U.S. patent application number 15/385126 was filed with the patent office on 2018-06-21 for excavator four-bar linkage length and angle offset determination using a laser distance meter.
This patent application is currently assigned to Caterpillar Trimble Control Technologies LLC. The applicant listed for this patent is Caterpillar Trimble Control Technologies LLC. Invention is credited to Samuel Joseph Frei, Mark Nicholas Howell.
Application Number | 20180171580 15/385126 |
Document ID | / |
Family ID | 62557332 |
Filed Date | 2018-06-21 |
United States Patent
Application |
20180171580 |
Kind Code |
A1 |
Howell; Mark Nicholas ; et
al. |
June 21, 2018 |
Excavator Four-Bar Linkage Length And Angle Offset Determination
Using A Laser Distance Meter
Abstract
An excavator calibration framework comprises an excavator, a
laser distance meter (LDM), and a laser reflector. The excavator
comprises a chassis, linkage assembly (LA), sensor, implement, and
control architecture. The LA comprises a boom, stick, and four-bar
linkage (4BL) with the sensor on a 4BL dogbone linkage. The control
architecture comprises a controller programmed to execute an
iterative process at successive implement curl positions. The
iterative process comprises generating a measured dogbone angle
.theta..sub.DF.sup.Measured, determining a height H and a distance
{circumflex over (D)} between an implement node and the LDM, and
determining an implement node position. The iterative process
further comprises determining an estimated implement angle
.theta..sub.GH.sup.Estimated, and generating a mapping equation
comprising linkage angle inputs (.theta..sub.DF.sup.Measured,
.theta..sub.GH.sup.Estimated) and n unsolved 4BL linkage length and
angle offset parameters. The controller is programmed to generate
and solve a set of m mapping equations comprising the n unsolved
parameters.
Inventors: |
Howell; Mark Nicholas;
(Christchurch, NZ) ; Frei; Samuel Joseph;
(Christchurch, NZ) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Caterpillar Trimble Control Technologies LLC |
Dayton |
OH |
US |
|
|
Assignee: |
Caterpillar Trimble Control
Technologies LLC
Dayton
OH
|
Family ID: |
62557332 |
Appl. No.: |
15/385126 |
Filed: |
December 20, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G01S 17/88 20130101;
E02F 9/265 20130101; E02F 3/32 20130101; E02F 3/435 20130101; E02F
9/264 20130101; G01S 17/08 20130101 |
International
Class: |
E02F 3/43 20060101
E02F003/43; G05D 1/02 20060101 G05D001/02; E02F 3/32 20060101
E02F003/32; E02F 9/26 20060101 E02F009/26; G01S 17/08 20060101
G01S017/08 |
Claims
1. An excavator calibration framework comprising an excavator, a
laser distance meter (LDM), and a laser reflector, wherein: the
excavator comprises a machine chassis, an excavating linkage
assembly, an implement dynamic sensor, an excavating implement, and
control architecture; the excavating linkage assembly comprises an
excavator boom, an excavator stick, and a four-bar linkage; the
excavating implement and the excavator stick are mechanically
coupled through the four-bar linkage comprising an implement
linkage of length GH, a rear side linkage of length FH, a dogbone
linkage of length DF, and a front side linkage of length DG; the
implement dynamic sensor is positioned on the dogbone linkage of
the four-bar linkage; the excavating implement is configured to
curl relative to the excavator stick to define a plurality of
implement curl positions; the LDM is configured to generate an LDM
distance signal D.sub.LDM indicative of a distance between the LDM
and the laser reflector and an angle of inclination signal
.theta..sub.INC indicative of an angle between the LDM and the
laser reflector; the laser reflector is configured to be disposed
at a position corresponding to a calibration node on the excavating
implement; the control architecture comprises one or more linkage
assembly actuators and an architecture controller programmed to
execute an iterative process at successive implement curl
positions, the iterative process comprising generating a measured
dogbone angle .theta..sub.DF.sup.Measured of the dogbone linkage
from the implement dynamic sensor, determining a height H and a
distance {circumflex over (D)} between the calibration node on the
excavating implement and the LDM based on the LDM distance signal
D.sub.LDM and the angle of inclination signal .theta..sub.INC,
determining a position of the calibration node at least partially
based on the height H and the distance {circumflex over (D)},
determining an estimated implement angle
.theta..sub.GH.sup.Estimated of the excavating implement at least
partially based on the position of the calibration node, and
generating a mapping equation comprising linkage angle inputs,
unsolved linkage length parameters, and unsolved angle offset
parameters, wherein the linkage angle inputs comprise the measured
