50 may contain three motors. A hoist motor is provided to
lower a fixture from the vehicle 10 on the monorail 30. A drive
motor is also provided to move the vehicle 10 along the monorail
30. Additionally, a rotation motor is provided to rotate a fixture
mounted on the vehicle 10 about the monorail 30. In a preferred
embodiment, the motors are typically commercially available
electric motors (e.g., Allen-Bradley 160 SCC variable frequency
drives and Bauer electric motors) requiring 120 to 480 volts AC,
0.5 to 1 horsepower and 0.37 to 0.75 kW of power. Therefore, a
converter can be required to convert the 480 volts AC signal to the
appropriate voltage.
The vehicle 10 contains a braking mechanism to assist in stopping
the vehicle 10 from moving along the monorail 30. Specifically, the
drive motor 50 has a braking mechanism that can be controlled by
the remote controller 70 through a relay, not shown. The relays are
commercially available (e.g., Allen-Bradley 100-M05). The drive
motor 50 has a failsafe feature that engages the braking mechanism
whenever power is removed from the driver motor 50.
As shown in FIG. 3, the vehicle 10 may also contain a remote device
310 (e.g., a motor) to perform tasks. Typically, the tasks are
performed at the ground level, and may include lifting or moving
objects in a warehouse or moving construction devices (e.g., a
welding mechanism or electronic readers for inventory control). In
addition, a robotic mechanism may be attached to the vehicle 10 to
perform any desired task. However, it should be appreciated that
the remote device 310 may perform tasks at any position relative to
the vehicle 10. The remote device 310 may perform tasks above, on
the side, in front of, in back of, inside of and outside of the
vehicle 10 or any similar variation thereof.
In operation, the vehicle 10 has conventional wheels 90 that
contact either a top portion 160 (FIG. 1) and/or a bottom portion
180 (FIG. 1) and/or sides 820 (FIG. 8) of the monorail 30. Also
shown in FIG. 8, guide wheels 810 may be connected to the vehicle
10. The guide wheels 810 contact the sides 820 of the monorail 30
to assist in movement of the vehicle 10 around the curved portions
of the monorail 30. Typically, the motor 50 drives one of the
wheels 90 to propel the vehicle 10 along the monorail 30. The speed
of the motor 90 and other variables are controlled by the remote
controller 70 that receives instructions from the system controller
20. This program control from the system controller 20 to the
remote controller 70 may occur at initialization or may occur in
real-time during operation of the AEM system 100. The instructions
are transmitted over the wireless ethernet LAN system 440 by the
remote RF ethernet transceiver 40 and the ethernet access point
110.
In summary, any of a number of different motor, braking and remote
devices can be utilized under the teachings of the present
invention and the system 100 is not limited to any one design.
Furthermore, any suitable remote device for performing any number
of desired activities could be
utilized under the teachings of the present invention.
b. Controllers and Radio-Frequency Devices
In a preferred embodiment, the system controller 20 contains a
commercially available system controlled programmable logic
controller (PLC) (e.g., Allen-Bradley 5/40E) that is
ethernet-enabled. The system controller 20 is hardwired via an
ethernet link to a commercially available mainframe computer (e.g.,
Hewlett-Packard 9000). The system controller 20 is connected to a
commercially available ethernet access point 110 (e.g., Symbol
Spectrum 24 Ethernet Access Point).
The vehicle 10 contains a remote controller 70, such as, a
commercially available carrier PLC (e.g., Allen-Bradley SLC 5/05)
that is ethernet-enabled. The remote controller 70 is hardwired to
a commercially available remote RF ethernet transceiver 40 (e.g.,
Symbol Spectrum 24 Ethernet Bridge). In one embodiment, the remote
RF ethernet transceiver 40 and the ethernet access point 110
operate in the 2.4 GHz frequency range with 1-2 Mbps throughput on
the wireless connection and 10 Mbps throughput on the hardwired
connection. This data throughput is significantly greater
throughput than that achieved with the prior bus-bar-type
conductors. However, it should be noted that the remote RF ethernet
transceiver 40 and ethernet access point 110 may operate at any
desired ethernet frequency and the present invention should not be
limited to the examples discussed herein. Further, it should be
appreciated that, in other embodiments, the ethernet access point
110 may comprise a commercially available ethernet bridge and the
remote RF ethernet transceiver 40 may compromise a commercially
available ethernet access point and/or any combination thereof.
