Spraying System Flow Control via Pulse-Width Modulation Feedback
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current fluid spraying systems for agricultural applications face challenges in maintaining a constant dose per hectare due to varying nozzle configurations and field geometries, leading to non-linearity in liquid flow and pressure modulation, which complicates real-time adjustment of spraying parameters.
Innovation Solution
A method involving a pulse-width modulation generator and control unit that adjusts the flow rate in real-time by measuring and comparing the actual and expected flow rates, allowing for constant pressure and modulated flow rate control, even with non-continuous fluid circulation, and enabling individual control of each nozzle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If pulse-width modulation is used to maintain constant pressure and modulate flow rate, then spraying precision is improved, but non-linearity between control signal and actual liquid flow increases
Solution Approach 1:
The patent implements a feedback mechanism where the control unit continuously receives information about the actual liquid flow rate from flowmeters and compares it with the expected flow rate. Based on this comparison, the control unit automatically adjusts the pulse-width modulation duty cycle to compensate for non-linearities. This closed-loop feedback system resolves the contradiction by maintaining spraying precision despite the inherent non-linearity of pulse-width modulation control.
Solution Approach 2:
The patent dynamically changes the duty cycle parameter of the pulse-width modulation signal based on the comparison between actual and expected flow rates. By adjusting this key parameter in real-time, the system compensates for non-linear effects and maintains precise control over the liquid flow, thereby preserving spraying precision while managing the complexity of the modulation system.
2Manufacturing precision
If flow rate is adjusted according to machine speed to maintain constant dose per hectare, then dosing accuracy is improved, but the system cannot adapt to varying nozzle configurations and field geometries
Solution Approach 1:
The patent transitions from a static dosing system to a dynamic one by continuously measuring the actual liquid flow rate using flowmeters and automatically adjusting the pulse-width modulation duty cycle in real-time. This dynamic adaptation allows the system to maintain accurate dose per hectare calculations while accommodating variations in machine speed, nozzle configurations, and field geometries, thereby resolving the contradiction between dosing accuracy and adaptability.
Solution Approach 2:
The control unit uses feedback from flowmeters to continuously monitor actual liquid flow and compares it with the expected flow rate calculated based on machine speed and dosing requirements. This feedback mechanism enables automatic adjustment of the modulation duty cycle to compensate for changes in operational conditions, maintaining dose accuracy while adapting to varying nozzle configurations and field geometries.
3Ease of operation
If flowmeter regulation is used to control liquid flow rate, then flow rate measurement is simplified, but precision deteriorates at low flow rates compared to pressure regulation
Solution Approach 1:
The patent introduces pressure regulation as an intermediary mechanism to improve low flow rate precision. By maintaining constant supply pressure to the nozzles through pressure regulation, the system ensures more accurate and stable flow rate measurement at low flow conditions. This intermediary pressure control works in conjunction with the flowmeter to compensate for its limitations at low flow rates, thereby improving measurement precision while retaining the simplicity of flowmeter-based regulation.
Data Source
AI summary
The present invention relates to a method for controlling the fluid circulation in a spraying system comprising a boom comprising a nozzle, supply means, at least one pulse-width modulation generator of a signal and a pressure sensor, said method comprising the following steps:a) setting a reference pressure;b) calculating a percentage of flow rate reduction to be applied according to said pressure, said percentage of flow rate reduction corresponding to the expected flow rate; thenc) generating a control signal corresponding to said expected flow rate;d) spraying a liquid, by measuring the supply pressure of said nozzle;e) measuring a flow rate of liquid supplying the boom;f) determining the outgoing liquid flow rate of liquid leaving said nozzleg) modifying the control of the generator according to a comparison between the determined outgoing liquid flow rate and the expected flow rate.