Hydraulic Position Feedback for Precise Surface Engagement Depth
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Solution Overview
Problem
Conventional agricultural surface engaging machines face challenges in maintaining constant surface engagement position and downforce due to varying soil conditions, especially at higher speeds, as traditional methods like springs, weights, or airbags are inadequate for precise control.
Innovation Solution
A position control system utilizing a fluid control system with a cylinder actuator, proportional control valve, and sensors to adjust fluid force and maintain desired surface engagement position, incorporating a pressure control valve and position sensor for precise control of downforce and engagement depth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional downforce methods (springs, weights, airbags) are used, then the machine can maintain basic surface contact, but the surface engagement position cannot be precisely controlled under varying soil conditions
Solution Approach 1:
The system employs a position sensor to detect the actual surface engagement position of the implement and feeds this information back to the controller. The controller compares the detected position with the desired position and adjusts the fluid pressure accordingly to eliminate any deviation, thereby achieving precise control under varying soil conditions.
Solution Approach 2:
The patent utilizes a fluid power cylinder actuator with controllable fluid pressure to apply downforce to the implement. By varying the fluid pressure through a proportional control valve, the system can precisely control the magnitude of the downforce applied to the implement, enabling accurate surface engagement position control.
2Ease of operation
If force or pressure feedback systems are used to modify surface engaging force, then downforce can be adjusted, but sufficient information cannot be obtained to ensure precise engagement at a particular position
Solution Approach 1:
The system replaces force or pressure sensors with a position sensor that directly measures the engagement position of the implement. This substitution provides more direct and accurate information about the actual engagement position, enabling precise control of the implement's position on the surface.
3Loss of information
If force or pressure sensors are used, then downforce information can be provided to the controller, but malfunction of mechanisms cannot be detected
Solution Approach 1:
The system replaces force or pressure sensors with a position sensor that directly measures the engagement position. The position sensor provides direct feedback about the implement's position and can detect malfunctions such as actuator failures or mechanical binding, as these would manifest as position deviations that cannot be corrected by normal control adjustments.
4Productivity
If traditional downforce methods are used, then the machine structure remains simple, but precise surface engagement control cannot be achieved at higher speeds
Solution Approach 1:
The position feedback system continuously monitors the implement's engagement position and provides real-time information to the controller. This enables the system to make rapid adjustments to the downforce applied through the fluid power actuator, maintaining precise position control even at higher operating speeds where soil conditions change more rapidly.
Solution Approach 2:
The system transitions from static downforce methods (springs, weights) to a dynamic fluid power actuator system that can rapidly adjust downforce magnitude. This dynamic capability allows the system to respond to changing soil conditions and maintain precise engagement position control at higher operating speeds.
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
This system enables precise control of surface engagement depth and downforce, ensuring consistent seeding or planting depth across varying soil conditions and speeds, enhancing the reliability and performance of agricultural machines.
Implementation Method 1
a chamber within the cylinder configured to receive fluid to apply a fluid force on the piston
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
An example control system includes a cylinder actuator comprising a cylinder, a piston movable within the cylinder and configured to be coupled to a surface engaging implement, and a chamber within the cylinder configured to receive fluid to apply a fluid force on the piston; a proportional control valve configured to control fluid flow from a source of fluid to the chamber; a position sensor coupled to the cylinder actuator and configured to provide position sensor information indicative of a position of the piston; and a controller having access to a desired surface engagement position for the surface engaging implement, wherein the controller is configured to receive the position sensor information, and send a valve command signal to the proportional control valve to change the fluid force applied to the piston to achieve the desired surface engagement position.