Agricultural Header Height Control Using Ground-Inclination Sensing
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Solution Overview
Problem
Existing agricultural harvesters face significant lag and slow response times in automatically adjusting the header height relative to the ground, especially at high speeds, due to retrospective derivative signal calculations based on past height measurements.
Innovation Solution
A proportional-integral-derivative (PID) control system that calculates the derivative signal based on real-time local ground inclination using sensors, anticipating imminent changes in header height to achieve smoother and more accurate control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If retrospective derivative signal calculations based on past height measurements are used, then the control system can be simpler to implement, but the response time becomes slow and lag increases significantly at high speeds
Solution Approach 1:
The patent applies preliminary action by using inclination sensors to detect ground slope changes before they affect header height, allowing the control system to anticipate and compensate for upcoming height variations. This proactive approach eliminates the lag inherent in retrospective calculations, enabling the system to respond to ground contours in advance rather than after they occur.
Solution Approach 2:
The patent introduces inclination sensors as intermediary devices that measure ground slope information and feed this data to the control system. These sensors act as mediators between the ground surface conditions and the header height control, providing forward-looking information about terrain changes without requiring complex retrospective analysis of past height measurements.
2Extent of automation
If electronically controlled height and tilt cylinders are used to automatically adjust header height, then automation is improved, but significant lag and slow response times occur at high ground speeds
Solution Approach 1:
The system performs preliminary detection of ground inclination changes before they manifest as header height deviations. By measuring the slope of the ground surface in advance and calculating the anticipated height change, the control system can initiate cylinder actuation before the actual height deviation occurs, eliminating lag and achieving instantaneous response even at high ground speeds.
Solution Approach 2:
The patent implements a feedback mechanism that continuously monitors both actual header height and predicted height changes based on ground inclination. This dual feedback approach compares real-time measurements with predicted values and adjusts cylinder actuation accordingly, ensuring the header maintains optimal height despite rapid ground variations at high speeds.
3Reliability
If conventional height control systems are used, then the system can maintain basic functionality, but jitter and jerk in header height control are significant
Solution Approach 1:
By detecting ground inclination changes in advance and calculating the anticipated header height deviation before it occurs, the system can apply smooth, proactive adjustments rather than reactive corrections. This preliminary action eliminates abrupt changes and reduces jitter, resulting in smooth and stable header height control even when traversing uneven terrain at high speeds.
Data Source
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AI summary
In one aspect, a method (300) for automatically controlling a height of an implement (32) of an agricultural work vehicle (10) relative to a ground surface (19) may include monitoring the height (120) of the implement (32) relative to the ground surface (19); determining a proportional signal by comparing the height (120) of the implement (32) with a predetermined target height; detecting a local inclination (66) of the ground surface (19); calculating a derivative signal based on the local inclination (66) of the ground surface (19); and adjusting the height (120) of the implement (32) relative to the ground surface (19)based on an output signal that includes the proportional signal and the derivative signal.