U.S. patent application number 14/661225 was filed with the patent office on 2016-09-22 for automatic leveling control system.
The applicant listed for this patent is Benjamin Jesse Funk, Fred Funk. Invention is credited to Benjamin Jesse Funk, Fred Funk.
Application Number | 20160273196 14/661225 |
Document ID | / |
Family ID | 56924536 |
Filed Date | 2016-09-22 |
United States Patent
Application |
20160273196 |
Kind Code |
A1 |
Funk; Benjamin Jesse ; et
al. |
September 22, 2016 |
AUTOMATIC LEVELING CONTROL SYSTEM
Abstract
An automatic leveling control system for a machine having a work
attachment adapted for leveling as the machine is propelled about a
worksite is provided. A single laser receiver is mounted to one of
two lift arms of the machine. The laser receiver is configured to
receive a laser signal from a laser plane generator and to provide
a height signal. A tilt sensor is mounted to a work attachment
mounting structure and is configured to sense a tilt angle of the
work attachment mounting structure and to provide a tilt angle
signal and a lateral tilt signal in dependence on lateral tilt of
the machine. A controller is configured for generating a control
signal based on the height signal, the tilt angle signal and the
lateral tilt signal and for communicating the control signal to the
machine to adjust at least one of a height of the lift arms and the
tilt angle of the work attachment mounting structure such that a
grading edge of the work attachment is maintained at elevation as
the machine is propelled about the worksite.
Inventors: |
Funk; Benjamin Jesse;
(Wymark, CA) ; Funk; Fred; (Neville, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Funk; Benjamin Jesse
Funk; Fred |
Wymark
Neville |
|
CA
CA |
|
|
Family ID: |
56924536 |
Appl. No.: |
14/661225 |
Filed: |
March 18, 2015 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
E02F 3/437 20130101;
E02F 3/847 20130101; E02F 3/432 20130101; E02F 9/265 20130101 |
International
Class: |
E02F 9/26 20060101
E02F009/26; E02F 3/84 20060101 E02F003/84; E02F 3/76 20060101
E02F003/76 |
Claims
1. An automatic leveling control system for a machine having a work
attachment adapted for leveling as the machine is propelled about a
worksite, the system comprising: a. a single laser receiver mounted
to one of two lift arms of the machine, the laser receiver being
configured to receive a laser signal from a laser plane generator
associated with a predetermined level and to provide a height
signal in dependence thereupon; b. a tilt sensor mounted to a work
attachment mounting structure, the work attachment mounting
structure being pivotally movable mounted to a front end portion of
the lift arms and having the work attachment mounted thereto, the
tilt sensor being configured to sense a tilt angle of the work
attachment mounting structure and to provide a tilt angle signal in
dependence thereupon, the tilt sensor further being configured to
sense a lateral tilt of the machine and to provide a lateral tilt
signal in dependence thereupon; c. a controller connected to the
laser receiver and the tilt sensor, the controller being configured
for generating a control signal based on the height signal, the
tilt angle signal and the lateral tilt signal and for communicating
the control signal to the machine to adjust at least one of a
height of the lift arms and the tilt angle of the work attachment
mounting structure such that a grading edge of the work attachment
is maintained at an elevation substantially corresponding to the
predetermined level as the machine is propelled about the
worksite.
2. The system according to claim 1 wherein the laser receiver is
mounted to a front end portion of the lift arm.
3. The system according to claim 1 wherein the controller is an
automotive programmable logic controller having CAN interfaces
connected to a CAN network of the machine.
4. The system according to claim 3 wherein the controller is
connected to at least a button of a joystick of the machine.
5. The system according to claim 3 comprising a human-machine
interface connected to the controller.