dogbone angle .theta..sub.DF.sup.Measured and the estimated
implement angle .theta..sub.GH.sup.Estimated at the implement curl
position, the unsolved linkage length parameters comprise the
linkage lengths GH, FH, DF, and DG of the four-bar linkage, and the
unsolved angle offset parameters comprise an offset dogbone angle
.theta..sub.DF.sup.Bias of the dogbone linkage, and an offset
implement angle .theta..sub.GH.sup.Bias of the excavating
implement; and the architecture controller is further programmed to
repeat the iterative process for successive implement curl
positions to generate a set of m mapping equations, wherein the set
of m mapping equations comprises n unsolved linkage length and
unsolved angle offset parameters, and the iterative process is
repeated until m>n, solve the generated set of m mapping
equations comprising the n unsolved parameters to determine the
linkage lengths GH, FH, DF, and DG of the four-bar linkage, the
offset dogbone angle .theta..sub.DF.sup.Bias of the dogbone
linkage, and the offset implement angle .theta..sub.GH.sup.Bias of
the excavating implement, and operate the excavator using the
linkage lengths GH, FH, DF, and DG, the offset dogbone angle
.theta..sub.DF.sup.Bias, and the offset implement angle
.theta..sub.GH.sup.Bias.
2. An excavator calibration framework as claimed in claim 1,
wherein: the four-bar linkage comprises a node D, a node F, a node
G, a node H; the implement linkage is disposed between respective
positions corresponding to the node G and the node H; the rear side
linkage is disposed between respective positions corresponding to
the node F and the node H; the dogbone linkage is disposed between
respective positions corresponding to the node D and the node F;
and the front side linkage is disposed between respective positions
corresponding to the node D and the node G.
3. An excavator calibration framework as claimed in claim 2,
wherein the node G of the four-bar linkage is disposed at a
position corresponding to a terminal point of the excavator stick
through which the excavator stick is coupled to the excavating
implement.
4. An excavator calibration framework as claimed in claim 1,
wherein the iterative process is repeated until m passes a
threshold greater than n.
5. An excavator calibration framework as claimed in claim 4,
wherein n is equal to 6 and the threshold is 17 such that m is
equal to 18 to generate a set of 18 mapping equations comprising 6
unsolved linkage length and unsolved angle offset parameters.
6. An excavator calibration framework as claimed in claim 1,
wherein the laser reflector is on a pole or secured directly to the
excavating implement.
7. An excavator calibration framework as claimed in claim 1,
wherein the calibration node is positioned at a terminal point J at
a bucket tooth tip of the excavating implement.
8. An excavator calibration framework as claimed in claim 1,
wherein the machine chassis is mechanically coupled to a terminal
pivot point A of the excavator boom.
9. An excavator calibration framework as claimed in claim 1,
wherein the excavator stick comprises a stick terminal point
corresponding to the position of a node G of the four-bar linkage
and is mechanically coupled to a terminal pivot point B of the
excavator boom; and the excavator stick is mechanically coupled to
the excavating implement through the stick terminal point.
10. An excavator calibration framework as claimed in claim 9,
wherein a position of the terminal pivot point B and the node G are
identified.
11. An excavator calibration framework as claimed in claim 10,
wherein the estimated implement angle .theta..sub.GH.sup.Estimated
of the excavating implement is determined at least partially based
on the position of the node G and the position of the terminal
pivot point B.
12. An excavator calibration framework as claimed in claim 9,
wherein: the four-bar linkage comprises a node D, a node F, a node
G, a node H; the calibration node is positioned at a terminal point
J at a heading tooth tip of the excavating implement; a position of
the terminal pivot point B is identified; a position of the node D
of the four-bar linkage is determined based on the measured dogbone
angle .theta..sub.DF.sup.Measured; and the estimated implement
angle .theta..sub.GH.sup.Estimated of the excavating implement is
determined at least partially based on the position of the node D
and the position of the terminal pivot point B.
13. An excavator calibration framework as claimed in claim 12,
wherein the estimated implement angle .theta..sub.GH.sup.Estimated
of the excavating implement is determined at least partially based
on: a determined internal angle .theta..sub.DGJ.sup.i based on the
positions of nodes D and G and the terminal point J such that a
determined external angle
.theta..sub.DGJ.sup.e=360.degree.-.theta..sub.DGJ.sup.i.
