Tire Adhesion Estimation Using Thermomechanical Models at Low Load

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing methods for estimating tire-to-ground adhesion are inadequate, particularly under low-load conditions, and lack the ability to provide preventive estimates, leading to ineffective corrective actions in vehicle safety systems.

Innovation Solution

A method that estimates tire adhesion potential using a vehicle model and thermomechanical tire model, combined with statistical comparison and Bayesian or Monte-Carlo Markov Chain methods, to account for thermal and other parameters, enabling real-time determination of adhesion coefficients.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If sensorless methods are used to estimate adhesion, then cost and industrial intrusiveness are reduced, but measurement precision deteriorates under low-load conditions

Engineering Contradiction:
Improvecost and industrial intrusivenessVSAvoidadhesion estimation accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The method segments the adhesion estimation problem into two distinct phases: a learning phase where the system collects and stores adhesion data under various conditions, and an operational phase where pre-established models are used for real-time estimation. This segmentation allows the system to achieve high precision without requiring complex sensors during normal operation, thus resolving the contradiction between measurement precision and ease of manufacture.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system performs preliminary actions by collecting adhesion data and establishing statistical models during a learning phase before actual vehicle operation. This pre-processing of information creates lookup tables and models that enable accurate real-time estimation without requiring complex sensing equipment during critical moments, thereby achieving high measurement precision with simple implementation.

Inventive Principle:
Principle #10Preliminary action

2Device complexity

If existing sensorless methods are used, then equipment complexity is reduced, but reliability deteriorates when load is below 40% of maximum

Engineering Contradiction:
Improveequipment complexityVSAvoidadhesion estimation reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The method changes the approach from direct real-time measurement to using pre-established statistical models that account for various parameters including temperature, vehicle speed, and load conditions. By storing adhesion coefficients under different conditions during a learning phase and retrieving appropriate values during operation, the system achieves reliable estimation across all load conditions including low-load scenarios below 40% of maximum, while maintaining simple equipment.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention introduces statistical models and lookup tables as intermediaries between the physical tire-ground interaction and the adhesion estimation. These intermediaries, established during a learning phase, enable reliable estimation under all conditions by mapping observed parameters to adhesion coefficients, thereby achieving high reliability without increasing equipment complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If methods focus on estimating adhesion when attained or close to being attained, then immediate corrective action can be triggered, but ability to provide preventive estimate deteriorates

Engineering Contradiction:
Improveresponse speed for corrective actionVSAvoidpreventive estimation capability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The system performs preliminary estimation of adhesion potential using the learned statistical models before the vehicle actually reaches critical adhesion conditions. By continuously estimating adhesion based on current temperature, speed, and load parameters against the pre-established models, the system can provide preventive warnings and allow behavioral modifications before skidding occurs, while still maintaining the capability for immediate corrective action when adhesion is actually attained.

Inventive Principle:
Principle #10Preliminary action

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 approach provides a reliable and accurate estimation of tire adhesion potential, even at low loads, allowing for preventive measures to avoid skidding and improving vehicle safety by considering thermal effects and other parameters.

Implementation Method 1

Another method uses a tire model but does not take into account the thermal characteristics of the tire, thus falsifying the values determined for low loads

Methodology Applied
Scientific EffectThermal effects: Heating

Data Source

PatentUS20240198742A1Method for estimating potential tire-to-ground adhesion
Publication Date: 2024.06.20 MICHELIN & CO (CIE GEN DES ESTAB MICHELIN)
  • US20240198742A1 patent drawing
  • US20240198742A1 patent drawing
  • US20240198742A1 patent drawing

AI summary

The rolling parameters of a tire on a rolling surface are evaluated, and more specifically a tire's adhesion potential on a rolling surface is estimated. A method and a system enabling such estimation are disclosed.