U.S. patent application number 16/194646 was filed with the patent office on 2019-03-21 for system and method for automatically adjusting a target ground speed of a machine.
This patent application is currently assigned to Caterpillar Inc.. The applicant listed for this patent is Caterpillar Inc.. Invention is credited to Joseph FAIVRE.
Application Number | 20190084573 16/194646 |
Document ID | / |
Family ID | 58558263 |
Filed Date | 2019-03-21 |
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United States Patent
Application |
20190084573 |
Kind Code |
A1 |
FAIVRE; Joseph |
March 21, 2019 |
SYSTEM AND METHOD FOR AUTOMATICALLY ADJUSTING A TARGET GROUND SPEED
OF A MACHINE
Abstract
A method for automatically adjusting a target ground speed of a
machine includes receiving data from a sensor, at a work monitor
unit of an electronic control module of the machine, analyzing the
data received from the sensor on the work monitor unit, receiving
the data from the work monitor unit at a target model unit of the
electronic control module, calculating, at the target model unit
based on the data, ground engagement data for the machine,
receiving the ground engagement data for the machine at a work
monitor library unit of the electronic control module, calculating,
at the work monitor library unit, the target ground speed, and
adjusting a speed of the machine to the target ground speed.
Inventors: |
FAIVRE; Joseph; (Edelstein,
IL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Caterpillar Inc. |
Deerfield |
IL |
US |
|
|
Assignee: |
Caterpillar Inc.
Deerfield
IL
|
Family ID: |
58558263 |
Appl. No.: |
16/194646 |
Filed: |
November 19, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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14919871 |
Oct 22, 2015 |
|
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16194646 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B60W 40/105 20130101;
E02F 3/841 20130101; B60W 30/18172 20130101; E02F 9/2029
20130101 |
International
Class: |
B60W 30/18 20060101
B60W030/18; E02F 9/20 20060101 E02F009/20; B60W 40/105 20060101
B60W040/105; E02F 3/84 20060101 E02F003/84 |
Claims
1-14. (canceled)
15. A system for automatically adjusting a target ground speed of a
machine, the system comprising: an electronic control module having
a processor and a memory configured to store a plurality of machine
units; a deceleration control configured to provide a deceleration
command to one of the machine units; and wherein the machine units
are configured to determine, with the processor and based on the
deceleration command, a target track pull, a target track speed,
and a blade position.
16. The system of claim 15, wherein said machine units comprise: a
work monitor unit configured to determine a raw target track pull
and a raw target track speed based on data received from one or
more sensors, wherein the data includes properties of a material on
which the machine is operating; a target model unit configured to
determine the target track pull and the target track speed based on
the raw target track pull and the raw target track speed; and a
work monitor library unit configured to determine the target ground
speed based on the target track pull and the target track
speed.
17. The system of claim 16, wherein the work monitor unit
comprises: a material properties algorithm unit configured to
analyze the properties of the material on which the machine is
operating based on the data received from the one or more sensors;
and a performance optimization algorithm unit configured to
determine the raw target track pull and the raw target track speed
based on the properties of the material on which the machine is
operating.
18. The system of claim 17, wherein the target model unit
comprises: a first driveline model unit for calculating a converter
torque; a first torque converter model unit for generating a
constant track pull curve and a maximum torque converter absorption
curve based on the converter torque; an engine model unit for
determining an engine torque and an engine speed based on the
constant track pull curve and the maximum torque converter
absorption curve; a second torque converter model unit for
determining the converter torque and a converter speed based on the
engine torque and the engine speed; a second driveline model unit
for determining an adjusted track pull and an adjusted track speed;
and a target operating model unit for determining a target track
pull and a target track speed.
19. The system of claim 17, wherein the work monitor library unit
comprises a track slip model unit for determining the target ground
speed based on the target track pull and the target track speed
received from the target operating model unit.
20. The system of claim 19, wherein the track slip model unit
determines the target ground speed also based on the properties of
the material on which the machine is operating.
21. A method for automatically adjusting a target ground speed of a
machine, the method comprising: receiving, by one or more
processors of an electronic control module of the machine, data
from a plurality of sensors; analyzing, by the one or more
processors, the data received from the plurality of sensors;
calculating, by the one or more processors and based on the data,
ground engagement data for the machine, wherein calculating the
ground engagement data includes calculating a target track pull and
a target track speed, calculating, by the one or more processors,
the target ground speed based on the ground engagement data; and
receiving a deceleration command, wherein the deceleration command
includes deceleration speed offsets based on a speed of an engine
being limited by a deceleration control, and wherein the
deceleration control introduces a positive feedback loop to
continuously measure a derated torque of the engine.
22. The method of claim 21, further including adjusting, by the one
or more processors, a speed of the machine to the target ground
speed, wherein adjusting the speed of the machine to the target
ground speed includes adjusting an implement on the machine to
adjust an amount of load being applied to the machine.
