U.S. patent application number 13/332024 was filed with the patent office on 2013-06-20 for implement control system for a machine.
This patent application is currently assigned to CATERPILLAR INC.. The applicant listed for this patent is Joshua Callaway. Invention is credited to Joshua Callaway.
Application Number | 20130158819 13/332024 |
Document ID | / |
Family ID | 48610982 |
Filed Date | 2013-06-20 |
United States Patent
Application |
20130158819 |
Kind Code |
A1 |
Callaway; Joshua |
June 20, 2013 |
Implement control system for a machine
Abstract
A system for automated movement of a ground engaging blade of a
machine includes an acceleration sensor and a roll rate sensor on
the blade to indicate a cross slope angular position of the blade.
A controller stores a target cross slope and compares the target
cross slope to the cross slope angular position. Movement of the
ground engaging blade is at least in part based upon a difference
between the target cross slope and the cross slope angular position
to maintain the ground engaging blade at the target cross
slope.
Inventors: |
Callaway; Joshua; (Cary,
NC) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Callaway; Joshua |
Cary |
NC |
US |
|
|
Assignee: |
CATERPILLAR INC.
Peoria
IL
|
Family ID: |
48610982 |
Appl. No.: |
13/332024 |
Filed: |
December 20, 2011 |
Current U.S.
Class: |
701/50 |
Current CPC
Class: |
E02F 3/845 20130101;
E02F 9/265 20130101; E02F 9/2041 20130101 |
Class at
Publication: |
701/50 |
International
Class: |
E02F 3/84 20060101
E02F003/84 |
Claims
1. A control system for automated movement of a ground engaging
blade of a machine, the ground engaging blade being configured for
rotational movement about an axis to define a cross slope of the
ground engaging blade, comprising: a first sensor disposed on the
ground engaging blade configured to provide a measured cross slope
signal indicative of a measured cross slope of the ground engaging
blade; a second sensor disposed on the ground engaging blade
configured to provide a roll rate signal indicative of a roll rate
of the ground engaging blade; and a controller configured to: store
a target cross slope signal indicative of a target cross slope of
the ground engaging blade; determine the cross slope angular
position based upon the measured cross slope signal and the roll
rate signal; compare the target cross slope to the cross slope
angular position; generate a command signal at least in part based
upon a difference between the target cross slope and the cross
slope angular position; and transmit the command signal to maintain
the ground engaging blade at the target cross slope.
2. The control system of claim 1, wherein the controller is further
configured to receive an operator command signal, override the
command signal with the operator command signal and transmit the
operator command signal to control movement of the ground engaging
blade.
3. The control system of claim 2, wherein the controller is further
configured to return the ground engaging blade to the target cross
slope upon termination of the operator command signal.
4. The control system of claim 1, wherein the cross slope angular
position is a measurement of the ground engaging blade relative to
a gravity reference.
5. The control system of claim 1, wherein the controller initially
generates the command signal primarily based upon the roll rate
signal.
6. The control system of claim 5, wherein the controller
subsequently generates the command signal primarily based upon the
measured cross slope signal.
7. The control system of claim 5, wherein the first sensor is an
accelerometer.
8. The control system of claim 6, wherein the second sensor is a
gyroscope.
9. The control system of claim 1, wherein the controller is further
configured to compare the target cross slope to a maximum cross
slope, and generate a modified command signal to prevent movement
of the ground engaging blade past a predetermined maximum
displacement.
10. The control system of claim 1, wherein the first sensor is an
accelerometer.
11. The control system of claim 1, wherein the command signal moves
the ground engaging blade when an operator has not commanded a
specific movement of the ground engaging blade.