14. An excavator calibration framework as claimed in claim 13,
wherein the determined external angle .theta..sub.DGJ.sup.e is a
sum of the estimated implement angle .theta..sub.GH.sup.Estimated
of the excavating implement and a implement angle .PSI. that is a
constant angle formed between the surfaces of the excavating
implement disposed between the terminal point J and the nodes G and
H, such that:
.theta..sub.GH.sup.Estimated=.theta..sub.DGJ.sup.e-.PSI..
15. An excavator calibration framework as claimed in claim 1,
wherein: the four-bar linkage comprises a diagonal length FG
between a front end node of the implement linkage of length GH and
a rear end node of the dogbone linkage of length DF; and the
mapping equation comprises a following equation, including an
actual dogbone angle .theta..sub.DF.sup.Actual and an actual
implement angle .theta..sub.GH.sup.Actual: .theta. GH Actual = DG -
DF * cos ( 180 .degree. - .theta. DF Actual ) FG + DF 2 + DG 2 + GH
2 - 2 * DF * DG * cos ( 180 .degree. - .theta. DF Actual ) - FH 2 2
* FG * GH . ##EQU00004##
16. An excavator calibration framework as claimed in claim 15,
wherein the actual dogbone angle .theta..sub.DF.sup.Actual is based
on the measured dogbone angle .theta..sub.DF.sup.Measured and the
offset dogbone angle .theta..sub.DF.sup.Bias such that:
.theta..sub.DF.sup.Actual=.theta..sub.DF.sup.Measured-.theta..sub.DF.sup.-
Bias.
17. An excavator calibration framework as claimed in claim 15,
wherein the actual implement angle .theta..sub.GH.sup.Actual is
based on the estimated implement angle .theta..sub.GH.sup.Estimated
and the offset implement angle .theta..sub.GH.sup.Bias such that:
.theta..sub.GH.sup.Actual=.theta..sub.GH.sup.Estimated-.theta..sub.GH.sup-
.Bias.
18. An excavator calibration framework as claimed in claim 15,
wherein the mapping equation is based on an implement angle
equation, as follows: .theta. GH Actual = DG 2 + FG 2 - DF 2 2 * FG
* DG + FG 2 + GH 2 - FH 2 2 * FG * GH ##EQU00005## and a
substitution of a FG.sup.2 term in the implement angle equation
with a diagonal length squared equation, as follows:
FG.sup.2=DF.sup.2+DG.sup.2-2*DF*DG*cos(180.degree.-.theta..sub.DF.sup.Act-
ual).
19. An excavator calibration framework as claimed in claim 18,
wherein the diagonal length squared equation is based on a diagonal
length equation, as follows: FG= {square root over
(DF.sup.2+DG.sup.2-2*DF*DG*cos(180.degree.-.theta..sub.DF.sup.Actual))}.
20. An excavator calibration framework as claimed in claim 18,
wherein the implement angle equation is based on an implement angle
summation equation, as follows:
.theta..sub.GH.sup.Actual=.theta..sub.FGD+.theta..sub.HGF.
Description
BACKGROUND
[0001] The present disclosure relates to excavators which, for the
purposes of defining and describing the scope of the present
application, comprise an excavator boom and an excavator stick
subject to swing and curl, and an excavating implement that is
subject to swing and curl control with the aid of the excavator
boom and excavator stick, or other similar components for executing
swing and curl movement. For example, and not by way of limitation,
many types of excavators comprise a hydraulically or pneumatically
or electrically controlled excavating implement that can be
manipulated by controlling the swing and curl functions of an
excavating linkage assembly of the excavator. Excavator technology
is, for example, well represented by the disclosures of U.S. Pat.
No. 8,689,471, which is assigned to Caterpillar Trimble Control
Technologies LLC and discloses methodology for sensor-based
automatic control of an excavator, US 2008/0047170, which is
assigned to Caterpillar Trimble Control Technologies LLC and
discloses an excavator 3D laser system and radio positioning
guidance system configured to guide a cutting edge of an excavator
bucket with high vertical accuracy, and US 2008/0000111, which is
assigned to Caterpillar Trimble Control Technologies LLC and
discloses methodology for an excavator control system to determine
an orientation of an excavator sitting on a sloped site.