23. The method of claim 21, further comprising: determining, with a
work monitor unit, a raw target track pull and a raw target track
speed based on data received from one or more sensors of the
plurality of sensors, wherein the data includes properties of a
material on which the machine is operating; determining, with a
target model unit, the target track pull and the target track speed
based on the raw target track pull and the raw target track speed;
and determining, with a work monitor library unit, the target
ground speed based on the target track pull and the target track
speed.
24. The method of claim 23, further comprising: analyzing, with the
work monitor unit implementing a material properties algorithm, the
properties of the material on which the machine is operating based
on the data received from the one or more sensors of the plurality
of sensors; and determining, with the work monitor unit
implementing a performance optimization algorithm, the raw target
track pull and the raw target track speed based on the properties
of the material on which the machine is operating.
25. The method of claim 24, further comprising: calculating, with
the target model unit implementing a first driveline model, a
converter torque; generating, with the target model unit
implementing a first torque converter model, a constant track pull
curve and a maximum torque converter absorption curve based on the
converter torque; determining, with the target model unit
implementing an engine model, an engine torque and an engine speed
based on the constant track pull curve and the maximum torque
converter absorption curve; determining, with the target model unit
implementing a second torque converter model, the converter torque
and a converter speed based on the engine torque and the engine
speed; determining, with the target model unit implementing a
second driveline model, an adjusted track pull and an adjusted
track speed; and determining, with the target model unit
implementing a target operating model, the target track pull and
the target track speed.
26. The method of claim 24, further comprising: determining, with
the work monitor library unit implementing a track slip model, the
target ground speed based on the target track pull and the target
track speed received from the target operating model unit.
27. The method of claim 26, wherein the track slip model determines
the target ground speed at least partially based on information
identifying properties of the material on which the machine is
operating.
28. The method of claim 21, wherein calculating the ground
engagement data includes calculating, with a target operating model
unit, the target track pull and the target track speed based on an
adjusted track pull and an adjusted track speed received from a
driveline model unit, and wherein the track slip model unit also
receives material properties from the one or more processors.
29. The method of claim 21, wherein calculating the ground
engagement data includes calculating an adjusted track pull and an
adjusted track speed with a driveline model unit and transmitting
the adjusted track pull and the adjusted track speed from the
driveline model unit to a target operating model unit; wherein
calculating the ground engagement data includes calculating, with
the driveline model unit, the adjusted track pull and the adjusted
track speed based on a converter torque and a converter speed
received from a torque converter model unit; and further including
adjusting, by the one or more processors, a speed of the machine to
the target ground speed, wherein adjusting the speed of the machine
to the target ground speed includes adjusting an implement on the
machine to adjust an amount of load being applied to the
machine.
30. A system for automatically adjusting a target ground speed of a
machine, the system comprising: an electronic control module having
a processor and a memory configured to store a plurality of monitor
and model units for the machine; a deceleration control configured
to provide a deceleration command to one of the monitor and model
units, wherein the monitor and model units are configured to
determine, with the processor and based on the deceleration
command, a target track pull and a target track speed.
31. The system of claim 30, wherein the deceleration control is
configured to receive the deceleration command from a pedal.
32. The system of claim 30, wherein the deceleration command
includes deceleration speed offsets based on a speed of an engine
being limited by the deceleration control, and wherein the
deceleration control introduces a positive feedback loop to
continuously measure a derated torque of the engine.
33. The system of claim 32, wherein the monitor and model units
include: a work monitor unit configured to determine a raw target
track pull and a raw target track speed based on data received from
one or more sensors, wherein the data includes properties of a
material on which the machine is operating, and wherein the work
monitor unit comprises: a material properties algorithm unit
configured to analyze the properties of the material on which the
machine is operating based on the data received from the one or
more sensors; and a performance optimization algorithm unit
configured to determine the raw target track pull and the raw
target track speed based on the properties of the material on which
the machine is operating; a target model unit configured to
determine the target track pull and the target track speed based on
the raw target track pull and the raw target track speed; and a
work monitor library unit configured to determine the target ground
speed based on the target track pull and the target track speed,
wherein the work monitor library unit, wherein the work monitor
library unit comprises a track slip model unit for determining the
target ground speed based on the target track pull, the target
track speed received from the target operating model unit, and the
properties of the material on which the machine is operating.
34. The system of claim 33, wherein the target model unit
comprises: a first driveline model unit for calculating a converter
torque; a first torque converter model unit for generating a
constant track pull curve and a maximum torque converter absorption
curve based on the converter torque; an engine model unit for
determining an engine torque and an engine speed based on the
constant track pull curve and the maximum torque converter
absorption curve; a second torque converter model unit for
determining the converter torque and a converter speed based on the
engine torque and the engine speed; a second driveline model unit
for determining an adjusted track pull and an adjusted track speed;
and a target operating model unit for determining a target track
pull and a target track speed.
Description
TECHNICAL FIELD
[0001] This disclosure relates to a system and method for
automatically adjusting a target ground speed of a machine.