12. A controller implemented method of adjusting a ground engaging
blade of a machine, the ground engaging blade having a first sensor
configured to provide a measured cross slope signal indicative of a
measured cross slope of the ground engaging blade, and a second
sensor disposed on the ground engaging blade configured to provide
a roll rate signal indicative of a roll rate of the ground engaging
blade, comprising: storing within a controller a target cross slope
signal indicative of a target cross slope of the ground engaging
blade; determining a cross slope angular position based upon the
measured cross slope signal and the roll rate signal; comparing the
target cross slope to the cross slope angular position; generating
a command signal within the controller at least in part based upon
a difference between the target cross slope and the cross slope
angular position; and transmitting the command signal from the
controller to a control system to maintain the ground engaging
blade at the target cross slope.
13. The controller implemented method of claim 12, further
including receiving an operator command signal within the
controller, overriding the command signal with the operator command
signal and transmitting the operator command signal from the
controller to control movement of the ground engaging blade.
14. The controller implemented method of claim 13, further
including returning the ground engaging blade to the target cross
slope upon termination of the operator command signal.
15. The controller implemented method of claim 12, further
including measuring cross slope as a measurement of the ground
engaging blade relative to a gravity reference.
16. The controller implemented method of claim 12, further
including initially generating the command signal primarily based
upon the roll rate signal and subsequently generating the command
signal primarily based upon the measured cross slope signal.
17. The controller implemented method of claim 12, further
including comparing the target cross slope to a maximum
displacement cross slope, and generating within the controller a
modified command signal to prevent movement of the ground engaging
blade past a predetermined maximum displacement.
18. A machine comprising: a ground engaging blade; a first sensor
on the ground engaging blade configured to provide a measured cross
slope signal indicative of a measured cross slope of the ground
engaging blade; a second sensor disposed on the ground engaging
blade configured to provide a roll rate signal indicative of a roll
rate of the ground engaging blade; and a controller configured to:
store a target cross slope signal indicative of a target cross
slope of the ground engaging blade; determine a cross slope angular
position based upon the measured cross slope signal and the roll
rate signal; compare the target cross slope to the cross slope
angular position; generate a command signal at least in part based
upon a difference between the target cross slope and the cross
slope angular position; and transmit the command signal to maintain
the ground engaging blade at the target cross slope.
19. The machine of claim 18, wherein the controller initially
generates the command signal primarily based upon the roll rate
signal.
20. The machine of claim 19, wherein the first sensor is an
accelerometer and the second sensor is a gyroscope.
Description
TECHNICAL FIELD
[0001] This disclosure relates generally to controlling an
implement and, more particularly, to a system and method for
controlling the cross slope of a ground engaging blade.
BACKGROUND
[0002] Machines such as a tractors, bulldozers and the like are
often equipped with attached implements for performing various
tasks. For example, a tractor may be equipped with a ground
engaging blade for performing tasks such as scraping the ground and
moving material in a controlled fashion. An operator may move the
blade in various directions relative to the ground. This helps the
tractor complete the task of properly leveling or contouring the
ground on which the tractor is operating. This is a task often
performed during the construction of roads, buildings, or other
structures.
[0003] One difficulty when operating such a machine is maintaining
a consistent position of the blade as the tractor moves over uneven
terrain. Movement of the machine up and down and from side to side
results in similar movements of the blade despite a desire to
maintain the blade in a fixed orientation relative to a ground
reference. As a result of such movement, the work surface created
by the machine may be uneven and require additional work to create
a desired work surface.
[0004] An operator of a machine may correct for uneven terrain by
adjusting the motion of the blade as the machine moves to
compensate for the machine's movement, resulting in a smoother
surface. However, the quality of the resulting grade is dependent
on the skill of the operator in anticipating the need to adjust the
blade. The operator may, in addition or alternatively, slow the
speed of the machine while adjusting the blade position in response
to uneven terrain. Such operations tend to reduce efficiency and
increase cost.
[0005] U.S. Pat. No. 7,121,355 to Lumpkins et. al ("Lumpkins")
discloses a control system for controlling the position of a
machine blade for grading. The control system determines the
difference between a target position of the blade and its actual
position, and generates a control signal calculated to move the
blade to the target position.
