Road Finisher Layer Thickness Detection Using Dual Sensor Segmentation

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Solution Overview

Problem

Existing road finisher systems for determining layer thickness are complex and lack sufficient accuracy, leading to potential premature road surface failure due to inadequate material thickness and excessive material usage.

Innovation Solution

A road finisher system with separate, rigidly supported sensors positioned at different distances and heights relative to the screed's rear edge, using ultrasonic, laser, or microwave sensors to calculate layer thickness based on distance signals and sensor mounting heights, simplifying the calculation and enhancing accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If complex measurement systems are used to determine layer thickness, then measurement capability is provided, but measurement precision and system simplicity deteriorate

Engineering Contradiction:
Improvelayer thickness measurement accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The measurement system is segmented into two independent sensor units: a first sensor mounted on the towing arm to measure distance to the subsurface, and a second sensor mounted on the screed to measure distance to the material layer. This segmentation allows each sensor to perform a specific measurement function independently, simplifying the overall system architecture while maintaining high measurement precision through separate, dedicated measurement paths.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary calculation approach where the layer thickness is determined by combining measurements from two separate sensors rather than using a single complex sensor. The control unit acts as an intermediary that processes the distance signals from both sensors and calculates the layer thickness based on the difference between the two measurements, simplifying the measurement system while maintaining accuracy.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If layer thickness is not accurately monitored, then material costs are reduced, but road surface quality and reliability deteriorate

Engineering Contradiction:
Improveroad surface qualityVSAvoidmaterial usage
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The control unit continuously receives distance signals from both sensors and calculates the layer thickness in real-time, providing feedback on the actual material application thickness. This feedback mechanism allows for continuous monitoring and adjustment of material application to ensure the layer thickness remains within specified tolerances, thereby maintaining road surface quality while optimizing material usage.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs preliminary measurements of the subsurface distance before material application and continues monitoring during application. By establishing the baseline subsurface position in advance and continuously comparing it with the material layer position, the system ensures proper layer thickness from the beginning of the paving process, preventing both insufficient and excessive material application.

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

Enables continuous, precise determination of layer thickness, improving the quality control of road surfaces by ensuring optimal material application without excessive material usage.

Implementation Method 1

The first sensor 38 is an ultrasonic sensor, a laser sensor or a microwave sensor

Methodology Applied
Scientific EffectUltrasonic measurement: Ultrasound

Implementation Method 2

The first sensor 38 is an ultrasonic sensor, a laser sensor or a microwave sensor

Methodology Applied
Scientific EffectLaser measurement: Laser

Implementation Method 3

The first sensor 38 is an ultrasonic sensor, a laser sensor or a microwave sensor

Methodology Applied
Scientific EffectMicrowave measurement: Microwave Radiation

Data Source

PatentEP3048199B2Road finisher with layer thickness detection device and method for detecting the thickness of an installed material layer
Publication Date: 2020.01.22 MOBA MOBILE AUTOMATION AG
  • EP3048199B2 patent drawingFigure 1
  • EP3048199B2 patent drawingFigure 2
  • EP3048199B2 patent drawingFigure 3

AI summary

A road paver comprises a screed (16) for laying a layer of material (42) on a substrate (14) and a layer thickness sensing device for measuring the thickness (hB) of the laid material layer (42). The layer thickness sensing device comprises a first sensor (38) for measuring a first distance to the laid material layer (42) and a second sensor (40) for measuring a second distance to the substrate (14). The layer thickness sensing device comprises a rigid first support (36a) attached to the screed (16) and a second support (36b) attached to a pull arm (18) that rotates the screed (16). The first sensor (38) is attached to the first support (36a), and the second sensor (40) is attached to the second support (36b).The layer thickness detection device comprises a signal processing unit (44) configured to detect the layer thickness (hB) of the installed material layer (42) based on the sensor signals (s1, s2) from the first sensor (38) and from the second sensor (40), the distances (a, b) of the first sensor (38) and the second sensor (40) from the plank trailing edge (26), and the mounting heights of the first sensor (38) and the second sensor (40) relative to the plank trailing edge (26).