Vibration Sensor Mounting for Foreign Object Detection
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Solution Overview
Problem
Existing foreign object detection devices for agricultural harvesting machines suffer from detection lag and false positives, particularly when detecting smaller objects, due to inertia-related delays and signal degradation issues with existing acceleration and acoustic detection methods.
Innovation Solution
A detection device utilizing directional vibration sensors mounted on the central shaft of the feed roll assembly, which analyze vibrations transverse to the rotational axis, generating a detection signal by squaring and summing sampled signals to quickly identify foreign object impacts without the need for acoustic isolation, and incorporating a wireless transmission system for efficient signal processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If acceleration sensors monitor the top rolls of the feeder assembly, then foreign objects can be detected, but detection lags considerably due to large inertia and only large objects are detected
Solution Approach 1:
The patent replaces mechanical acceleration sensors monitoring top rolls with piezoelectric sensors mounted on the central shaft. This substitution detects vibrations directly at the source before inertia delays detection, eliminating the time lag while maintaining detection capability for smaller objects.
Solution Approach 2:
The central shaft serves as an intermediary structure that transmits vibrations from foreign object impacts on the feed roll to the piezoelectric sensors. This intermediary position allows early detection before the vibrations are dampened by the inertial effects of the feed roll assembly.
2Measurement precision
If piezoelectric sensors are mounted on the rotating feed roll, then detection sensitivity improves, but signal quality degrades due to inductive transmission requirements
Solution Approach 1:
The central shaft acts as a stationary intermediary that carries the piezoelectric sensors away from the rotating feed roll. Vibrations are transmitted through the shaft from the impact point, allowing sensor placement on a non-rotating component. This eliminates the need for rotating connections and inductive transmission, preserving signal quality and reliability.
3Reliability
If acoustic isolation is implemented for microphone-based detection, then detection reliability improves, but device complexity and installation difficulty increase
Solution Approach 1:
The patent replaces acoustic detection methods (microphones requiring isolation) with piezoelectric vibration sensors mounted on the central shaft. This mechanical vibration detection approach inherently filters out acoustic noise without requiring complex isolation structures, simplifying the system while maintaining reliability.
4Speed
If detection occurs closer to the impact location, then detection speed improves, but false detections from crop material lumps increase
Solution Approach 1:
The system uses feedback through signal processing and threshold setting to distinguish between genuine foreign object impacts and normal crop material variations. The control unit analyzes vibration patterns and compares them against predetermined thresholds, allowing rapid detection while filtering out false positives from benign crop lumps.
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 solution enhances the reliability and speed of foreign object detection, minimizing detection lag and false positives, while maintaining the structural integrity and operational stability of the harvesting machine, allowing for timely intervention before processing.
Implementation Method 1
at least one piezoelectric vibration sensor (20) is mounted on the central shaft (34)
Data Source
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AI summary
According to the invention the vibration sensor (20) is mounted on the central shaft (34), such that it senses vibrations induced into the feed roll assembly in a direction (41) transverse to the rotational axis (40) of the feed roll (32).