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Description  |
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TECHNICAL FIELD
The invention generally relates to monitoring and controlling the movement
of a fleet of hauling vehicles and, more particularly, to dispatching each
vehicle in a fleet of hauling vehicles to various destinations in response
to accumulated data indicative of hauling conditions and vehicle location.
BACKGROUND
Truck haulage is widely used in open-pit mining and similar operations. It
is also the largest cost item in the operation of an open-pit mine. Truck
replacements, which are necessary from time to time, involve large amounts
of capital. These and other factors have led mine operators to search for
ways to improve the effectiveness of the truck-loading equipment fleet in
order to lower costs and maintain a profitable operation in the face of
declining markets and increasing, worldwide competition.
In the past, control of truck haulage in an open-pit mine was usually
accomplished in one of two ways. In the first way, the trucks are given a
fixed assignment or route for an entire working shift. In the second way,
a dispatcher located at a vantage point radios instructions to each driver
after he has dumped a load. Obviously, the use of a dispatcher is more
desirable than a fixed route since the dispatcher may react to changing
conditions occurring in the mine during the course of a working shift. For
operations utilizing a relatively small fleet of trucks, the number of
trucks is manageable, and a dispatcher may be successful in improving the
efficiency of the fleet. But as the fleet of trucks grows to a number in
excess of 25 trucks, a dispatcher is not capable of effectively routing
the trucks in a manner which significantly improves the efficiency of the
fleet. The dispatcher simply does not have sufficient time to make the
necessary decisions which are a prerequisite to each dispatch order.
Recent advances in computer technology have made it possible to use
computers to help the dispatcher make the necessary decisions. In fact,
computers have been used to implement semi-automated dispatch systems for
a fleet of trucks. To the best of applicant's knowledge, the computerized
systems currently available rely on the manual inputting of data by each
truck operator: the data is downloaded via a radio link to the dispatching
computer, where it is analyzed, and a dispatch order is sent from the
computer to each truck as it leaves a dump site. The system must rely on
each truck operator to manually enter data, such as the current status of
the truck, into an on-board device for transmission to the dispatch
computer via a transceiver.
In applicant's copending applications, Ser. Nos. 604,739 and 717,042, an
on-board device for heavy-duty, off-road trucks is disclosed which
provides a full set of load hauling data for each truck in a fleet without
the necessity of any intervention by the truck operator. In applicant's
application Ser. No. 717,042, a fully automated dispatch system is
disclosed. The dispatch system utilizes data gathered by on-board devices
placed on each of the trucks.
SUMMARY OF THE INVENTION
It is a general object of the invention to improve the performance and the
flexibility of an automatic dispatch system incorporating the on-board
weighing device described in U.S. application Ser. No. 604,739.
It is a more detailed object of the invention to provide a system for
locating each vehicle in a fleet of vehicles within its working
environment and associating values of predetermined operating parameters
with a location so as to construct a data base from which vehicle movement
may be monitored and commands may be generated.
It is a specific object of the invention to provide a system that uses the
foregoing data base to automatically dispatch vehicles in the fleet of
vehicles to specific locations.
It is another specific object of the invention to provide an automatic
dispatch system which indicates to the system operator when an equipment
imbalance exists.
It is also a specific object of the invention to bias operation of the
automatic dispatch system in order that a dispatch order takes into
account factors related to overall system goals.
It is a further specific object of the invention to provide means for
automatically locating the approximate location of each vehicle within the
work area of the fleet.
Briefly, in accordance with the invention, signposts having indicia
associated therewith are located at key locations in the working area, and
the indicia are detected by sensors on board each vehicle in the fleet.
On-board sensors provide a control circuit with data indicative of vehicle
performance, and the control circuit associates location data retrieved
from the indicia of the signposts with performance data so as to provide a
data base from which a dispatch decision can be made.