6. An automatic leveling control system for a machine having a work
attachment adapted for leveling as the machine is propelled about a
worksite, the system comprising: a. a laser receiver mounted to the
machine, the laser receiver being configured to receive a laser
signal from a laser plane generator associated with a predetermined
level and to provide a height signal in dependence thereupon; b. an
automotive programmable logic controller connected to the laser
receiver, the controller being configured for generating a control
signal based on the height signal and for communicating the control
signal to the machine to adjust the work attachment such that a
grading edge thereof is maintained at an elevation substantially
corresponding to the predetermined level as the machine is
propelled about the worksite.
7. The system according to claim 6 wherein the controller is
connected to at least a button of a joystick of the machine.
8. The system according to claim 6 comprising a human-machine
interface connected to the controller.
9. The system according to claim 6 wherein the laser receiver is
mounted to a lift arm of the machine.
10. The system according to claim 9 comprising a tilt sensor
mounted to a work attachment mounting structure, the work
attachment mounting structure being pivotally movable mounted to a
front end portion of the lift arms and having the work attachment
mounted thereto, the tilt sensor being configured to sense a tilt
angle of the work attachment mounting structure and to provide a
tilt angle signal in dependence thereupon, the tilt sensor further
being configured to sense a lateral tilt of the machine and to
provide a lateral tilt signal in dependence thereupon.
11. An automatic leveling control method for a machine having a
work attachment adapted for leveling as the machine is propelled
about a worksite, the method comprising: a. using a controller,
receiving at least a sensor signal associated with a predetermined
level; b. using the controller, generating a control signal based
on the at least a sensor signal and communicating the control
signal to at least a hydraulic actuator of the machine to adjust
the work attachment such that a grading edge thereof is maintained
at an elevation substantially corresponding to the predetermined
level as the machine is propelled about the worksite, wherein the
control signal is determined such that hydraulic power for
adjusting the work attachment is started at a predetermined minimum
hydraulic power and is increased according to a predetermined ramp
time until a predetermined maximum hydraulic power is reached or
the adjustment is completed.
12. The method according to claim 11 comprising receiving from a
human-machine interface connected to the controller data indicative
of the minimum hydraulic power, the maximum hydraulic power, and
the ramp time.
13. The method according to claim 12 comprising receiving from the
human-machine interface first data indicative of the minimum
hydraulic power, the maximum hydraulic power, and the ramp time for
moving a grading edge of the work attachment in an upward direction
and second data indicative of the minimum hydraulic power, the
maximum hydraulic power, and the ramp time for moving the grading
edge of the work attachment in a downward direction.
14. The method according to claim 12 comprising receiving from the
human-machine interface: a. first data indicative of the minimum
hydraulic power, the maximum hydraulic power, and the ramp time for
moving lift arms of the machine in an upward direction; b. second
data indicative of the minimum hydraulic power, the maximum
hydraulic power, and the ramp time for moving the lift arms of the
machine in a downward direction; c. third data indicative of the
minimum hydraulic power, the maximum hydraulic power, and the ramp
time for tilting a grading edge of the work attachment in an upward
direction; and, fourth data indicative of the minimum hydraulic
power, the maximum hydraulic power, and the ramp time for tilting
the grading edge of the work attachment in a downward
direction.
15. The method according to claim 14 comprising: a. moving the work
attachment to a predetermined tilt angle; b. sensing the
predetermined tilt angle; and, c. communicating to the controller
data indicative of the predetermined tilt angle.
16. The method according to claim 15 comprising moving the grading
edge of the work attachment to the predetermined level.
17. The method according to claim 16 comprising adjusting the work
attachment such that the grading edge is maintained at an elevation
substantially corresponding to the predetermined level and at the
predetermined tilt angle as the machine is propelled about the
worksite.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to grading implements, and
more particularly, to an automatic leveling control system for
maintaining a grading edge at a predetermined elevation during
movement over uneven terrain.
BACKGROUND OF THE INVENTION
[0002] Worksite preparations often include grading the ground to be
level. Particularly, prior to the construction of concrete floors
and foundations, the ground has to be leveled with high accuracy to
ensure structural integrity of the same. Typically, such grading
work is done with a skid-steer having a worker continually check
the level, using a rotating construction laser and a laser
receiver, and direct the skid-steer operator.
