STEERING SYSTEM WITH AUTOMATED ARTICULATION CONTROL

• US 20110035109A1
• Filed: 08/05/2009
• Published: 02/10/2011
• Est. Priority Date: 08/05/2009
• Status: Active Grant

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Newberry, Phillip A., Bhaskar, Vivek, Wiewel, Bruce, Ryerson, Cody J., Zhu, Yongliang
• Granted Patent: US 8,548,680 B2
• Time in Patent Office: Days
• US Class Current: 701/42
• CPC Class Codes: B62D 12/00 Steering specially adapted for vehicles operating in tandem or having pivotally connected frames steering endless tracks or the like B62D11/00; steering specially adapted for trailers B62D13/00
• CPC Class Codes: B62D 53/045 with rigid linkage in the horizontal plane luggage trailers B62D63/064 - B62D63/067
• CPC Class Codes: B62D 9/00 Steering deflectable wheels not otherwise provided for steering positon indicators B62D15/02
• CPC Class Codes: E02F 9/0841 Articulated frame, i.e. having at least one pivot point between two travelling gear units tractor-trailer combinations B62D53/00
• CPC Class Codes: E02F 9/225 Control of steering, e.g. for hydraulic motors driving the vehicle tracks steering in general B62D
• CPC Class Codes: E02F 9/264 Sensors and their calibration for indicating the position of the work tool

Abstract

An articulated machine and method of operation, the articulated machine having a first frame with a first traction device and a steering apparatus that controls a steering angle thereof, the first frame pivotally coupled to a second frame at an articulation joint, the second frame having a second traction device, a steering sensor configured to provide a steering signal indicative of the steering angle, and an electronic controller configured to automatically control an articulation angle based on the steering signal.

Claims

1. An articulated machine, comprising:

a first frame having a first traction device and a steering apparatus operable to control a steering angle of the first traction device;

a second frame pivotally coupled to the first frame at an articulation joint, the second frame having a second traction device;

a steering sensor configured to provide a steering signal indicative of the steering angle; and

an electronic controller configured to automatically control an articulation angle of the first frame relative to the second frame based on the steering signal.

2. The articulated machine of claim 1, wherein the controller is configured to command an articulation angle to conform a turning radius of the first frame to a turning radius of the second frame.

3. The articulated machine of claim 2, wherein the first traction device includes a first wheel and a second wheel disposed on opposing sides of the first frame, and the turning radius of the first frame is defined by a point equidistant between the first wheel and the second wheel.

4. The articulated machine of claim 3, wherein the second traction device includes a first wheel and a second wheel disposed on opposing sides of the second frame, and the turning radius of the second frame is defined by a point equidistant between the first and second wheels of the second frame.

5. The articulated machine of claim 3, wherein the second traction device includes a first tandem and a second tandem pivotally connected on opposing sides of the second frame, and the turning radius of the second frame is defined by a point equidistant between a pivotal connection of the opposing first and second tandems.

6. The articulated machine of claim 1, further comprising an articulation sensor configured to provide an articulation signal indicative of an articulation angle, the controller further configured to control the articulation angle based on the articulation signal.

7. The articulated machine of claim 1, wherein the controller is configured to limit the steering angle of the first traction device based on a maximum articulation angle.

8. The articulated machine of claim 1, wherein the controller is configured to provide a communication signal to an operator indicator when the steering angle exceeds a maximum steering angle allowable based on a maximum articulation angle.

9. The articulated machine of claim 1, further comprising a mode selector that provides a mode signal to the controller selecting between an automatic mode, wherein control of the articulation angle by the controller is based on the steering angle, and a manual mode wherein the articulation angle and the steering angle are manually controlled.

10. The machine of claim 9, further comprising a powertrain sensor configured to monitor machine speed, wherein the automatic mode is disengaged when the machine speed is above a desired machine speed.

11. The machine of claim 9, further comprising a transmission sensor configured to monitor a transmission output ratio or gear selection, wherein the automatic mode is disengaged based upon the output ratio or gear selection.

12. The articulated machine of claim 1, wherein the controller is configured to control the articulation angle by calculating a desired articulation angle at which a turning radius of the first frame equals a turning radius of the second frame based on the steering angle, and responsively commanding an actuator to the desired articulation angle.

13. The articulated machine of claim 1, wherein the controller is configured to employ the steering signal in connection with one of a table or map to command the articulation angle.

14. The articulated machine of claim 1, wherein the first traction device includes a first wheel and a second wheel disposed on opposing sides of the first frame, the machine having a first steering sensor associated with the first wheel and a second steering sensor associated with the second wheel, wherein the steering angle is an average steering angle calculated by the controller based on signals received from the first and second steering sensors.

15. A method of operating a motor grader having steerable front wheels and a front and rear frame pivotally connected at an articulation joint, comprising:

selecting an automatic articulation mode;

propelling the motor grader along a direction of travel;

commanding front wheel steering to turn the motor grader; and

providing a front wheel steering signal to an electronic controller, the electronic controller automatically commanding articulation of the front frame relative to the rear frame about the articulation joint in response to the front wheel steering signal.

16. The method of claim 15, wherein the front wheel steering signal is indicative of a front wheel steering angle, the controller being configured to command an articulation angle that conforms a turning radius of the front frame to a turning radius of the rear frame based upon the steering angle.

17. The method of claim 15, wherein the front wheel steering signal is indicative of a front wheel steering angle, and the controller derives the commanded articulation by comparing the front wheel steering angle to a table or map stored in a memory of the controller.

18. The method of claim 15, further comprising providing a travel speed, transmission gear, or transmission output ratio signal to the controller, the controller determining whether or not to command articulation based upon the travel speed, transmission gear or transmission output ratio.

19. The method of claim 15, the controller limiting front wheel steering based upon a maximum allowable articulation angle.

20. A motor grader, comprising:

a front frame having a first and second steerable wheel disposed on opposing sides of the frame;

a rear frame pivotally coupled to the front frame at an articulation joint, a first and second articulation cylinder disposed between the front and rear frames in opposing orientation, the rear frame having a tandem with two rear wheels pivotally connected on opposing sides of the rear frame;

a steering sensor configured to provide a steering signal indicative of a steering angle of the first and second steerable wheels; and

an electronic controller configured to automatically command the first and second articulation cylinders to control an articulation angle of the first frame relative to the rear frame based on the steering angle.