BACKGROUND
[0002] A system on some machines, such as a track-type tractor
machine, may maintain a constant speed of the machine by adjustment
of an implement, such as a blade, and hence an adjustment of the
load experienced by the implement. For example, adjusting an
implement may include raising or lowering the implement. As more
force is applied to the implement of the machine, ground engaging
members of the machine such as tracks may slip, meaning the
machine's track speed is not equal to its actual ground speed. For
example, a drawbar holding the implement on some machines may
experience increased force. Subsequently the tracks of the machine
may slip. In such a case, the system may adjust the implement, such
as by raising the blade, to reduce the load on the machine to
maintain the desired speed and to reduce slip of the ground
engaging members.
[0003] Often times, such as when the machine pushes a material, it
is of interest to the operator to slow the machine. In this regard,
the use of a deceleration control, such as a deceleration pedal,
may limit engine speed, thereby reducing the speed of the machine.
However, the above-noted system may determine that the machine is
being slowed by the load on the implement and may raise the
implement undesirably.
[0004] U.S. Patent Application Publication Number 2011/0040458A1,
titled "Working vehicle engine output control system and method,"
discloses an engine output control system which can compute a speed
ratio of the torque converter and reduce an output torque of the
engine without changing the target speed of the engine. However,
this Application does not automatically adjust the target speed of
the machine to maintain the load applied to the machine.
[0005] Accordingly, a system and method are needed to automatically
adjust the target speed of the machine and maintain the load on the
implement even when a deceleration control is applied.
SUMMARY
[0006] In one aspect, a method for automatically adjusting a target
ground speed of a machine includes receiving data from a sensor, at
a work monitor unit of an electronic control module of the machine,
analyzing the data received from the sensor on the work monitor
unit, receiving the data from the work monitor unit at a target
model unit of the electronic control module, calculating, at the
target model unit based on the data, ground engagement data for the
machine, receiving the ground engagement data for the machine at a
work monitor library unit of the electronic control module,
calculating, at the work monitor library unit, the target ground
speed, and adjusting a speed of the machine to the target ground
speed.
[0007] In another aspect, a system for automatically adjusting a
target ground speed of a machine includes an electronic control
module having a processor and a memory to store machine units, a
deceleration control to provide a deceleration command to one of
the machine units, and the machine units to determine, with the
processor and based on the deceleration command, a target track
pull, a target track speed, and a blade position.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 illustrates an exemplary machine according to the
disclosure.
[0009] FIG. 2 illustrates a schematic of machine drivetrain system
of the machine of FIG. 1 according to the disclosure.
[0010] FIG. 3 illustrates a system for automatically adjusting a
speed of the machine of FIG. 1 by using the system of FIG. 2,
according to the disclosure.
[0011] FIG. 4 illustrates an exemplary box diagram representing a
method performed by the work module according to FIG. 3.
[0012] FIG. 5 illustrates an exemplary box diagram representing a
method performed by the target model according to FIG. 3.
[0013] FIG. 6 illustrates an exemplary box diagram representing a
method performed by a unit according to the disclosure.
[0014] FIG. 7 illustrates another exemplary box diagram
representing a method according to the disclosure.
[0015] FIG. 8 illustrates a flow chart of a method performed by the
units illustrated in FIG. 3 according to the disclosure.
DETAILED. DESCRIPTION
[0016] FIG. 1 illustrates an exemplary aspect of the machine
according to the disclosure. In particular, FIG. 1 illustrates an
exemplary view of a machine 100, which may be a track type tractor
or the like. The machine 100 may have a drive transmission and a
torque converter that may utilize certain aspects of the
disclosure. The machine 100 may have rear work implements 102 for
performing operations. The machine 100 may also have additional
work implements for performing operations such as a blade 104,
tracks 106, a ripper lift arm 108, a machine drivetrain 110, and
the like. While the machine 100 may use a mechanical drive
transmission in one aspect of the present disclosure, the machine
100 may alternatively utilize a hydrostatic drive/steer system or
an electric drive that may also utilize certain aspects of the
disclosure.
[0017] Drawbar pull as used in the present disclosure refers to the
force delivered to the tracks 106. This force may be expended
primarily by moving the machine 100, e.g., pushing a load, and by
moving material under the tracks 106 in the form of track slip.
Other force may be expended via friction losses and may be
accounted for in drawbar pull. Conversely, energy diverted for
other purposes such as air conditioning may be outside drawbar pull
calculations, but may affect overall operation of the machine
100.
[0018] FIG. 2 illustrates a schematic of the machine drivetrain 110
of the machine 100 of FIG. 1. The machine 100 may have a powertrain
200 and an engine 202, which may include a fuel supply system 204,
such as an injector (INJ shown in FIG. 2) or the like, used to
control the amount of fuel delivered to the engine 202. The engine
202 may also have an engine output shaft 206 connected to a torque
converter 208 and may be configured for providing a variable output
speed and torque to the torque converter 208. The torque converter
208 may include a torque converter output shaft 210 connected to a
transmission 212 and may be configured for rotating at a variable
speed and for delivering torque to the transmission 212. The torque
converter 208 may have an impeller which is mechanically driven by
a prime mover, a turbine to drive the load, and a stator to
facilitate oil flow between the turbine and the impeller. The
torque converter 208 may also have a lock-up clutch which, when
mechanically engaged, may link the impeller and turbine. The
transmission 212 may include a transmission output shaft 214
connected to the machine drivetrain 110. The machine drivetrain 110
in the present disclosure may have a drive axle 216 that rotates
the tracks 106 of the machine 100, but is not limited in the
present disclosure to being connected to an axle that drives a pair
of tracks. Alternatively, the powertrain 200 may utilize a
hydrostatic drive/steer system or an electric drive that may also
utilize certain aspects of the disclosure.
