Vehicle Traction Control via Real-Time Road Mu Estimation

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Solution Overview

Problem

Traditional traction control systems in vehicles arbitrarily reduce power to wheels when wheel slip is detected, failing to determine and adjust the appropriate drive force for optimal traction on various road surfaces.

Innovation Solution

An electronic control unit with a tractive force model calculates and adjusts drive force based on real-time wheel slip conditions, road mu estimation, and vehicle mass, dynamically determining the maximum drive force to prevent wheel slip while maintaining vehicle performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional traction control systems arbitrarily reduce power to wheels when wheel slip is detected, then wheel slip is reduced, but vehicle performance is compromised due to excessive power reduction

Engineering Contradiction:

Improvetraction control effectivenessVSAvoidvehicle performance

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The system dynamically adjusts drive force based on real-time wheel slip conditions and road mu estimation, transitioning from static arbitrary power reduction to adaptive force management that responds to changing operating conditions

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the parameter of drive force based on estimated road mu and detected wheel slip, using a tractive force model to calculate optimal force levels that prevent slip while maintaining performance

Inventive Principle:

Principle #35Parameter changes

2Reliability

If arbitrary power reduction is applied to prevent wheel slip, then wheel spin condition is mitigated, but appropriate drive force is not determined

Engineering Contradiction:

Improvewheel slip preventionVSAvoiddrive force determination

Core Design Contradiction:

ReliabilityVSLoss of information

Solution Approach 1:

The system uses feedback from wheel slip detection and road mu estimation to continuously adjust drive force, creating a closed-loop control system that determines appropriate force levels based on actual vehicle conditions

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system replaces arbitrary mechanical power reduction with a computational tractive force model that calculates appropriate drive force based on vehicle mass, road mu, and wheel slip conditions

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If snow mode manually detunes transmission shifts, then wheel slip is reduced, but drive force control is not optimized

Engineering Contradiction:

Improvetraction on slippery surfacesVSAvoidpower management system

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The electronic control unit performs multiple functions including wheel slip detection, road mu estimation, tractive force calculation, and drive force adjustment, replacing multiple separate systems with a unified multi-functional control system

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS8706378B2Systems and methods for determining road mu and drive force

Publication Date: 2014.04.22 TOYOTA JIDOSHA KK

AI summary

The vehicle described herein employs a mu logic module. The mu logic module monitors vehicle operating conditions, and based on those operating conditions determines a road surface mu in response to a wheel slip event. The road surface mu is then used to determine a drive force to minimize or control the wheel slip event. The mu logic module continually monitors and adjusts the drive force provided to at least one of the wheels to maximize the applied drive force, while stabilizing and controlling wheel slip events to ensure safe operation of a vehicle.