[0003] Alternatively, a skid-steer automatic laser grading
attachment is used. The skid-steer automatic laser grading
attachment comprises a grading blade mounted to a stabilizing boom
and wheels and is mounted to the attachment mounting structure of
the skid-steer. One or two laser receivers are mounted via booms to
the grading blade for detecting the laser beam of a rotating
construction laser for controlling the elevation of the grading
blade. Unfortunately, the skid-steer automatic laser grading
attachment is expensive, difficult to operate in small spaces and
to transport due to its large size and weight, and is not able to
dig, push or carry a large amount of material at a time. An
attachment that allowed for the movement of a larger amount of
material in a shorter time by more efficient leveling activity
would be desirable.
[0004] Other existing automatic laser grading systems lack the
accuracy for preparing the ground prior to the construction of
concrete floors and foundations and are difficult to implement, in
particular as a retro-fit. Prior art systems are not integrated to
the earth moving equipment--for example in prior art skid steer
equipment, the automatic leveling systems consist of customized
bucket attachments powered by the auxiliary hydraulics on the skid
steer unit. None of them use the factory produced excavation
attachments with the full power primary hydraulics and as such
their utility or power is limited. These attachments, while
accurate, are expensive and bulky in addition to their minimized
utility.
[0005] Another major difficulty in designing an accurate integrated
automatic leveling control system is the control of the hydraulic
system of the skid steer, since the amount of power required to
move the hydraulics at a certain speed can vary substantially
dependent on, for example, solenoid valve heating and bucket
weight/loading. It is desirable to provide an integrated automatic
leveling control system that is sufficiently compact and accurate
for preparing the ground prior to the construction of concrete
floors and foundations.
[0006] It is also desirable to provide an automatic leveling
control system that is implementable as a retro-fit to a
pre-existing skid steer unit, which ideally does not rely upon
custom bucket attachments. It is also desirable to provide an
automatic leveling control system that enables customization of the
hydraulic response of the grading equipment.
SUMMARY OF THE INVENTION
[0007] Accordingly, one object of the present invention is to
provide an automatic leveling control system that is sufficiently
accurate for preparing the ground prior to the construction of
concrete floors and foundations.
[0008] Another object of the present invention is to provide an
automatic leveling control system that is implementable as a
retro-fit, which would in installation be completely integrated to
the skid steer unit.
[0009] Another object of the present invention is to provide an
automatic leveling control system that enables customization of the
hydraulic response of the grading equipment.
[0010] Another object of the invention is to be able to potentially
use the skid steer machine, with the existing buckets, forks or the
like, without having to switch the attachment on the skid steer
unit to enter into auto leveling mode--being able to enter into
leveling mode from the operator position in the unit, using an
integrated control modification to the pre-existing hydraulic
system and attachments on the skid steer unit is the most desirable
implementation of the present invention.
[0011] According to one aspect of the present invention, there is
provided an automatic leveling control system for a machine having
a work attachment adapted for leveling as the machine is propelled
about a worksite. A single laser receiver is mounted to one of two
lift arms of the machine. The laser receiver is configured to
receive a laser signal from a laser plane generator associated with
a predetermined level and to provide a height signal in dependence
thereupon.
[0012] A tilt sensor is mounted to a work attachment mounting
structure. The work attachment mounting structure is pivotally
movable mounted to a front end portion of the lift arms and has the
work attachment mounted thereto. The tilt sensor is configured to
sense a tilt angle of the work attachment mounting structure and to
provide a tilt angle signal in dependence thereupon. The tilt
sensor is further configured to sense a lateral tilt of the machine
and to provide a lateral tilt signal in dependence thereupon.
[0013] A controller is connected to the laser receiver and the tilt
sensor. The controller is configured for generating a control
signal based on the height signal, the tilt angle signal and the
lateral tilt signal and for communicating the control signal to the
machine to adjust at least one of a height of the lift arms and the
tilt angle of the work attachment mounting structure such that a
grading edge of the work attachment is maintained at an elevation
substantially corresponding to the predetermined level as the
machine is propelled about the worksite.
