System and method for controlling slope of cut of work implement

• US 5,764,511 A
• Filed: 06/20/1995
• Issued: 06/09/1998
• Est. Priority Date: 06/20/1995
• Status: Expired due to Term

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Henderson, Daniel E.
• Primary Examiner(s): Elmore, Reba I.
• Assistant Examiner(s): Garland, Steven R.
• Application Number:
  US08/492,644
• Time in Patent Office: 1,085 Days
• Field of Search: 364/167.01, 364/424.07, 364/443, 364/449, 364/474.28, 364/474.34, 364/474.35, 172/4.5, 404/84.2, 404/84.5, 356/3, 356/12
• US Class Current: 700/66
• CPC Class Codes: E02F 3/842 using electromagnetic, optical or photoelectric beams, e.g. laser beams
• CPC Class Codes: E02F 3/847 using electromagnetic, optical or acoustic beams to determine the blade position, e.g. laser beams
• CPC Class Codes: G05D 1/0236 in combination with a laser lasers per se H01S
• CPC Class Codes: G05D 1/0278 using satellite positioning signals, e.g. GPS
• CPC Class Codes: G05D 1/028 using a RF signal

Abstract

A system and method for automatically controlling the position of a work implement movably connected to a work machine and maintaining the work implement at a preselected slope of cut relative to a geographic surface is provided. The system has first and second receiving devices mounted on the work implement for receiving position signals from a plurality of remote locations. A processor determines the actual slope of cut of the work implement based on the received position signals. An implement controller delivers an implement control signal in response to a difference between the actual and a preselected desired slope of cut of the work implement. An implement control system elevationally changes the slope of cut of the work implement at an automatic mode of operation of the system. The system is particularly suited for use on a geographic surface altering work machine.

Claims

1. A system for controlling the position of a work implement movably connected to a work machine and maintaining the work implement at a preselected slope of cut relative to a geographic surface, comprising:

first receiving means for receiving electromagnetic radiation delivered from a plurality of remote locations and responsively producing a first position signal, said first receiving means being connected to said work implement and being at a first preselected location relative to a first point location on the work implement;

second receiving means for receiving electromagnetic radiation delivered from said plurality of remote locations and responsively producing a second position signal, said second receiving means being connected to said work implement and being at a second preselected location relative to a second point location on the work implement, said second location being spaced a preselected distance from said first location;

slope means for selecting a desired cross slope of cut of the implement and delivering a responsive desired slope signal;

processing means for receiving said first and second position signals, determining the first and second point positions of the implement in a site coordinate system, determining the actual cross slope of cut of the work implement based on the first and second point positions and previous first and second point position and delivering a responsive actual slope signal;

control means for receiving said desired and actual slope signals and elevationally moving the work implement to change the relative elevational positions of the first and second point locations on the implement in response to a difference between the desired and actual cross slope of cut of the work implement, said implement moving in an elevational direction based on the difference between the desired and actual cross slope of cut of the work implement, said control means being connected to said processing means.

2. A system, as set forth in claim 1, wherein said control means stopping elevational movement of the work implement in response to the desired and actual cross slope of cut of the work implement being substantially equal in magnitude.

3. A system, as set forth in claim 1, including mode means for manually selecting one of an "automatic" and "manual" mode of operation and delivering a responsive mode signal, said control means receiving said mode signal and enabling automatic slope control of the work implement in response to the mode signal being "automatic".

4. A system, as set forth in claim, 3 wherein said slope means includes a slope selector having a dial and being rotatable to a plurality of positions, said selector delivering a different slope signal at each of the positions of the slope selector.

5. A system, as set forth in claim 3, wherein said control means receiving said mode signal and disabling automatic slope control of the implement in response to the mode signal being "manual", and including an implement position selector means for manually selecting the speed and elevational direction of movement of the work implement and delivering a responsive implement control signal, said control means receiving said implement control signal and responsively elevationally moving said implement.

6. A system, as set forth in claim 5, wherein said implement position selector means includes a joy stick selectively manually movable to a plurality of positions at which the speed and direction of elevational movement of the implement is selected.

