Single-Sided Contactless Wheel Toe Measurement for Accurate Alignment

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Solution Overview

Problem

Existing contactless wheel angle measurement systems require two opposite acquisition units on both lateral sides of the vehicle, leading to increased size and cost, while single-sided systems lack accuracy for precise angle determination.

Innovation Solution

A contactless wheel angle measurement system using a single vertical structure with distance sensors positioned orthogonally to the vehicle path, allowing precise angle determination by measuring distances from one side, combining multiple sensor pairs for enhanced accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If two opposite acquisition units are used on both lateral sides of the vehicle, then measurement accuracy is improved, but device complexity and cost increase

Engineering Contradiction:
Improvewheel angle measurement accuracyVSAvoidnumber of acquisition units
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies asymmetry by transitioning from a symmetric dual-sided measurement system to an asymmetric single-sided system. The invention positions acquisition units on only one lateral side of the vehicle, using asymmetric geometric relationships and computational methods to determine wheel angles without requiring opposite units on both sides. This reduces device complexity while maintaining measurement capability through mathematical reconstruction of the complete wheel orientation state from partial measurements.

Inventive Principle:
Principle #4Asymmetry

2Measurement precision

If two opposite acquisition units are used on both lateral sides of the vehicle, then measurement accuracy is improved, but system cost increases

Engineering Contradiction:
Improvewheel angle measurement accuracyVSAvoidsystem cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent reduces system cost by eliminating the need for symmetric dual-sided acquisition units. By implementing measurement on only one lateral side and using computational geometry to derive complete wheel angle information, the system requires fewer sensors and less complex infrastructure, directly reducing manufacturing and deployment costs while maintaining adequate measurement precision for wheel angle determination.

Inventive Principle:
Principle #4Asymmetry

3Device complexity

If a single vertical structure is used on one side, then device complexity is reduced, but measurement precision deteriorates

Engineering Contradiction:
Improvenumber of measuring structuresVSAvoidwheel angle measurement accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent compensates for the reduction in physical measurement structures by introducing computational dimensions. Instead of relying solely on multiple physical acquisition units, the system uses mathematical models and geometric calculations that operate in an additional computational dimension. This allows the single vertical structure to provide sufficient measurement data through sophisticated algorithms that reconstruct complete wheel orientation information from partial physical measurements.

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

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 system reduces size and cost by using a single-sided setup, providing accurate wheel angle measurements and detecting potential alignment issues, even if errors are present on the undetected side, with minimal vehicle impact.

Implementation Method 1

the beam reflected from the surface of the wheel is detected, and this defines a signal representative of the spatial position of measurement points on the wheel

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 2

at least two distance detection units capable of measuring the distance between a reference plane and the lateral surface of a vehicle, moving in a direction substantially orthogonal to the acquisition directrices of the distance detection units

Methodology Applied
Scientific EffectElectromagnetic radiation detection: Electromagnetic Induction

Data Source

PatentEP4235094B1System for checking the attitude angles of the wheels of a land vehicle, in particular for a contactless check, and associated method of checking
Publication Date: 2025.09.03 VAMAG
  • EP4235094B1 patent drawingFigure 1~2
  • EP4235094B1 patent drawingFigure 3
  • EP4235094B1 patent drawingFigure 4~5

AI summary

There is described a checking system and an associated method for the contactless checking of the attitude angles of the wheels of a land vehicle (V), comprising - at least one device for detecting the toe angle of the wheels of a vehicle (V) equipped with a pair of distance detection units (S1, S2, ... Sn) each capable of measuring a wheel distance between a common reference plane (A-A') parallel to a through-lane (P-P') and a reference point on a lateral surface of a vehicle (V) including a wheel moving with respect to said at least one pair of distance detection units (S1, S2, ... Sn), wherein - the system includes a single toe angle detection device incorporated on a single vertical measuring structure (1), which is arranged on only one side of said through-lane (P-P'), on which said at least one pair of distance detection units (S1, S2, ... Sn) is installed at a height (h) from a running plane (F) of said wheels of the land vehicle (V) and at a mutual separation (D) along a horizontal plane, - said wheel distance being detected on a front wheel and a rear wheel of the vehicle (V) along directrix lines (L1 and L2) orthogonal to said through-lane (P-P') and wherein - said at least one pair of distance detection units (S1, S2, ... Sn) is configured so as to detect said wheel distance of at least two points ((a(N-1), b(N-1), c(N-1), d(N-1), a(N), b(N), c(N), d(N)) for each of said front and rear wheels and to determine at least the following parameters: a first direction of advancement of the vehicle (V) on a front wheel as α = (a(N)-a(N-1))/D; a direction on a horizontal plane of a front wheel as β = (a(N-1)-b(N-1))/Ha; an apparent front wheel toe angle as β - α; a second direction of advancement of the vehicle (V) on a rear wheel as α1 = (c(N)-c(N-1))/D; a direction on a horizontal plane of a rear wheel as γ = (c(N-1)-d(N-1))/Hp; an apparent rear wheel toe angle as γ - α1; where D is said mutual separation, Ha is a horizontal distance between two points (a, b) on the front wheel and Hp is a horizontal distance between two points (c, d) on the rear wheel; at least said parameters being combined to supply a check index.