Agricultural Spray Nozzle Monitoring for PWM Blockage Detection
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Solution Overview
Problem
Sprayers and fluid application systems in agricultural fields often become plugged, leading to improper fluid application, and existing monitoring technologies are inadequate for real-time detection of nozzle conditions.
Innovation Solution
A system comprising cameras and processors that capture images of nozzle sprays, assign ratings to account for intermittent nozzle operation, and determine a running average to assess nozzle conditions, using pulse width modulation (PWM) actuation and image capture frequencies to avoid aliasing, with thresholds for fluid flow indicators to identify proper, low, or no flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a camera captures images of nozzle spray to monitor nozzle condition, then real-time detection capability is improved, but false positives occur when nozzles are intermittently off due to PWM actuation
Solution Approach 1:
The system dynamically adjusts the image capture frequency to match the PWM actuation frequency of the nozzles. The processor receives PWM signals and synchronizes image capture accordingly, enabling the system to distinguish between intentional nozzle shutdown and actual plugging conditions by analyzing spray patterns only during active nozzle cycles.
Solution Approach 2:
The processor uses feedback from the PWM actuator signals to control the timing of image capture. By receiving and responding to the PWM control signals that regulate nozzle operation, the system captures images at optimal moments when nozzles are actively spraying, thereby avoiding false plugging detections while maintaining accurate monitoring.
2Measurement precision
If image capture frequency is increased to avoid aliasing with PWM frequency, then measurement precision is improved, but energy consumption and data processing load increase
Solution Approach 1:
The system employs periodic image capture synchronized with the PWM actuation cycle of the nozzles. Instead of continuous high-frequency capture, the camera takes images at specific intervals corresponding to the nozzle spray cycles, achieving sufficient measurement precision while minimizing energy consumption and data processing requirements.
Solution Approach 2:
The image capture frequency parameter is dynamically adjusted to be slightly more than twice the PWM frequency, satisfying the Nyquist criterion for accurate measurement while optimizing energy usage. This parameter optimization balances measurement precision requirements with energy conservation and processing efficiency.
Data Source
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AI summary
In an aspect of the disclosure there is provided a system including nozzles disposed along an implement, a camera disposed on the implement to capture images of a spray from a nozzle of the nozzles over a time period and a processor to assign a rating to the images to account for the nozzle intermittently being off and not counting the nozzle as plugged. The processor to determine a running average for a condition of the nozzle using the assigned rating for the images.