[0006] The foregoing background discussion is intended solely to
aid the reader. It is not intended to limit the innovations
described herein, nor to limit or expand the prior art discussed.
Thus, the foregoing discussion should not be taken to indicate that
any particular element of a prior system is unsuitable for use with
the innovations described herein, nor is it intended to indicate
that any element is essential in implementing the innovations
described herein. The implementations and application of the
innovations described herein are defined by the appended
claims.
SUMMARY
[0007] In one aspect, a control system is provided for controlling
automated movement of a ground engaging blade of a machine. The
ground engaging blade is configured for rotational movement about
an axis to define a cross slope of the ground engaging blade. A
first sensor is located on the ground engaging blade and configured
to provide a measured cross slope signal indicative of a cross
slope of the ground engaging blade. A second sensor is disposed on
the ground engaging blade configured to provide a roll rate signal
indicative of a roll rate of the ground engaging blade. A
controller is configured to store a target cross slope signal
indicative of a target cross slope of the ground engaging blade,
determine a cross slope angular position based upon the measured
cross slope signal and the roll rate signal, and compare the target
cross slope to the cross slope angular position. The controller
further generates a command signal at least in part based upon a
difference between the target cross slope and the cross slope
angular position to control movement of the ground engaging blade
by transmitting the command signal to control movement of the
ground engaging blade. In this way, the ground engaging blade may
be maintained at or near the target cross slope.
[0008] In another aspect, a controller implemented method of
adjusting a ground engaging blade of a machine is provided. The
ground engaging blade has a first sensor configured to provide a
measured cross slope signal indicative of a cross slope of the
ground engaging blade and second sensor configured to provide a
roll rate signal indicative of a roll rate of the ground engaging
blade. The method includes storing within a controller a target
cross slope signal indicative of a target cross slope of the ground
engaging blade, determining the cross slope angular position based
upon the measured cross slope signal and the roll rate signal, and
comparing the target cross slope to the cross slope angular
position. The controller generates a command signal at least in
part based upon a difference between the target cross slope and the
cross slope angular position to control movement of the ground
engaging blade and to maintain the ground engaging blade at the
target cross slope. The command signal is transmitted from the
controller to control movement of the ground engaging blade.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 shows a side view of a machine including a system in
accordance with the disclosure;
[0010] FIG. 2 shows a front view of a machine similar to that of
FIG. 1 with certain components removed and broken away for
clarity;
[0011] FIG. 3 shows a flowchart illustrating a cross slope control
process in accordance with the disclosure; and
[0012] FIG. 4 is an exemplary performance graph of the cross slope
of a machine moving along a simulated path;
[0013] FIG. 5 is an exemplary performance graph of the cross slope
of the ground engaging blade of the machine of FIG. 4 moving along
the simulated path and after being corrected based upon a signal
from a first sensor;
[0014] FIG. 6 is an exemplary performance graph of the cross slope
of the ground engaging blade of the machine of FIG. 4 moving along
the simulated path and after being corrected based upon a signal
from a second sensor; and
[0015] FIG. 7 is an exemplary performance graph of the cross slope
of the ground engaging blade of the machine of FIG. 4 moving along
the simulated path and after being corrected based upon signals
from the first sensor and the second sensor.
DETAILED DESCRIPTION
[0016] FIG. 1 shows a diagrammatic illustration of a machine that
may be used in accordance with an embodiment of the disclosure. A
machine 10 includes a frame 12 and a prime mover such as an engine
13. A pair of drive wheels (one of which is illustrated as a drive
wheel 14) are disposed on each side of machine 10 and operate to
drive a pair of tracks (one of which is shown as a track 15) to
propel machine 10. Although machine 10 is shown in a "track-type"
configuration, other configurations, such as a wheeled
configuration, may be used. In addition, the systems and methods of
the disclosure may be used with any machine propulsion and drive
train mechanisms applicable in the art. Further, the systems and
methods disclosed herein may also be used on machines other than a
tractor having a ground engaging blade, such as a loader or a motor
grader.