Typically, information is transferred to and from the system
controller 20 and the remote controller 70. The information
typically contains PLC programming commands (e.g., Allen-Bradley
MSG commands). As shown in FIG. 4, the remote controller 70 is
capable of interfacing with the system controller 20 through the
wireless ethernet LAN system 440. Since the controllers are
ethernet-enabled, the wireless ethernet LAN system 440 between the
controllers uses standard ethernet protocol. Therefore, there is no
need for protocol converters. The wireless ethernet LAN system 440
identifies each remote controller 70 by a separate and unique
vehicle identification address defined by the transmission control
protocol/internet protocol (TCP/IP) standards or the media access
control (MAC) protocol defined by the MAC layer of the ethernet
protocol. Such an identification protocol is standard over the
wireless ethernet LAN system 440. The unique vehicle identification
address of the vehicle 10 is resident in memory located on the
vehicle in the remote controller 70. This memory saved address can
be easily changed at any time by the system controller 20. In
another embodiment, the unique vehicle identification address can
be hardwired on the vehicle, such as using configurable switches.
In one embodiment, the remote RF ethernet transceiver 40 and the
ethernet access point 110 operate in a base-mobile unit
relationship with the system controller 20 being the base and the
remote controller 70 being the mobile unit. However, this
relationship may be reversed depending upon the requirements of the
AEM system 100.
In the embodiment shown in FIG. 2, the cellular network 200
comprises a number of cells 210, 212, 214, 216, 218, 220, 222 and
224. Each cell contains an access point 202 that is connected to
the ethernet backbone 206 by lines 204. The ethernet backbone 206
can optionally be connected to an ethernet hub 208 that is
connected to the system controller 20. The remote RF ethernet
transceiver 40 communicates with one of the strategically placed,
access points 202. The cellular network 200 has automatic roaming
features that provide continuous real-time communication with the
remote RF ethernet transceiver 40. The cellular network 200 is a
frequency hopping, spread-spectrum RF wireless ethernet LAN system
440 complying with IEEE 802.11 standard. It should be noted that
additional access points 202 can be added to the AEM system 100 to
increase the size of the coverage area of the cellular network
200.
It is expressly understood that while the above discussion sets
forth two basic preferred embodiments for implementing the
invention along with preferred frequency ranges of operation, any
suitable implementation design could be constructed under the
teachings herein and any suitable RF transmission frequency range
or ranges could be used.
c. Location Markers
As shown in FIG. 1, the AEM system 100 contains location markers 80
that allow the system controller 20 to track the location of the
vehicles 10 on the monorail 30. The vehicle 10 contains a reader 60
that typically comprises a commercially available (e.g., Micron
Communications, Inc.) tuned antenna that operates at 125 MHz. The
location marker 80 contains a commercially available (e.g., Micron
Communications, Inc.) RF electronic marker that operates at 125
MHz. This frequency range is different from the ethernet range of
2.4 GHz and, therefore, provides separate RF communication.
In operation, the location marker 80 is sensed by the reader 60 as
the vehicle 10 is near the location marker 80. As shown in FIGS. 3
and 7, typically, more than one location marker 80a-80k is
contained in the AEM system 100. The location markers 80a-80k are
located in strategic positions along the monorail 30 and are
attached on the monorail 30. It should be appreciated that
attachment to the monorail 30 contains placement near, on or at the
monorail 30. In a preferred embodiment, the location markers
80a-80k are attached to the monorail 30 using a suitable adhesive
that is capable of withstanding the shock and vibrations inherent
in the AEM system 100. This attachment allows the location markers
80a-80k to be physically moved as desired or required by the AEM
system 100.