[0019] A powertrain electronic controller module (PECM) 218 may be
provided to control the operation of the powertrain 200 with one or
more units, algorithms, and/or models stored on and executed by the
PECM 218. The PECM 218 may include a microprocessor, which may
include one or more microcomputers, integrated circuits and the
like, configured for being programmed and for executing modules and
algorithms to control the operation of the machine 100. A torque
converter output shaft sensor 220 may be operatively connected to
the PECM 218 and may produce a torque converter output speed signal
222 indicative of the rotational speed of the torque converter
output shaft 210, which may be proportional to the track speed of
the machine 100. Alternatively, any one of a plurality of sensors
may be operatively connected to the PECM 218. The sensors may
include a transmission output sensor 224 for measuring the
rotational output speed of the transmission output shaft 214, an
axle speed sensor 226 for measuring the rotational speed of the
drive axle 216, and an engine speed sensor 232 for measuring the
actual engine speed of the machine 100, a speed sensor for
measuring another speed, or any like sensor configured for
producing a signal that is proportional to the track speed of the
machine 100.
[0020] An engine electronic controller module (EECM) 230 may be
provided to control the operation of the engine 202. The EECM 230
may include one or more units, algorithms, and models to control
the operation of the engine 202. The EECM 230 may include a
microprocessor, which may include one or more microcomputers,
integrated circuits and the like, configured for being programmed
and for executing modules and algorithms to control the operation
of the machine 100. The EECM 230 may be operatively connected to
the fuel supply system 204 for controlling the amount to fuel being
delivered to the engine 202. Alternatively, any one of a plurality
of sensors may be operatively connected to the EECM 230.
[0021] The EECM 230 may receive the engine output speed signal 234
and the torque converter output speed signal 222 from the PECM 218,
and may calculate a torque converter speed ratio, which may be a
torque converter output speed divided by engine output speed. The
EECM 230 may include a unit and/or an algorithm for calculating a
desired engine RPM and for delivering a modulated fuel signal to
the fuel supply system 204.
[0022] The EECM 230 may increase or decrease fueling based on load.
As load increases, engine speed will drop and fueling may increase,
resulting in increased engine torque, but not increased speed.
Because engine speed and machine speed are driven by a load on the
machine 100, controlling the machine speed requires controlling
machine load, which may require adjusting an implement on the
machine 100. The load may come from material on the front of the
blade 104, for example, or other forces applied to the machine 100.
Raising the blade 104 will typically decrease load and increase
speed, and lowering the blade 104 will typically have the opposite
effect. Therefore, engine speed and machine speed can be adjusted
by changing the load applied to the machine 100.
[0023] The system may calculate a target load, track speed, and
ground speed with the EECM 230 and/or PECM 218. Under normal (e.g.,
non-deceleration) conditions, the system may raise and lower the
blade 104 to control the machine 100 at this speed. A ground speed
sensor 228 is used to drive a controller error signal for the PECM
218. The ground speed sensor 228 is typically a location (e.g.,
GPS, Galileo, Glonass, and the like) receiver, but could be a
ground speed radar or other device.
[0024] Under deceleration conditions, the operator expects a load
to be maintained and speed to decrease, so the system may need to
determine a new target speed that maintains the load under the
decelerated conditions. Deceleration results in less power, and
less power with a constant load results in a lower speed.
[0025] In an aspect of the present disclosure, the ground speed is
the track speed adjusted for slippage, as any slippage would reduce
the ground speed. Alternatively, other calculations may be made
using any one of the aforementioned sensors to produce desired
engine RPMs. The system in FIG. 2 may also be controlled by a
ground speed governor switch 238. The ground speed governor switch
238 may be operatively connected to the EECM 230 to activate a
ground speed governor, which may be an asynchronous governor. For
exemplary purposes, the machine 100 may limit the maximum RPMs of
the engine 202 through a plurality of variable parameters. One such
parameter may utilize the asynchronous governor to limit the
maximum RPMs. This limit may be hard-coded into the logic of the
EECM 230. Another parameter may implement a deceleration control
240 for the operator to engage. The deceleration control 240 may be
implemented as a pedal. Other implementations are contemplated as
well. For example, implementing the deceleration control 240
throughout its range of motion may produce a proportional decrease
in engine RPMs. In addition, when the deceleration control 240 is
engaged, the machine 100 may use the system illustrated in FIG. 2,
in particular the PECM 218 and/or the EECM 230, to adjust a target
speed of the machine 100 and to maintain a target load. If an
excessive load would cause slippage of the tracks 106 beyond a
predetermined threshold, for example 14%, the system in FIG. 2 may
automatically raise the blade 104 and thereby reduce the load on
the machine 100. In addition, the system may reduce the machine's
load to reduce the risk of stalling if the deceleration from the
deceleration control 240 limits torque below a value required to
maintain a non-decelerated load and to continue moving the machine
100.
