Real-Time Tire Force Simulation via Precomputed Lookup Tables

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Solution Overview

Problem

Existing tire simulation methods, such as the 'Magic Formula' developed by Pacejka, fail to accurately model forces transmitted by tires, especially under significant and variable stress conditions, and do not provide real-time values for longitudinal, transverse forces, and self-aligning torque.

Innovation Solution

A method that establishes a mechanical model of tire forces using dynamic and specific parameters, with iterative calculations to solve equations, accounting for temperature influences and thermal models to update parameters in real-time, enabling precise calculation of longitudinal, transverse forces, and self-aligning torque during vehicle rolling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a physical model of the tire is used to accurately model forces transmitted by the tire, then the accuracy of force modeling is improved, but the calculation time increases and real-time values cannot be provided

Engineering Contradiction:
Improveaccuracy of force modelingVSAvoidcalculation time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent pre-calculates and stores force characteristics in lookup tables during an offline phase, so that during real-time operation, only table lookups and simple interpolations are needed, eliminating the need for time-consuming iterative physical model calculations while maintaining accuracy

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent creates simplified representations of the complex physical model by storing pre-computed force characteristics in lookup tables, which serve as copies that can be quickly accessed and interpolated during real-time operation without requiring the full computational complexity of the original physical model

Inventive Principle:
Principle #26Copying

2Productivity

If parameters devoid of causal link with physics are used to model the tire, then the calculation speed is improved, but the accuracy of force transmission modeling deteriorates

Engineering Contradiction:
Improvecalculation speedVSAvoidaccuracy of force transmission modeling
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent creates simplified representations of the complex physical model by storing pre-computed force characteristics in lookup tables, which serve as copies that can be quickly accessed and interpolated during real-time operation without requiring the full computational complexity of the original physical model

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent transforms the continuous physical model into a discrete set of pre-computed values stored in lookup tables, changing the parameter representation from continuous mathematical functions to discrete tabulated data that can be quickly accessed and interpolated

Inventive Principle:
Principle #35Parameter changes

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 real-time simulation of tire forces and self-aligning torque, improving accuracy and responsiveness under varying stress conditions, and optimizing tire behavior modeling.

Implementation Method 1

a process for modeling the temperatures of a tire in a rolling situation on the ground by taking into account the effects of hysteresis in the elastomer

Methodology Applied
Scientific EffectHysteresis: Hysteresis

Implementation Method 2

a third model, a global model of heating and heat flow, this third model taking the form of a system of equations expressing variations over a wheel revolution period of a peripheral temperature of the tread and an internal temperature of the tire as a function of previously known or estimated values of the peripheral and internal temperatures, of a coefficient thermal conduction of the tread

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP2062176B1Method for the simulation of the physical behaviour of a tyre rolling on the ground
Publication Date: 2018.07.18 MICHELIN & CO (CIE GEN DES ESTAB MICHELIN)
  • EP2062176B1 patent drawingFigure 1~3
  • EP2062176B1 patent drawingFigure 4~5
  • EP2062176B1 patent drawingFigure 6

AI summary

The invention relates to a method for simulating the behaviour of a tyre mounted on a vehicle in running conditions on the ground, wherein said method comprises a mechanical model for essentially computing the longitudinal (Fx) and transverse (Fy) stresses transmitted by the tyre between the ground and the vehicle according to dynamic parameters related to the physical conditions of the tyre running and use and according to physical tyre-specific parameters. According to the invention, the mechanical model is set and solved in an iterative manner (8-10), assuming that the tyre contact surface with the ground comprises an adherence contact area and a sliding contact area and assuming that there is a unique x-coordinate point b indicative of the transition between the two contact areas. Applicability: real-time simulation of a vehicle dynamic behaviour.