Driven Tire Load Estimation Using Acceleration Energy Density

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Solution Overview

Problem

Current methods for measuring the load applied to a pneumatic casing while in rolling condition face challenges in precision due to sensitivity to ground irregularities and energy consumption, requiring high spatial sampling frequencies and memory spaces.

Innovation Solution

A method involving sensors on the pneumatic casing to detect acceleration signals, constructing wheel revolution signals, and calculating energy densities to determine deformation and load, allowing for precise load measurement with reduced spatial discretization and energy consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If high spatial sampling frequencies are used to precisely determine contact patch dimensions, then measurement precision is improved, but energy consumption increases

Engineering Contradiction:
Improvecontact patch dimension measurement precisionVSAvoidmeasuring device energy consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent extracts only the essential information needed for load determination from the acceleration signal, specifically focusing on contact patch entry and exit points rather than continuously sampling the entire tire circumference. This selective extraction approach maintains measurement precision while significantly reducing the data processing burden and energy consumption.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of implementing fine discretization across the entire tire surface, the patent applies partial action by concentrating sampling efforts only at critical locations (contact patch boundaries). This approach achieves sufficient measurement precision for load determination without the excessive energy consumption that would result from uniform high-resolution sampling of the complete tire circumference.

Inventive Principle:
Principle #16Partial or excessive action

2Measurement precision

If fine discretization of deformation signal is applied to obtain precise contact patch image, then measurement precision is improved, but memory space requirements increase

Engineering Contradiction:
Improvecontact patch image precisionVSAvoidmemory space
Core Design Contradiction:
Measurement precisionVSVolume of stationary object

Solution Approach 1:

The patent extracts only the critical boundary information of the contact patch from the deformation signal, storing only the entry and exit points rather than maintaining a complete high-resolution map of the entire contact area. This extraction approach preserves the essential measurement precision needed for load calculation while dramatically reducing memory space requirements.

Inventive Principle:
Principle #2Taking out (Extraction)

3Measurement precision

If continuous monitoring of the entire tire surface is performed, then measurement precision is improved, but use of energy increases

Engineering Contradiction:
Improvetire load measurement precisionVSAvoidcontinuous monitoring energy consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent extracts only the essential load information from selective acceleration measurements taken at specific locations and moments during tire rotation, rather than continuously monitoring the entire tire surface. This approach maintains sufficient measurement precision for accurate load determination while significantly reducing the continuous energy consumption that would be required for comprehensive surface monitoring.

Inventive Principle:
Principle #2Taking out (Extraction)

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

This method provides precise evaluation of the load applied to the pneumatic casing with reduced energy and memory usage, improving accuracy and robustness against external disturbances.

Implementation Method 1

Fix at least one sensor on the pneumatic casing at the apex, having a radial position R relative to the natural axis of rotation in its mounted state, capable of generating at least one output signal proportional to the acceleration experienced by the sensor in the pneumatic casing

Methodology Applied
Scientific EffectAcceleration detection: Accelerometer

Data Source

PatentEP4084972B1Determining method of the applied load on a driven tire
Publication Date: 2024.07.24 MICHELIN & CO (CIE GEN DES ESTAB MICHELIN)
  • EP4084972B1 patent drawingFigure 1~2
  • EP4084972B1 patent drawingFigure 3~4
  • EP4084972B1 patent drawingFigure 5~6

AI summary

Disclosed is a method for ascertaining a load applied to a pneumatic tire casing of a mounted assembly, comprising the following steps: - acquiring a signal comprising the amplitude of the acceleration in the direction normal to the crown when rolling at the rotational speed W; - determining a reference acceleration; - identifying a series of increments I; - delimiting the signal between Imin and Imax for constructing a wheel revolution signal; - defining a first energy density S, which is a function of the wheel revolution signal, of the reference acceleration, designated S+ when the wheel revolution signal is greater than a threshold A and S- when it is not; - identifying the deformation Def% of the tire casing generated by the load as a function of the reference acceleration and the first energy density S; - determining the load Z applied using a bijection F comprising the deformation Def% of the tire casing.