System for determining an implement arm position

• US 20040117094A1
• Filed: 12/17/2002
• Published: 06/17/2004
• Est. Priority Date: 12/17/2002
• Status: Active Grant

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Colburn, Stephen
• Granted Patent: US 6,865,464 B2
• Time in Patent Office: Days
• US Class Current: 701/50
• CPC Class Codes: E02F 3/435 for dipper-arms, backhoes or the like
• CPC Class Codes: E02F 9/264 Sensors and their calibration for indicating the position of the work tool

Abstract

A control system for determining a position of an implement arm having a work implement is disclosed. The implement arm includes mating components. The control system includes at least one sensor operably associated with the implement arm and configured to sense positional aspects of the implement arm. A controller is adapted to calculate a position of the implement arm based on signals received from the at least one sensor. The calculated position takes into account shifting of the implement arm caused by clearances existing between the mating components of the implement arm.

Claims

1. A control system for determining a position of an implement arm having a work implement, the implement arm having mating components, comprising:

at least one sensor operably associated with the implement arm and configured to sense positional aspects of the implement arm; and

a controller adapted to calculate a position of the implement arm based on signals received from the at least one sensor, the calculated position taking into account shifting of the implement arm caused by clearances existing between the mating components of the implement arm.

2. The control system of claim 1, wherein the mating components are connected by a pin connection and the clearances existing between the mating components include a pin clearance at the pin connection.

3. The control system of claim 2, wherein the mating components of the implement arm include:

a boom;

a stick attached at a stick joint to the boom; and

a work implement attached at a work implement joint to the stick.

4. The control system of claim 1, wherein the controller is adapted to take into account the shifting by determining an angular rotation of the mating components of the implement arm caused by the clearances.

5. The control system of claim 1, wherein the controller is adapted to determine a first calculated position and a second calculated position and determine a movement distance of the implement arm by comparing the first calculated position with the second calculated position.

6. The control system of claim 5, further including a display configured to show the movement distance.

7. The control system of claim 1, wherein the at least one sensor includes a load sensor operably associated with the implement arm, the controller being adapted to determine a load applied to the implement arm based on signals received from the load sensor, so as to determine the shifting when external loads are applied to the implement arm.

8. The control system of claim 7 wherein the load sensor is a strain gauge.

9. The control system of claim 1, further including:

a fluid powered actuator associated with the implement arm for moving the implement arm; and

the at least one sensor includes a load sensor operably associated with the fluid powered actuator, the controller being adapted to determine a load applied to the implement arm based on signals from the load sensor, so as to determine the shifting when external loads are applied to the implement arm.

10. The control system of claim 1, wherein the controller is adapted to determine shifting based upon a static equilibrium analysis.

11. A method for determining a position of an implement arm having a work implement, the implement arm having mating components, comprising:

sensing a positional aspect of the implement arm with a sensor; and

calculating a position of the implement arm based on signals received from the sensor, wherein calculating the position includes taking into account shifting of the implement arm caused by clearances existing between the mating components of the implement arm.

12. The method of claim 11, wherein the mating components are connected by a pin connection and the clearances existing between the mating components include a pin clearance at the pin connection.

13. The method of claim 11, wherein taking into account the shifting includes determining an angular rotation of the mating components of the implement arm caused by the clearances.

14. The method of claim 11, further including:

determining a first calculated position;

determining a second calculated position; and

determining a movement distance of the implement arm by comparing the first calculated position with the second calculated position.

15. The method of claim 14, further including displaying the movement distances of the implement arm to an operator.

16. The method of claim 15, further including displaying the movement distances of the implement arm in real-time.

17. The method of claim 14, further including determining the movement distance on board the work machine.

18. The method of claim 11, further including

sensing an external load applied to the implement arm with a load sensor operably associated with the implement arm based on signals from the load sensor;

and

determining the shifting when the external load is applied to the implement arm.

19. The method of claim 11, wherein a fluid powered actuator is associated with the implement arm for moving the implement arm, the method further including:

sensing pressure of the fluid within the fluid powered actuator with a load sensor;

determining a load applied to the implement arm based on signals from the load sensor; and

determining the shifting when the external load is applied to the implement arm.

20. A method for determining a position of an implement arm having a work implement, the implement arm having mating components connected at joints, comprising:

sensing a positional aspect of the implement arm with a sensor;

determining an angular rotation of the mating components of the implement arm due to shifting at the joints caused by clearances between the mating components of the implement arm;

calculating a first position of the implement arm based on signals received from the sensor, wherein calculating the first position includes taking into account the shifting at the joints between mating components;

storing the calculated position as a first position;

calculating a second position of the implement arm, wherein calculating the second position includes taking into account the shifting at the joints between mating components;

obtaining a movement distance of the implement arm by comparing the first position of the implement arm with the second position of the implement arm; and

displaying the movement distance to an operator in real-time.