[0026] A deceleration command caused by the deceleration control
240 may also impose a maximum engine speed constraint. Due to the
torque converter 208, however, the engine speed and the machine
speed may not be proportionate. As load increases, the torque
converter's torque ratio increases and the speed ratio decreases,
rendering the output torque greater than the engine torque, but the
output speed less than engine speed. Thus, when considering the
target speed against the maximum engine speed constraint, the
system must also consider the target load and use both the target
speed and target load to determine a target engine speed. If the
target engine speed is less than the deceleration limit, the system
may continue operating at the machine speed target. If the target
engine speed is greater than the deceleration limit, the engine 202
may no longer have enough power to produce the required torque to
maintain the load and propel the machine 100 at the target vehicle
speed, so the system must reduce the speed of the machine 100.
Below a certain engine speed, however, the torque converter 208 may
not absorb enough power to maintain the blade load and move the
tracks 106, so the system may also reduce the blade load by, for
example, raising the blade 104.
[0027] Alternatively, the use of one electronic control module
(ECM), which may be the PECM 218, the EECM 230, the like, or a
combination thereof, may be used to control both the powertrain 200
and the engine 202. The ECM may have one or more processors and a
memory for storing units, algorithms, and modules to operate the
machine 100. The ECM may receive a plurality of signals including
but not limited to the engine output speed signal 234, the torque
converter output speed signal 222, the transmission output sensor
224, the axle speed sensor 226, and the ground speed sensor 228 or
any like sensor configured for producing a signal that is
proportional to the ground speed of the machine 100 and the like.
Furthermore, the ECM may be configured for storing various data,
such as a table of predetermined torque converter performance data,
material properties data, gear and drag models, drawbar pull
curves, power limits, soil models, and the like. The ECM may also
be configured for calculating the torque converter speed ratios and
engine RPMs. Furthermore, the ECM may control the fuel supply
system 204 and may receive additional data from one or more
sensors. The operation of the machine 100 by the ECM may be based
at least in part on the data received by the sensors.
[0028] The operation of the machine 100 may be based on three
different speeds: the speed of the engine 202, the speed of the
tracks 106, and a ground speed. The speed of the tracks 106 may be
inferred from a transmission input or output speed. The ground
speed may also differ from the speed of the tracks 106 due to
slippage. In addition, the speed of the engine 202 may not be the
same as the transmission input speed due to slippage of the torque
converter 208. These speeds are discussed in more detail in
relation to FIG. 5.
[0029] FIG. 3 illustrates a system for automatically adjusting the
speed of the machine 100 and may be implemented with the system of
FIG. 2. The system may include units such as a work monitor unit
302, a target model unit 304, and a work monitor library unit 306,
and the like, each of which may be stored on the ECM memory and
executed by the ECM processor, or may alternatively be units
separate from the ECM capable of transmitting, generating, and
calculating data. Each of the units may have one or more algorithms
and models stored thereon to control operation of the machine 100,
and may have one or more processors to perform calculations,
receive and generate data, and the like. The work monitor unit 302,
target model unit 304, and work monitor library unit 306 components
may cause the elements of the powertrain 200 to perform specific
functions and to implement specific parameters.
[0030] For example, the work monitor unit 302 may estimate and
analyze material properties of the terrain on which the machine 100
is working and may optimize the performance of the machine 100
based on those material properties and a variety of tables and
equations for the engine and converter parameters to determine
target outputs such as track pull and track speed for the machine
100. The target model unit 304 may make adjustments to the target
outputs based on operator constraints (e.g., a deceleration
command) and a variety of tables and equations for the engine and
torque converter parameters. The work monitor library unit 306 may
consider the adjusted target outputs and the material properties to
determine, based on estimated track slippage at the adjusted target
outputs and estimated material properties, the target ground speed
for the machine 100.
[0031] FIG. 4 illustrates an exemplary box diagram representing a
method performed by the work monitor unit 302. The work monitor
unit 302 may receive sensor data 402 from the sensors in the system
of FIG. 2. The sensor data 402 may include information related to
the surface on which the machine 100 is operating and information
regarding the performance of the machine 100. A material properties
algorithm unit 404 may receive and use the sensor data 402 and may
consider the type of surface on which the machine 100 is operating
to estimate material properties 406, which may include a
coefficient of traction (COT) for that surface, a shear modulus
adjustment, slope, side slope, temperature, and the like. The
material properties 406 may therefore relate to the properties of
the surface on which the machine 100 is operating.