In a preferred embodiment, the location markers 80a-80k
conventionally comprise passive or active radio frequency
electronics and the reader 60, comprising a tuned antenna, is
capable of sensing the location markers 80a-80k. In another
embodiment, the location markers 80a-80k comprise a bar code that
is attached on the monorail 30 and the reader 60, comprising a bar
code reader, is capable of physically reading the location markers
80a-80k as the vehicle 10 passes by. It should be noted that any
suitable pair of devices that provide an identification marker on
the monorail and a sensor on the vehicle that is capable of reading
the marker may be used in the present invention.
The reader 60, typically, contains a commercially available
electronic reader (e.g., Micron Communications, Inc., Model No.
MPIPEA2321) and a commercially available antenna (e.g., Micron
Communications, Inc., Model No. MPAPE8X22P). In a preferred
embodiment, the antenna of the present invention has the dimensions
of about 12 centimeters by 36 centimeters and is tuned. The antenna
has been optimized for the present invention to allow for quicker
read times as the moving vehicle 10 passes the location marker 80
and to add more flexibility for directional reading. The optimal
characteristics of the antenna in the reader 60 were found by
increasing the length of the antenna. In conventional readers, the
antenna has a length of about 11 to 21 centimeters. In the present
invention, the reader 60 has an antenna with a length of 36
centimeters. This increase of about 170-320 percent in antenna
length allows the reader 60 to sense the location markers 80 as the
vehicle 10 moves along the monorail 30.
In a preferred embodiment, as shown in FIGS. 1 and 3, the reader 60
of the present invention is typically located on the vehicle 10 to
face the bottom portion 180 of the monorail 30. In this position,
the location markers 80, which are attached to the bottom portion
180 of monorail 30, pass directly above the reader 60. However, it
should be appreciated that the reader 60 may face the top 160 or
side 820 portions of the monorail 30 or may be placed in any other
configuration that allows the reader 60 to sense and read the
location marker 80.
As shown in FIGS. 3 and 7, when the vehicle 10 travels along the
monorail 30, each one of the location markers 80a-80k is sensed by
the reader 60. The location markers 80a-80k provide location
information, such as a string of characters or numbers.
In one embodiment, the location markers 80a-80k and the reader 60
have been optimized to decrease time delays associated with sensing
location information contained in the location markers 80a-80k. In
this regard, the location markers 80a-80k typically contain an
ASCII string that converts to a number because numbers decrease the
time delay associated with processing the information in the remote
controller 70.
The reader 60 supplies the location information to the remote
controller 70 where the location information is then compared to a
program list of commands that is supplied to the remote controller
70 from the system controller 20 and which is stored in memory in
the remote controller 70. In a preferred embodiment, the program
list uses the Allen-Bradley PLC programming language. The program
list may contain several programmed tasks. For example, a
"slow-down" command sensed from a location marker 80 is used by the
remote controller 70 to command the vehicle 10 to reduce its
traveling speed, such as, to reduce the current speed to
"creep-speed". A "transmission" command is used to command the
vehicle 10 to transmit information to the system controller 20. A
"permission" command is used to command the vehicle 10 to query the
system controller 20 for permission to enter a movement area, such
as a curve area. A "stop" command is used to command the vehicle 10
to stop at a specified location. A "stop-at-next-tag" command is
used to command the vehicle 10 to stop when the next location
marker 80 is sensed. A "perform-task" command is used to command
the vehicle 10 to perform a predetermined task at a specified
location. When the remote controller 70 matches the location
information received from a location marker 80 to the stored
program list, the command associated with the location marker 80 is
performed. If the location information is not on the programmed
list then the remote controller 70 transmits an error message to
the system controller 20. While the commands set forth above are
used in the preferred embodiment, any suitable command (and
corresponding "name" for the command) can be used under the
teachings of the present invention.
