Dual Feedback Control for Agricultural Sprayer Accuracy
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Solution Overview
Problem
Current spray control systems for agricultural sprayers rely on single feedback mechanisms, such as flow volume-based or pressure-based closed loop control systems, which are limited in accuracy and reliability due to mechanical wear, downstream pipe breakages, and variable orifice sizes, requiring manual calibration and 'catch tests'.
Innovation Solution
A dual feedback control system that combines flow-based and pressure-based feedback circuits, where the flow sensor and pressure transducer provide simultaneous inputs to the controller, allowing switching between control systems based on operational conditions and component reliability, ensuring continuous calibration and accurate fluid application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a flow volume-based feedback system is used, then the fluid delivery rate can be measured, but the system cannot detect downstream pipe breakages and mechanical wear limits measurement accuracy
Solution Approach 1:
The patent combines flow volume-based feedback and pressure-based feedback into a hybrid control system. The flow meter measures actual fluid delivery rate while the pressure sensor monitors system pressure to detect downstream blockages or breakages. This merging of two feedback mechanisms allows the system to maintain measurement precision while improving reliability through cross-validation of the two independent measurement methods.
2Device complexity
If a pressure-based feedback system is used, then the system is predictable and simple, but accuracy decreases when orifice size or material properties vary
Solution Approach 1:
The patent implements a hybrid feedback system where pressure-based feedback provides a predictive model of fluid delivery rate, and flow-based feedback provides actual measurement. The controller compares the predicted rate from pressure data with actual flow measurements and adjusts the pump accordingly. This dual-feedback approach maintains the simplicity of pressure-based control while compensating for its inaccuracy when orifice or material properties change.
3Measurement precision
If manual calibration and catch tests are performed, then pressure-based systems can be compensated for variability, but operator time and operational complexity increase
Solution Approach 1:
The patent implements automatic calibration through the hybrid system where the flow meter continuously provides reference measurements that automatically adjust the pressure-based feedback scaling factors. Instead of requiring manual operator intervention for calibration, the system self-calibrates by comparing actual flow measurements with pressure-predicted values and automatically adjusting the relationship between pressure and expected flow rate, eliminating catch tests and manual calibration procedures.
4Device complexity
If a single feedback mechanism is used, then the control system is simple, but reliability and accuracy decrease due to component failures
Solution Approach 1:
The patent implements redundancy by incorporating both flow-based and pressure-based feedback mechanisms simultaneously. This beforehand cushioning ensures that if one feedback mechanism fails (such as a blocked pressure sensor or malfunctioning flow meter), the other mechanism can continue to provide control, maintaining system reliability and preventing complete control failure.
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 dual feedback system enhances the flexibility, accuracy, and reliability of sprayer control by automatically switching between feedback sources, maintaining precise fluid application rates and compensating for component failures, thereby improving overall performance.
Implementation Method 1
a flow sensor for sensing a flow volume within the fluid application means
Implementation Method 2
a pressure transducer for sensing fluid pressure within the fluid application means
Data Source
Figure 1
AI summary
The present invention provides an advanced spray control system for controlling a sprayer, which comprises a controller (20), a plurality of sensors (50, 60) and feedback means, and an output means (30) for controlling the application system (40) of the sprayer. The controller receives inputs from the operator through a user interface (10), and/or various feedback signals from the sensors of the system (e.g., a flow meter, or a pressure transducer). After processing these inputs, the controller sends signals to other components of the sprayer, such as, the pump, the storage means, the boom sections, and/or the nozzles, to maintain or change their operating conditions. Also provided are a method of controlling a sprayer using the spray control system and a sprayer comprising the spray control system of the present invention.