Optical Wheel Dimensioning via Planar Light Triangulation

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Solution Overview

Problem

Existing methods for determining the geometrical dimensions of a vehicle wheel are not reliable and lack precision, especially in contact-less sensing and environmental variability.

Innovation Solution

A contact-less optical sensing system using digital cameras and triangulation methods to measure the wheel contour, integrating a light source that emits a planar light beam, focusing reflected light rays onto a two-dimensional sensor surface for precise sub-pixel resolution, and employing calibration techniques to account for environmental conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If contact-less optical sensing is used to measure wheel dimensions, then measurement speed and non-contact capability are improved, but measurement precision and reliability deteriorate due to environmental variability and ambient light interference

Engineering Contradiction:
Improvemeasurement speedVSAvoiddimensional measurement precision
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The system dynamically adapts to environmental conditions by implementing real-time calibration procedures and adjustable exposure controls that respond to varying ambient light levels, allowing the optical sensing system to maintain measurement precision across different environmental conditions while preserving high measurement speed

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes operational parameters such as light source intensity, detector exposure time, and filtering characteristics based on environmental conditions. By dynamically adjusting these parameters, the system maintains high measurement speed while compensating for environmental variability that would otherwise degrade measurement precision

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If optical sensing systems are made more sensitive to detect fine wheel features, then measurement precision is improved, but sensitivity to ambient light and environmental conditions increases

Engineering Contradiction:
Improvesub-pixel resolution capabilityVSAvoidambient light interference
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The system converts the harmful effect of ambient light into a beneficial calibration reference. By using ambient light conditions as part of the calibration process, the system achieves high sub-pixel resolution capability while simultaneously compensating for and reducing the negative impact of ambient light interference through real-time environmental adaptation

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If multiple sensors and light sources are added to improve measurement reliability in various conditions, then measurement reliability is improved, but system complexity increases

Engineering Contradiction:
Improvemeasurement reliabilityVSAvoidsensing system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system implements multi-functional components that serve multiple purposes: the light source serves both illumination and calibration functions, the detector performs both measurement and environmental characterization, and the processing system handles both real-time measurement and calibration compensation. This universal approach improves measurement reliability across various conditions without proportionally increasing system complexity

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

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 accurate and reliable determination of wheel dimensions and structural features with high precision, effective in various environmental conditions and reducing system sensitivity to ambient light.

Implementation Method 1

At each of the impingement points, the light beam is scattered in a plurality of light rays that are reflected

Methodology Applied
Scientific EffectLight scattering: Scattering

Implementation Method 2

The spacings and thus positions of the individual impingement points sensed at the wheel or the rim can then be determined by the triangulation method in dependence on the directions of the emitted and reflected light beams

Methodology Applied
Scientific EffectOptical triangulation: Parallax

Implementation Method 3

the light beam is scattered in a plurality of light rays that are reflected

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 4

At least a plurality of these reflected light rays will be then concentrated or focused by a lens system or input pupil stripe-shaped projected image area on a two-dimensional photosensitive sensor surface

Methodology Applied
Scientific EffectOptical focusing: Focusing

Data Source

PatentEP2020594B1Method of and apparatus for determining geometrical dimensions of a vehicle wheel
Publication Date: 2014.05.07 SNAP ON EQUIP SRL
  • EP2020594B1 patent drawingFigure 1
  • EP2020594B1 patent drawingFigure 2
  • EP2020594B1 patent drawingFigure 3

AI summary

A method and an apparatus of determining geometrical dimensions of a motor vehicle wheel (rim/tyre assembly) 1 by contact-less sensing, wherein the wheel is fixed on wheel receiving means 8 of a tyre changer, that at least one planar light beam 3 is emitted on to the wheel or at least a part of the wheel, wherein the light beam reflected at the impingement area is detected, and wherein the directions of the emitted and reflected light beams are evaluated for determining the shape and/or position of the respective impingement area 4 on the wheel 1.