Tractor Stabilizer Control Logic for Mode Transition Safety
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Solution Overview
Problem
Existing lower link stabilizers for three-point hitches on agricultural tractors unpredictably transition between rigid and float modes, leading to unexpected sideways movement of agricultural implements, potentially causing damage and safety hazards when operators are unaware of these transitions, especially when using fender switches.
Innovation Solution
A control system with logic that manages the operation of automatic lower link stabilizers, using threshold values to predictably transition between rigid and float modes based on the position and direction of the three-point hitch movement, ensuring controlled lateral movement and preventing unexpected shifts by requiring operator intervention when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lower link stabilizers are made capable of both rigid mode and float mode operation, then the stabilizers can prevent excessive sway and uncontrolled movement, but unexpected transitions between modes can cause sudden sideways movement of the implement that may strike the operator
Solution Approach 1:
The control system proactively transitions the stabilizer to float mode before the implement is lowered to the ground, based on detected vertical movement of the lower link. This preliminary action prevents the harmful effect of sudden rigid mode engagement that would strike the operator, while still maintaining the ability to provide rigid stabilization when needed during implement operation
Solution Approach 2:
The control system continuously monitors the vertical movement of the lower link and uses this feedback to automatically transition between rigid and float modes. This closed-loop control ensures mode transitions occur at appropriate times based on actual implement position and operator actions, eliminating unpredictable transitions that could harm the operator
2Stability of the object's composition
If the stabilizer transitions from float mode to rigid mode while the implement is in an un-centered position, then the implement is centered and stabilized, but the sudden movement can strike the operator standing next to the tractor
Solution Approach 1:
The control system transitions to float mode in advance before the implement reaches a position where centering would occur, allowing the implement to be safely repositioned. This preliminary transition prevents the harmful effect of sudden centering movement that would strike the operator, while still achieving the goal of implement centering through controlled, gradual adjustment
Solution Approach 2:
The control system dynamically adjusts the stabilizer mode based on real-time conditions, including implement position and operator presence. By making the stabilizer mode dynamic rather than fixed, the system can transition between rigid and float modes at optimal moments, achieving implement centering stability while avoiding sudden movements that would harm the operator
3Reliability
If the stabilizer is in rigid mode during implement lowering, then lateral movement is prevented, but the operator cannot safely lower the implement from outside the tractor without risk of being struck by sudden implement movement
Solution Approach 1:
The control system automatically transitions between rigid and float modes based on detected vertical movement of the lower link, eliminating the need for the operator to manually switch modes. This self-service approach maintains lateral movement control reliability while greatly simplifying ease of operation, as the system adapts to the operator's actions without requiring additional input or awareness of mode transitions
Data Source
Figure 1
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Figure 3A~3B
AI summary
A system (50) controls a three point hitch (12) of an agricultural tractor (10), including automatic lower link stabilizers (16) with a rigid mode and a float mode. A controller (54) is connected to the automatic lower link stabilizers (16) and controls the selection of the rigid mode or the float mode. An external switch (58) allows an operator to raise or lower the three point hitch (12) from a position adjacent to the tractor (10). Control logic (64) stops raising the three point hitch (12), notwithstanding input from the external switch (58), when the three point hitch (12) is raised to a position (108) corresponding to a rigid mode transition threshold value (102). The control logic (64) places the automatic lower link stabilizers (16) in the rigid mode and resumes raising the three point hitch (12) only upon release and reactuation of the at least one external switch (58).