[0014] According to another aspect of the present invention, there
is provided an automatic leveling control system for a machine
having a work attachment adapted for grade leveling as the machine
is propelled about a worksite. A level grade is achieved by
movement of the unit around the work surface by maintaining the
working edge of the work attachment in a desired plane in relation
to a laser plane projected at the worksite. A laser receiver is
mounted to the machine. The laser receiver is configured to receive
a laser signal from a laser plane generator associated with a
predetermined level and to provide a height signal in dependence
thereupon.
[0015] An automotive programmable logic controller is connected to
the laser receiver. The controller is configured for generating a
control signal based on the height signal and for communicating the
control signal via DC electric current to the hydraulic valves of
the machine, to adjust the work attachment such that a grading edge
thereof is maintained at an elevation substantially corresponding
to the predetermined level as the machine is propelled about the
worksite.
[0016] According to yet another aspect of the present invention,
there is provided an automatic leveling control method for a
machine having a work attachment adapted for leveling as the
machine is propelled about a worksite. At least a sensor signal
associated with a predetermined level is received at a controller.
Using the controller, a control signal based on the at least a
sensor signal is generated and communicated to at least a hydraulic
actuator of the machine to adjust the work attachment such that a
grading edge thereof is maintained at an elevation substantially
corresponding to the predetermined level as the machine is
propelled about the worksite. The control signal is determined such
that hydraulic power for adjusting the work attachment is started
at a predetermined minimum hydraulic power and is increased
according to a predetermined ramp time until a predetermined
maximum hydraulic power is reached or the adjustment is completed.
If the adjustment of the work attachment is not completed by the
time that the maximum hydraulic power is reached, the maximum
hydraulic power is maintained until the adjustment of the work
attachment is completed.
[0017] The advantage of the present invention is that it provides
an automatic leveling control system that is sufficiently accurate
for preparing the ground prior to the construction of concrete
floors and foundations.
[0018] A further advantage of the present invention is that it
provides an integrated and automatic leveling control system that
is implementable as a retro-fit.
[0019] A further advantage of the present invention is that it
provides an automatic leveling control system that enables
customization of the hydraulic response of the grading
equipment.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] A preferred embodiment of the present invention is described
below with reference to the accompanying drawings, in which:
[0021] FIG. 1a is a simplified block diagram illustrating a side
view of a skid-steer with an automatic leveling control system
according to a preferred embodiment of the invention;
[0022] FIG. 1b is a simplified block diagram illustrating a side
view of a bucket of the skid-steer with the automatic leveling
control system according to a preferred embodiment of the
invention;
[0023] FIG. 1c is a simplified block diagram illustrating in a side
view the displacement of the bucket of the skid-steer with the
automatic leveling control system according to a preferred
embodiment of the invention;
[0024] FIG. 1d is a simplified block diagram illustrating in a
front view the lateral tilt of the bucket and the laser receiver of
the skid-steer with the automatic leveling control system according
to a preferred embodiment of the invention;
[0025] FIGS. 2a and 2b are simplified block diagrams illustrating
the automatic leveling control system according to a preferred
embodiment of the invention connected to the control network of the
skid-steer;
[0026] FIG. 3 is a simplified block diagram illustrating the
increase of hydraulic power for adjusting the bucket in an
automatic leveling control method according to a preferred
embodiment of the invention;
[0027] FIGS. 4a and 4b are simplified block diagrams illustrating
an HMI of the automatic leveling control system according to a
preferred embodiment of the invention with the display being in
home mode and configuration mode, respectively; and,
[0028] FIG. 5 is a simplified flow diagram illustrating an
automatic leveling control method according to a preferred
embodiment of the invention.
DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS
[0029] Unless defined otherwise, all technical and scientific terms
used herein have the same meaning as commonly understood by one of
ordinary skill in the art to which the invention belongs. Although
any methods and materials similar or equivalent to those described
herein can be used in the practice or testing of the present
invention, the preferred methods and materials are now
described.
