Road Milling Machine Leveling Device Asymmetric Sensor Control

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Solution Overview

Problem

Existing road milling machines face challenges in precisely processing road surfaces without additional information about the inclination of the area, especially when milling on roads with crown profiles or wider surfaces, as they require costly additional data for accurate depth control on both sides.

Innovation Solution

A self-propelled road milling machine equipped with a machine frame, multiple drives, and a leveling device featuring two distance measuring devices and a control unit that adjusts the machine frame's height and inclination based on distance measurements, allowing for precise milling depth control without needing additional inclination data, using a control mode that adjusts lifting devices based on deviations from specified distance values.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional road milling machines use distance measuring devices mounted on both sides to detect actual milling depth and cross slope, then milling depth control is improved, but device complexity and cost increase due to requiring additional sensors and inclination data

Engineering Contradiction:
Improvemilling depth control precisionVSAvoidsensor configuration complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The distance measuring devices mounted on only one side of the machine frame serve multiple functions: they detect both the actual milling depth and the cross slope of the road surface by measuring distances to multiple points. This eliminates the need for separate sensors on both sides while maintaining control precision.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The invention extracts and eliminates the requirement for distance measuring devices on the opposite side of the machine frame. By using the one-side mounted sensors to detect both depth and slope information, the system removes unnecessary components and reduces device complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

2Manufacturing precision

If road milling machines acquire additional inclination data for accurate depth control on roads with crown profiles, then manufacturing precision is improved, but loss of information and data processing complexity increase

Engineering Contradiction:
Improvemilling depth accuracyVSAvoidadditional data requirements
Core Design Contradiction:
Manufacturing precisionVSLoss of information

Solution Approach 1:

The control unit uses feedback from the distance measuring devices to dynamically adjust the milling depth. By continuously measuring distances and calculating cross slope in real-time, the system maintains accurate depth control without requiring pre-acquired inclination data, reducing information loss and processing complexity.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The distance measuring devices on one side self-service by providing both depth and slope information needed for control. The system uses its own measurement data to compensate for road profile variations, eliminating the need for external inclination data sources.

Inventive Principle:
Principle #25Self-service

3Device complexity

If distance measuring devices are mounted on one side only, then device complexity is reduced, but measurement precision may be insufficient for controlling milling depth on both sides of the road

Engineering Contradiction:
Improvesensor arrangement simplicityVSAvoidbilateral depth control accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The invention transitions from a symmetric two-side sensor arrangement to an asymmetric one-side arrangement that measures in multiple dimensions. By measuring distances to multiple points on the same side and calculating cross slope from these measurements, the system achieves bilateral control capability from a unilateral sensor position.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent applies asymmetry by mounting all distance measuring devices on only one side of the machine frame rather than symmetrically on both sides. This asymmetric configuration, combined with cross slope calculations, enables the system to control milling depth on both sides of the road effectively.

Inventive Principle:
Principle #4Asymmetry

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 precise processing of road surfaces without additional inclination data, reducing costs by using existing hardware and algorithms for both traffic directions, with only minor programming adjustments, and minimizing the need for additional sensors, thus improving operational efficiency and accuracy.

Implementation Method 1

a first distance measuring device (16), in particular with a distance sensor (16A), for measuring a distance (a) between at least one reference point (R1) and the traffic surface (8), thereby determining a first distance value (a)

Methodology Applied
Scientific EffectDistance measurement:

Data Source

PatentEP3647494B1Road construction machine and method for operating a road construction machine
Publication Date: 2022.04.27 WIRTGEN GMBH
  • EP3647494B1 patent drawingFigure 1
  • EP3647494B1 patent drawingFigure 2
  • EP3647494B1 patent drawingFigure 3

AI summary

The self-propelled construction machine 1 according to the invention, in particular a road milling machine, has a machine frame 3 on which a milling drum 10 is arranged, and at least one left-hand undercarriage 4, 6 and at least one right-hand undercarriage 5, 7 in the working direction A, to which lifting devices 4A, 5A, 6A, 7A are assigned, supporting the machine frame 3. Furthermore, the construction machine has a leveling device 15 for controlling the lifting devices 4A, 5A, 6A, 7A, which is designed such that the height and/or inclination of the machine frame 3 is adjustable with respect to the road surface (8). The leveling device 15 provides a special control mode intended for operating the construction machine 1 when a section of road is to be milled on the outer side 20A of the roadway.This leveling device 15 provides distance measurements for the control of the lifting devices 4A, 5A, 6A, 7A only on one common side of the machine frame 3.