Information
-
Patent Grant
-
6278955
-
Patent Number
6,278,955
-
Date Filed
Thursday, December 10, 199825 years ago
-
Date Issued
Tuesday, August 21, 200122 years ago
-
Inventors
-
Original Assignees
-
Examiners
- Assouad; Patrick
- Bui; Bryan
Agents
-
CPC
-
US Classifications
Field of Search
US
- 702 105
- 702 152
- 700 302
- 700 303
- 700 304
- 701 29
- 172 45
-
International Classifications
-
Abstract
A system and method for automatically adjusting the blade of a motor grader to an operator programmed blade position. The method includes the steps of: providing an electronic controller and blade controls having position sensors; monitoring the output of the position sensors to ascertain the position of the blade controls; receiving a first input signal for setting a memory blade position; determining the memory blade position based on the output of the position sensors; receiving a second input signal for requesting the memory blade position; determining the present blade position based on the output of the position sensors; and producing a control signal for actuating the blade controls to move the blade from the present blade position to the memory blade position.
Description
TECHNICAL FIELD
This invention relates generally to a method for automatically positioning the blade of a motor grader to a memory position and, more particularly, to a method for automatically adjusting the blade to an operator programmed blade position.
BACKGROUND ART
Motor graders are used primarily as a finishing tool to sculpt a surface of earth to a final arrangement. To perform such earth sculpting tasks, motor graders include a blade, also referred to as a moldboard or implement. The blade moves relatively small quantities of earth from side to side. Motor graders must produce a variety of final earth arrangements. As a result, the blade must be set to many different blade positions.
The blade may be adjusted for blade height, blade cutting angle, blade tip, blade sideshift, and drawbar sideshift. Accordingly, motor graders include several hand controls to operate the multiple blade adjustments. Positioning the blade of a motor grader is a complex and time consuming task. Frequently, an operator will desire one or more unique blade positions. Thus, to improve efficiency and consistency, it is desirable to provide a method for automatically positioning the blade of a motor grader to an operator programmed blade position.
The present invention is directed to overcoming one or more of the problems as set forth above.
DISCLOSURE OF THE INVENTION
The present invention provides a method for automatically positioning the blade of a motor grader to a memory position. The method includes the steps of: providing an electronic controller and blade controls having position sensors; monitoring the output of the position sensors to ascertain the position of the blade controls; receiving a first input signal for setting a memory blade position; determining the memory blade position based on the output of the position sensors; receiving a second input signal for requesting the memory blade position; determining the present blade position based on the output of the position sensors; and producing a control signal for actuating the blade controls to move the blade from the present blade position to the memory blade position.
BRIEF DESCRIPTION OF THE DRAWINGS
Other advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:
FIG. 1
is a side view of a motor grader;
FIG. 2
is a top view of the motor grader;
FIG. 3
is a schematic block diagram of an electro-hydraulic control system for the motor grader; and
FIG. 4
is a flow chart illustrating a method for automatically positioning the blade of the motor grader to a memory position in accordance with the present invention.
BEST MODE FOR CARRYING OUT THE INVENTION
Referring to the Figures, wherein like numerals indicate like or corresponding parts throughout the several views, a motor grader is shown generally at
10
in
FIGS. 1 and 2
. The motor grader
10
is used primarily as a finishing tool to sculpt a surface of earth
11
to a final arrangement. Rather than moving large quantities of earth in the direction of travel like other machines, such as a bulldozer, the motor grader
10
typically moves relatively small quantities of earth from side to side. In other words, the motor grader
10
typically moves earth across the area being graded, not straight ahead.
The motor grader
10
includes a front frame
12
, a rear frame
14
, and a blade
16
. The front and rear frames
12
and
14
are supported by tires
18
. An operator cab
20
containing the many controls necessary to operate the motor grader
10
is mounted on the front frame
12
. An engine, shown generally at
21
, is used to drive or power the motor grader
10
. The engine
21
is mounted on the rear frame
14
. The blade
16
, sometimes referred to as a moldboard, is used to move earth. The blade
16
is mounted on a linkage assembly, shown generally at
22
. The linkage assembly
22
allows the blade
16
to be moved to a variety of different positions relative to the motor grader
10
. Starting at the front of the motor grader
10
and working rearward toward the blade
16
, the linkage assembly
22
includes a drawbar
24
.
The drawbar
24
is mounted to the front frame
12
with a ball joint. The position of the drawbar
24
is controlled by three hydraulic cylinders, commonly referred to as a right lift cylinder
28
, a left lift cylinder
30
, and a center shift cylinder
32
. A coupling, shown generally at
34
, connects the three cylinders
28
,
30
, and
32
to the front frame
12
. The coupling
34
can be moved during blade repositioning but is fixed stationary during earthmoving operations. The height of the blade
16
with respect to the surface of earth
11
below the motor grader
10
, commonly referred to as blade height, is controlled primarily with the right and left lift cylinders
28
and
30
. The right and left lift cylinders
28
and
30
can be controlled independently and, thus, used to angle a bottom cutting edge
35
of the blade
16
relative to the surface of earth
11
. The center shift cylinder
32
is used primarily to sideshift the drawbar
24
, and all the components mounted to the end of the drawbar, relative to the front frame
12
. This sideshift is commonly referred to as drawbar sideshift or circle centershift.