[0030] While the description of the preferred embodiments
hereinbelow is with reference to automatic leveling using a
skid-steer digging bucket, it will become evident to those skilled
in the art that the embodiments of the invention are not limited
thereto, but is also adaptable for use with various other
attachments having a suitable front edge or working surface such
as, for example, other types of buckets and blades, as well as for
use with other types of machines such as, for example, front
loaders and bulldozers.
[0031] Referring to FIGS. 1a to 1d, 2a, and 2d, an automatic
leveling control system 100 according to a preferred embodiment of
the invention is provided. Hereinbelow, the automatic leveling
control system 100 is implemented using a skid-steer 10 having a
digging bucket 22 as work attachment with its digging edge being
adapted as grading edge 26 for leveling as the skid-steer 10 is
propelled about a worksite. Laser receiver 102 is mounted to one of
two lift arms 14 of the skid-steer 10 using a conventional
fastening technique, preferably, a removable magnetic mount. The
laser receiver 102 is configured to receive a laser signal 30 from
a laser plane generator such as, for example, a rotating
construction laser (not shown), associated with a predetermined
level 31 and to provide a signal indicative of height H1 in
dependence thereupon. To provide sufficient accuracy, the laser
receiver 102 is, preferably, mounted in proximity to the digging
bucket 22, for example, to a front end portion of the lift arm 14,
as illustrated in FIGS. 1a and 1b. Preferably, the laser receiver
102 is an off-the-shelf construction laser receiver.
[0032] Tilt sensor 104 is mounted to work attachment mounting
structure 20, which is pivotally movable mounted at pivot 24 to a
front end portion of the lift arms 14 and has the digging bucket 22
mounted thereto, using a conventional fastening technique,
preferably, a removable magnetic mount. The tilt sensor 104 is
configured to sense a tilt angle of the work attachment mounting
structure 20, which is indicative of a tilt angle of the digging
bucket 22, for example angle .alpha. between a line connecting the
pivot 24 with the grading edge 26 and a parallel to the laser plane
30, and to provide a tilt angle signal in dependence thereupon.
Height H2 can then be calculated based on the tilt angle .alpha.
and the length L.sub.GE between the pivot 24 and the grading edge
26. The tilt sensor 104 is further configured to sense a lateral
tilt .beta. of the skid-steer 10 and to provide a lateral tilt
signal in dependence thereupon. Preferably, the tilt sensor 104 is
an off-the-shelf tilt sensor.
[0033] Controller 106 is connected to the laser receiver 102 and
the tilt sensor 104. The controller 106 is configured for
generating a control signal based on the height signal, the tilt
angle signal and the lateral tilt signal and for communicating the
control signal to the skid-steer hydraulic control controlling
actuation of hydraulic cylinders 18, 28 to adjust at least one of a
height of the lift arms 14 and the tilt angle of the work
attachment mounting structure 20 such that the grading edge 26 is
maintained at an elevation substantially corresponding to the
predetermined level 31 as the machine is propelled about the
worksite. The adjustment is determined, for example, based on the
geometry illustrated in FIG. 1c and the length of the lift arm
L.sub.LA between the pivots 16 and 24 using standard trigonometry.
For example, the predetermined elevation 31--position "0" of the
pivot 24 and the grading edge 26--is set prior to starting the
automatic leveling and respective signal data indicative of H1.0
and .alpha..0 are received at the controller 106 from the laser
receiver 102 and the tilt sensor 104. Heights H2.0 and H.0 are then
determined therefrom. As the skid-steer 10 is propelled over
un-even terrain, the pivot 24 and the grading edge 26 are moved to
current position "1" and signal data indicative of H1.1 and
.alpha..1 are received at the controller 106 which then determines
heights H2.1 and H.1 therefrom. The controller 106 then calculates
the necessary adjustment of the tilt angle of the digging bucket 22
and the height of the lift arm 14 based on the difference between
.alpha..1 and .alpha..0 and the difference between H.1 and H.0.