[0032] The work monitor unit 302 may also determine, with a
performance optimization algorithm unit 408, an optimal performance
of the machine 100 based on the material properties 406 and a
variety of tables and equations for the engine and torque converter
parameters. Optimal performance parameters may include a target
track speed, a target ground speed and a target track pull based on
the material properties 406 and a variety of tables and equations
for the engine and torque converter parameters. The optimal
performance may represent the track speed, ground speed and track
pull of the machine 100 with track slippage at a particular range
or value. The track pull and the track speed with a particular
track slippage may represent the raw target track pull 410 and the
raw target track speed 412. For example, the performance
optimization algorithm unit 408 may calculate the raw target track
pull 410 and the corresponding raw target track speed 412 based on
the material properties 406 associated with the surface materials
with which the machine 100 is interacting.
[0033] The target model unit 304 may receive a variety of inputs,
some of which may be received from the work monitor unit 302,
including the raw target track pull 410 and the raw target track
speed 412. The work monitor unit 302 may also output data,
including the material properties 406, to the work monitor library
unit 306.
[0034] FIG. 5 illustrates an exemplary box diagram representing a
method performed by the target model unit 304. The target model
unit 304 may receive inputs such as the raw target track pull 410,
the raw target track speed 412, gear information 502, a
deceleration command 504, and the like, and may determine ground
engagement data as described herein. The ground engagement data may
include track data such as speed, slippage, and the like.
[0035] The gear information 502 may include a gear ratio and the
like. For example, the gear ratio may represent the number of
output gear teeth to the number of input gear teeth in a gear
train. The deceleration command 504 may include deceleration speed
offsets, which may occur when the engine speed is limited by the
deceleration control 240. In addition, the deceleration control 240
may introduce a positive feedback loop in the system. In one aspect
of the disclosure, the deceleration command 504 may be filtered,
thus may add a lag time to the various calculations of the target
model unit 304.
[0036] The target model unit 304 may input the raw target track
pull 410 and the gear information 502 into a first driveline model
unit 506 which may calculate a converter output torque 508, which
may be a driveline input torque. The driveline may generally
include the components of the powertrain 200, including the
transmission 212. The first driveline model unit 506 may be a
mathematical model representing the mechanical behavior of the
actual driveline. To determine the converter output torque 508 with
the first driveline model unit 506, the gear information 502 may
include pitch information and/or transmission data and the like.
The gear information 502 may be used as a product with the raw
target track pull 410 on the machine 100 to determine the converter
output torque 508, which represents the torque of the torque
converter 208. The first driveline model unit 506 may transmit the
converter output torque 508 to a first torque converter model unit
510.
[0037] Based on the converter output torque 508, the first torque
converter model unit 510 may determine a table of torque converter
input speed and torque converter input torque representing a curve
of constant track putt 512 equivalent to the raw target track pull
410, and a table of torque converter input speed and input torque
representing maximum torque converter absorption curve 514. The
constant track pull curve 512 may be assumed to be a measurement of
engine speed to derated engine torque. Derated engine torque is a
torque that is limited relative to the normal torque. The maximum
torque converter absorption curve 514 may be generated by assuming
a torque converter speed ratio of zero at various torque converter
input speeds. The maximum torque converter absorption curve 514 may
measure the derated torque of the engine 202 against the speed of
the engine 202.
[0038] An engine model unit 516 may include various tables of data
or mathematical equations modeling the derated torque of the engine
202 against the speed of the engine 202, and may receive the
constant track pull curve 512 and the maximum torque converter
absorption curve 514 from the first torque converter model unit
510, and the deceleration command 504 (which may include a maximum
desired engine speed) from the deceleration control 240. The engine
model unit 516 may determine and output an engine torque 518 and an
engine speed 520 based on inputs such as a maximum converter
torque, another converter torque, a net lug torque (e.g., torque of
the engine 202 as a function of speed), and the like. The various
torque inputs can be used to determine a net torque of the engine
202, which may be analyzed with an engine curve showing the engine
lug, a line of constant drawbar pull, the maximum torque converter
absorption curve 514, and the like. For example, the net engine
torque 518 may take the minimum value from among a value of the
maximum torque converter absorption curve 514, a value from a
constant drawbar pull curve, and a value from a net lug curve.
[0039] In one aspect of the disclosure, when the machine 100 is
under a blade load and the engine 202 is reduced to a lugged speed
due to the ECM adjusting the RPMs of the engine 202, the engine
speed limit due to deceleration control 240 may be greater than the
lugged speed. In such a case, the machine 100 may be lugged to a
lower speed than the decelerator limit, and the system will not
need to adjust the raw target speed and load. In another aspect the
engine speed limit caused by the deceleration control 240 may be
less than lugged engine speed due to the load on the machine 100.
In this aspect the engine 202 may be controlled to the limited
engine speed range and the described system may adjust its target
machine speed range where the machine 100 can maintain a target
drawbar pull by reducing track speed. At this speed range, the
deceleration control 240 may cause the machine 100 to reduce speed
but attempt to maintain the blade load at full throttle. The
machine speed may be reduced up until a certain point below which
the torque converter 208 may not absorb enough power to maintain
the blade load and move the tracks 106. Thus, the engine torque 518
may depend on those variables and curves.