The drawbar
24
includes a large, flat plate, commonly referred to as a yoke plate
36
, as shown in
FIGS. 2 and 3
. Beneath the yoke plate
36
is a large gear, commonly referred to as a circle
38
. The circle
38
is rotated by a hydraulic motor, commonly referred to as a circle drive
40
, as shown in FIG.
2
. The rotation of the circle
38
by the circle drive
40
, commonly referred to as circle turn, pivots the blade
16
about an axis A fixed to the drawbar
24
to establish a blade cutting angle. The blade cutting angle is defined as the angle of the blade
16
relative to the front frame
12
. At a 0 degree blade cutting angle, the blade
16
is aligned at a right angle to the front frame
12
.
The blade
16
is mounted to a hinge on the circle
38
with a bracket. A blade tip cylinder
46
is used to pitch the bracket forward or rearward. In other words, the blade tip cylinder
46
is used to tip a top edge
47
of the blade
16
ahead of or behind the bottom cutting edge
35
of the blade
16
. The position of the top edge
47
of the blade
16
relative to the bottom cutting edge
35
of the blade
16
is commonly referred to as blade tip.
The blade
16
is mounted to a sliding joint in the bracket allowing the blade
16
to be slid or shifted from side to side relative to the bracket or the circle
38
. This side to side shift is commonly referred to as blade side shift. A side shift cylinder
50
is used to control the blade sideshift.
Referring now to
FIG. 2
, a right articulation cylinder, shown generally at
52
, is mounted to the right side of the rear frame
14
and a left articulation cylinder, shown generally at
54
, is mounted to the left side of the rear frame
14
. The right and left articulation cylinders
52
and
54
are used to rotate the front frame
12
about an axis B shown in FIG.
1
. The axis B is commonly referred to as the articulation axis. In
FIG. 2
, the motor grader
10
is positioned in a neutral or zero articulation angle.
FIG. 3
is a schematic block diagram of an electro-hydraulic control system
60
for the motor grader
10
. The control system
60
is designed to control the blade
16
and the articulation angle q. The system
60
includes electronic hand controls, represented by block
62
, which transform the actions of an operator's hands into electrical input signals. These input signals carry operational information to an electronic control computer, represented by block
64
.
The control computer
64
receives the electrical inputs signals produced by the hand controls
62
, processes the operational information carried by the input signals, and transmits control signals to drive solenoids in electro-hydraulic actuators, represented by block
66
.
The hydraulic portion of the control system
60
requires both high hydraulic pressure and low pilot pressure. High hydraulic pressure is provided by a hydraulic pump, represented by block
68
. The hydraulic pump
68
receives a rotary motion, typically from the engine
21
of the motor grader
10
, and produces high hydraulic pressure. Low pilot pressure is provided by a hydraulic pressure reducing valve, represented by block
70
. The hydraulic pressure reducing valve
70
receives high hydraulic pressure from the hydraulic pump
68
and supplies low pilot pressure to the electro-hydraulic actuators
66
.
Each electro-hydraulic actuator
66
includes an electrical solenoid and a hydraulic valve. The solenoid receives control signals from the electronic control computer
64
and produces a controlled mechanical movement of a core stem of the actuator
66
. The hydraulic valve receives both the controlled mechanical movement of the core stem of the actuator
66
and low pilot pressure from the hydraulic pressure reducing valve
70
and produces controlled pilot hydraulic pressure for hydraulic valves, represented by block
72
.
The hydraulic valves
72
receive both controlled pilot hydraulic pressure from the electro-hydraulic actuators
66
and high hydraulic pressure from the hydraulic pump
68
and produce controlled high hydraulic pressure for hydraulic actuators, cylinders, and motors, represented by block
74
.
The hydraulic actuators, cylinders, and motors
74
receive controlled high hydraulic pressure from the hydraulic valves
72
and produce mechanical force to move the front frame
12
of the grader
10
and several mechanical linkages, represented by block
76
. As described above, movement of the front frame
12
of the grader
10
with respect to the rear frame
14
of the grader
10
establishes the articulation angle q. Movement of the mechanical linkages establishes the position of the blade
16
.
Each hydraulic actuator, cylinder, and motor
74
, such as the lift cylinders
28
and
30
and the circle drive motor
40
, includes an electronic position sensor, represented by block
78
. The electronic position sensors
78
transmit information regarding the position of its respective hydraulic actuator, cylinder, or motor
76
to the electronic control computer
64
. In this mariner, the control computer
64
can determine the position of the blade
16
. The control computer
64
further receives articulation angle information from the rotary sensor, also represented by block
78
, positioned at the articulation joint
56
. With such position and angle information, the control computer
64
can perform additional operations.