[0034] When being propelled over un-even terrain, the skid-steer 10
experiences lateral tilt .beta., resulting in a different elevation
of the lift arms 14. For example, the right hand side lift arm
14.sub.R is elevated higher than the left hand side lift arm
14.sub.L, as illustrated in FIG. 1d, resulting in error .epsilon.
of the height H1 measured by the laser sensor 102 mounted to the
right hand side lift arm 14.sub.R. Knowing the distance D.sub.L of
the laser receiver 102 from the center between the right hand side
lift arm 14.sub.R and the left hand side lift arm 14.sub.L, the
error .epsilon. can be determined based on the measured lateral
tilt .beta.. Preferably, the lateral tilt .beta. is displayed to
the operator, giving the operator the opportunity to control the
lateral accuracy of the leveling and, for example, the opportunity
to stop the automatic leveling process if the lateral tilt .beta.
is above a threshold.
[0035] Mounting the tilt sensor 104 to the work attachment mounting
structure 20, enables grading using different work attachments
mounted thereto without having to remove/re-attach the tilt sensor
104. For example, a first pass of coarse grading is performed using
a digging bucket to be able to move larger quantities of material,
followed by a second pass of fine grading using a grading blade.
For facilitating the change to a different work attachment, data
indicative of the geometries of the different work attachments--in
particular, the distance L.sub.GE--could be stored, for example, in
the form of a look-up table, in non-volatile memory of the
controller 106. Some embodiments may contain geometric lookup
tables, and others may not, and it will be understood that both
such approaches are contemplated within the scope of the present
invention.
[0036] It is noted, that most present-day machines such as
skid-steers, loaders, etc. have a work attachment mounting
structure to enable use of the machine with different work
attachments. Alternatively, for example, in the absence of a work
attachment mounting structure, the tilt sensor 104 is mounted to
the work attachment itself.
[0037] As illustrated in FIG. 2a, the automatic leveling control
system 100 comprises the controller 106 connected to the laser
receiver 102, the tilt sensor 104 and a Human-Machine Interface
(HMI) 108 using conventional wiring, with the controller 106 being
disposed in the engine compartment of the skid-steer 10 and the HMI
108 being disposed in the cab 12 of the skid-steer 10. Preferably,
the controller 106 is a Programmable Logic Controller (PLC) for
executing executable commands preferably stored in non-volatile
memory such as, for example, flash-memory.
[0038] Further preferably, the PLC is an off-the-shelf automotive
PLC having CAN interfaces which are easily connected to the
two-wire CANBUS network of the skid-steer 10. It is noted that
CANBUS is a standard communications protocol developed for, and
widely used in, the automotive industry. Typically, the CANBUS
protocol only specifies a source address, thus enabling a CAN
device, once connected to the network, to immediately access the
communications of every device of the network. The automotive PLC
having CAN interfaces is easily connected to the CANBUS network of
the skid-steer 10 by unplugging one of the terminator resistors 36,
which are connected via standard automotive connectors to an end of
the network, connecting the controller 106 via a "Y" connector to
the network and the terminator resistor 36, as illustrated in FIG.
2b.
[0039] The controller 106 is then able to actuate the hydraulic
valves on the skid steer directly via DC electric current. The skid
steer would have its own hydraulic control unit in most cases,
which is bypassed by creating a shared electrical Y connection
directly to the hydraulic valves.
[0040] The integration or reading of other control inputs on the
human interface of the skid steers also shown--for example the
joystick buttons 34 of the skid-steer 10. In the current embodiment
shown, nothing is actually broadcast on the CAN network of the skid
steer and in fact the purpose of accessing an interface to that
network is to listen for hydraulic commands being broadcast from
the operator moves the joysticks or other controls on the unit.