BRIEF SUMMARY
[0002] According to the subject matter of the present disclosure,
an excavator calibration framework comprises an excavator, a laser
distance meter (LDM), and a laser reflector. The excavator
comprises a machine chassis, an excavating linkage assembly, an
implement dynamic sensor, an excavating implement, and control
architecture. The excavating linkage assembly comprises an
excavator boom, an excavator stick, and a four-bar linkage. The
excavating implement and the excavator stick are mechanically
coupled through the four-bar linkage comprising an implement
linkage of length GH, a rear side linkage of length FH, a dogbone
linkage of length DF, and a front side linkage of length DG. The
implement dynamic sensor is positioned on the dogbone linkage of
the four-bar linkage. The excavating implement is configured to
curl relative to the excavator stick to define a plurality of
implement curl positions. The LDM is configured to generate an LDM
distance signal D.sub.LDM indicative of a distance between the LDM
and the laser reflector and an angle of inclination signal
.theta..sub.INC indicative of an angle between the LDM and the
laser reflector. The laser reflector is configured to be disposed
at a position corresponding to a calibration node on the excavating
implement. The control architecture comprises one or more linkage
assembly actuators and an architecture controller programmed to
execute an iterative process at successive implement curl
positions. The iterative process comprises generating a measured
dogbone angle .theta..sub.DF.sup.Measured of the dogbone linkage
from the implement dynamic sensor, determining a height H and a
distance {circumflex over (D)} between the calibration node on the
excavating implement and the LDM based on the LDM distance signal
D.sub.LDM and the angle of inclination signal .theta..sub.INC, and
determining a position of the calibration node at least partially
based on the height H and the distance {circumflex over (D)}. The
iterative process further comprises determining an estimated
implement angle .theta..sub.GH.sup.Estimated of the excavating
implement at least partially based on the position of the
calibration node, and generating a mapping equation comprising
linkage angle inputs, unsolved linkage length parameters, and
unsolved angle offset parameters. The linkage angle inputs comprise
the measured dogbone angle .theta..sub.DF.sup.Measured and the
estimated implement angle .theta..sub.GH.sup.Estimated at the
implement curl position. The unsolved linkage length parameters
comprise the linkage lengths GH, FH, DF, and DG of the four-bar
linkage. The unsolved angle offset parameters comprise an offset
dogbone angle .theta..sub.DF.sup.Bias of the dogbone linkage, and
an offset implement angle .theta..sub.GH.sup.Bias of the excavating
implement. The architecture controller is further programmed to
repeat the iterative process for successive implement curl
positions to generate a set of m mapping equations, wherein the set
of m mapping equations comprises n unsolved linkage length and
unsolved angle offset parameters, and the iterative process is
repeated until m>n. The architecture controller is further
programmed to solve the generated set of m mapping equations
comprising the n unsolved parameters to determine the linkage
lengths GH, FH, DF, and DG of the four-bar linkage, the offset
dogbone angle .theta..sub.DF.sup.Bias of the dogbone linkage, and
the offset implement angle .theta..sub.GH.sup.Bias of the
excavating implement, and operate the excavator using the linkage
lengths GH, FH, DF, and DG, the offset dogbone angle
.theta..sub.DF.sup.Bias, and the offset implement angle
.theta..sub.GH.sup.Bias.
[0003] Although the concepts of the present disclosure are
described herein with primary reference to the excavator
illustrated in FIG. 1, it is contemplated that the concepts will
enjoy applicability to any type of excavator, regardless of its
particular mechanical configuration. For example, and not by way of
limitation, the concepts may enjoy applicability to a backhoe
loader including a backhoe linkage.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0004] The following detailed description of specific embodiments
of the present disclosure can be best understood when read in
conjunction with the following drawings, where like structure is
indicated with like reference numerals and in which:
[0005] FIG. 1 is a side view of an excavator incorporating aspects
of the present disclosure;
[0006] FIG. 2 is a perspective view of a dynamic sensor disposed on
a linkage of the excavator of FIG. 1 and according to various
concepts of the present disclosure;
[0007] FIG. 3 is a side elevation view of a linkage assembly of an
excavator calibration framework including a laser distance meter
(LDM) and implement dimension points of an excavating implement of
the excavator of FIG. 1;
[0008] FIG. 4 is a side elevation view of a four-bar linkage
assembly of the excavator of FIG. 1, according to various concepts
of the present disclosure;
[0009] FIG. 5 is another side elevation view of the four-bar
linkage assembly of FIG. 4, according to various concepts of the
present disclosure; and
[0010] FIG. 6 is a flow chart of a process used to determine
four-bar linkage dimensions and angle offsets of the excavator of
FIG. 1.