7. A system, as set forth in claim 5, wherein said control means includes:

an implement control system having first and second electrohydraulic control valves each movable between first and second fluid passing positions and first and second spaced apart jacks connected between said implement and frame, said first and second jacks being telescopically movable between first and second spaced positions and said work implement being elevationally movable in response to movement of said first and second jacks between said first and second positions, said first and second jacks being respectively connected to said first and second control valves, said first jack being telescopically movable toward said first position in response to said first valve being at the first position and telescopically movable toward said second position in response to said first valve being at said second position, said second jack being telescopically movable toward the first position in response to said second valve being at the first position and telescopically movable toward the second position in response to said second valve being at said second position;

an implement controller connected to said processing means and implement control system, said implement controller determining the required direction of movement of the implement based on the difference in the actual and desired cross slope of cut, and delivering a control signal to a selected one of the first and second electrohydraulic control valves, said selected control valve moving to one of the first and second positions in response to receiving said control signal.

8. A system, as set forth in claim 7, wherein said first and second electrohydraulic control valves each have a neutral position at which fluid flow is blocked, said implement controller stopping the delivery of the control signal to said selected one electrohydraulic control valve in response to the desired and actual cross slope of cut of the work implement being substantially equal in magnitude.

9. A system, as set forth in claim 1, including a database computer means for recording in real time the desired and actual cross slope of cut of the work implement in response to receiving actual and desired slope signals, said database computer means being connected to said control means and said processing means.

10. A system, as set forth in claim 9, including a monitor connected to said database computer means, said database computer means delivering a signal to said monitor and said monitor and graphically displaying the actual and desired cross slope of cut of the work implement.

11. A system, as set forth in claim 1, wherein said first and second receiving means each include a global position receiver.

12. A system, as set forth in claim 11, wherein the first and second receiving means each include a laser receiver.

13. A system, as set forth in claim 1, said processing means determining a current mid-point position along a current straight line passing between the first and second point locations on the work implement, determining a change in the midpoint position between the current and a previous midpoint position along a previous straight line passing between the first and second point locations on the work implement, determining a distance between a current second point location and the previous midpoint position, determine a length of a projection of the current straight line onto a horizontal plane, determine the angle φ

between the projection of the current straight line in the horizontal plane and a straight line connecting the midpoints of the current and previous straight lines, determining the length of a projection of the current straight line oriented normal to the straight line connecting the midpoints, determining the elevational difference between the first and second point locations, and determining the actual slope of the cross cut with respect to the second point location.

14. A method for automatically controlling the slope of cut of a work implement, comprising the steps of:

determining a current mid-point position alone a current straight line passing between a first and second point locations on the work implement;

determining a change in the midpoint position between the current and a previous midpoint position along a previous straight line passing between the first and second point locations on the work implement;

determining a distance between a current second point location and the previous mid-point position;

determining a length of a projection of the current straight line onto a horizontal plane;

determining an angle φ

between the projection of the current straight line in the horizontal plane and a straight line connecting the midpoints of the current and previous straight lines;

determining the length of a projection of the current straight line oriented normal to the straight line connecting the midpoints;

determining an elevational difference between the first and second point locations;

determining the actual slope of the cross cut with respect to the second point location;

determining a difference between the actual and desired slope of cut of the work implement;

determining the direction of movement of the work implement required to relatively move one of the first and the second point locations on the work implement and reduce the difference in magnitude between the actual and desired slope of cut of the work implement;

commanding an implement control system to elevationally move the work implement and change the relative elevational position of the first and second point locations; and

stopping relative elevational movement of the work implement in response to the actual and desired slope having substantially the same magnitude.

15. A method for automatically controlling the slope of cut of a work implement, comprising the steps of:

receiving electromagnetic radiation delivered from a plurality of remote locations and responsively producing a first and second position signal, said first and second position signal corresponding to a first and second point location on the work implement;

determining the first and second point positions of the implement in a site coordinate system;

determining the actual cross slope of cut of the work implement in response to the first and second point positions and a previous first and second point positions;

determining a difference between the actual and desired slope of cut of the work implement;

determining the direction of movement of the work implement required to relatively move one of a first and a second point locations on the work implement and reduce the difference in magnitude between the actual and desired slope of cut of the work implement; and

commanding an implement control system to elevationally move the work implement and change the relative elevational position of the first and second point locations.