[0017] Machine 10 includes an implement such as ground engaging
blade 16 pivotally connected to frame 12 by a pair of opposed arm
(one of which is illustrated as an arm 17) disposed on each side of
machine 10. A lift hydraulic cylinder 21 is coupled to frame 12 and
supports ground engaging blade 16 in the vertical direction, and
allow ground engaging blade 16 to move up or down vertically from
the point of view of FIG. 1. A pair of pitch hydraulic cylinders 22
on each side of machine 10 (FIG. 2) allow the pitch angle of blade
tip 18 to change relative to an axis or centerline of the machine
("CL" in FIG. 1). Actuating the pitch hydraulic cylinders 22 in
opposite directions may permit the ground engaging blade 16 to
rotate or tilt relative to the machine 10. In other words,
operating the pitch hydraulic cylinders 22 in this manner will
permit the rotation of the ground engaging blade 16 generally about
an attachment point of the ground engaging blade to the machine 10
so that opposite corners 19 of the bottom edge of the blade may be
disposed at different heights relative to the ground. The machine
of FIG. 2 depicts an alternate manner of affecting the rotation of
ground engaging blade 16 by utilizing a tilt hydraulic cylinder 23.
Each of the hydraulic cylinders may be electrically controlled and
receive signals from a controller 30. Controller 30 generates a
signal that may be translated into a direction and magnitude of
movement of the appropriate hydraulic cylinders as will be
understood by those skilled in the art.
[0018] Machine 10 includes cab 28 from which an operator may
provide input to control machine 10. Cab 28 includes one or more
controls with which the operator may issue commands. FIG. 1 shows a
joystick 27 from which an operator may control one or more machine
implements, such as ground engaging blade 16. Joystick 27 may be
configured to automatically return to a "neutral" position if the
operator is not moving joystick 27. The operator may move joystick
27 to either side to control the tilt or rotation of ground
engaging blade 16 relative to machine 10. Joystick 27 may operate
as part of a control system of machine 10 wherein the operator's
movement of joystick 27 (including the magnitude of the movement of
joystick 27) is translated into a signal and sent to a controller
30. Movement of joystick 27 generates a signal to controller 30
indicative of the magnitude and direction of the operator's
movement of the joystick. As described in more detail below, the
controller 30 may process the signal and potentially adjust the
signal prior to issuing or generating a command signal to the tilt
hydraulic cylinder 23 to adjust the cross slope or angular
orientation of ground engaging blade 16.
[0019] Machine 10 may be equipped with a plurality of sensors that
provide data indicative (directly or indirectly) of the performance
or conditions of various aspects of the machine. A first sensor 33
such as a 3-axis accelerometer may be provided on the ground
engaging blade 16 of machine 10. The first sensor 33 may be used to
provide an acceleration signal indicative of the measured
acceleration of the ground engaging blade 16 relative to a gravity
reference. As such, the cross slope angular position is a
measurement of the ground engaging blade relative to a gravity
reference. Changes in blade roll or cross slope may be determined
and controlled through the use of the measured acceleration of the
ground engaging blade 16.
[0020] A second sensor 34 such as a roll rate sensor (e.g., a
gyroscope) may also be provided on the ground engaging blade 16 of
machine 10. The second sensor 34 may be used to provide an
additional signal such as a roll rate signal indicative of a
measured roll rate of the ground engaging blade 16. The measured
roll rate is the rate of change of the ground engaging blade 16 as
it rotates about the axis of the machine 10. In other words, as the
tilt hydraulic cylinder 23 causes the ground engaging blade 16 to
rotate about an attachment point, the measured roll rate will be
indicative of the velocity or rate of change of the position of the
blade.
