Baffle Plate Sensor Signal Processing for Combine Harvester Grain Detection

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Solution Overview

Problem

Current baffle plate sensors in combine harvesters face challenges in accurately detecting grains due to varying impact angles caused by the moving screens or conveyor floors, leading to interference and background noise, which affects the accuracy of grain detection.

Innovation Solution

A sensor arrangement that includes a baffle plate sensor associated with a conveyor, which emits an electrical signal upon grain impact, and an evaluation circuit that processes these signals by accounting for the conveyor's position to compensate for the sensitivity dependent on the impact angle, applying amplification factors or threshold values based on the conveyor's position, and optionally ignoring signals at certain positions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If baffle plate sensors are used to detect grains impacting on screens or conveyor floors, then grain detection is enabled, but the varying impact angles due to conveyor motion cause signal interference and reduced detection accuracy

Engineering Contradiction:

Improvegrain detection accuracyVSAvoidsignal interference and background noise

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The evaluation circuit dynamically adjusts the threshold value based on the conveyor's position during its oscillating motion. When the conveyor is at positions where grains impact at unfavorable angles (generating weak signals), the threshold is lowered to prevent signal loss. This dynamic adaptation compensates for the varying impact angles and maintains detection accuracy throughout the conveyor's motion cycle.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the evaluation parameter (threshold value) according to the conveyor's position parameter. By correlating the threshold with the conveyor's angular position or linear displacement, the system adapts its sensitivity to match the expected signal strength at each position, thereby compensating for the impact angle variations without modifying the physical sensor or conveyor structure.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If the conveyor is set in periodic oscillating motion to separate grain from contaminants, then cleaning efficiency is improved, but the impact angle of grains on the sensor varies, reducing signal reliability

Engineering Contradiction:

Improvecleaning efficiencyVSAvoidsignal reliability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The system uses feedback from the conveyor's position (either from a position sensor or by calculating from the drive motor's rotation) to continuously adjust the evaluation threshold. This closed-loop approach ensures that the threshold always matches the current impact conditions, maintaining signal reliability throughout the oscillating motion cycle while preserving the beneficial cleaning action.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The threshold value is adjusted in advance based on the known conveyor position before grain impact occurs. Since the conveyor's motion cycle is predictable and periodic, the system can pre-calculate the appropriate threshold for each position, ensuring optimal detection sensitivity is ready before grains actually impact the sensor at each phase of the oscillation.

Inventive Principle:

Principle #10Preliminary action

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 approach improves the accuracy of grain detection by compensating for the sensitivity variations caused by impact angles, ensuring reliable grain identification even during the oscillating motion of the conveyor.

Implementation Method 1

The signal transducers can be designed as piezo crystals

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

pressure-sensitive layers

Methodology Applied

Scientific EffectPressure-sensitive detection: Piezoresistive Effect

Implementation Method 3

the screens and conveyor floor are set in a periodic, oscillating back-and-forth movement

Methodology Applied

Scientific EffectMechanical vibration: Vibration

Implementation Method 4

moved by means of an eccentric drive

Methodology Applied

Scientific EffectEccentric mechanism: Eccentric

Implementation Method 5

the screens are subjected to an air flow from below. This ensures that the mixture is periodically thrown upwards on the screen

Methodology Applied

Scientific EffectAir flow separation: Fluid Spray

Implementation Method 6

lands on the screen again after covering a throwing parabola

Methodology Applied

Scientific EffectGravitational force: Gravitation

Data Source

PatentUS20240361225A1Sensor arrangement for a combine harvester

Publication Date: 2024.10.31 DEERE & CO

AI summary

A sensor arrangement for a combine harvester that includes a conveyor for grain-containing crops. The conveyor can be set in a periodic movement by a drive. The sensor arrangement includes a baffle plate sensor associated with the conveyor and configured to emit an electrical signal in response to an impact of a grain. The sensor arrangement includes an evaluation circuit which is connected to the baffle plate sensor for signal transmission. The evaluation circuit is configured to process the signal generated by the baffle plate sensor and, taking into account the respective position of the conveyor along movement of the conveyor, to recognize a signal generated by a grain and to emit a corresponding output signal.