Agricultural Roller Controller for Stone Detection
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Solution Overview
Problem
Agricultural machines, such as forage harvesters, are prone to damage from unwanted objects like stones due to inadequate detection methods, which fail to reliably identify such objects before they reach critical components.
Innovation Solution
A controller system that utilizes roller-opening-values and roller-speed-values to determine a strength-value, comparing it with threshold-values to generate an output signal indicative of an unwanted object, improving detection reliability by considering both the size and rate of change of the roller opening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional detection methods using only roller-opening-value are used, then the detection system is simple, but the reliability of unwanted object detection is insufficient
Solution Approach 1:
The patent combines roller-opening-value and roller-speed-value into a unified strength-value calculation. This merging of multiple detection parameters allows the system to achieve higher reliability in unwanted object detection by considering both the magnitude and rate of change of roller opening, while maintaining a relatively simple evaluation circuit that computes a composite strength-value for threshold comparison.
Solution Approach 2:
The patent introduces dynamic evaluation by incorporating roller-speed-value (the rate of change of roller-opening-value) into the detection process. This dynamic approach allows the system to distinguish between static and dynamic conditions, improving reliability by detecting not just the position but also the velocity of roller opening changes, which helps differentiate between crop material and unwanted objects.
2Measurement precision
If only roller-opening-value is used for detection, then the detection method is simple to implement, but it cannot accurately differentiate between stone and crop-induced movements
Solution Approach 1:
By incorporating roller-speed-value (the time derivative of roller-opening-value) into the detection process, the system gains the ability to distinguish between different types of movements. Crop material typically causes gradual, low-velocity roller opening changes, while stones cause sudden, high-velocity changes. This dynamic measurement approach significantly improves the precision of object differentiation.
Solution Approach 2:
The strength-value serves as an intermediary parameter that combines both roller-opening-value and roller-speed-value. This intermediate calculation allows the system to process multiple detection parameters through a unified evaluation metric, making the differentiation between stones and crop material more precise while keeping the overall detection method manageable in complexity.
3Reliability
If the detection threshold is set low to increase sensitivity, then more objects are detected, but false detections from crop material increase
Solution Approach 1:
The system uses dynamic threshold evaluation by comparing the calculated strength-value (which incorporates both roller-opening-value and roller-speed-value) against a threshold. The inclusion of velocity information allows the system to set thresholds that account for the rate of change, thereby reducing false detections from crop material while maintaining sensitivity to actual stones, thus improving detection accuracy without unnecessarily stopping the machine.
Solution Approach 2:
The patent changes the detection parameter from a static roller-opening-value to a dynamic strength-value that incorporates both position and velocity information. This parameter transformation allows for more accurate threshold setting, as the strength-value naturally amplifies the signal from stones (which cause rapid opening changes) while keeping crop-induced variations below the threshold, thereby improving detection accuracy while maintaining machine productivity.
Data Source
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AI summary
A controller (134) for detecting an unwanted object (112) in an agricultural machine, wherein the agricultural machine includes a pair of rollers (102, 104) for receiving crop material (108) therebetween, the pair of rollers (102, 104) defining a variable roller opening (106) therebetween, wherein the controller (134) is configured to: receive a roller-opening-value (128) that is representative of the size of the roller opening (108); determine a strength-value based on the roller-opening-value (128) and a roller- speed-value (132), wherein the roller-speed-value (132) is representative of the rate of change of the roller-opening-value (128), with respect to time; compare the strength- value with a threshold-value (340, 342, 344, 346); and if the strength-value exceeds the threshold-value, then provide an output signal (136) that is indicative of an unwanted object (112) being detected.