Hydraulic Down Force Control for Agricultural Planters
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Solution Overview
Problem
Agricultural planter systems face challenges in accurately measuring gauge wheel down force due to noise from mechanical linkages and friction, leading to inconsistent down pressure control, especially at low gauge wheel loads and over uneven terrain.
Innovation Solution
A hydraulic control system using a pressure transducer coupled to a hydraulic cylinder with accumulators and self-latching or spring-biased valves, decoupling the sensor from mechanical linkages and reducing noise through fluid pressure measurement, and incorporating a modified equalizer arm with rollers to minimize friction and signal noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If mechanical linkages and strain gauge sensors are used to measure gauge wheel down force, then the measurement system is mechanically coupled to the implement, but this introduces friction and mechanical noise that degrade measurement precision
Solution Approach 1:
The patent replaces mechanical strain gauge sensors with a hydraulic pressure transducer system. The hydraulic cylinder converts down force into fluid pressure, which is then measured by an electronic pressure transducer. This substitution eliminates mechanical linkages between the sensor and the gauge wheel, removing friction and mechanical noise while preserving the measurement function.
Solution Approach 2:
The patent introduces hydraulic fluid as an intermediary between the down force application point and the measurement sensor. The force is transmitted through the hydraulic fluid pressure rather than direct mechanical contact, allowing the sensor to be decoupled from the mechanical linkage and positioned away from sources of mechanical noise.
2Reliability
If traditional hydraulic control systems use continuous duty cycles to valves, then down pressure control is achieved, but energy consumption increases and response time is prolonged
Solution Approach 1:
The patent employs periodic pulsed signals to actuate the solenoid valves instead of continuous duty cycles. The controller sends intermittent pulses to open or close valves, allowing the hydraulic system to maintain pressure control while consuming energy only during valve transitions. This periodic actuation significantly reduces overall energy consumption while preserving control stability.
Solution Approach 2:
The patent implements dynamic response by using fast-acting solenoid valves that can rapidly transition between open and closed states in response to controller signals. This dynamic valve actuation allows the system to respond quickly to changing down force requirements without maintaining continuous power consumption, improving both energy efficiency and response time.
3Adaptability or versatility
If gauge wheel loads are low or terrain is uneven, then the planter must navigate difficult conditions, but mechanical noise and friction become more significant relative to the measurement signal
Solution Approach 1:
The hydraulic pressure measurement system maintains high signal-to-noise ratio across varying load conditions because it eliminates mechanical friction entirely. The hydraulic fluid transmits pressure changes directly to the transducer without mechanical interference, allowing accurate measurement even when gauge wheel loads are low or terrain conditions create additional mechanical disturbances.
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 provides accurate and consistent down pressure control by reducing systematic noise, allowing for precise adjustment of down force on agricultural planters, minimizing soil compaction, and improving the accuracy of automatic control systems.
Implementation Method 1
A pressure transducer is preferably coupled to the cylinder on one side of the ram
Implementation Method 2
a source of pressurized fluid coupled to the hydraulic cylinder on a first side of the ram
Implementation Method 3
A pair of energy storage devices, such as accumulators, may be coupled to the cylinder on opposite sides of the ram
Implementation Method 4
The valves are preferably self-latching valves, such as magnetic latching valves, that remain in an open or closed position
Data Source
AI summary
A hydraulic control system for controlling the down force on an agricultural implement comprises a hydraulic cylinder containing a movable ram, a source of pressurized fluid coupled to the hydraulic cylinder on a first side of the ram by a first controllable valve, a fluid sump coupled to the hydraulic cylinder on the first side of the ram by a second controllable valve, and an electrical controller coupled to the valves for opening and closing the valves. The valves may be self-latching valves that remain in an open or closed position until moved to the other position in response to a signal from the controller.