In accordance with the scope of the present invention, one such operation is automatically adjusting the blade
16
of the motor grader
10
to an operator programmed blade position. Thus, the present invention provides a method for automatically positioning the blade
16
of the motor grader
10
to a memory position. The method includes the steps of: providing an electronic controller and blade controls having position sensors; monitoring the output of the position sensors to ascertain the position of the blade controls; receiving a first input signal for setting a memory blade position; determining the memory blade position based on the output of the position sensors; receiving a second input signal for requesting the memory blade position; determining the present blade position based on the output of the position sensors; and producing a control signal for actuating the blade controls to move the blade from the present blade position to the memory blade position.
In a first embodiment, the electronic controller includes a memory, the step of determining the memory blade position includes determining the three-dimensional coordinates of the memory blade position, and the step of determining the present blade position includes determining the three-dimensional coordinates of the present blade position. The method further includes the steps of: storing in the memory information identifying the three-dimensional coordinates of the memory blade position and retrieving from the memory information identifying the three-dimensional coordinates of the memory blade position.
In a second embodiment, the electronic controller includes a memory and the method further includes the steps of: storing in the memory information identifying the position of the blade controls when the blade is fixed in the memory blade position and retrieving from the memory information indicating the position of the blade controls necessary to achieve the memory blade position.
Referring now to
FIG. 4
, a flow chart illustrating a preferred method for automatically positioning the blade of the motor grader to a memory position is shown. As will be appreciated by one of ordinary skill in the art, although the flow chart illustrates sequential steps, the particular order of processing is not important to achieving the objects of the present invention. As will also be recognized, the method illustrated may be performed in software, hardware, or a combination of both as in a preferred embodiment of the present invention.
In the preferred method, an operator sets a memory blade position by transmitting a first input signal, as represented by block
90
. Upon receipt of the first input signal, the sensor readings are stored in the controller as memory sensor readings, as illustrated by block
92
. Over time, the blade is repositioned as the motor grader is used to sculpt a surface of earth, as represented by block
94
. The operator requests the memory blade position by transmitting a second input signal, as illustrated by block
96
. As a result of this request, the controller recalls the memory sensor readings, as represented by block
98
, and transforms the memory sensor readings into a memory blade position and orientation, as illustrated by block
100
. The controller transforms the current sensor readings into a current blade position and orientation, as represented by block
102
. With this positional information, the controller plans a path to move the blade from its current blade position and orientation to the memory or operator programmed position and orientation, as illustrated by block
104
. The controller executes the planned path by actuating the blade controls and monitoring feedback from the position sensors, as represented by block
106
.
The invention has been described in an illustrative manner, and it is to be understood that the terminology which has been used is intended to be in the nature of words of description rather than of limitation.
Obviously, many modifications and variations of the present invention are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims, wherein reference numerals are merely for convenience and are not to be in any way limiting, the invention may be practiced otherwise than as specifically described.
Industrial Applicability
The present invention relates generally to a method for automatically adjusting the blade of a motor grader, having an electronic controller and blade controls including position sensors, to an operator programmed blade position. By monitoring the output of the position sensors, the controller can ascertain the position of the blade controls. Upon receipt of a first input signal for setting a memory blade position, the controller determines the memory blade position based on the output of the position sensors. Upon receipt of a second input signal for requesting the memory blade position, the controller determines the present blade position based on the output of the position sensor and produces a unique control signal to actuate the blade controls and, thereby, automatically move the blade from its present blade position to the memory blade position. Frequently, an operator will desire one or more unique blade positions. In this manner, the operator can set a memory blade position by simply transmitting the first input signal. Thereafter, the operator can automatically adjust the blade to the memory blade position by simply transmitting the second input signal.
Other aspects, objects, and features of the present invention can be obtained from a study of the drawings, the disclosure, and the appended claims.
Claims
- 1. A method for automatically positioning the blade of a motor grader to a memory position comprising the steps of:providing an electronic controller and blade controls having position sensors; monitoring the output of the position sensors to ascertain the position of the blade controls; receiving a first input signal for setting a three-dimensional coordinate memory blade position; determining the three-dimensional coordinate memory blade position based on the output of the position sensors; receiving a second input signal for requesting the memory blade position; determining the present three-dimensional coordinate blade position based on the output of the position sensors; and producing a control signal for actuating blade controls to move the blade from the present three-dimensional coordinate blade position to the memory three-dimensional coordinate blade position.
- 2. A method as set forth in claim 1 wherein the electronic controller includes a memory and including the step of retrieving from the memory information identifying the three-dimensional coordinates of the memory blade position.
- 3. A method as set forth in claim 2 including the step of storing in the memory information identifying the three-dimensional coordinates of the memory blade position.
- 4. A method as set forth in claim 1 wherein the electronic controller includes a memory and including the step of retrieving from the memory information indicating the position of the blade controls necessary to achieve the memory blade position.
- 5. A method as set forth in claim 4 including the step of storing in the memory information identifying the position of the blade controls when the blade is fixed in the memory blade position.
US Referenced Citations (32)
Foreign Referenced Citations (4)
Number |
Date |
Country |
1390066 |
Apr 1975 |
GB |
57-071939 |
May 1982 |
JP |
58-164835 |
Sep 1983 |
JP |
59-102023 |
Jun 1984 |
JP |