Agricultural Sprayer PWM Control for Accurate Liquid Spreading
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing agricultural sprayers face issues with spreading accuracy and quality due to interactions between switching elements affecting output when limit opening durations are exceeded or undercut, leading to undesirable effects on the distribution of spraying liquids.
Innovation Solution
A method that adjusts the opening durations of switching elements in agricultural sprayers by correcting them when limit durations are exceeded or undercut, maintaining the required output quantity and pressure through closed-loop and open-loop control systems, using duty cycles and pulse width frequency modulation to optimize the spreading process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the opening duration of switching elements is adjusted independently to meet individual output requirements, then the output quantity and pressure for each nozzle can be optimized, but the interactions between switching elements cause unexpected changes in overall output and spreading accuracy deteriorates
Solution Approach 1:
The patent implements a feedback mechanism where the control unit monitors the actual opening durations of all switching elements and detects when any switching element exceeds its maximum or minimum opening duration limits. Based on this feedback, the control unit calculates correction factors and adjusts the opening durations of affected switching elements to maintain both individual nozzle performance and overall system accuracy.
Solution Approach 2:
The system dynamically adjusts the opening durations of switching elements in real-time based on detected limit violations. The control unit continuously monitors switching element performance and modifies opening durations adaptively, transitioning from static independent control to dynamic interdependent control that responds to system conditions.
2Stress or pressure
If the opening duration of switching elements is increased to maintain output pressure, then the output pressure can be sustained, but the opening duration may exceed maximum limits causing harmful effects on spreading quality
Solution Approach 1:
The control unit proactively detects when switching element opening durations are approaching maximum or minimum limits before harmful effects occur. By identifying limit violations in advance, the system can apply correction factors to adjust opening durations and prevent the harmful effects of excessive or insufficient opening durations on spreading quality.
Solution Approach 2:
The system uses feedback from monitoring switching element opening durations to detect when limits are exceeded or undercut. This feedback triggers corrective actions that adjust opening durations to remain within optimal ranges, preventing the harmful effects that would result from operating outside these limits.
3Ease of operation
If switching elements are controlled in open-loop or closed-loop manner with PWM, then the output can be influenced by opening duration, but interactions between switching elements are ignored leading to reduced spreading accuracy
Solution Approach 1:
The patent enhances open-loop and closed-loop control by introducing feedback specifically for detecting interactions between switching elements. The control unit monitors when switching elements exceed their opening duration limits and applies correction factors to compensate for interactions, thereby maintaining spreading accuracy while preserving the ease of PWM-based control operation.
Solution Approach 2:
The control unit acts as an intermediary that mediates between the PWM control signals and the actual switching element operation. It introduces correction factors that account for interactions between switching elements, ensuring that the control system maintains both operational ease and spreading accuracy despite the complex interactions inherent in multi-nozzle systems.
Data Source
AI summary
A method for spreading a spraying liquid onto arable agricultural land by way of several switching elements arranged on an agricultural sprayer and controllable in an open-loop and/or closed-loop manner and in the manner of a pulse width modulation, where the spraying liquid is spread as required onto the arable agricultural land; where a first opening duration associated with a first switching element and at least one further opening duration associated with a further switching element is determined; where spreading the spraying liquid is influenced at least in part by way of the respective opening duration; where at least one upper and/or lower limit opening duration associated with the switching elements is used; and where the first and further determined opening duration is compared with the upper and/or lower limit opening duration. In order to further improve in a simple manner, the spreading process of the spraying liquid, in particular to improve the achievable spreading precision and/or spreading quality, it is provided in the event of the upper limit opening duration being exceeded and/or the lower limit opening duration being undercut by one of the determined opening durations, that the first and further opening durations are accordingly jointly corrected.