Given the interface to the CAN network and the ability of the
controller of the present invention to listen in on all internal
skid steer communications and signals however, a lot more could be
done with this information in future versions and embodiments of
the system, to enhance capability, or accuracy thereof.
[0041] Some skid steer units may include binary or on off
electrical switches in the controls of the skid steer including
joysticks or other human control interface. Some of those switches,
or other buttons in the human interface, may broadcast on the CAN
network, of the power unit, and others may not and my simply
comprise on off electrical switches requiring tie-ins or Y
connections for the wiring of the controller.
[0042] Employment of an off-the-shelf automotive PLC having CAN
interfaces substantially facilitates connection of the automatic
leveling control system 100 to the control network of an existing
machine since most present-day machines such as skid-steers,
loaders, etc. have a two-wire CANBUS network. The use of existing
work attachments, the employment of only two sensors--which are
easily mounted--and the use of an off-the-shelf automotive PLC
having CAN interfaces substantially facilitates employment of the
automatic leveling control system 100 as a retro-fit.
[0043] A major problem in designing an accurate automatic leveling
control system is the control of the skid-steer's hydraulic system,
since the amount of power required to move the hydraulics at a
certain speed can vary substantially, dependent on, for example,
solenoid valve heating and bucket weight/loading. This problem is
addressed by an automatic leveling control method according to a
preferred embodiment of the invention. After determining the
adjustments to be made as described hereinabove, the controller 106
generates a control signal and communicates the same to the
hydraulic control 32 of the skid-steer 10 for actuating at least
one of the hydraulic cylinders 18, 28 to adjust the digging bucket
22 such that the grading edge 26 is maintained at an elevation
substantially corresponding to the predetermined level 31 as the
machine is propelled about the worksite. The controller 106
determines the control signal such that hydraulic power for
adjusting the digging bucket 22 is started at a predetermined
minimum hydraulic power P.sub.min and is increased according to a
predetermined ramp time t.sub.R until a predetermined maximum
hydraulic power P.sub.max is reached, as illustrated in FIG. 3, or
the adjustment is completed. If the adjustment of the digging
bucket 22 is not completed by the time that the predetermined
maximum hydraulic power Pmax is reached, maximum hydraulic power
will be maintained until the adjustment of the digging bucket 22 is
completed.
[0044] Preferably, the minimum hydraulic power P.sub.min, the ramp
time t.sub.R, and the maximum hydraulic power P.sub.max are
predetermined for each of the different movements of the work
attachment 22: [0045] moving lift arms 14 up; [0046] moving the
lift arms 14 down; [0047] tilting the grading edge 26 up; and,
[0048] tilting the grading edge 26 down.
[0049] Further preferably, the minimum hydraulic power P.sub.min,
the ramp time t.sub.R, and the maximum hydraulic power P.sub.max
are adjustable by the operator using the HMI 108, in order to
customize the hydraulic response.
[0050] Referring to FIGS. 4a and 4b, a preferred embodiment of the
HMI 108 is provided, with FIG. 4a illustrating a home screen mode
of the display and FIG. 4b illustrating a configuration screen mode
of the display, respectively.
[0051] In home screen mode the display shows: [0052] 110--The
real-time elevation of the skid-steer lift arms 14. [0053] 112--The
current operating mode of the automatic leveling system
(manual/automatic). [0054] While in manual mode, the automatic
leveling system does not make any hydraulic adjustments. [0055]
While in automatic mode, the automatic leveling system does make
hydraulic adjustments as described hereinabove. [0056] The
automatic mode is engaged by pressing, for example, the bottom
right button on the left skid-steer joystick. [0057] 114--Over
current, indicating an electrical short in the wiring. [0058]
115--Grade below available lift arm travel. [0059] 116--Real-time
side-to-side machine tilt angle .beta.. [0060] 118--Temporary
banner showing that the desired bucket tilt angle .alpha..0 has
been recorded. [0061] The tilt angle .alpha..0 is set by the
following procedure: [0062] manually positioning the bucket 22 to
the desired tilt angle .alpha..0; [0063] press and hold the top
right button of the left skid-steer joystick for 3 seconds; and,
[0064] the banner flashes when the tilt angle has been successfully
recorded. [0065] 120--Real-time bucket angle .alpha..1.
