Method and apparatus for calculating work cycle times

• US 5,955,706 A
• Filed: 11/26/1997
• Issued: 09/21/1999
• Est. Priority Date: 11/26/1997
• Status: Expired due to Term

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Heyveld, Doyle G., Reiners, Eric A., Fonkalsrud, Andrew O.
• Primary Examiner(s): Gibson, Randy W.
• Application Number:
  US08/979,885
• Time in Patent Office: 664 Days
• Field of Search: 177/136, 177/137, 177/138, 177/139, 177/141, 701/29, 701/35, 701/50
• US Class Current: 177/136
• CPC Class Codes: E02F 3/434 providing automatic sequences of movements, e.g. automatic dumping or loading, automatic return-to-dig
• CPC Class Codes: E02F 9/2025 Particular purposes of control systems not otherwise provided for E02F3/16, E02F3/26, sub-groups of E02F3/43, E02F3/651, sub-groups of E02F3/84, E02F3/907, E02F5/145 take precedence
• CPC Class Codes: G01G 19/083 lift truck scale

Abstract

In one aspect of the present invention, a method for determining the work cycle of an earth moving machine is disclosed. The machine has a transmission, a work implement, and a lift cylinder and a tilt cylinder connected to the work implement. The method includes the steps of determining a lift cylinder head end pressure, a displacement of the lift cylinder, a displacement of the tilt cylinder, and a direction of travel of the machine. The method further includes determining the work cycle of the machine in response to the displacement of the tilt and lift cylinders, and the lift cylinder head end pressure.

Claims

1. A method for determining the segments of a work cycle of an wheel loader, said wheel loader having a transmission, a work implement, a lift cylinder connected to said work implement, and a tilt cylinder connected to said work implement, the lift and tilt cylinders each having a rod end and a head end, comprising the steps of:

determining a current segment of the work cycle;

determining one of a lift cylinder head end pressure, a lift cylinder displacement, and a tilt cylinder displacement in response to said current segment;

determining a direction of travel of said earth moving machine; and

,

determining a beginning of a next segment of said work cycle in response to said direction of travel, said current segment, and said one of said tilt cylinder displacement, said lift cylinder displacement, and said lift cylinder head end pressure, and wherein said work cycle includes a dig segment, a travel loaded segment, a dump segment, and a travel empty segment.

2. A method as set forth in claim 1, wherein the step of determining a lift cylinder head end pressure includes determining a total lift force in response to said lift cylinder head end pressure.

3. A method as set forth in claim 2, wherein the step of determining said work cycle includes determining said work cycle in response to said direction of travel, said lift and tilt cylinder displacement, and said total lift force.

4. A method as set forth in claim 1, wherein the step of determining a direction of travel of said earth moving machine further comprises determining an output speed of said transmission.

5. A method as set forth in claim 1, wherein said step of determining said next segment of said work cycle further comprises the step of determining a beginning of said dig segment in response to said lift cylinder head end pressure and said current segment being said travel empty segment.

6. A method as set forth in claim 5, wherein the step of determining said work cycle further comprises the step of determining the beginning of said travel loaded segment in response to said direction of travel, said lift cylinder displacement and said current segment being said dig segment.

7. A method as set forth in claim 6, wherein the step of determining said work cycle further comprises the step of determining the beginning of said dump segment in response to said tilt cylinder displacement and said current segment being said travel loaded segment.

8. A method as set forth in claim 7, wherein the step of determining said work cycle further comprises the step of determining the beginning of said travel empty segment in response to said current segment being said dump segment, said direction of travel and said lift cylinder displacement.

9. A method as set forth in claim 5, wherein the step of determining the beginning of said dig segment further comprises determining the beginning of said dig segment in response to a current segment of said work cycle being said travel empty segment and said lift cylinder head end pressure being less than a first pre-determined value.

10. A method as set forth in claim 6, wherein the step of determining the beginning of said travel loaded segment further comprises determining the beginning of said travel loaded segment in response to a current segment of said work cycle being said dig segment and said direction of travel being a reverse direction and said lift cylinder displacement being less than a second pre-determined value.

11. A method as set forth in claim 7, wherein the step of determining the beginning of said dump segment includes determining the beginning of said dump segment in response to said current segment of said work cycle being said travel loaded segment and determining a velocity of said tilt cylinder.

12. A method as set forth in claim 8, wherein the step of determining the beginning of said travel empty segment includes determining the beginning of said travel empty segment in response to a current segment of said work cycle being a dump segment and said direction of travel being a reverse direction, and said lift cylinder displacement being one of greater than and equal to a second predetermined value.