[0021] As described in more detail below, controller 30 may utilize
the acceleration signal from first sensor 33 to determine changes
in the cross slope of ground engaging blade 16. Controller 30 may
perform various functions such as integrating, filtering and
scaling the acceleration signal so as to provide a signal
indicative of the angular position or cross slope of the ground
engaging blade 16. The cross slope angular position may then be
compared to a desired cross slope to determine whether and how the
cross slope angular position of the ground engaging blade 16 should
be adjusted.
[0022] Controller may also utilize the measured roll rate from
second sensor 34 as further input to control the cross slope of
ground engaging blade 16. Controller 30 may also perform various
functions such as integrating, filtering and scaling the roll rate
signal to provide a signal indicative of the angular position or
cross slope of the ground engaging blade 16.
[0023] The signal generated from the first sensor 33 may be
combined with the signal from the second signal 34 to provide a
more responsive and accurate measurement of the cross slope angular
position of ground engaging blade 16. An accelerometer such as
first sensor 33 may be used to provide the angular position of the
ground engaging blade 16 but the determination of such position may
be relatively slow, in part due to various functions and
calculations that must be performed. A roll rate sensor such as
second sensor 34 may be used to provide the angular position of the
ground engaging blade 16 more quickly than an accelerometer but the
determination of such position is generally less accurate over
time. Accordingly, the signals from the first sensor 33 and the
second sensor 34 may be combined, if desired, to provide a combined
representation of the cross slope angular position of the ground
engaging blade 16. Such combined representation includes the
benefits of both the first sensor 33 and the second sensor 34. More
specifically, the first sensor 33 generally provides greater
accuracy over time and the second sensor 34 generally provides a
more rapid response.
[0024] A control system may be provided to control the operation of
the machine 10 including the cross slope control aspects of the
system. The control system may include an electronic control module
such as controller 30. The controller 30 may receive operator input
command signals and control the operation of the hydraulic systems
that operate the various hydraulic cylinders. The controller 30 may
be mounted at any convenient location on machine 10. The control
system may include one or more input devices such as joystick 27 to
control the machine 10 and one or more sensors, including first
sensor 33 and second sensor 34, to provide data and other input
signals representative of various operating parameters of the
machine 10.
[0025] The controller 30 may be an electronic controller that
operates in a logical fashion to perform operations, execute
control algorithms, store and retrieve data and other desired
operations. The controller 30 may include or access memory,
secondary storage devices, processors, and any other components for
running an application. The memory and secondary storage devices
may be in the form of read-only memory (ROM) or random access
memory (RAM) or integrated circuitry that is accessible by the
controller. Various other circuits may be associated with the
controller such as power supply circuitry, signal conditioning
circuitry, driver circuitry, and other types of circuitry.
[0026] The controller 30 may be a single controller or may include
more than one controller disposed to control various functions
and/or features of the machine 10. The term "controller" is meant
to be used in its broadest sense to include one or more controllers
and/or microprocessors that may be associated with the machine 10
and that may cooperate in controlling various functions and
operations of the machine. The functionality of the controller 30
may be implemented in hardware and/or software without regard to
the functionality employed. The controller 30 may rely on one or
more data maps relating to the operating conditions of the machine
10 that may be stored in the memory of controller. Each of these
maps may include a collection of data in the form of tables,
graphs, and/or equations. The controller 30 may use the data maps
to maximize the efficiency of the machine 10.
[0027] Referring to FIG. 3, machine 10 may be equipped with a user
switch (not shown) to activate the cross slope control aspects of
the control system at stage 41. If the user switch is activated,
the cross slope control system will operate in accordance with the
flowchart of FIG. 3. If user switch is not activated or the cross
slope control functionality is not operating properly, machine 10
will operate in accordance with the operator's commands regardless
of the operating conditions encountered by the machine.
