Brake-to-Steer Control With Mu Estimation for Vehicle Stability

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Solution Overview

Problem

Brake-to-Steer (BtS) braking and powertrain commands can cause vehicle instability or unintended vehicle oversteer, especially in low surface coefficient of friction driving scenarios, and current mitigation methods are reactive and transitory.

Innovation Solution

A method that modifies brake or powertrain torque in real-time to enhance lateral stability during Brake-to-Steer functionality, using vehicle dynamics data and stability indicators to proactively adjust commands and estimate surface mu.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If Brake-to-Steer commands are applied to improve lateral control, then vehicle controllability is improved, but vehicle instability or unintended oversteer occurs

Engineering Contradiction:

Improvelateral controlVSAvoidvehicle stability

Core Design Contradiction:

Ease of operationVSStability of the object's composition

Solution Approach 1:

The system continuously monitors vehicle dynamics parameters (lateral acceleration, yaw rate, wheel speeds) and uses this feedback to detect instability conditions. When instability is detected, the system automatically modifies or cancels BtS commands, creating a closed-loop control system that adapts to real-time vehicle behavior.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts BtS command application based on real-time stability assessment. Rather than applying fixed BtS commands, the system modulates their application based on current vehicle state, surface conditions, and detected stability margins, making the control adaptive rather than static.

Inventive Principle:

Principle #15Dynamics

2Reliability

If reactive mitigation methods are used to address instability, then vehicle control is restored, but the solution is transitory and does not prevent recurrence

Engineering Contradiction:

Improvecontrol restorationVSAvoidduration of control solution

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The system performs preliminary stability assessment before applying BtS commands and maintains continuous monitoring during command application. By detecting potential instability conditions in advance and proactively adjusting commands, the system prevents instability rather than merely reacting to it after occurrence.

Inventive Principle:

Principle #10Preliminary action

3Device complexity

If surface mu estimation is not implemented, then system complexity is reduced, but accurate surface condition awareness is lost

Engineering Contradiction:

Improvesystem complexityVSAvoidsurface condition information

Core Design Contradiction:

Device complexityVSLoss of information

Solution Approach 1:

The system estimates surface mu by analyzing data already being collected for BtS operation (wheel speeds, vehicle dynamics parameters) rather than requiring separate sensors or systems. The existing vehicle dynamics data is repurposed to derive surface friction characteristics, making the estimation function self-service rather than adding separate measurement infrastructure.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS12583424B2Vehicle stability learning for brake-to-steer and Mu estimation

Publication Date: 2026.03.24 STEERING SOLUTIONS IP HOLDING CORP

AI summary

A number of variations may include a method that may include modifying, in real-time, at least one brake or powertrain torque or force to one or more roadwheels of a vehicle to increase lateral stability during Brake-to-Steer functionality.