As shown in FIG. 9, the data sequence 940 that is transmitted to
and from the system controller 20 and the remote controller 70 has
a format containing packets 900, 910, 920 and 930. In one
embodiment, the entire data sequence 940 has a length of 50
characters. Data packet 900 contains the unique vehicle
identification address according to the TCP/IP standard. This
transmission of the unique vehicle identification address is
redundant because the wireless ethernet LAN system 440 used the
vehicle identification address to establish RF communication
between ethernet transceiver 60 and ethernet access point 110.
However, the unique vehicle identification address is included in
data packet 900 as a double-checking safety consideration. The
second packet 910 contains a message sequence number that is used
to identify the messages that have been sent between the system
controller 20 and the remote controller 70. The next packet 920
contains the current location marker 80 information that was sensed
by the reader 60 on the vehicle 10. The final data packet 930
contains "current location status" or "performance" commands. The
"current location status" command is a request for the status at
current location of the vehicle 10, and the "performance" command
is a command for the vehicle 10 to perform a function or task.
It should be appreciated that, under the teaching of the present
invention, additional data packets can be added to the data
sequence 940 such that the length of the data sequence is larger or
smaller than 50 characters. Also the data packets 900, 910, 920 and
930 may be combined or divided into a smaller number of data
packets. Further, the embodiment shown in FIG. 9 is used for
illustration and should not be construed to limit the present
invention to the embodiment explained herein.
As shown in FIG. 7, the location markers 80a-80k delineate specific
movement zones 710-750 on the monorail 30 where the vehicles
10a-10d must perform some type of activity (e.g., change speeds or
switching from one AEM system to another); also shown in FIG. 7 are
stations 750 ("slow-down" areas or "actual destination"); curve
portions 710 and 740 (speed change and collision avoidance); switch
entry and exit areas 720 (speed change and switch positioning).
As shown in FIG. 7, movement zone 750 represents a station. The
vehicles 10a-10d are typically stopped at the station 750. To
perform this stopping, a paired marker scheme (80j and 80k) is
used. The location markers 80j and 80k are attached on the monorail
30 and are sensed by the vehicles 10a-10d. The vehicles 10a-10d
travel around the monorail 30 in the direction of arrow A. When
location marker 80j is sensed, the vehicles 10a-10d slow down
(e.g., from "medium speed" to "creep-speed"), and when location
marker 80k is sensed the vehicles 10a-10d stop. The location
markers 80j and 80k, as earlier discussed, provide the command
information to the remote controller 70 in the vehicles
10a-10d.
In FIG. 8, proximity sensors 830 that sense proximity markers 840,
positioned on or near the monorail 30, may also be used to position
the vehicle 10 on the monorail 30. The proximity sensors 830 are
attached to the vehicle 10 and connected to the remote controller
70. The proximity sensors 830 are used to accurately control the
movement of the vehicle 10 on the monorail 30. The proximity marker
840 is aligned with the proximity sensor 830 such that a signal may
be emitted from the proximity sensor 830 and reflected off the
proximity marker 840 back to the proximity sensor 830. For example,
the vehicle 10 may sense location marker 80 which corresponds to a
command on the program list in memory on the remote controller 70
to reduce its speed and to monitor for the proximity sensors 830.
Once the proximity sensor 830 on vehicle 10 senses the proximity
marker 840 the vehicle 10 will stop. The proximity sensors 830
allow the vehicle 10 to be positioned on the monorail 30 within an
accuracy of about 2 millimeters. In one embodiment, the proximity
sensors 830 comprise infrared or photo sensors, and the proximity
markers 840 comprise reflective-type or non-reflective-type
materials that are secured to the monorail 30 by any suitable
attachment mechanisms (e.g., adhesives, clamps, screws or bolts).
However, it should be appreciated that any suitable pair of
alignment detection devices may be utilized to control the
precision movements of the vehicle 10.
