Hydraulic Top Link Force Control for Three-Point Hitch Alignment
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Solution Overview
Problem
Operators of agricultural tractors face challenges in maintaining the correct extended position of the hydraulic upper link during tillage, requiring manual adjustments and experience to ensure proper attachment alignment and traction control, especially when dealing with varying ground contours.
Innovation Solution
A method for controlling the hydraulic upper link that adjusts its extended position based on sensor-detected tensile or compressive forces using a characteristic curve, allowing for automated adjustments within a predetermined range, and optionally modifying the curve based on topographical information to optimize traction and attachment alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the operator manually adjusts the top link extension position during tillage, then the attachment alignment can be maintained, but this requires continuous operator attention and experience
Solution Approach 1:
The system automatically adjusts the top link extension position based on sensor-detected tensile or compressive forces without requiring operator intervention. The control unit autonomously determines the appropriate extension position using a characteristic curve that relates force to position, enabling the system to self-regulate and maintain proper attachment alignment
Solution Approach 2:
A sensor continuously detects the tensile or compressive force acting on the top link and feeds this information back to the control unit. The control unit processes this feedback signal and automatically adjusts the hydraulic top link extension position to maintain optimal alignment, creating a closed-loop control system
2Adaptability or versatility
If the top link extension position is fixed, then the system structure is simple, but it cannot adapt to varying ground contours and terrain
Solution Approach 1:
The top link extension position is made dynamically adjustable through a hydraulic actuator controlled by a control unit. The system continuously adapts the extension position based on real-time force sensor readings and a characteristic curve, enabling automatic adaptation to varying ground contours and terrain conditions without requiring complex mechanical adjustment mechanisms
Solution Approach 2:
The system changes the extension position parameter of the top link based on detected force variations. By using a characteristic curve that relates force to optimal extension position, the system automatically adjusts this parameter in response to terrain changes, implementing adaptability through parameter modification rather than structural complexity
3Adaptability or versatility
If the coupling pin is used in the slotted hole for movement compensation, then ground irregularities are accommodated, but the top link extension position requires manual readjustment
Solution Approach 1:
The system automatically compensates for ground irregularities by detecting force changes on the top link and autonomously adjusting the extension position using the hydraulic actuator. This eliminates the need for manual readjustment of the coupling pin position in the slotted hole, saving time while maintaining movement compensation capability
Solution Approach 2:
The force sensor provides continuous feedback about the interaction between the implement and ground irregularities. The control unit processes this feedback and automatically adjusts the top link extension position to maintain proper alignment, eliminating the need for manual intervention that would otherwise be required when using a slotted hole configuration
Data Source
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AI summary
Method for controlling a hydraulic top link of a three-point linkage, in which an extension position (lo) of the top link articulated to a fixed hole of an implement is adjusted within a predetermined adjustment range (lo-, ..., lo+) depending on a sensor-detected tensile or compressive force (Fo) acting on the top link or a predetermined setpoint value (Fo,set) for the tensile or compressive force (Fo), and/or in which the extension position (lo) of the top link articulated to a slotted hole of the implement is adjusted depending on a predetermined minimum value (Fo,min) for the tensile or compressive force (Fo).