[0028] The operator provides a desired or target cross slope of
ground engaging blade 16 at stage 42. This may be accomplished by
entering the target cross slope through an input device such as a
dial. The controller then stores a target cross slope signal
indicative of the target cross slope. In an alternative embodiment,
an operator may set the target cross slope by moving the ground
engaging blade 16 to a desired orientation and engaging an input
device such as by pressing a button (not shown). At stage 43, the
controller 30 receives a measured cross slope signal from the first
sensor 33 on the ground engaging blade 16 and a roll rate signal
from the second sensor 34 on the ground engaging blade. The
controller 30 determines a cross slope angular position based upon
the measured cross slope signal and the roll rate signal. As used
herein, the term "cross slope angular position" refers to the cross
slope as determined by one or more sensors.
[0029] The controller 30 then compares at decision stage 44 the
cross slope angular position to the desired or target cross slope
set by the operator. If the difference between the cross slope
angular position and the desired cross slope is zero or less than a
predetermined amount, the controller 30 will not generate a command
signal and the blade will be maintained at its current angular
orientation at stage 45.
[0030] If the cross slope angular position is different from the
desired or target cross slope, the controller 30 will determine at
decision stage 46 whether certain predetermined threshold
conditions have been met to activate the cross slope control
system. One threshold condition may be that the machine
transmission (not shown) is in a certain state (e.g. not in
neutral). Another example of a threshold condition may be that the
machine ground speed is above or below a threshold amount or that
the engine speed is within a predetermined range. Still another
threshold condition may be that one or more other control systems
are not active in controlling the implement. This type of condition
may be desirable if the machine is equipped with multiple different
implement control systems that are mutually exclusive and therefore
cannot operate together. Another threshold condition may be based
upon the receipt of predetermined steering commands. For example,
the controller may turn off the cross slope control system during
certain turning operations. Other threshold conditions may be set
as desired.
[0031] It should be noted that the determination of whether the
threshold conditions have been met may be based upon monitoring the
operating characteristics of aspects of the machine 10 for a
particular period. In addition, different time periods may apply to
different threshold conditions. If one or more of the threshold
conditions have not been met at decision stage 46, the controller
30 will not generate a command signal and the cross slope of ground
engaging blade 16 will not change. In other words, even if the
machine 10 is undergoing a change in cross slope, the blade will
follow the machine 10 during such change.
[0032] If, on the other hand, the necessary threshold conditions
have been met at decision stage 46, the control determines at
decision stage 47 whether the operator is issuing a tilt angle
change command to change the cross slope of ground engaging blade
16. If the operator has issued a tilt angle change command at
decision stage 47, the controller 30 will generate a command signal
approximately or substantially equal to the operator tilt angle
change command at stage 51. This command signal will then be
transmitted at stage 52 by controller 30 to control the hydraulic
cylinders necessary to implement the operator command. In other
words, if the operator issues a tilt angle change command, the
controller 30 will override the portion of the cross slope control
system that would otherwise generate a command signal based upon
the difference between the cross slope angular position and the
target cross slope. The controller 30 will utilize the operator
tilt angle change command signal as the command signal that is
transmitted to control movement of the ground engaging blade
16.
[0033] If the operator did not issue a tilt angle change command at
decision stage 47, the controller 30 generates a command signal
based upon the difference between the cross slope angular position
and the desired or target cross slope. At decision stage 54, the
controller determines whether the ground engaging blade 16 is at
its maximum travel position. In other words, the controller
determines whether the command signals generated at stage 53 will
cause the tilt hydraulic cylinder 23 to reach its maximum travel
position and cause the ground engaging blade to reach its maximum
cross slope position. In doing so, the controller 30 may compare
the target cross slope to a maximum cross slope.
[0034] If the tilt hydraulic cylinder 23 has reached its maximum
travel position, the controller at stage 55 will modify the command
signal to generate a modified command signal to limit the travel of
the tilt hydraulic cylinder 23 and prevent movement of the ground
engaging blade 16 past its predetermined maximum displacement. As
such, the ground engaging blade will be maintained within its
operating parameters and not exceed its maximum travel position.