As shown in FIG. 7, movement zones 710 and 740 represent curve
areas. When one of the vehicles 10a-10d enters the curve areas 710
and 740, a paired marker scheme (80a-80b and 80h-80i) is also used.
Specifically referring to movement zone 710, vehicle 10b senses the
location marker 80a which provides a command to the remote
controller 70 which in turn transmits to the system controller 20
and query whether another vehicle, such as vehicle 10c, is in the
curve area 710. If the system controller 20 responds that vehicle
10c is in curve area 710, vehicle 10b is instructed to enter creep
speed. If vehicle 10c is not in the curve area 710 or the system
controller 20 notifies vehicle 10b that the curve area 710 is
unoccupied, vehicle 10b enters the curve area 710 at a
predetermined speed. If, as shown in FIG. 7, vehicle 10c is located
in curve area 710, vehicle 10c will notify the system controller 20
when vehicle 10c passes location marker 80b. When vehicle 10c has
passed identification marker 80b, the system controller 20 will
instruct vehicle 10b to enter the curve area 710. Using this
technique, the system controller 20 makes the determination that
vehicle 10b is in the curve area 710 and the system controller 20
will not allow another vehicle 10a, 10c or 10d into the curve area
710 until vehicle 10b exits the curve area 710.
It is to be appreciated that FIG. 7 illustrates several functional
features found in the use of the location markers 80a-80k of the
present invention. The location markers 80a-80k can be easily moved
and/or their command content changed, in stark contrast to the
prior AEM systems requiring physical cutting of the bus-bar-type
conductors. For example, if it is decided to add or remove a stop
on the monorail 30, it can be easily accomplished under the
teachings of the present invention by simply adding or removing
location markers 80a-80k and/or proximity sensors 830 and proximity
markers 840. The embodiment shown in FIG. 7 is shown to illustrate
the use of such location markers 80a-80k and that the location
markers 80a-80k can be used to implement any of a number of
equivalent features including, but not limited to: stopping,
slowing down, speeding-up, turning, entering, exiting,
transmitting, querying and
performing tasks.
As shown in FIG. 5, a method is shown that illustrates the
functional steps to be performed when a location marker 80 is
sensed. In step 510, the remote controller 70 determines by
monitoring the output from the reader 60 whether one of the
location markers 80a-80k has been sensed. If one of the location
markers 80a-80k has not been sensed, the remote controller 70 keeps
monitoring the output of the reader 60. If one of the location
markers 80a-80k has been sensed, the location information is
transmitted to the system controller 20 in step 522 and in step
512, the remote controller 70 determines whether a program change
has been made. It should be noted that in step 522 the location
information is sent to the system controller 20 when it is sensed
by one of the vehicles 10a-10d. This location information allows
the system controller 70 to approximately know where the vehicle 10
is located on the monorail 30, such as during a curve entry or
exit. If a program change has not been initiated then the
associated task is automatically performed in automatic mode
520.
Automatic mode is a programmed state where the vehicles 10a-10d
proceed along the monorail 30 and perform tasks as instructed by
the commands on the program list located in memory on the remote
controller 70 corresponding to the location markers 80a-80k.
Before, the vehicles 10a-10d can travel in automatic mode, the
vehicles 10a-10d must receive a program list from the system
controller 20 and the vehicles 10a-10d must sense one of the
location marker 80a-80k. Typically, upon initialization or upon a
program change, the vehicles 10a-10d will move at "creep-speed"
until one of the location markers 80a-80k has been sensed. Once one
of the location markers 80a-80k has been sensed, one of the
vehicles 10a-10d will continue along the monorail 30 according to
the programmed instruction set in the remote controller 70.
Typically, when the system controller 20 changes the program list
located in memory on the remote controller 70, a program change
will continue to be indicated by the remote controller 70 until one
of the vehicles 10a-10d has verified its location on the monorail
30, typically, by sensing one of location markers 80a-80k. Once
this procedure has been followed, the vehicles 10a-10d proceed
along the monorail 30 and perform tasks as instructed by the
commands on the program list located in memory on the remote
controller 70 corresponding to the location markers 80a-80k. It
should be noted that the program in the vehicles 10a-10d can be
changed at anytime without stopping the vehicles 10a-10d on the
monorail 30 or without shutting down the AEM system 100, in
general. This automatic procedure is used for safety considerations
to make sure the program list is correct.
