Soil Milling Machine Cross-Slope Control via Inclination Sensor

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Solution Overview

Problem

Existing soil milling machines struggle to achieve precise soil processing without requiring additional information about the cross slope of the soil surface, especially when a suitable reference surface is not available on one side of the path to be processed, and they fail to maintain the same cross slope during milling when the road surface changes along its length.

Innovation Solution

The soil milling machine employs a chassis with front and rear tracks that are positively coupled or connected via a pendulum axle system, equipped with lifting devices and sensors to measure distance and cross-slope, allowing the control unit to adjust the milling depth and cross slope dynamically based on real-time data without prior surveying, ensuring the milling drum remains parallel to the ground surface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If traditional distance measurement methods are used on both sides of the milling drum, then milling depth can be controlled, but the method becomes infeasible when a suitable reference surface is not available on one side (e.g., roadside ditch or embankment)

Engineering Contradiction:
Improvemilling depth controlVSAvoidreference surface availability
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The patent introduces an intermediary solution by using the machine frame's own inclination (measured by inclination sensor) as a substitute for the missing external reference surface. Instead of requiring a reference surface on both sides, the system uses the measured inclination of the machine frame relative to horizontal, combined with distance measurement on the available side, to calculate and control the milling depth on both sides of the milling drum.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If the cross slope of the road surface changes along its length, then the milling drum must be continuously repositioned to maintain parallel alignment, but traditional methods require prior surveying and marking of the path

Engineering Contradiction:
Improvecross slope consistencyVSAvoidpre-milling surveying
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent implements a feedback control system where the inclination sensor continuously measures the actual inclination of the machine frame, and the control unit uses this real-time data to adjust the lifting devices and maintain the desired cross slope. This eliminates the need for prior surveying and marking, as the system automatically adapts to changing road profiles through continuous measurement and adjustment.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces the traditional mechanical surveying and marking process with an electronic sensing and control system. Instead of physically marking the path beforehand, the system uses an inclination sensor to detect the machine frame's orientation and a control unit to automatically adjust the milling depth, substituting manual mechanical procedures with automated electronic control.

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

3Device complexity

If the milling drum is kept at a fixed inclination, then the machine structure is simple, but the milling depth varies when the cross slope of the ground changes

Engineering Contradiction:
Improvemachine structureVSAvoidmilling depth consistency
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent transforms the static, fixed inclination system into a dynamic, adjustable system. The lifting devices are controlled to actively adjust the inclination of the milling drum based on real-time feedback from the inclination sensor and distance measurement, allowing the system to adapt to changing ground conditions while maintaining consistent milling depth.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4249680B1Self-propelled ground milling machine and method for controlling a self-propelled ground milling machine
Publication Date: 2025.12.31 WIRTGEN GMBH
  • EP4249680B1 patent drawingFigure 1
  • EP4249680B1 patent drawingFigure 2
  • EP4249680B1 patent drawingFigure 3A~3B

AI summary

The invention relates to a self-propelled soil milling machine 1, which comprises a machine frame 3 supported by a chassis 2 having front and rear, left and right tracks 4, 5, 6, 7, wherein a milling drum 10 is arranged on the machine frame 3. Furthermore, the invention relates to a method for controlling such a soil milling machine. The soil milling machine according to the invention is characterized by a cross-slope detection device 21, which is designed for controlling the soil milling machine such that the position of the front left and right tracks 4, 5, which stand on the unworked soil 8, is detected with respect to the machine frame 3, and cross-slope values ​​describing the cross-slope of the soil surface transverse to the working direction A of the soil milling machine with respect to the machine frame are determined from the position of these tracks, and these values ​​form the basis for controlling the soil milling machine.The cross slope detection device 21 functions as a cross slope sensor system for detecting the cross slope of the track.