[0040] The engine torque 518 and engine speed 520 may be received
by a second torque converter model unit 522, which may determine
and output another converter torque 524 and a converter speed 526.
The converter torque 524 may be the same as or different from the
converter output torque 508, and may be determined by converting
the engine speed 520 and engine torque 518 to converter output
speed and output torque using known torque converter performance
tables and/or a series of mathematical calculations which model the
physical behavior of the torque converter 208. The converter speed
526 may be calculated by multiplying the engine speed 520 with a
speed ratio based on the pump torque. The second torque converter
model unit 522 may output the converter torque 524 and converter
speed 526 to a second driveline model unit 528.
[0041] The second driveline model unit 528 may determine a force
applied to the machine 100 based on torque, efficiency, and the
like. The force may be the track pull 530, which may be the current
track pull. For example, the force may be a product of the
converter torque 524, driveline efficiency, and gear reduction
ratios based on pitch and gear information. The second driveline
model unit 528 may also determine the track speed 532 based on
pitch and gear information, and may output the track pull 530 and
the track speed 532 to the target operating model unit 534. For
example, the track speed 532 may be a product of the converter
velocity and a reduction ratio, which may be determined based in
part on pitch and gear information. The track pull 530 may be the
actual track pull at the current time, and the track speed 532 may
be the actual track speed at the current time, or may be an
adjusted track pull and adjusted track speed. The adjusted track
pull and adjusted track speed variables may be based in part on
driveline efficiency, track pitch, gear ratio, and the like.
[0042] The track pull 530 and track speed 532 may be received by
and input into the target operating model unit 534 along with the
raw target track speed 412 provided by the work monitor unit 302.
The target operating model unit 534 may determine the target track
pull 536 and the target track speed 538 to apply to the machine
100. The target model unit 304 may transmit the target track pull
536 and the target track speed 538 to the work monitor library unit
306. The work monitor library unit 306, as discussed below, may
determine the target ground speed 540. For example, if the target
track speed 538 is less than or equal to the raw target track speed
412, the system may adopt the target track speed 538 for the
machine 100. If the target track speed 538 is greater than the raw
target track speed 412, however, the ECM may adopt the raw target
track speed 412.
[0043] FIG. 6 illustrates an exemplary box diagram representing a
method performed by the work monitor library unit 306. The target
track pull 536 and target track speed 538 may be received by and
input into the work monitor library unit 306, which may have a
track slip model unit 602. The track slip model unit 602 may
calculate, based on the target track pull 536, the target track
speed 538, and the material properties 406 from the work monitor
unit 302, the target ground speed 540 for the machine 100.
[0044] FIG. 7 illustrates another exemplary box diagram
representing a method performed by a unit. In this alternative
aspect, the target track speed 538 may be input into a drawbar pull
curve 702. The drawbar pull curve 702 may help determine the target
track drawbar pull 704 based on the drawbar pull at full throttle.
The target track drawbar pull 704 may be received by and input into
a gear ratio and drag model unit 706, which may determine a target
torque converter torque 708. A deceleration position 710 and a
throttle position 712 may be received by and input into
deceleration logic 714 to determine an engine speed limit 716. The
target torque converter torque 708 and the engine speed limit 716
may be input into a lookup table 718, which may help determine a
target torque converter speed 720 and a target torque converter
torque 722 to be input into a unit imposing a minimum power limit
724. The minimum power limit 724 may be implemented to generate
another target torque converter speed 726 and another target torque
converter torque 728 based at least in part on a power limit
imposed on the machine 100.
[0045] The target torque converter speed 726 and the target torque
converter torque 728 may be received by and input into a gear ratio
and drag model unit 730 to determine the target track speed 538 and
a target drawbar load 732 to implement on the machine 100. The
target track speed 538 and a target drawbar load 732 may be
received by input into a soil model unit 734 in the work monitor
library unit 306. The soil model unit 734 may also account for a
shear model unit 736 and the COT 738 in order to determine the
target ground speed 540.
[0046] In one aspect of the present disclosure, the data received
by the sensors may correspond to a ground slope on which the
machine 100 is currently working and on one or more of a track
velocity, a ground speed, a drawbar pull, and the COT 738.
