System and method for detecting a crest

1. A system for automated control of a machine having a ground engaging work implement, comprising:

an implement load sensor system configured to measure a load on the ground engaging work implement indicative of an amount of material being moved by the ground engaging work implement along a work surface and provide an implement load signal indicative of the load on the ground engaging work implement to a controller;

the controller configured to:

store a threshold change in elevation, the threshold change in elevation being indicative of proximity to a crest;

receive the implement load signal;

determine a reduction in load on the ground engaging work implement;

determine a change in elevation of the work surface based at least in part upon the reduction in load on the ground engaging work implement;

determine whether the change in elevation of the work surface exceeds the threshold change in elevation of the work surface; and

generate an alert command signal if the change in elevation of the work surface exceeds the threshold change in elevation of the work surface.

2. The system of claim 1 , wherein the controller is further configured to store a work area for the machine including a crest zone adjacent a crest, the alert command signal includes a reverse command signal, and the controller only generates the reverse command signal while the machine is operating within the crest zone.

3. The system of claim 2 , further including a position sensing system to provide a signal indicative of a position of the machine and the controller is configured to determine whether the machine is within the crest zone.

4. The system of claim 2 , wherein the controller is configured to store a data map of implement load signals and associated operating characteristics for use while the machine is operating within the crest zone, and compare the implement load signal to the data map of implement load signals while the machine is within the crest zone to determine the change in elevation of the work surface.

5. The system of claim 1 , further including a pitch angle sensor, and the controller determines the change in elevation of the work surface at least in part based upon a signal from the pitch angle sensor.

6. The system of claim 1 , wherein the alert command signal includes a reverse command signal.

7. The system of claim 1 , wherein the implement load sensor system includes a sensor for monitoring a difference between output from a prime mover and output from a torque converter, and the controller determines a reduction in the load on the ground engaging work implement based at least in part upon the reduction in the difference between the output from the prime mover and the output from the torque converter.

8. The system of claim 1 , wherein the implement load sensor system includes a pressure sensor for monitoring pressure within a hydraulic cylinder operatively connected to the ground engaging work implement, and the controller determines the reduction in load on the ground engaging work implement based at least in part upon a decrease in pressure within the hydraulic cylinder.

9. The system of claim 1 , wherein the implement load sensor system includes an acceleration sensor for monitoring acceleration of the machine, and the controller determines the reduction in load on the ground engaging work implement based at least in part upon acceleration of the machine.

10. A controller implemented method of detecting a change in elevation of a work surface, comprising:

providing a machine having a ground engaging work implement;

providing an implement load sensor system configured to measure a load on the ground engaging work implement indicative of an amount of material being moved by the ground engaging work implement along the work surface;

receiving the implement load signal;

determining a reduction in load on the ground engaging work implement;

determining a change in elevation of the work surface based at least in part upon the reduction in load on the ground engaging work implement;

determining whether the change in elevation of the work surface exceeds a threshold change in elevation of the work surface; and

generating an alert command signal if the change in elevation of the work surface exceeds the threshold change in elevation of the work surface.

11. The controller implemented method of claim 10 , further including generating a reverse command signal.

12. The controller implemented method of claim 10 , wherein the implement load sensor system includes a sensor for monitoring a difference between output from a prime mover and output from a torque converter, and further including determining the reduction in the load on the ground engaging work implement based at least in part upon a reduction in the difference between the output from the prime mover and the output from the torque converter.

13. The controller implemented method of claim 10 , wherein the implement load sensor system includes a pressure sensor for monitoring pressure within a hydraulic cylinder operatively connected to the ground engaging work implement, and further including determining the reduction in load on the ground engaging work implement based at least in part upon a decrease in pressure within the hydraulic cylinder.

14. The controller implemented method of claim 10 , wherein the implement load sensor system includes an acceleration sensor for monitoring acceleration of the machine and further including determining the reduction in load on the ground engaging work implement based at least in part upon acceleration of the machine.

15. The controller implemented method of claim 10 , further including storing a work area for the machine including a crest zone adjacent a crest, and determining whether the machine is operating within the crest zone and only generating a reverse command signal as part of the alert command signal if the machine is operating within the crest zone.

16. The controller implemented method of claim 10 , further including a pitch angle sensor, receiving a signal from the pitch angle sensor indicative of the pitch angle of the machine and determining the change in elevation of the work surface at least in part based upon the pitch angle of the machine.

17. A machine comprising:

a prime mover;

a blade for moving material along a work surface;

an implement load sensor system configured to measure a load on the blade, the load being indicative of an amount of material being moved by the blade, and provide an implement load signal indicative of the load on the blade to a controller; and

the controller configured to:

receive the implement load signal;

determine a reduction in load on the ground engaging work implement;

determine a change in elevation of the work surface based at least in part upon the reduction in load on the blade;

determine whether the change in elevation of the work surface exceeds a threshold change in elevation of the work surface; and

generate an alert command signal if the change in elevation of the work surface exceeds the threshold change in elevation of the work surface.

18. The machine of claim 17 , wherein the implement load sensor system includes a sensor for monitoring a difference between output from a prime mover and output from a torque converter, and the controller determines the reduction in the load on the blade based at least in part upon a reduction in the difference between the output from the prime mover and the output from the torque converter.

19. The machine of claim 17 , wherein the implement load sensor system includes a pressure sensor for monitoring pressure within a hydraulic cylinder operatively connected to the blade, and the controller determines the reduction in load on the blade based at least in part upon a decrease in pressure within the hydraulic cylinder.

20. The machine of claim 17 , wherein the implement load sensor system includes an acceleration sensor for monitoring acceleration of the machine, and the controller determines the reduction in load on the blade based at least in part upon acceleration of the machine.

21. A system for automated control of a machine having a ground engaging work implement, comprising:

means for measuring a load on the ground engaging work implement, the load being indicative of an amount of material being moved by the ground engaging work implement along a work surface;

means for determining a reduction in load on the ground engaging work implement;

means for determining a change in elevation of the work surface based at least in part upon the reduction in load on the ground engaging work implement;

means for determining whether the change in elevation of the work surface exceeds a threshold change in elevation of the work surface and signifies proximity to a crest; and

means for generating an alert command signal if the machine is in proximity to the crest.