This modified command signal is then transmitted at stage 52 to
control the tilt hydraulic cylinder 23. If the ground engaging
blade 16 is not at its maximum travel position at decision stage
54, the controller does not change the generated command signal at
stage 56, and the command signal is transmitted at stage 52 to
control movement of the ground engaging blade 16 and maintain the
ground engaging blade at the target cross slope. As such, the
command signal is at least in part based upon a difference between
the target cross slope and the cross slope angular position.
[0035] It can be seen from FIG. 3 that once an operator is no
longer issuing an operator command (i.e., upon termination of the
operator command signal) at decision stage 47, the controller 30
will follow stage 53 and attempt to return the ground engaging
blade to the target cross slope. The cross slope control system
will continue to operate until the operator suspends or disables
the system such as by the user switch (not shown) or any of the
threshold conditions are no longer met. In addition, it should be
noted, that the operator may change the desired cross slope by
returning to stage 42 at any time by inputting a new desired or
target cross slope.
[0036] FIGS. 4-7 depict graphs of examples of the cross slope of a
machine 10 and its ground engaging blade 16 as a function of time
for a simulated movement of the machine 10. In FIG. 4, the change
in machine roll angle is denoted by a line 61 as a function of time
for the simulated movement of the machine 10. For this simulated
movement, the target cross slope of the ground engaging blade 16
has been set to 0 degrees and the machine is initially operating at
a 0 degrees cross slope. At time 0.0, the machine begins a constant
change of roll angle for approximately 1.0 seconds and then
maintains a new cross slope of 5 degrees. If the cross slope
control system disclosed herein is not engaged or the threshold
conditions not met, the ground engaging blade 16 would rotate with
machine 10 so that it would have a cross slope of 5 degrees. If the
system were to work instantaneously without any error, the ground
engaging blade 16 would be maintained at 0 degrees even as the
machine engages the slope.
[0037] As described above, if desired, the cross slope control
system may utilize only the acceleration signal from the first
sensor 33 to adjust the cross slope of the ground engaging blade
16. In FIG. 5, the cross slope angular position of ground engaging
blade 16 is denoted at line 62 as a function of time for the same
simulated movement of the machine 10 as FIG. 4 and with the control
system receiving only the acceleration signal from first sensor 33.
It can be seen that when utilizing only the first sensor 33, the
ground engaging blade 16 will initially follow the machine 10 and
the cross slope control system will not cause a significant
deviation between the angular orientation of the ground engaging
blade and the machine until after approximately 0.4 seconds. The
cross slope control system will then adjust the angular orientation
of the ground engaging blade so that the difference between the
cross slope angular position and the target cross slope is
decreased until the ground engaging blade 16 is rotated past the
target cross slope as depicted at approximately 1.3 seconds. The
system then corrects itself and the cross slope angular position
moves closer to the target cross slope until they are identical.
Thus, it can be seen, that the cross slope control system will
change the angular orientation of the ground engaging blade 16 in a
relatively slow manner but such change will result in the cross
slope angular position closely matching the desired cross slope
over some period of time.
[0038] As also described above, if desired, the cross slope control
system may also utilize the roll rate signal from the second sensor
34 to adjust the cross slope of the ground engaging blade 16. In
FIG. 6, the cross slope angular position of ground engaging blade
16 is denoted at line 63 as a function of time for the same
simulated movement of the machine 10 as FIG. 4 and with the control
system receiving only the roll rate signal from second sensor 33.
It can be seen that the cross slope control system quickly adjusts
the cross slope so that the cross slope angular position of ground
engaging blade 16 relatively closely matches the target cross
slope. However, by using only the roll rate signal from second
sensor 34, the cross slope control system is unable to determine
the actual cross slope and adjust the ground engaging blade 16
accordingly. As a result, the actual angular position of the ground
engaging blade 16 continues to increase from time 0.0 to
approximately 1.0 seconds and then maintains a generally constant
cross slope thereafter. Thus, the correction generated by utilizing
only the second sensor 34 is relatively fast but does not rotate
the ground engaging blade 16 back to the target cross slope.