Producing the COT 738 includes calculating a plurality of
instantaneous pull-weight ratios using the drawbar pull and the
slope, removing from the plurality of instantaneous pull-weight
ratios the instantaneous pull-weight ratios that fail to meet a
first screening criteria, the first screening criteria including
removing the instantaneous pull-weight ratios corresponding to a
predetermined slip value, and averaging the instantaneous
pull-weight ratios that meet the first screening criteria to
produce the COT 738. The method of producing the COT 738 may also
include normalizing, at the ECM, a nominal pull-slip curve by the
COT 738 to produce a normalized pull-slip curve, and producing, at
the ECM, the shear modulus adjustment factor. Producing the shear
modulus adjustment factor includes calculating a plurality of
normalized pull-weight ratio values, removing normalized
pull-weight ratio values that fail to meet a second screening
criteria, the second screening criteria including removing the
normalized pull-weight ratio values corresponding to a slip outside
a predetermined range, calculating the shear modulus adjustment
factor from the normalized pull-weight ratio values meeting the
second screening criteria, applying the shear modulus adjustment
factor to the normalized pull-slip curve to obtain an adjusted
pull-slip curve, and using the adjusted pull-slip curve, the COT
738, and the slope to determine optimum performance parameters. The
method may further include using the optimum performance parameters
to adjust an operating state of the machine 100 to achieve a
performance closer to the optimum performance.
INDUSTRIAL APPLICABILITY
[0047] The disclosure is applicable to a machine 100, such as a
track-type tractor machine, with speed control systems in general,
and specifically to automatically adjusting the speed of the
machine 100 having a deceleration control 240. When the
deceleration control 240 is engaged, the engine speed of the
machine 100 may be limited, which could in turn reduce the speed of
the machine 100. Instead of reducing the speed of the machine 100,
a system on board the machine 100 may raise the blade 104 to reduce
the load on the machine 100.
[0048] Referring to FIGS. 1 and 2, as the machine 100 pushes more
material, drawbar force increases and the track speed reduces. As
the drawbar force increases, the tracks 106 may shear material at a
higher rate and slip more. The system illustrated in FIG. 2, in
particular the ECM, may adjust the load of the blade 104 to
maintain a desired ground speed and slip when the drawbar force
increases. Application of the deceleration control 240, however,
limits engine speed and machine speed. The one or more ECMs in FIG.
2 may implement the units responsible for the calculations shown in
FIGS. 3-6, or alternatively the units may be external from the
ECM.
[0049] Referring to FIGS. 2-6, the system of FIG. 2, using the ECM
and the units, may determine a target track pull 536 and a target
track speed 538 to be fed into the work monitor library unit 306,
which may determine the target ground speed 540 for the machine
100. The system of FIG. 2 may use one or more ECMs having the work
monitor unit 302, the target model unit 304, and the work monitor
library unit 306 stored thereon.
[0050] The work monitor unit 302 may use a material properties
algorithm unit 404 and a performance optimization algorithm unit
408 to determine variables such as the raw target track pull 410
and the raw target track speed 412. Those variables may be
determined at least in part by the sensor data 402.
[0051] The target model unit 304 may receive the raw target track
speed 412 and the raw target track pull 410, among other inputs,
and may calculate a variety of torque and speed variables using a
first driveline model unit 506, a first torque converter model unit
510, an engine model unit 516, a second torque converter model unit
522, a second driveline model unit 528, and a target operating
model unit 534. The outputs of the target operating model unit 534
may include the target track pull 536 and the target track speed
538.
[0052] The work monitor library unit 306 may receive the target
track pull 536 and the target track speed 538 and may input them
into the track slip model unit 602. The track slip model unit 602
may also consider the material properties 406 from the work monitor
unit 302 to determine the target ground speed 540. The system of
FIG. 2, controlled by the ECM, may then adjust the speed of the
machine 100 to the target ground speed 540. Each of the units;
models, algorithms, libraries, and the like may be executed in one
or more modules of the ECM or may exist and/or perform operations
separately from the ECM.
[0053] FIG. 8 illustrates a flow chart of a method performed by the
units illustrated in FIG. 3. At box 802, the work monitor unit 302
may receive the sensor data 402. At box 804, the work monitor unit
302 may analyze the received sensor data 402. At box 806, the
target model unit 304 may receive the data from the work monitor
unit 302. At box 808, the target model unit 304 may calculate
ground engagement data for the machine 100. At box 810, the work
monitor library unit 306 may receive the ground engagement data. At
box 812, the work monitor library unit 306 may calculate the target
ground speed 540. Once the target ground speed 540 has been
calculated, the ECM may help adjust the actual speed of the machine
100 to the target ground speed 540. To adjust the speed of the
machine 100, the ECM may adjust the load being applied to the
machine 100 by adjusting the ground engaging implement, such as the
blade.
[0054] It will be appreciated that the foregoing description
provides examples of the disclosed system and technique. However,
it is contemplated that other implementations of the disclosure may
differ in detail from the foregoing examples references to the
disclosure or examples thereof are intended to reference the
particular example being discussed at that point and are not
intended to imply any limitation as to the scope of the disclosure
more generally. All language of distinction and disparagement with
respect to certain features is intended to indicate a lack of
preference for those features, but not to exclude such from the
scope of the disclosure entirely unless otherwise indicated.
[0055] Recitation of ranges of values herein are merely intended to
serve as a shorthand method of referring individually to each
separate value falling within the range, unless otherwise indicated
herein, and each separate value is incorporated into the
specification as if it were individually recited herein. All
methods described herein can be performed in any suitable order
unless otherwise indicated herein or otherwise clearly contradicted
by context.
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