13. An apparatus for determining the segments of a work cycle of an wheel loader, said wheel loader having a transmission, a work implement, a lift cylinder connected to said work implement, and a tilt cylinder connected to said work implement, the lift and tilt cylinders each having a rod end and a head end, comprising:

a first lift cylinder sensing means for sensing a lift cylinder head end pressure and responsively producing a lift cylinder pressure signal;

a second lift cylinder sensing means for sensing a displacement of said lift cylinder and responsively producing a lift cylinder displacement signal;

a tilt cylinder sensing means for sensing a displacement of said tilt cylinder and responsively producing a tilt cylinder displacement signal;

a direction sensing means for sensing a direction of travel of said earth moving machine and responsively generating a direction signal; and

,

a processing means for receiving said lift cylinder pressure signal, said lift cylinder displacement signal, said tilt cylinder displacement signal, and said direction signal, determining a current segment of the work cycle, and responsively determining a next segment of said work cycle in response to said direction of travel signal, said tilt cylinder displacement signal, said lift cylinder displacement signal, said lift cylinder head end pressure signal, and said current segment of said work cycle, wherein said work cycle includes a dig segment, a travel loaded segment, a dump segment, and a travel empty segment.

14. An apparatus as set forth in claim 13 wherein said processing means further comprises determining a total lift force in response to said lift cylinder head end pressure signal, and determining said work cycle in response to said total lift force, said direction signal, said lift cylinder displacement signal, and said tilt cylinder displacement signal.

15. An apparatus as set forth in claim 13, wherein said means for sensing a direction of travel of said earth moving machine further comprises determining an output speed of said transmission.

16. An apparatus as set forth in claim 13, said processing means further comprises determining a beginning of said dig segment in response to said lift cylinder head end pressure signal.

17. An apparatus as set forth in claim 16, wherein said processing means further comprises determining the beginning of said travel loaded segment in response to said direction of travel and said lift cylinder displacement.

18. An apparatus as set forth in claim 17, wherein said processing means further comprises determining the beginning of said dump segment in response to said tilt cylinder displacement.

19. An apparatus as set forth in claim 18, wherein said processing means further comprises determining the beginning of said travel empty segment in response to said direction of travel and said lift cylinder displacement.

20. An apparatus as set forth in claim 19, wherein said processing means further comprises determining the beginning of said dig segment in response to a current segment of said work cycle being said travel empty segment and said lift cylinder head pressure is less than a first pre-determined value.

21. An apparatus as set forth in claim 17, wherein said processing means further comprises determining the beginning of said travel loaded segment in response to a current segment of said work cycle being said dig segment and said direction of travel being a reverse direction, and said lift cylinder displacement being less than a second predetermined value.

22. An apparatus as set forth in claim 18, wherein said processing means further includes determining the beginning of said dump segment in response to a current segment of said work cycle being said travel loaded segment, and determining a velocity of said tilt cylinder.

23. An apparatus as set forth in claim 19, wherein said processing means further includes determining the beginning of said travel empty segment in response to a current segment of said work cycle being said dump segment, and said direction of travel being a reverse direction, and said lift cylinder displacement being one of greater than and equal to a second pre-determined value.

24. An apparatus for determining the segments of a work cycle of an wheel loader, said wheel loader having a transmission, a work implement, a lift cylinder connected to said work implement, and a tilt cylinder connected to said work implement, the lift and tilt cylinders each having a rod end and a head end, comprising:

a first lift cylinder sensor adapted to sense a lift cylinder head end pressure and responsively produce a lift cylinder pressure signal;

a second lift cylinder sensor adapted to sense a displacement of said lift cylinder and responsively produce a lift cylinder displacement signal;

a tilt cylinder sensor adapted to sense a displacement of said tilt cylinder and responsively produce a tilt cylinder displacement signal;

a direction sensor adapted to sense a direction of travel of said earth moving machine and responsively generate a direction signal; and

,

a process system adapted to receive said lift cylinder pressure signal, said lift cylinder displacement signal, said tilt cylinder displacement signal, and said direction signal, determine a current segment of the work cycle, and responsively determine a next segment of said work cycle in response to said direction of travel signal, said tilt cylinder displacement signal, said lift cylinder displacement signal, said lift cylinder head end pressure signal, and said current segment of said work cycle, wherein said work cycle includes a dig segment, a travel loaded segment, a dump segment, and a travel empty segment.