Hydraulic Header Flotation Control With Dynamic Pressure Feedback
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Solution Overview
Problem
Traditional hydraulic header flotation systems in crop machines face limitations due to high static friction in cylinder seals, leading to poor ground following capabilities and increased wear on ground-contacting components, especially when the header is lifted by obstacles or navigating uneven terrain.
Innovation Solution
An electronically controlled hydraulic cylinder system with a proportional pressure reducing relieving (PPRR) valve and an electronic control system that dynamically adjusts the lifting force based on sensor feedback from position, velocity, and acceleration, reducing friction effects and improving ground following by varying pressure in real-time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If traditional hydraulic float systems are used with high ground pressure (15% of header mass), then the header can overcome static friction from cylinder seals, but wear on ground contacting components increases significantly
Solution Approach 1:
The patent applies dynamics by using an electronically controlled proportional pressure reducing relieving valve that continuously adjusts hydraulic pressure based on real-time sensor feedback about header position, velocity, and acceleration. This dynamic control allows the system to provide exactly the right amount of lifting force needed to overcome static friction during terrain transitions, rather than maintaining constant high ground pressure, thereby reducing wear on ground contacting components while ensuring reliable header flotation.
2Reliability
If hydraulic pressure is increased to improve ground following capabilities, then the header can better follow uneven terrain, but the friction resistance from cylinder seals increases
Solution Approach 1:
The patent implements feedback control through sensors that continuously monitor header position, velocity, and acceleration, feeding this information to an electronic control system. The controller processes this feedback and dynamically adjusts the proportional pressure reducing relieving valve to maintain optimal hydraulic pressure. This feedback mechanism ensures the system provides sufficient lifting force to overcome seal friction only when and where needed for ground following, rather than applying excessive pressure continuously.
Solution Approach 2:
The system dynamically changes the hydraulic pressure parameter in response to real-time operating conditions. The electronically controlled proportional valve adjusts pressure levels based on sensor feedback, allowing the system to transition between different pressure states - higher pressure when ground following is critical and lower pressure when friction resistance would be excessive - thereby optimizing the balance between reliability and friction resistance.
3Stability of the object's composition
If static flotation pressure is maintained to support header weight, then the header remains stable, but the system cannot quickly respond to terrain changes or obstacles
Solution Approach 1:
The patent resolves this contradiction by transitioning from static to dynamic pressure control. The electronically controlled proportional valve can rapidly adjust hydraulic pressure in response to real-time sensor feedback about header motion and terrain conditions. This dynamic capability allows the system to maintain stability during normal operation while quickly responding to terrain changes or obstacles, as the pressure can be modulated instantaneously based on actual operating conditions rather than being fixed at a static level.
Solution Approach 2:
The feedback control system continuously monitors header position, velocity, and acceleration, enabling the electronic controller to detect terrain changes or obstacles in real-time. When changes are detected, the controller immediately adjusts the proportional valve to modify hydraulic pressure, providing rapid response while maintaining overall header stability. This closed-loop feedback ensures the header remains stable during normal operation but can quickly adapt when terrain conditions change.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system enhances ground following capabilities, reduces wear on components, and allows for smoother operation over uneven terrain by dynamically controlling the lifting force, thereby improving the efficiency and effectiveness of crop harvesting.
Implementation Method 1
application of a hydraulic fluid under hydraulic pressure to said at least one float cylinder causes a lifting force to be applied to the crop engaging assembly by movement of said at least one float cylinder which lifting force is proportional to said hydraulic pressure
Implementation Method 2
the effect of static friction provided by cylinder seals is significantly reduced so as to reduce resistance to motion of the cylinder in the floating action
Data Source
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AI summary
In a crop harvesting machine (100) there is provided a pair of hydraulic float cylinders (116, 117) for a header (104) relative to a vehicle (102), where a float pressure to the cylinders (116, 117) is directly controlled by an electronic control (28) supplying a variable control signal to a PPRR valve arrangement (18, 20) to maintain the float pressure at a predetermined value. At the set pressure a predetermined lifting force is provided to the header (104). A position sensor (120, 121) is used to generate an indication of movement and/or acceleration. The electronic control (28) is arranged, in response to changes in the sensor signal, to temporarily change the control signal to vary the lifting force and thus change the dynamic response of the hydraulic float cylinder (116, 117). In order to reduce static friction so that the system can react quickly, an arrangement is provided for causing relative reciprocating movement in an alternating wave pattern between the piston and cylinder.