Method and system for controlling the height of an agricultural implement relative to the ground

1. A method for automatically controlling a height of an implement of an agricultural work vehicle relative to a ground surface, the method comprising:

monitoring, with one or more computing devices, the height of the implement relative to the ground surface;

determining, with the one or more computing devices, a proportional signal by comparing the height of the implement with a predetermined target height;

detecting, with the one or more computing devices, a local inclination of the ground surface in a direction of travel of the agricultural work vehicle;

calculating, with the one or more computing devices, a derivative signal based on the local inclination of the ground surface; and

adjusting, with the one or more computing devices, the height of the implement relative to the ground surface based on an output signal of a PD or PID control loop calculated as a function of both the proportional signal and the derivative signal.

2. The method of claim 1 , further comprising calculating an integral signal based on the height of the implement relative to the ground surface, and wherein the output signal further comprises the integral signal and is output from the PID control loop.

3. The method of claim 2 , wherein detecting the local inclination of the ground surface comprises receiving signals from at least one inclination sensor.

4. The method of claim 3 , wherein the at least one inclination sensor is coupled to at least one of the implement or a component coupled to the implement.

5. The method of claim 1 , wherein detecting the local inclination of the ground surface comprises detecting the local inclination of a portion of the ground surface that is aft of a leading edge of the implement with respect to the direction of travel of the work vehicle.

6. The method of claim 1 , wherein:

monitoring the height of the implement relative to the ground surface comprises monitoring the height of the implement at a height monitoring location; and

detecting the local inclination of the ground surface comprises detecting the local inclination of a portion of the ground surface that is forward of the height monitoring location and aft of a leading edge of the implement with respect to the direction of travel of the work vehicle.

7. The method of claim 1 , wherein detecting the local inclination of the ground surface comprises:

detecting a first distance between at least one inclination sensor and a first location on the ground surface;

detecting a second distance between the at least one inclination sensor and a second location on the ground surface that is spaced apart from the first location in the direction of travel of the agricultural work vehicle; and

calculating the local inclination based on the first distance and the second distance.

8. The method of claim 7 , wherein each of the first location and second location is located aft of a leading edge of the implement with respect to the direction of travel.

9. The method of claim 7 , wherein the second location is spaced apart from the first location in the direction of travel of the agricultural work vehicle by a distance that is less than half of a width of the implement in a lateral direction that is perpendicular to the direction of travel of the agricultural work vehicle.

10. The method of claim 1 , wherein detecting the local inclination of the ground surface comprises detecting an inclination of a portion of the ground surface that is located below at least a portion of the implement.

11. The method of claim 1 , wherein calculating the derivative signal based on the local inclination of the ground surface is free of calculating a rate of change of an implement height error.

12. A height control system for an implement of an agricultural work vehicle, the control system comprising:

an implement;

an inclination sensor configured to detect a local inclination of a ground surface;

a controller communicatively coupled to the inclination sensor, the controller including a processor and associated memory, the memory storing instructions that, when executed by the processor, configure the controller to:

monitor a height of the implement relative to the ground surface;

determine a proportional signal by comparing the height of the implement with a predetermined target height;

detect a local inclination of the ground surface in a direction of travel of the agricultural work vehicle based on signals received from the inclination sensor;

calculate a derivative signal based on the local inclination of the ground surface; and

adjust the height of the implement relative to the ground surface based on an output signal of a PD or PID control loop calculated as a function of both the proportional signal and the derivative signal.

13. The system of claim 12 , wherein the controller is further configured to calculate an integral signal based on the height of the implement relative to the ground surface, and wherein the output signal further comprises the integral signal and is output from the PID control loop.

14. The system of claim 12 , wherein the inclination sensor is coupled to at least one of the implement or a component coupled to the implement.

15. The system of claim 12 , wherein detecting the local inclination of the ground surface comprises detecting the local inclination of a portion of the ground surface that is aft of a leading edge of the implement with respect to the direction of travel of the work vehicle.

16. The system of claim 12 , wherein:

the height of the implement relative to the ground surface is monitored at a height monitoring location; and

the local inclination of the ground surface is detected for a portion of the ground surface that is forward of the height monitoring location and aft of a leading edge of the implement with respect to the direction of travel of the work vehicle.

17. The system of claim 12 , wherein:

the inclination sensor is configured to detect a first distance between the inclination sensor and a first location on the ground surface and configured to detect a second distance between the inclination sensor and a second location on the ground surface that is spaced apart from the first location in the direction of travel of the agricultural work vehicle; and

the controller is configured to calculate the local inclination based on the first distance and the second distance to detect the local inclination of the ground surface.

18. The system of claim 17 , wherein the first location is located aft of a leading edge of the implement with respect to the direction of travel.

19. The system of claim 17 , wherein the second location is spaced apart from the first location in the direction of travel of the agricultural work vehicle by a distance that is less than half of a width of the implement in a lateral direction that is perpendicular to the direction of travel of the agricultural work vehicle.

20. The system of claim 12 , the local inclination of the ground surface is detected for a portion of the ground surface that is located below at least a portion of the implement.