Resonant Crop Flow Sensor for Grain and Straw Identification

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Solution Overview

Problem

Existing combine harvesters lack the ability to accurately distinguish between grain and non-grain elements in the harvested crop stream using existing sensor systems, as these systems cannot identify the type of elements impacting their surfaces.

Innovation Solution

A sensor system comprising a resonant circuit with a capacitive and inductive element is used to detect crop flow elements, where the capacitive element's capacitance is influenced by individual elements, allowing the system to determine the resonant frequency and infer properties like permittivity, thereby distinguishing between grain and non-grain elements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a sensor measures force or impact to detect crop elements, then the number of elements can be detected, but the sensor cannot identify the type of elements (grain vs. straw)

Engineering Contradiction:
Improveelement type identificationVSAvoidelement classification information
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent applies parameter changes by measuring the permittivity (dielectric constant) of crop elements, which is a fundamental physical property that differs between grain and straw. By detecting this parameter through capacitance changes in the resonant circuit, the system can identify element types rather than just counting impacts, thus resolving the information loss problem.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces mechanical impact sensing with an electromagnetic field-based sensing system. Instead of relying on mechanical force or impact sensors that cannot distinguish element types, the system uses a resonant circuit with capacitive elements that detect permittivity changes, substituting mechanical measurement with electromagnetic measurement to enable element identification.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Speed

If the measurement frequency is increased to detect faster crop flow speeds, then detection accuracy improves, but the resonant frequency determination becomes less accurate due to fewer oscillation periods

Engineering Contradiction:
Improvecrop flow detection speedVSAvoidresonant frequency determination accuracy
Core Design Contradiction:
SpeedVSMeasurement precision

Solution Approach 1:

The patent applies preliminary action by pre-calibrating the relationship between resonant frequency shifts and crop element properties before actual measurement. This allows the system to process high-speed measurements more accurately by comparing real-time data against pre-established reference patterns, effectively compensating for the reduced number of oscillation periods at higher speeds.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements feedback by continuously monitoring the resonant frequency and adjusting measurements based on detected patterns. The feedback mechanism allows the system to maintain measurement accuracy at high speeds by using real-time frequency data to refine element detection, compensating for the reduced oscillation period count.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If the capacitive element is placed in the crop flow path, then element detection is enabled, but the crop flow may be disturbed or blocked

Engineering Contradiction:
Improveelement detection capabilityVSAvoidcrop flow disturbance
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent uses the electromagnetic field as an intermediary between the capacitive element and the crop flow. Instead of direct physical contact that would disturb the flow, the capacitive element generates an electromagnetic field that penetrates the crop stream, allowing detection of permittivity changes without mechanical interference. The field acts as a mediator that enables measurement while preserving natural crop flow.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces mechanical sensing that would require physical contact with the crop flow with electromagnetic field-based sensing. The capacitive element detects crop elements through field interactions rather than mechanical contact, substituting a potentially disruptive mechanical system with a non-contact electromagnetic system that eliminates flow disturbance.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 sensor system accurately counts and distinguishes between grain and straw elements, providing more detailed information on the harvested crop stream, enhancing the efficiency of the combine harvester's working elements and enabling real-time adjustments.

Implementation Method 1

the sensor system comprises a resonant circuit and a measuring device, wherein the resonant circuit comprises at least one capacitive element with a capacitance and an inductive element with an inductance

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

The magnitude of the change in capacitance and resonant frequency depends on the permittivity of the element in the crop flow

Methodology Applied
Scientific EffectPermittivity: Dielectric Permittivity

Implementation Method 3

the resonant circuit has a resonant frequency, the resonant frequency depending on the capacitance and the inductance

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP3913807B1Combine harvester with a sensor system
Publication Date: 2026.05.06 CLAAS SELBSTFAHRENDE ERNTEMASCHINEN GMBH
  • EP3913807B1 patent drawingFigure 1
  • EP3913807B1 patent drawingFigure 2
  • EP3913807B1 patent drawingFigure 3~4

AI summary

Sensor system for counting elements of a crop flow, particularly in an agricultural machine, wherein the sensor system comprises a resonant circuit and a measuring device, wherein the resonant circuit consists of at least one capacitive element with a capacitance and an inductive element with an inductance, wherein the resonant circuit has a resonant frequency, the resonant frequency depending on the capacitance and the inductance, wherein the measuring device is provided and configured to determine the resonant frequency of the resonant circuit, wherein the capacitive element is arranged in the area of ​​the crop flow, wherein the capacitive element is configured so that the capacitance is influenced by individual elements of the crop flow, and wherein the sensor system is provided and configured to infer at least one property of the respective element of the crop flow from the resonant frequency of the resonant circuit.