[0066] The home screen buttons are: [0067] SAV--Saves the current
hydraulic and tilt settings to the controller in non-volatile
memory. [0068] LOAD--Loads the previously saved hydraulic and tilt
settings from non-volatile memory. [0069] RST--Resets the
controller to factory defaults. [0070] DISP--Adjusts screen
brightness. [0071] CLR--Clears error codes. [0072] ZERO
TILT--Zeroes the tilt angle on the display only. This allows the
operator to see the true bucket angle. [0073] CFG--Navigates to the
hydraulic configuration screens.
[0074] Procedure for modifying the hydraulic parameters in
configuration screen mode: [0075] Press the SEL button that
corresponds to the parameter you wish to modify. For the example
in
[0076] FIG. 4b, press the top left SEL button. Selection will show
green highlight 122. [0077] Turn the Rotary Encoder 130 to change
the New Setpoint 124 parameter. [0078] Press the SAV button to save
all New Setpoints 124 to the Current Setpoints 126 on the
screen.
[0079] The configuration screen buttons are: [0080] SEL--Select the
parameter to be modified. [0081] TEST--Have the controller activate
the hydraulics according to the parameters on the current screen.
While the test is active, the Testing Banner will appear 128.
[0082] CLR--Resets the New Setpoint parameters to equal the Current
Setpoint parameters. [0083] SAV--Saves the New Setpoints on screen
to the Current Setpoints. [0084] <--Navigate to the previous
screen. [0085] >--Navigate to the next screen.
[0086] There are four sets of hydraulic parameters that can be
adjusted with each set corresponding to one movement of the work
attachment 22, as described hereinabove. Each set has its own
screen as illustrated in FIG. 4b.
[0087] Preferably, the controller 106 is mounted in the engine
compartment of the skid-steer 10 while the HMI 108 is mounted
inside the operator cab 12 such that the operator can view the
display during operation of the skid-steer 10. Alternatively, the
controller 106 is disposed in the cab 12, for example, in a single
housing with the HMI 108. Optionally, the display and the control
buttons of the HMI 108 are integrated in a touch-screen.
[0088] Referring to FIG. 5, an automatic leveling control method
according to a preferred embodiment of the invention is provided:
[0089] 210--The operator starts the skid-steer 10. [0090] 212--The
operator presses a button on the existing joystick controls 34 to
wake the auto leveling system electronics. [0091] 214--The operator
sets hydraulic response parameters: minimum hydraulic power,
maximum hydraulic power, and power ramp time. [0092] 216--The
operator manually adjusts bucket 22 to the desired tilt angle
.alpha..0. [0093] 218--The operator presses and holds a button on
existing joystick 34 controls for 3 seconds for the controller 106
to record the current tilt angle as the desired tilt angle
.alpha..0 when in automatic mode. [0094] 220--The operator sets up
rotating construction laser for the laser to provides a fixed
elevation reference plane 30. [0095] 222--The operator adjusts the
grading edge 26 to the predetermined elevation 31. [0096] 224--The
operator presses button on existing joystick controls 34 to engage
auto leveling mode. [0097] 226--The controller 106 controls the
skid-steer hydraulics 32 to maintain the grading edge 26 at the
predetermined elevation 31 and tilt angle .alpha..0, wherein the
hydraulic power is started at a predetermined minimum hydraulic
power and is increased according to a predetermined ramp time until
a predetermined maximum hydraulic power is reached or the
adjustment is completed. [0098] 228--The operator disengages the
auto leveling mode by manually controlling the hydraulics 32 of the
skid-steer 10.
[0099] The present invention has been described herein with regard
to preferred embodiments. However, it will be obvious to persons
skilled in the art that a number of variations and modifications
can be made without departing from the scope of the invention as
described herein.
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