Friction coefficient calculation device

The friction coefficient calculation device accurately estimates the maximum friction coefficient using a tire brush model for infinitesimal slip ratios, addressing the challenge of inaccuracy in existing methods by adjusting parameters to ensure precise calculation without tire spinning.

JP7722292B2Active Publication Date: 2025-08-13DENSO CORP +2
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Patent Information

Application Number
JP2022121748
Authority / Receiving Office
JP · JP
Patent Type
Patents
Current Assignee / Owner
Filing Date
2022-07-29
Publication Date
2025-08-13
Estimated Expiration
2042-07-29

AI Technical Summary

Technical Problem

Existing methods for calculating the maximum friction coefficient of a road surface using a tire brush model are inaccurate because they require rotating the tire until just before it starts to spin, which is difficult to achieve, and approximating the tire brush model as a linear or quadratic function leads to inaccuracies in estimating the friction coefficient.

Method used

A friction coefficient calculation device that estimates the maximum friction value by using a tire brush model equation for infinitesimal slip ratios, excluding parameter values that cause the model to become a linear or quadratic function, and adjusting parameters to ensure the slope of the inflection point approaches zero, thereby accurately calculating the friction coefficient.

Benefits of technology

Enables precise estimation of the maximum friction coefficient without requiring the tire to spin, improving accuracy by excluding parameter values that lead to inaccurate calculations.

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Abstract

To provide a friction coefficient calculation device which can accurately calculate an estimation maximum value of a friction coefficient.SOLUTION: A friction coefficient calculation device for estimating an estimation friction maximum value μp includes: a calculation part 10 for calculating a slip rate and a friction coefficient; and a maximum friction estimation part 20 for calculating an estimation friction maximum value, using a tire brush model expression which has a plurality of parameters changing the inclination and calculates an estimation friction coefficient in which the slip rate is in a fine region, which is a function of slip rate of tire brush model, a calculation slip rate Sc and a calculation friction coefficient μc. The maximum friction estimation part includes: a model calculation part 21 for calculating a tire model friction μm; and a parameter estimation part 23 for estimating the values of the parameters. The parameter estimation part includes a parameter restriction part 232 which eliminates the value of the parameter in which the tire brush model expression becomes a linear function and a quadratic function, and determines the value of the parameter which can make the inclination of an inflection point of the tire brush model expression close to 0.SELECTED DRAWING: Figure 1
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Citation Information

Patent Citations

  • Estimation device of friction coefficient of road surface

    JP2010120600A

  • Method and arrangement for tire to road friction estimation

    US20160368503A1