DETAILED DESCRIPTION
[0011] The present disclosure relates to earthmoving machines and,
more particularly, to earthmoving machines such as excavators
including components subject to control. For example, and not by
way of limitation, many types of excavators typically have a
hydraulically controlled earthmoving implement that can be
manipulated by a joystick or other means in an operator control
station of the machine, and is also subject to partially or fully
automated control. The user of the machine may control the lift,
tilt, angle, and pitch of the implement. In addition, one or more
of these variables may also be subject to partially or fully
automated control based on information sensed or received by an
adaptive environmental sensor of the machine. In the embodiments
described herein, an excavator calibration framework utilizes a
laser distance meter to determine four-bar linkage lengths of
excavator limb components and related angle offsets, such as an
angle offset of one or more sensors disposed on those respective
linkages, as described in greater detail further below. Such
determined values may be utilized by an excavator control to
operate the excavator.
[0012] Referring initially to FIG. 1, an excavator calibration
framework comprises an excavator 100, a laser distance meter (LDM)
124, and a laser reflector 130. The excavator 100 comprises a
machine chassis 102, an excavating linkage assembly 104, an
implement dynamic sensor 120, an excavating implement 114, and
control architecture 106. The excavating linkage assembly 104
comprises an excavator boom 108, an excavator stick 110, and a
four-bar linkage 112. The excavating implement 114 and the
excavator stick 110 are mechanically coupled through the four-bar
linkage 112. In embodiments, the laser reflector 130 is on a pole
or secured directly to the excavating implement 114. The LDM 124
may be, for example, a Bosch GLM 100C LDM as made commercially
available by Robert Bosch GmbH of Germany. A laser signal from the
LDM 124, which is placed on ground 126, may be transmitted in a
direction of an arrow 132 to the calibration node and an aligned
laser reflector, such as, for example, the laser reflector 130, and
the laser signal may be reflected back to the LDM 124 in the
direction of an arrow 134, as illustrated in FIG. 1.
[0013] In embodiments, the implement dynamic sensor 120 comprises
an inertial measurement unit (IMU), an inclinometer, an
accelerometer, a gyroscope, an angular rate sensor, a rotary
position sensor, a position sensing cylinder, or combinations
thereof. The IMU may include a 3-axis accelerometer and a 3-axis
gyroscope. As shown in FIG. 2, the implement dynamic sensor 120
includes accelerations A.sub.x, A.sub.y, and A.sub.z, respectively
representing x-axis, y-axis-, and z-axis acceleration values.
[0014] The four-bar linkage 112 comprises an implement linkage of
length GH, a rear side linkage of length FH, a dogbone linkage of
length DF, and a front side linkage of length DG. The implement
dynamic sensor 120 is positioned on the dogbone linkage of length
DF of the four-bar linkage 112. In embodiments, the four-bar
linkage comprises a node D, a node F, a node G, a node H. As a
non-limiting example, the implement linkage is disposed between
respective positions corresponding to the node G and the node H.
The rear side linkage is disposed between respective positions
corresponding to the node F and the node H. The dogbone linkage is
disposed between respective positions corresponding to the node D
and the node F, and front side linkage is disposed between
respective positions corresponding to the node D and the node G.
Further, the node G of the four-bar linkage 112 may be disposed at
a position corresponding to the terminal point of the excavator
stick 110 through which the excavator stick 110 is coupled to the
excavating implement 114. Referring to FIG. 5, the four-bar linkage
112 comprises a diagonal length FG between a front end node of the
implement linkage of length GH and a rear end node of the dogbone
linkage of length DF.
[0015] The excavating implement 114 is configured to curl relative
to the excavator stick 110 to define a plurality of implement curl
positions. In embodiments, the excavating linkage assembly 104 may
be configured to swing with, or relative to, the machine chassis
102, and the excavator stick 110 may be configured to curl relative
to the excavator boom 108. Further, the machine chassis 102 may be
mechanically coupled to a terminal pivot point A of the excavator
boom 108. The excavator stick 110 may comprise a stick terminal
point corresponding to the position of the node G of the four-bar
linkage 112 and may be mechanically coupled to a terminal pivot
point B of the excavator boom 108. Further, the excavator stick 110
may be mechanically coupled to the excavating implement 114 through
the stick terminal point. A position of the terminal pivot point B
and the node G may be identified prior to, for example, the
iterative process being executed by the architecture
controller.
