Optical Sensor Duty Cycle Measurement for Air Seeder Flow Accuracy
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Solution Overview
Problem
Existing optical sensors in air seeders are unreliable and inaccurate for high-flow crops like wheat or fertilizer due to their insufficient cross-sectional area, leading to unreliable particle counts and inaccurate planting populations.
Innovation Solution
Utilizing a closed loop feedback control system with ultrasonic sensors and particle sensors to measure the duty cycle of optical sensors, allowing for the calculation of estimated particle frequency and population metrics, and adjusting airflow to ensure accurate seed/fertilizer distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If typical optical sensors with small cross-sectional area (25 mm or 32 mm) are used, then the sensor size and cost are manageable, but the particle counts become unreliable and inaccurate for high-flow crops like wheat or fertilizer
Solution Approach 1:
The patent introduces an intermediary relationship between the optical sensor and particle detection by using duty cycle measurement as a mediator. Instead of directly counting particles with a small sensor, the system measures the duty cycle (percentage of time the sensor is blocked) and uses this as an intermediate parameter to infer particle flow rate, thereby achieving accurate measurement without requiring a large sensor area
Solution Approach 2:
The patent changes the measurement parameter from direct particle counting to duty cycle measurement. By measuring the percentage of time the optical sensor is blocked rather than counting individual particle events, the system can accurately determine particle flow rates for high-flow crops using a smaller sensor cross-sectional area
2Measurement precision
If the optical sensor cross-sectional area is increased to detect individual particles in high-flow crops, then particle detection accuracy improves, but the sensor size and system complexity increase
Solution Approach 1:
The patent replaces the mechanical approach of using a large physical sensor area to detect particles with an optical/electrical approach. By measuring the duty cycle of the optical sensor signal and processing this electrical parameter, the system achieves reliable particle detection without increasing the physical sensor dimensions or mechanical complexity
3Measurement precision
If duty cycle measurement is used to determine particle flow rate, then accurate flow rate determination is achieved, but additional processing and control system complexity is introduced
Solution Approach 1:
The patent implements a feedback control system where the duty cycle measurement is fed back to adjust particle flow. The system continuously monitors the duty cycle and uses this information to control airflow or particle feed rate, creating a closed-loop system that maintains accurate flow rate determination while managing complexity through systematic feedback control
Solution Approach 2:
The patent makes the optical sensor serve multiple functions: it acts as both a traditional particle presence detector and a duty cycle measurement device for flow rate determination. By enabling the same sensor to perform both functions, the system achieves accurate flow measurement without adding separate dedicated sensors, thereby limiting the increase in system complexity
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
Enables precise control of seed/fertilizer distribution by accurately determining particle flow rates and populations, reducing mechanical issues and improving seed/fertilizer uniformity across rows.
Implementation Method 1
Utilizing a closed loop feedback control system with ultrasonic sensors and particle sensors to measure the duty cycle of optical sensors
Implementation Method 2
When a particle (seed or fertilizer) passes through the optical sensor a light beam is broken and a particle is then detected
Data Source
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AI summary
In one embodiment, an electronic system comprises a display device to display data and processing logic coupled to the display device. The processing logic is configured to determine a duty cycle of at least one sensor for sensing flow of a product or particle through a product or particle line of an agricultural implement and to determine an amount of product or particles flowing through a line of the agricultural implement based on the duty cycle of the at least one sensor.