Referring back to step 512 in FIG. 5, if a program change has been
initiated, the vehicles 10a-10d do not enter automatic mode.
Instead the remote controller 70 checks the location marker 80a-80k
information with the program list in step 516. If the location
information is on the program list, the task associated with the
location information is performed in step 520. However if the
location information is not on the program list an error message is
optionally transmitted to the system controller 20 from the remote
controller 70 in step 518.
d. Collision Avoidance System
As shown in FIG. 3, the vehicles contain a collision avoidance
device 300 that is also connected to the remote controller 70. The
collision avoidance device 300 typically contains commercially
available photo-sensors or infrared-sensors (e.g., SUNX PX-22 photo
sensors) that are attached to the front of the vehicle 10 so as to
have a clear view of the monorail 30 in front of the vehicle 10. In
a preferred embodiment, the collision avoidance device 300 should
have at least a three meter range and provides adjustable multiple
lobe sensing areas, as shown in FIG. 10a. In addition, as shown in
FIG. 7, each of the collision avoidance devices 300a-300d should be
capable of sensing a other vehicles 10a-10d that is at a D.sub.1 of
three meters, within a 90 degree radius of the vehicle 10a-10d. It
should be noted that, in another embodiment, the collision
avoidance device 300 has a detection range of at least 5
meters.
In FIGS. 10a and 10b, two embodiments of the collision avoidance
system 300 are illustrated. In FIG. 10a, the collision avoidance
system 300 contains a single sensor 1010 that has multiple
detection lobes 1012, 1014 and 1016. Each lobe 1012, 1014 and 1016
have an adjustable range. In another embodiment, as shown in FIG.
10b, the collision avoidance system 300 contains multiple sensors
1020 and 1030. The sensors 1020 and 1030 have detection lobes 1022
and 1032, respectively that have adjustable ranges. The embodiments
shown in FIGS. 10a and 10b can be interchanged such that the
multiple sensor configuration includes sensors that have multiple
detection zones. Furthermore, the single sensor configuration may
contain a sensor that has a single detection lobe. Furthermore, the
single lobe and multiple lobe sensors can also be combined on one
vehicle. It should be appreciated that the present invention
expressly encompasses other sensor combinations or configurations
that can be employed.
It should be noted that in the embodiments, shown in FIGS. 3, 7,
10a and 10b, each of the collision avoidance devices 300 and
300a-300d are shown to be attached to the front of the vehicles 10
and 10a-10d. However, the present invention should encompass any
other obvious positioning of the collision avoidance devices 300
and 300a-300d (e.g., on the rear portion, top portion, side portion
or bottom portion of the vehicles 10 and 10a-10d, and located
either above or below the monorail 30).
In operation, as shown in FIGS. 6 and 7 in movement zone 730, the
collision avoidance system 300a operates to prevent a collision
between the vehicle 10a and another object, such as another vehicle
10b located on the monorail 30. The collision avoidance device 300a
is capable of sensing the presence of vehicle 10b and its projected
distance from the vehicle 10a.
In the method of FIG. 6 and as illustrated in FIG. 7, the first
step 610 determines whether the sensors on the collision avoidance
device 300a have detected vehicle 10b. If the vehicle 10b has been
detected, the collision avoidance device 300a determines whether
vehicle 10b is located at a distance of less than D.sub.1 in step
614. In a preferred embodiment D.sub.1 is three meters. If the
vehicle 10b is at a distance greater than D.sub.1, then in step
612, the current speed of the vehicle 10a is maintained and
collision avoidance device 300a continues to monitor for vehicle
10b. If vehicle 10b is at a distance of D.sub.1 or less, vehicle
10a is commanded to enter "slow speed" in step 616. As shown in
FIG. 7, after vehicle 10a senses that vehicle 10b is at a distance
less than D.sub.1, vehicle 10a will keep moving along the monorail
30 to be positioned at the location of vehicle 10a'. In step 618, a
second determination is made as to whether the distance is less
than D.sub.2. In a preferred embodiment, distance D.sub.2 is one
meter. If the distance is not less than D.sub.2, the distance is
checked again in step 614. In step 612, if the distance is greater
than D.sub.1, the vehicle 10a is commanded to resume the previous
speed (the speed before the vehicle 10a entered "slow speed").
