Tire Tread Depth Measurement Using Multi-Line Optical Triangulation

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Solution Overview

Problem

Existing tire tread depth measurement methods lack versatility and accuracy, particularly for varying tire widths, and often require complex setups or moving parts, which can lead to measurement errors and operational challenges.

Innovation Solution

A device and method utilizing multiple light lines projected onto the tire surface, encoded for identification, combined with area image sensors and optical elements for enhanced accuracy, allowing for robust and accurate tread depth measurement across various tire widths without moving parts, and integrated sensors for speed and ambient light compensation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single light line is used for measurement, then the device complexity is reduced, but the measurement precision and robustness deteriorate

Engineering Contradiction:
Improvemeasurement device structureVSAvoidtread depth measurement accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The single light line is segmented into multiple parallel light lines (at least three) that are projected onto the tire tread simultaneously. Each light line independently measures tread depth at different positions, and the measurements are combined to provide both high precision and broad coverage across varying tire widths without requiring multiple separate measurement devices

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The measurement system transitions from one-dimensional single-line measurement to two-dimensional multi-line measurement by projecting multiple parallel light lines across the tire width. This dimensional expansion enables simultaneous measurement across different tire widths while maintaining system simplicity

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

2Adaptability or versatility

If moving parts are used in the measurement device, then the adaptability to different measurement scenarios is improved, but the reliability and measurement precision deteriorate due to motion errors

Engineering Contradiction:
Improvemeasurement scenario flexibilityVSAvoidmeasurement consistency
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent replaces mechanical moving parts with a stationary optical measurement system. The device uses fixed light sources and sensors that remain stationary while the tire rotates or moves through the measurement zone. This eliminates motion-induced measurement errors while maintaining versatility through optical field manipulation

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

Solution Approach 2:

The stationary device achieves universal applicability by using multiple light lines that can be adjusted in number and spacing to accommodate different tire widths. The same fixed装置 can measure various tire types without mechanical reconfiguration, achieving versatility through optical design rather than mechanical adaptation

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

3Device complexity

If ambient light is not compensated, then the device complexity is reduced, but the measurement precision deteriorates due to environmental light interference

Engineering Contradiction:
Improvesystem configurationVSAvoidtread depth measurement accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent employs wavelength-multiplexed light sources where different light lines use different wavelengths (colors) of light. The sensors are configured to detect specific wavelengths, enabling discrimination between the projected measurement light and ambient light. This spectral encoding allows precise measurement even in varying ambient light conditions without adding complex active compensation mechanisms

Inventive Principle:
Principle #32Color changes

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

The solution provides high measurement accuracy and robustness, suitable for diverse tire widths, minimizes environmental light interference, and prevents measurement errors due to motion blur, enabling reliable detection of tread wear and potential obstructions, with visual feedback for easy operator assessment.

Implementation Method 1

the triangulation sensor, mounted on a movable carriage, is moved along a line transverse to the direction of tire rotation

Methodology Applied
Scientific EffectTriangulation:

Implementation Method 2

a beam fan emanating from a light source is reflected at the tire surface, and a signal from the reflected beam fan is recorded by a sensor

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP2936049B1Apparatus and method for measuring the profile depth of a tire
Publication Date: 2020.09.30 BEISSBARTH GMBH
  • EP2936049B1 patent drawingFigure 1
  • EP2936049B1 patent drawingFigure 2
  • EP2936049B1 patent drawingFigure 3

AI summary

An apparatus for measuring the profile of the tread of a tire (12) has a plurality of measurement modules (26), which are arranged transversely with respect to the running direction (F) of the tire (12) and connected to a common evaluation device (30), wherein each measurement module (26) has at least one illumination device (4), which is configured and arranged such that it projects, during operation, at least one line of light (6) onto the profile to be measured, and has at least one image recording device (18), which is configured for recording at least one image of at least one region of the profile to be measured. The at least one illumination device (4) and the at least one image recording device (18) are configured and arranged such that the illumination direction of the illumination device (4) and the image recording direction of the image recording device (18) are aligned to be neither mutually parallel nor orthogonal to the tread of the tire (12).