[0039] If desired, the control system may use signals from both the
first sensor 33 and the second sensor 34 to adjust the cross slope
of ground engaging blade 16. Such a cross slope control system may
relatively quickly and accurately adjust the angular orientation of
the ground engaging blade 16 as denoted by line 64 in FIG. 7. The
cross slope control system may combine or use the two signals in a
variety of manners to obtain the maximum performance of the system.
In one example, the cross slope control system may use the roll
rate signal from the second sensor 34 for some period of time to
initially control the ground engaging blade 16 and then use the
acceleration signal from the first sensor 33 or a combination of
the signals from the first sensor 33 and the sensor 34 to maintain
the overall accuracy of the roll rate correction. For example,
referring to FIGS. 4-7, it may be seen that the control system
utilizes the roll rate controlled blade angle of FIG. 6 for
approximately 0.4 seconds. At that point, the accelerometer
controlled blade angle starts to correct for the change in cross
slope (FIG. 5). The control system may either use only the
accelerometer based correction or a combination of the roll rate
based correction and the accelerometer based correction to guide
the control system and adjust the cross slope of the ground
engaging blade.
INDUSTRIAL APPLICABILITY
[0040] The industrial applicability of the system described herein
will be readily appreciated from the foregoing discussion. The
foregoing discussion is applicable to machines 10 that utilize an
implement such as a ground engaging blade 16 for which it is
desirable to control its angular orientation or cross slope. In one
aspect, a control system is provided for controlling automated
movement of a ground engaging blade 16 of a machine 10. The ground
engaging blade 16 is configured for rotational movement about an
axis to define a cross slope of the ground engaging blade. A first
sensor is located on the ground engaging blade and configured to
provide a measured cross slope signal indicative of a cross slope
of the ground engaging blade. A second sensor is disposed on the
ground engaging blade configured to provide a roll rate signal
indicative of a roll rate of the ground engaging blade. A
controller 30 is configured to store a target cross slope signal
indicative of a target cross slope of the ground engaging blade 16,
determine a cross slope angular position based upon the measured
cross slope signal and the roll rate signal, and compare the target
cross slope to the cross slope angular position. The controller
further generates a command signal at least in part based upon a
difference between the target cross slope and the cross slope
angular position to control movement of the ground engaging blade
16, maintain the ground engaging blade at the target cross slope,
and transmit the command signal to control movement of the ground
engaging blade.
[0041] In another aspect, a controller implemented method of
adjusting a ground engaging blade 16 of a machine 10 is provided.
The ground engaging blade 16 has a first sensor configured to
provide a measured cross slope signal indicative of a cross slope
of the ground engaging blade and second sensor configured to
provide a roll rate signal indicative of a roll rate of the ground
engaging blade. The method includes storing within a controller 30
a target cross slope signal indicative of a target cross slope of
the ground engaging blade 16, determining a cross slope angular
position based upon the measured cross slope signal and the roll
rate signal, and comparing the target cross slope to the cross
slope angular position. A command signal is generated within the
controller at least in part based upon a difference between the
target cross slope and the cross slope angular position to control
movement of the ground engaging blade and maintain the ground
engaging blade at the target cross slope. The command signal is
transmitted from the controller to control movement of the ground
engaging blade.
[0042] 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. In this regard, the
disclosed system may employ roll rate and acceleration sensors that
are already disposed on the blade for use in other control
functions. That is, other roll rate and/or acceleration sensors may
be employed to determine the cross slope of the ground engaging
blade which may then be used to determine the difference between
the target cross slope and the cross slope. All 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.
[0043] 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.
[0044] Accordingly, this disclosure includes all modifications and
equivalents of the subject matter recited in the claims appended
hereto as permitted by applicable law. Moreover, any combination of
the above-described elements in all possible variations thereof is
encompassed by the disclosure unless otherwise indicated herein or
otherwise clearly contradicted by context.
* * * * *