[0016] Referring to FIG. 3, a boom limb length L.sub.B is a limb
length of the excavator boom 108, a boom angle .theta..sub.B is an
angle of the excavator boom 108 between the terminal pivot points A
and B relative to gravity, a stick limb length L.sub.S is a limb
length of the excavator stick 110, and a stick angle .theta..sub.S
is an angle of the excavator stick 110 between the terminal pivot
point B and the node G relative to gravity. One or more dynamic
sensors may be disposed on excavator components such as the limbs
of the excavator boom 108 or the excavator stick 110 or on any of
the linkages of the four-bar linkage 112.
[0017] The LDM 124 is configured to generate an LDM distance signal
D.sub.LDM indicative of a distance between the LDM 124 and the
laser reflector 139 and an angle of inclination signal
.theta..sub.INC indicative of an angle between the LDM 124 and the
laser reflector 130. The laser reflector 130 is configured to be
disposed at a position corresponding to a calibration node on the
excavating implement 114. In embodiments, the calibration node is
positioned at a terminal point J at a bucket tooth tip of the
excavating implement 114. A height H.sub.0 of the LDM 124 from the
terminal pivot point A of the excavator boom 108 and a distance
D.sub.0 of the LDM from a terminal pivot point A of the excavator
boom may be identified or determined prior to, for example, the
iterative process being executed by the architecture
controller.
[0018] The control architecture 106 comprises one or more linkage
assembly actuators and an architecture controller programmed to
execute an iterative process at successive implement curl
positions. In embodiments, the control architecture comprises a
non-transitory computer-readable storage medium comprising machine
readable instructions that the architecture controller is
programmed to execute. The one or more linkage assembly actuators
may facilitate movement of the excavating linkage assembly 104.
Further, the one or more linkage assembly actuators may comprise a
hydraulic cylinder actuator, a pneumatic cylinder actuator, an
electrical actuator, a mechanical actuator, or combinations
thereof.
[0019] The iterative process is illustrated in FIG. 6 through a
control scheme 200 and steps 202-218. In step 202, the iterative
process may start with a first iteration in which m=1. The
calibration node may be aligned through the excavating linkage
assembly 104 to align with the LDM 124 in step 204. The iterative
process comprises generating a measured dogbone angle
.theta..sub.DF.sup.Measured of the dogbone linkage from the
implement dynamic sensor 120, as illustrated in step 206. The
iterative process further comprises determining a height H and a
distance {circumflex over (D)} between the calibration node on the
excavating implement 114 and the LDM 124 based on the LDM distance
signal D.sub.LDM and the angle of inclination signal
.theta..sub.INC, as illustrated in step 208. As shown in step 210,
the iterative process comprising determining a position of the
calibration node at least partially based on the height H and the
distance {circumflex over (D)}. Additionally, the iterative process
comprises, as shown in step 212, determining an estimated implement
angle .theta..sub.GH.sup.Estimated of the excavating implement 114
at least partially based on the position of the calibration
node.
[0020] In embodiments, the estimated implement angle
.theta..sub.GH.sup.Estimated of the excavating implement 114 may be
determined at least partially based on the position of the node G
and the position of the terminal pivot point B. Additionally or
alternatively, the estimated implement angle
.theta..sub.GH.sup.Estimated of the excavating implement is
determined at least partially based on a lookup table estimating
the based on the measured dogbone angle
.theta..sub.DF.sup.Measured. In another embodiment, a position of
the node D of the four-bar linkage 112 is determined based on the
measured dogbone angle .theta..sub.DF.sup.Measured, or may be
otherwise identified, and the estimated implement angle
.theta..sub.GH.sup.Estimated of the excavating implement is
determined at least partially based on the position of the node D
and the position of the terminal pivot point B. As a non-limiting
example, the estimated implement angle .theta..sub.GH.sup.Estimated
of the excavating implement is determined at least partially based
on a determined internal angle .theta..sub.DGJ.sup.i that based on
the positions of nodes D and G and the terminal point J. Referring
to FIGS. 4-5, a determined external angle .theta..sub.DGJ.sup.e may
be determined based on the determined internal angle
.theta..sub.DGJ.sup.i per a following equation:
.theta..sub.DGJ.sup.e=360.degree.-.theta..sub.DGJ.sup.i (Equation
1)
[0021] Further, the determined external angle .theta..sub.DGJ.sup.e
is a sum of the estimated implement angle
.theta..sub.GH.sup.Estimated of the excavating implement and a
implement angle .PSI. that is a constant angle formed between
surfaces of the excavating implement 114 disposed between the
terminal point J and the nodes G and H, such that:
.theta..sub.DGJ.sup.e=.theta..sub.GH.sup.Estimated+.PSI. (Equation
2)
[0022] which is rearranged into a following equation:
.theta..sub.GH.sup.Estimated=.theta..sub.DGJ.sup.e-.PSI. (Equation
3)
[0023] The iterative process further comprises, as shown in step
214 of FIG. 6, generating a mapping equation comprising linkage
angle inputs, unsolved linkage length parameters, and unsolved
angle offset parameters. The linkage angle inputs comprise the
measured dogbone angle .theta..sub.DF.sup.Measured and the
estimated implement angle .theta..sub.GH.sup.Estimated at the
implement curl position. The unsolved linkage length parameters
comprise the linkage lengths GH, FH, DF, and DG of the four-bar
linkage. The unsolved angle offset parameters comprise an offset
dogbone angle .theta..sub.DF.sup.Bias of the dogbone linkage, and
an offset implement angle .theta..sub.GH.sup.Bias of the excavating
implement 114.