However, in step 618, if vehicle 10b is at a distance of less than
D.sub.2, vehicle 10c is commanded to stop in step 620. In one
embodiment, the sensing of the vehicle 10b may optionally be
transmitted to the system controller 20 in an "object sensed"
command.
Therefore, the collision avoidance device 300a will avoid a
collision with vehicle 10b by stopping vehicle 10a if the vehicle
10b is at a distance of less than D.sub.2. It should be appreciated
that the preferred distances of one and three meters are examples
in the embodiment presented. These distances may be changed as the
requirements of the system changes. Thus, the present invention
should not be construed to be limited to any such distance.
Further, it should be appreciated that the collision avoidance
device 300a is also capable of changing the detection range D.sub.1
and D.sub.2 as the speed of the vehicle 10a increases or decreases.
This change in detection distance may be programmed in the remote
controller 70. For example, if the vehicle 10a is traveling at a
speed of 30 meters/minute, the detection distances D.sub.1 and
D.sub.2 are to be set at distances of 800 millimeters and 200
millimeters, respectively. Whereas if the vehicle 10a was traveling
at a speed of 100 meters/minute, the detection distances D.sub.1
and D.sub.2 are to be set at distances of 2400 millimeters and 500
millimeters, respectively. The distances and speed relate to the
ability of the vehicle 10 to stop upon the detection of an
object.
As shown in FIG. 7, vehicle 10d may be programmed to ignore an
obstacle 700 that is sensed by the collision avoidance device 300d.
This avoidance is accomplished by placing location marker 80f on
the monorail 30 where the obstacle 700 is most likely to be sensed
by the collision avoidance device 300d. The program list contains
an ignore object detection command when the location marker
information on the location marker 80f is compared to the program
list. Therefore, when the location marker 80f is first sensed by
vehicle 10d, the controller 70 ignores detection of the object 700.
Additionally, location marker 80g is placed after the obstacle 700
to instruct the vehicle 10d to begin to monitor the collision
avoidance device 300d. In some designs of the present invention,
the use of the second location marker 80a is optional. For example,
a programmed time-out feature may be used to instruct the vehicle
10d to begin to monitor the collision avoidance device 300d.
Additionally, as shown in FIGS. 10a, portions detection lobes 1012,
1014 and 1016 of the sensor 1010 may be selectively disabled
without disabling the entire collision avoidance device 300. For
example, detection lobe 1012 may be disabled as the vehicle 10
passes object 1070. However, while detection lobe 1012 is disabled
detection lobes 1014 and 1016 are still activated to prevent a
collision with other objects or vehicles. In FIG. 10b, the sensors
1020 and 1030 may be individually disabled without disabling the
entire collision avoidance system 300. In this embodiment, the
sensor 1030 may be disabled as the vehicle 10 passes object 1072.
While sensor 1030 is disabled, sensor 1020 is still activated to
avoid a collision with a vehicle or other object.
3. Method of Operation
The present invention provides a novel method for controlling a
vehicle 10 as it moves and performs tasks along the monorail 30.
The method includes assigning a unique vehicle identification
address to the vehicle located on the monorail 30. The system
controller 20 selectively transmits operation instructions to the
vehicle 10 using the wireless RF ethernet network 150. The
operation instructions comprise a program list of commands or a
single command. The transmitted operation instruction contains the
unique vehicle identification address. The vehicle 10, having the
assigned unique vehicle identification address, receives the
selectively transmitted operation instructions. The transmitted
operation instructions are stored in memory on the vehicle 10 that
has been assigned the unique vehicle identification address.
