Laser Rangefinder Signal Evaluation for Agricultural Interference

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Solution Overview

Problem

Laser rangefinders on self-propelled agricultural machines face challenges in distinguishing useful signals from interference signals, particularly due to environmental factors like dust and dirt, which affect signal quality and require efficient methods to improve measurement accuracy.

Innovation Solution

A method that separates measuring points into useful and interference signals by setting limit values for distance, differentiating between dust and dirt signals based on reflection distances, and assigning signals to specific measuring ranges and angular ranges to identify and address the cause of interference, triggering cleaning or dust extraction measures as needed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If signal separation based on distance limit values is implemented, then signal quality is improved, but device complexity increases

Engineering Contradiction:
Improvesignal qualityVSAvoiddata processing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments measurement signals into different categories (useful signals, dust signals, dirt signals) based on distance threshold values. By dividing the signal processing into distinct segments with specific distance criteria, the system can apply targeted evaluation and filtering to each segment, improving overall signal quality while maintaining manageable processing complexity through structured classification.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If interference signals are differentiated into dust and dirt signals, then measurement accuracy is improved, but processing time increases

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies preliminary classification of interference signals by establishing distance threshold values that pre-categorize signals as either dust signals (within threshold) or dirt signals (beyond threshold). This preliminary action enables the system to quickly identify signal types before detailed processing, reducing overall processing time while maintaining accurate differentiation between interference sources.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If rangefinder is mounted on agricultural machine, then productivity is improved, but signal reliability deteriorates due to dust and dirt

Engineering Contradiction:
Improveagricultural machine performanceVSAvoidsignal reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent implements a feedback mechanism that continuously monitors measurement signals for patterns indicative of dust or dirt interference. Based on this feedback, the system can identify when signal quality is compromised by environmental factors and trigger appropriate responses (such as cleaning operations or data filtering), thereby maintaining signal reliability despite the rangefinder's exposure to harsh agricultural conditions.

Inventive Principle:
Principle #23Feedback

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 enhances signal quality by distinguishing and addressing the source of interference, improving the accuracy of distance measurements and reducing data processing complexity, thereby optimizing the performance of agricultural machines.

Implementation Method 1

The distance is determined from the travel time of the measurement signals

Methodology Applied
Scientific EffectTime of Flight: Time of Flight

Implementation Method 2

Rangefinders operate by emitting measurement signals and receiving the reflected measurement signals

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 3

The rangefinder is preferably a laser rangefinder. Laser rangefinders are also known as LiDAR systems

Methodology Applied
Scientific EffectLaser: Laser

Data Source

PatentEP3786663B1Method for signal evaluation of signals from a rangefinder
Publication Date: 2024.08.28 CLAAS SELBSTFAHRENDE ERNTEMASCHINEN GMBH
  • EP3786663B1 patent drawingFigure 1
  • EP3786663B1 patent drawingFigure 2
  • EP3786663B1 patent drawingFigure 3

AI summary

Method for signal evaluation of signals from a rangefinder (2), in particular a laser rangefinder, wherein the rangefinder (2) cyclically performs measurements and outputs a plurality of measurement points (20a, 20b, 22, 25a, 25b, 25c) for each measurement, wherein each measurement point indicates a distance, wherein the rangefinder (2) measures distances in a plurality of directions and a horizontal angle (24) is assigned to each measurement point (20a, 20b, 22, 25a, 25b, 25c), wherein a plurality of the measurement points (20a, 20b, 22, 25a, 25b, 25c) are distinguished into useful signals (22) and noise signals based on the distance, wherein measurement points (20a, 20b, 22, 25a, 25b, 25c) with a distance below a first limit value (12) are identified as interference signals (20a, 20b, 25a, 25b, 25c) and measurement points above the first limit value (12) are identified as useful signals (22), the number of interference signals is determined and a warning signal is issued,when the number of interference signals meets a predetermined condition.