In one approach, a sensor processing unit mounted on the vehicle is
responsive to signals from an on-board weighing device which are
indicative of the hauling condition of the truck. Hauling signals from the
on-board weighing device are processed by the sensor processing unit and
the resulting data is downloaded via an RF link from each vehicle to a
central station or base station wherein a data base is formed. From this
data base, the central station monitors vehicle performance and reports
values of predetermined parameters that fall outside an acceptable range
of values. The data base may also be used for transmitting dispatch
signals to selected vehicles in order to control the movement of the
vehicles between destinations. In order to locate each vehicle within a
work area, signposts are strategically located and each vehicle includes
apparatus for detecting unique indicia from each signpost which indicates
to the central station the location of the vehicle.
In an open-pit mining operation, the data base formed by the central
station includes files for each important segment of a haul cycle--i.e.,
load time, return time, hauling time and total time. Based on the time
information available from the data base, the central station finds for
each possible destination the amount of time that the vehicle to be
dispatched may expect to be delayed upon arrival at the destination. From
this information, the central station may simply dispatch the vehicle to
the destination with the shortest expected delay, or it may bias the delay
times to take account of factors such as the desired ore blend at the dump
site before selecting a destination. Furthermore, by knowing the delay
times to each destination, the central station is able to determine an
imbalance in the vehicle/load site availability. Specifically, in a mining
operation, if the sum of all the delay times is greater in magnitude than
a predetermined number, then the working site either has too much or too
little of loading or hauling equipment and corrective action such as
adding or retiring equipment is required.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an elevated perspective view of a dump-body vehicle with the
vehicle body in a raised or dump position so as to expose an on-board
weighing device;
FIG. 1a is an enlarged elevated perspective view of the dump-body vehicle
in FIG. 1 that more clearly shows the on-board weighing device;
FIG. 2 is a system-level diagram of an on-board apparatus for detecting,
storing and analyzing hauling parameters and location data according to
the invention which includes the on-board weighing device as well as other
sensor inputs;
FIG. 3 is a schematic diagram of a sensor processing unit included in the
on-board apparatus of FIG. 2;
FIG. 4a is a system-level diagram illustrating a vehicle location system
according to a first embodiment of the invention, wherein stationary
signposts cooperate with the on-board apparatus of FIG. 2 to supply
location and hauling data to a central station for monitoring vehicle
performance and for controlling movement of the vehicle fleet within a
work area;
FIG. 4b is a system-level diagram illustrating a vehicle location system
according to an alternative embodiment of the invention;
FIGS. 5a and 5b are schematic diagrams of the format used to transmit data
from each vehicle to the central station in FIGS. 4a and 4b and from the
central station to a desired vehicle, respectively;
FIG. 6 is a schematic diagram illustrating the data transfer links between
(1) the stationary signposts and the sensor processing unit of FIG. 3 on
board each vehicle and (2) the sensor processing unit and the remote
central station;
FIG. 7 is an enlarged, partial cross-sectional view of the bed of the body
of a vehicle in FIGS. 4a or 4b showing an apparatus mounted below the bed
as an alternative to the on-board weighing device illustrated in FIGS. 1
and la for sensing the presence of a load in connection with the
monitoring and controlling of the vehicles of FIGS. 4a and 4b;
FIGS. 8a-d are schematic diagrams of the data files formed in an electronic
memory associated with the central station of FIGS. 4a and 4b which
receives data from the on-board apparatus of various vehicles;
FIG. 9 is a flowchart diagram for the software program preferably
implemented in connection with the sensor processing unit of the on-board
apparatus as shown in FIG. 3;
FIGS. 10 through 13 are flowchart diagrams for the software program of the
central station preferably implemented in connection with the vehicle
location system of FIG. 4a;
FIG. 14 illustrates a side view of a fixed-body vehicle wherein the body is
supported on the frame of the vehicle by an on-board weighing device
similar to that illustrated in FIGS. 1 and 1a, and the vehicle includes an
on-board apparatus for providing location data according to an alternative
embodiment of the invention;
FIG. 15 is a schematic diagram of a sensor processing unit for receiving
and processing load data from the on-board weighing device associated with
the vehicle illustrated in FIG. 14; and
FIG. 16 is a system-level diagram of the data transfer of location and load
data from on board the vehicle of FIG. 14 to a remote central station via
an RF link in accordance with the invention;
While the invention will be described in connection with a preferred
embodiment and certain alternative embodiments, it will be understood that
it is not intended to limit the invention to those particular embodiments.
