Machine, Control System And Method For Hovering An Implement

• US 20130108403A1
• Filed: 11/02/2011
• Published: 05/02/2013
• Est. Priority Date: 11/02/2011
• Status: Active Grant

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Atkinson, David C.
• Granted Patent: US 8,843,282 B2
• Time in Patent Office: Days
• US Class Current: 414/685
• 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 3/439 Automatic repositioning of the implement, e.g. automatic dumping, auto-return E02F3/438 takes precedence
• CPC Class Codes: E02F 9/2041 Automatic repositioning of implements, i.e. memorising determined positions of the implement for dipper-arms or bucket-arms E02F3/434, E02F3/437, E02F3/438, E02F3/439 take precedence
• CPC Class Codes: E02F 9/265 with follow-up actions (e.g. control signals sent to actuate the work tool)

Abstract

A machine such as a wheel loader includes a frame and ground engaging propulsion elements coupled with the frame. A hydraulically actuated implement system of the machine includes a linkage and an implement and is adjustable from a starting configuration to a second configuration according to a substrate collision avoiding pattern. In the second configuration, the implement hovers above a substrate beneath the machine. Related methodology and control logic is also disclosed.

Claims

1. A method of controlling a hydraulically actuated implement system having a linkage and an implement, in a self-propelled ground engaging machine, comprising the steps of:

electronically reading a stored value which is linked with a starting configuration of the implement system, responsive to an implement hover command;

outputting a control signal to the implement system which is based at least in part on the stored value; and

actuating the implement system responsive to the control signal, such that the implement system moves according to a substrate collision avoiding pattern from the starting configuration to a second configuration at which the implement hovers above a substrate beneath the machine.

2. The method of claim 1 further comprising a step of receiving the implement hover command while the linkage is raised, and wherein the step of actuating further includes lowering the implement system from the starting configuration to the second configuration.

3. The method of claim 2 further comprising a step of receiving data indicative of a starting linkage state, the starting configuration being defined at least in part by the starting linkage state from among a plurality of possible starting configurations.

4. The method of claim 3 wherein the linkage includes a lift arm and the implement includes a bucket, and wherein the step of receiving data further includes receiving data indicative of position, travel speed, and travel direction, of the lift arm.

5. The method of claim 4 wherein the step of actuating further includes tilting the bucket responsive to the starting linkage state.

6. The method of claim 3 wherein the step of electronically reading further includes reading the stored value at an address having a starting linkage state coordinate.

7. The method of claim 6 wherein the step of electronically reading further includes reading the stored value at an address having an implement type coordinate.

8. The method of claim 6 wherein the step of electronically reading includes reading a stored gain.

9. The method of claim 8 wherein the step of receiving the implement hover command includes receiving the command from an operator input device having a total of two different states.

10. The method of claim 1 wherein the step of actuating further includes actuating the implement system such that the implement hovers at a height above the substrate which is less than about 5% of a maximum lift height of the implement, during forward travel of the machine.

11. A control system for a hydraulically actuated implement system having a linkage and an implement, in a self-propelled ground engaging machine, comprising:

a computer readable memory storing a value linked with a starting configuration of the implement system;

an electronic control unit coupled with the computer readable memory and configured to read the stored value, in response to an implement hover command; and

the electronic control unit being further configured to output a control signal to the implement system which is based at least in part on the stored value, such that the implement system moves according to a substrate collision avoiding pattern from the starting configuration to a second configuration at which the implement hovers above a substrate beneath the machine.

12. The control system of claim 11 wherein the value is one of a plurality of values stored on the computer readable memory and each being linked to a different one of a plurality of possible starting configurations of the implement system.

13. The control system of claim 12 wherein each of the plurality of stored values has an address on the computer readable memory including a starting linkage position coordinate, whereby the plurality of stored values are linked to the plurality of possible starting configurations.

14. The control system of claim 12 wherein the electronic control unit is further configured to receive data indicative of a throttle position in the machine and to output the control signal responsive to the data indicative of throttle position.

15. The control system of claim 12 wherein the value includes a stored gain.

16. The control system of claim 12 further comprising a sensor configured to sense a position of the linkage, and wherein the electronic control unit is coupled with the sensor and configured to read the stored value responsive to a sensed starting position of the linkage.

17. The control system of claim 16 wherein the electronic control unit is further configured to output the control signal to a control valve for a lift actuator of the linkage and to output another control signal to a control valve for a tilt actuator of the implement.

18. The control system of claim 17 wherein the substrate collision avoiding pattern is defined in part by a speed of rotation of the linkage about a pivot axis with the machine and in part by a speed of rotation of the implement about a pivot axis with the linkage, and wherein the electronic control unit is further configured to output the another control signal such that a commanded speed of the implement is responsive to a commanded speed of the linkage.

19. A machine comprising:

a frame;

ground engaging propulsion elements coupled with the frame;

a hydraulically actuated implement system having a linkage and an implement;

an electronic control unit in control communication with the implement system and configured to adjust the implement system from a starting configuration to a second configuration at which the implement hovers above a substrate beneath the machine; and

the electronic control unit being further configured to receive data indicative of the starting configuration and responsively adjust the implement system to the second configuration according to a substrate collision avoiding pattern.

20. The machine of claim 19 comprising a wheel loader wherein the linkage includes a lift arm and the implement includes a bucket, and further comprising a sensor group configured to sense a position of the lift arm and a position of the bucket in a reference frame defined by the machine;

and

wherein the electronic control unit is further configured to adjust the implement system to the second configuration responsive to the sensed positions such that the implement hovers at a height above the substrate which is less than about 5% of a maximum lift height of the implement.