The stored instructions are then performed by the vehicle 10. In a
preferred embodiment, the performance of the stored instruction
includes sensing a location marker 80 that is attached to the
monorail 30 as the vehicle 10 moves. The location marker 80
contains location information in the form of a unique location
string which is compared to the stored program in the remote
controller 70 in the vehicle 10. The stored program contains an
instruction set having a number of instructions, and each
instruction has a unique identifier. A specific instruction from
the number of instructions in the instruction set is then executed.
The specific executed instruction has a unique identifier that is
correlated to the unique location string. The instructions
typically include, but are not limited to, stopping the vehicle 10,
slowing down the vehicle 10, speeding up the vehicle 10, turning
the vehicle 10, entering a movement zone 190, exiting a movement
zone 190, transmitting to the system controller 20, querying the
system controller 20 and performing tasks. A confirmation command
is transmitted from the vehicle 10 that has the unique vehicle
identification address to the system controller 20 over said
wireless RF ethernet network 150. The confirmation command contains
the unique vehicle identification address, among other identifier
information, to identify the vehicle 10 that should receive the
data. It should be noted that the system controller 20 may transmit
a new program list of commands to the remote controller 70 of
vehicle 10. It should also be noted that the transmission of the
new program list may occur in any vehicle 10 on the monorail 30 and
at any time during operation without having to shut down the system
100.
The present invention also includes a novel method for precisely
positioning the vehicle 10 on the monorail 30. The method includes
the steps of sensing a location marker 80 which includes location
information that correlates to commands on the stored program list
of commands. The correlated commands include a command for the
remote controller 70 to begin to monitor the proximity sensor 830
and a command for the motor 50 to move the vehicle 10 at a
predetermined slow speed. The vehicle 10 continues along the
monorail 30 at the predetermined slow speed until the proximity
sensor 830 senses the proximity marker 840. When the proximity
marker 840 is sensed, the vehicle 10 is commanded to stop.
The method also includes the steps of identifying an obstacle 700
in the movement path of the vehicle 10, and avoiding a collision
with the obstacle 700. In avoiding the obstacle 700, the obstacle
700 is sensed by the vehicle 10 within at least about three meters
of the vehicle 10. After sensing the obstacle 700, the vehicle 10
is instructed to move at a first predetermined low velocity. If the
obstacle 700 is sensed to be within at least about one meter of the
vehicle 10, the vehicle 10 is instructed to stop moving.
In a second aspect of the p resent method, the vehicle 10 may be
instructed to ignore the obstacle 700. In this method, the vehicle
10 senses a location marker 80 which is correlated to an
instruction that commands the remote controller 70 in the vehicle
10 to ignore the detection of the object 700. Once the vehicle 10
has passed the object 700, the remote controller 70 of the vehicle
10 may be instructed to again begin to detect object 700. This
instruction to begin sensing may be accomplished by placing another
location marker 80 on the monorail 30 that correlates to an
instruction to again avoid other obstacles 700. In another
embodiment, the remote controller 70 of the vehicle 10 may include
a programmed timer that instructs the remote controller 70 to again
begin to avoid object 700 after a specified predetermined time has
elapsed.
The foregoing discussion of the invention has been presented for
purposes of illustration and description. Further, the description
is not intended to limit the invention to the form disclosed
herein. Consequently, variation and modification commensurate with
the above teachings, within the skill and knowledge of the relevant
art, are within the scope of the present invention. The embodiment
described herein and above is further intended to explain the best
mode presently known of practicing the invention and to enable
others skilled in the art to utilize the invention as such, or in
other embodiments, and with the various modifications required by
their particular application or uses of the invention. It is
intended that the appended claims be construed to include
alternative embodiments to the extent permitted by the prior
art.
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