On the contrary, it is intended to cover all alternatives and equivalents
as may be included within the spirit and scope of the invention as defined
by the appended claims.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Turning to the drawings, and referring first to FIGS. 1 and 1a, an off-road
vehicle 11 is exemplary of the types of vehicles suitable for hauling in
an open-pit mine. The vehicle 11 includes a vehicle body 13 which is
hinged to the vehicle frame 15 at hinge assemblies 17. By controlling the
extension of telescoping hydraulic cylinders 19 and 21, the vehicle body
13 is pivoted between a fully inclined or dump position and a lowered or
rest position. One end of each hydraulic cylinder 19 and 21 is fastened to
a hinge assembly located on the bottom of the vehicle body 13. The
opposing end of each cylinder 19 and 21 is fastened to an articulation on
the vehicle frame 15. Structurally, the vehicle body 13 consists of steel
panels 23, which form the shape of the body, and beams 25 which provide
the structural framework of the body. Since other dump-body trucks may
also use the on-board weighing device of this invention, the truck in
FIGS. 1 and 1a is intended as an exemplary vehicle frame and vehicle body
utilized in connection with the invention.
Often, off-road vehicles, such as the one shown in FIGS. 1 and 1a, are very
large. For instance, it is not uncommon for the tire diameter of the
vehicle to be as great as the height of an average man. Accordingly, the
tremendous size of these vehicles makes them expensive to operate and
repair. Since these vehicles represent both a large capital investment and
a large operating expense, preventing both overloading of the vehicle body
and under utilization of the vehicle's load capacity (i.e., underloading)
are important considerations in insuring the vehicle is operated in the
most profitable manner. In particular, if the vehicle is overloaded it
will tend to have a shorter usable life because of the excessive wear
caused by the overloading. On the other hand, if the vehicle is
underloaded, the vehicle must be operated over a longer period of time,
thereby consuming more fuel and wearing the vehicle's parts to a greater
degree. Therefore, the ability to accurately measure the load carried by
the vehicle is important to the efficient operation of large off-road
vehicles. Also, since these off-road, heavy duty vehicles are extremely
expensive to operate, loading and hauling parameters indicative of vehicle
performance can be of great economic value by using the parameters to
discover areas of the performance which may be improved.
As most clearly shown in FIG. 1a the vehicle frame 15 is composed of two
parallel beams 26 and 27 connected by transverse beams (not shown) to form
a support surface for the vehicle body 13 over the rear axle of the
vehicle. In order to provide a pivot axis for the vehicle body 13, each of
the hinge assemblies 17 integrally connects one end of each of the
parallel beams 26 and 27 to one of beams 28 and 29 on the underside of the
vehicle body. In its lowered position, the beams 28 and 29 of the vehicle
body 13 mate with the beams 26 and 27 of the vehicle frame 15. When the
vehicle body 13 is in its lowered position, the entire weight of the
vehicle body and its load is transferred to the vehicle frame 15 by way of
the interface between the beams 26 and 27 of the frame and the beams 28
and 29 of the body.
Each of the hinge assemblies 17 includes first and second complementary
hinge members 30 and 31 which are secured to the frame 15 and body 13,
respectively, and interconnected by a pivot pin 32. The hinge assembly 17
is constructed to provide a "floating" assembly so that no weight is
transferred to the frame 15 via the assembly when the body is in its
lowered position. The hydraulic cylinders 19 and 21 and the vehicle body
13 are interconnected by hinge assemblies 33. (Only one of the hinge
assemblies 33 can be seen in the view of FIGS. 1 and 1a). Hoist pins 35
interconnect the complementary hinge members 37 and 39 of the hinge
assemblies 33. Although, as the cylinders extend, the hinge assemblies 33
accommodate the relative repositioning between the hydraulic cylinders 19
and 21 and the vehicle body 13, articulating assemblies 41 (only one is
shown in FIGS. 1 and 1a), which connect the cylinders to the truck frame
15, allow a similar relative repositioning between the hydraulic cylinders
and the truck frame 15.