[0024] In embodiments, the mapping equation comprises a following
equation, which includes an actual dogbone angle
.theta..sub.DF.sup.Actual and an actual implement angle
.theta..sub.GH.sup.Actual:
.theta. GH Actual = DG - DF * cos ( 180 .degree. - .theta. DF
Actual ) FG + DF 2 + DG 2 + GH 2 - 2 * DF * DG * cos ( 180 .degree.
- .theta. DF Actual ) - FH 2 2 * FG * GH ( Equation 4 )
##EQU00001##
[0025] The actual dogbone angle .theta..sub.DF.sup.Actual is based
on the measured dogbone angle .theta..sub.DF.sup.Measured and the
offset dogbone angle .theta..sub.DF.sup.Bias such that:
.theta..sub.DF.sup.Actual=.theta..sub.DF.sup.Measured-.theta..sub.DF.sup-
.Bias (Equation 5)
[0026] the actual implement angle .theta..sub.GH.sup.Actual is
based on the estimated implement angle .theta..sub.GH.sup.Estimated
and the offset implement angle .theta..sub.GH.sup.Bias such
that:
.theta..sub.GH.sup.Actual=.theta..sub.GH.sup.Estimated-.theta..sub.GH.su-
p.Bias (Equation 6)
[0027] Further, the mapping equation is based on an implement angle
equation, as follows:
.theta. GH Actual = DG 2 + FG 2 - DF 2 2 * FG * DG + FG 2 + GH 2 -
FH 2 2 * FG * GH ( Equation 7 ) ##EQU00002##
[0028] The implement angle equation is based on an implement angle
summation equation, as follows:
.theta..sub.GH.sup.Actual=.theta..sub.FGD+.theta..sub.HGF (Equation
8)
[0029] In Equation 8, .theta..sub.HGF is an angle between nodes H,
G, and F, and .theta..sub.FGD is an angle between nodes F, G, and
D. Further, .theta..sub.HGF and .theta..sub.FGD are based on a
following pair of equations:
.theta. FGD = DG 2 + FG 2 - DF 2 2 * FG * DG and .theta. HGF = FG 2
+ GH 2 - FH 2 2 * FG * GH ( Equations 9 - 10 ) ##EQU00003##
[0030] The mapping equation is further based on a substitution of a
FG.sup.2 term in the implement angle equation with a diagonal
length squared equation, which follows:
FG.sup.2=DF.sup.2+DG.sup.2-2*DF*DG*cos(180.degree.-.theta..sub.DF.sup.Ac-
tual) (Equation 11)
[0031] Further, the diagonal length squared equation of Equation 11
is based on a diagonal length equation, as follows:
FG= {square root over
(DF.sup.2+DG.sup.2-2*DF*DG*cos(180.degree.-.theta..sub.DF.sup.Actual))}
(Equation 12)
[0032] In embodiments, the mapping equation maps a waveform as, for
example, a graphical empirical chart or display, the waveform
comprising linear and non-linear regions at least partially based
on one or more linkage lengths.
