Tire Force Model Updating From Multi-Axis Acceleration Sensing

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Solution Overview

Problem

Existing methods for estimating the friction coefficient between a tire and a road surface, such as those using vehicle information, do not accurately reflect tire behavior, leading to low calculation accuracy of tire forces.

Innovation Solution

An arithmetic model generation system and method that acquires tire acceleration, calculates tire forces using a learning-type model like a neural network, and updates the model based on measured tire axial forces to improve estimation accuracy, considering both radial and axial directions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If vehicle information (acceleration, engine torque) is used to estimate friction coefficient, then the estimation method is simple, but calculation accuracy of tire force is low because actual tire behavior (vibrations) is not reflected

Engineering Contradiction:
Improvecalculation accuracy of tire forceVSAvoidcomplexity of measurement system
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces an acceleration sensor as an intermediary device mounted on the tire to directly measure tire vibrations. This mediator captures the actual tire behavior that cannot be obtained from vehicle information alone, thereby improving tire force calculation accuracy while maintaining relative system simplicity

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the indirect mechanical estimation method (using vehicle information) with a direct measurement approach using acceleration sensors and signal processing. The mechanical vibration measurements are converted into tire force data through arithmetic models, substituting the need for complex mechanical analysis

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

2Measurement precision

If only radial acceleration is measured, then the measurement system is simple, but tire force estimation in lateral and vertical directions is inaccurate

Engineering Contradiction:
Improveaccuracy of tire force estimationVSAvoidnumber of acceleration sensors
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent makes a single acceleration sensor multi-functional by strategically mounting it on the tire rim so that it can measure acceleration components in radial, axial, and longitudinal directions simultaneously. This universal positioning allows one sensor to provide data for estimating tire forces in multiple directions (vertical, lateral, and longitudinal), eliminating the need for separate sensors for each direction

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

Data Source

PatentEP3674159B1Arithmetic model generation system and arithmetic model generation method
Publication Date: 2023.09.06 TOYO TIRE CORP
  • EP3674159B1 patent drawingFigure 1
  • EP3674159B1 patent drawingFigure 2
  • EP3674159B1 patent drawingFigure 3A~3B

AI summary

An arithmetic model generation system (100) includes a sensor information acquisition unit (31), a tire force calculator (32), and an arithmetic model update unit (33). The sensor information acquisition unit (31) acquires acceleration of a tire (10). The tire force calculator (32) includes an arithmetic model (32b) for calculating tire force F based on the acceleration, and calculates the tire force F by inputting the acceleration acquired by the sensor information acquisition unit (31). The arithmetic model update unit (33) compares tire axial force measured by the tire (10) and the tire force F calculated by the tire force calculator (32), and updates the arithmetic model (32b).