Ordinarily, cushioning support materials such as rubber pads (not shown)
are added along the length of the two parallel beams 26 and 27 of the
vehicle frame 15 so when the vehicle body 13 is in its lowered position
the material provides a cushioned interface between the beams 28 and 29 of
the vehicle body and the beams 26 and 27 of the vehicle frame. In order to
evenly distribute the weight of the vehicle body 13 along the length of
the frame 15 and thereby provide the best possible weight distribution for
the frame, the cushioning support material is characterized by a thickness
dimension which, as explained hereinafter, cooperates with the hinge
assemblies 17 when the vehicle body is moved to its lowered position. The
cooperation of the cushioning support material and the hinge assemblies 17
frees the assemblies from supporting any of the vehicle body's weight when
the body is in its lowered position.
In order to provide the critical hauling data required in connection with
the invention, the cushioning support materials mounted by the
manufacturer on the parallel beams 26 and 27 of the vehicle frame 15 are
replaced by lengths of fluidfilled tubings that are laid along the lengths
of the parallel beams to provide, when combined with pressure sensors, an
on-board weighing device which accurately measures the weight of the
vehicle body 13 while it is in its lowered position. Each of the tubings
is capped by an inverted U-shaped metallic shield to protect the tubing at
its interface with the vehicle body 13. The inverted U-shaped shields 49
which protect the tubings are free to move vertically on the parallel
beams 26 and 27. Each of the fluid-filled tubings 47 is preferably divided
into fore and aft sections which may be created either by clamping the
center of one long tubing or providing two separate sections of tubing. At
the ends of each of the fluid-filled tubings 47 is one of the pressure
sensors 51a-d which measure the liquid pressure within the tubing. These
pressure sensors 51a-d may be remotely mounted as indicated in FIG. 2.
The foregoing on-board weighing device is preferably a commercially
available load sensor assembly used in connection with a vehicle weighing
system identified as the OBDAS Truck Weighing System, manufactured and
sold by Philippi-Hagenbuch, Inc., 7424 W. Plank Rd., Peoria, Ill. 61604.
In addition to the tubing 47, the shields 49 and the sensors 51a-d, the
on-board weighing apparatus includes a sensor processing unit 101,
generally as illustrated in FIG. 2, that is responsive to signals from the
sensors 51a-d. By providing the sensor processing unit 101, the raw
pressure data from the on-board weighing device can be converted to useful
hauling information for the real-time control of the vehicle by a base
station or central station. As a complement to the pressure data, the
on-board weighing apparatus illustrated in FIG. 2 includes other input
data sources which provide raw data to the sensor processing unit 101. As
will be explained more fully hereinafter, in keeping with the invention
the hauling information provided by the sensor processing unit 101 is
downloaded to a central station for use in monitoring, locating and
dispatching vehicles to particular locations in order to maintain
operation of the vehicle fleet at peak efficiency.
Referring to FIG. 2, the complementary input data sources in the on-board
weighing apparatus include, but are not limited to, a hoist cylinder
pressure transducer 102, a distance sensor 105, a forward-neutral-reverse
(F-N-R) direction switch 107, a dump switch 109, an inclinometer 110, a
fuel sensor 113 and a compass 116. A keypad integral with the housing of
the sensor processing unit 101 is used by the operator to request data and
to enter information such as an operator number which identifies the
operator or vehicle status to the system.
Various on-board outputs controlled by the processing unit 101 provide the
vehicle operator with indications of vehicle operating conditions in
response to the raw data from the on-board weighing device and
complementary sensors. Specifically, a printer 117 provides a hard copy
output for analysis by the vehicle operator or management personnel. An
audio output 119 alerts the operator to situations requiring immediate
attention. A fore/aft imbalance signal 121 gives a visual warning signal
to the operator of the piece of loading equipment if the vehicle is loaded
to carry too much weight in either the fore or aft area of the vehicle
body. In order to provide the operator with non-permanent data
information, such as current weight, a digital display is mounted to the
housing of the sensor processing unit 101. Load indicator lights 123 are
preferably mounted on the side of the vehicle in order to give the
operator of the loading equipment an idea of the remaining capacity in the
vehicle body as determined by a comparison of present weight with a stored
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