Capacitive Crop Flow Sensing for Uniform Forage Harvester Feeding
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Solution Overview
Problem
Self-propelled forage harvesters experience uneven and non-rectangular cross-sectional distribution of crop flow, leading to poorer chopping quality and uneven wear of components due to the M-shaped distribution of crop strands, resulting in shortened service life of knives and cracking rollers.
Innovation Solution
A measuring device with spaced-apart electrodes in the intermediate channel forms capacitors to determine electrical capacitances, allowing for the measurement of conveying-specific and crop-specific parameters, which are used to control actuators for optimizing the lateral distribution of the crop flow, ensuring a uniform and rectangular cross-sectional distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If several crop strands are conveyed from the header into the processing channel, then the crop flow is formed, but the cross-sectional distribution becomes uneven and M-shaped, leading to poorer chopping quality
Solution Approach 1:
The patent applies preliminary action by introducing a pre-compression device with adjustable actuators before the chopping drum to pre-shape and uniformly distribute the crop flow. This pre-positioning of the crop strands ensures they are evenly distributed across the processing channel width before reaching the chopping drum, preventing the M-shaped distribution pattern and ensuring consistent chopping quality from the start of the processing operation.
Solution Approach 2:
The patent implements dynamics by using adjustable actuators that can dynamically modify the position and spacing of the pre-compression elements during operation. This dynamic adjustment capability allows the system to adapt to varying crop conditions and maintain optimal uniform distribution, thereby consistently achieving good chopping quality while processing different volumes of crop material.
2Productivity
If several crop strands are conveyed into the processing channel, then crop flow is formed, but uneven cross-sectional distribution leads to uneven wear of components such as knives and cracking rollers
Solution Approach 1:
The pre-compression device with adjustable actuators performs preliminary distribution of crop strands uniformly across the processing channel before the crop reaches the chopping and cracking components. This pre-positioning prevents concentrated loads and uneven stress distribution on knives and cracking rollers, thereby reducing uneven wear and extending the service life of these stationary components while maintaining high productivity.
3Measurement precision
If a measuring bar with sensors penetrates the crop processing channel to detect lateral distribution, then measurement capability is provided, but the structure becomes complex and may interfere with crop flow
Solution Approach 1:
The patent extracts the measurement function from a complex physical measuring bar structure and implements it through capacitive sensors that can be integrated into the existing processing channel walls or support structures. This extraction approach provides accurate lateral distribution detection while minimizing structural complexity and avoiding interference with crop flow, as the sensors can operate through non-contact capacitive coupling.
Solution Approach 2:
The patent applies universality by designing the measuring device to serve multiple functions: the same capacitive sensor array used for lateral distribution detection can also monitor crop moisture content and density variations. This multi-functionality reduces the need for separate measurement systems, thereby lowering overall device complexity while maintaining high measurement precision for lateral distribution.
4Manufacturing precision
If actuators in the header are adjusted to optimize crop distribution, then chopping quality improves, but the control system becomes more complex
Solution Approach 1:
The patent implements feedback by connecting the capacitive measurement sensors to the actuator control system. The sensors continuously monitor the lateral distribution of crop strands, and this measurement feedback is used to automatically adjust the actuator positions to optimize distribution uniformity. This closed-loop feedback control achieves high chopping quality while the control complexity is managed through automated algorithms that process sensor data and generate actuator commands.
Solution Approach 2:
The system applies self-service by enabling the header actuators to automatically adjust crop distribution based on real-time sensor feedback without requiring external operator intervention. The control system autonomously processes measurement data and modifies actuator positions to maintain optimal lateral distribution, thereby achieving high chopping quality while the self-adjusting capability reduces the operational complexity for the operator.
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
The solution improves chopping quality by ensuring uniform pre-compression and maximizes harvester utilization while minimizing flow resistance and wear on components, extending their service life.
Implementation Method 1
The measuring device has several spaced-apart electrodes arranged in the intermediate channel of the crop processing channel, forming multiple capacitors. By measuring the electrical capacitances of these capacitors, conveying-specific and/or crop-specific parameters can be determined.
Implementation Method 2
Two spaced-apart electrodes can form one capacitor. The arrangement of the electrodes in the intermediate channel has the advantage that, for example, it is possible to measure the cross-sectional distribution of the conveyed crop upstream of the post-accelerator.
Data Source
Figure 1
Figure 2
Figure 3~3a
AI summary
The present invention relates to a self-propelled forage harvester (1) and a method for controlling this forage harvester (1). The present invention is based on the general concept that a measuring device (10) of the forage harvester (1) has several spaced-apart electrodes (11), wherein these electrodes (11) are arranged in an intermediate channel (8) of a crop processing channel (4) of the forage harvester (1) and form several capacitors (12), wherein conveying-specific parameters and/or crop-specific parameters can be determined by measuring the electrical capacitances of the several capacitors (12).