[0033] The architecture controller is further programmed to repeat
the iterative process for successive implement curl positions to
generate a set of m mapping equations, wherein the set of m mapping
equations comprises n unsolved linkage length and unsolved angle
offset parameters, and the iterative process is repeated until
m>n. For example, as shown in step 216 of FIG. 6, if m>n is
not true, then the iterative process continues to step 218 and the
next iteration of m to repeat through steps 204-216. If, in step
216, m>n is true, the control scheme 200 continues on to step
220. In embodiments, the iterative process is repeated until m
passes a threshold greater than n. As a non-limiting example, n may
be equal to 6 and the threshold may be 17 such that m is equal to
18 to generate a set of 18 mapping equations comprising 6 unsolved
linkage length and unsolved angle offset parameters.
[0034] As shown in step 220 of FIG. 6, the architecture controller
is further programmed to solve the generated set of m mapping
equations comprising the n unsolved parameters to determine the
linkage lengths GH, FH, DF, and DG of the four-bar linkage, the
offset dogbone angle .theta..sub.DF.sup.Bias of the dogbone
linkage, and the offset implement angle .theta..sub.GH.sup.Bias of
the excavating implement 114. Further, as shown in step 222 of FIG.
6, the architecture controller is programmed to operate the
excavator 100 using the n solved parameters of linkage lengths GH,
FH, DF, and DG, the offset dogbone angle .theta..sub.DF.sup.Bias,
and the offset implement angle .theta..sub.GH.sup.Bias.
[0035] It is contemplated that the embodiments of the present
disclosure may assist to permit a speedy and more cost efficient
method of determining linkage lengths, sensor offsets of sensors on
excavator linkages, and offsets of angular estimations of excavator
linkages in a manner that minimizes a risk of human error with such
value determinations. Further, the controller of the excavator or
other control technologies are improved such that the processing
systems are improved and optimized with respect to speed,
efficiency, and output.
[0036] A signal may be "generated" by direct or indirect
calculation or measurement, with or without the aid of a
sensor.
[0037] For the purposes of describing and defining the present
invention, it is noted that reference herein to a variable being a
"function" of a parameter or another variable is not intended to
denote that the variable is exclusively a function of the listed
parameter or variable. Rather, reference herein to a variable that
is a "function" of a listed parameter is intended to be open ended
such that the variable may be a function of a single parameter or a
plurality of parameters.
[0038] It is also noted that recitations herein of "at least one"
component, element, etc., should not be used to create an inference
that the alternative use of the articles "a" or "an" should be
limited to a single component, element, etc.
[0039] It is noted that recitations herein of a component of the
present disclosure being "configured" or "programmed" in a
particular way, to embody a particular property, or to function in
a particular manner, are structural recitations, as opposed to
recitations of intended use. More specifically, the references
herein to the manner in which a component is "configured" or
"programmed" denotes an existing physical condition of the
component and, as such, is to be taken as a definite recitation of
the structural characteristics of the component.
[0040] It is noted that terms like "preferably," "commonly," and
"typically," when utilized herein, are not utilized to limit the
scope of the claimed invention or to imply that certain features
are critical, essential, or even important to the structure or
function of the claimed invention. Rather, these terms are merely
intended to identify particular aspects of an embodiment of the
present disclosure or to emphasize alternative or additional
features that may or may not be utilized in a particular embodiment
of the present disclosure.
[0041] For the purposes of describing and defining the present
invention it is noted that the terms "substantially" and
"approximately" are utilized herein to represent the inherent
degree of uncertainty that may be attributed to any quantitative
comparison, value, measurement, or other representation. The terms
"substantially" and "approximately" are also utilized herein to
represent the degree by which a quantitative representation may
vary from a stated reference without resulting in a change in the
basic function of the subject matter at issue.
[0042] Having described the subject matter of the present
disclosure in detail and by reference to specific embodiments
thereof, it is noted that the various details disclosed herein
should not be taken to imply that these details relate to elements
that are essential components of the various embodiments described
herein, even in cases where a particular element is illustrated in
each of the drawings that accompany the present description.
Further, it will be apparent that modifications and variations are
possible without departing from the scope of the present
disclosure, including, but not limited to, embodiments defined in
the appended claims. More specifically, although some aspects of
the present disclosure are identified herein as preferred or
particularly advantageous, it is contemplated that the present
disclosure is not necessarily limited to these aspects.
[0043] It is noted that one or more of the following claims utilize
the term "wherein" as a transitional phrase. For the purposes of
defining the present invention, it is noted that this term is
introduced in the claims as an open-ended transitional phrase that
is used to introduce a recitation of a series of characteristics of
the structure and should be interpreted in like manner as the more
commonly used open-ended preamble term "comprising."
* * * * *