Vehicle Stability Control on Descending Roads

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Solution Overview

Problem

Vehicle stability control systems struggle to maintain stability when a vehicle is turning on a descent inclined road, as load transfer to the front wheels increases side forces, leading to a smaller turning radius and higher risk of rollover.

Innovation Solution

A vehicle stability control system that includes a sensing portion to detect yaw rate, steering angle, and vehicle speed, a controller to determine a target yaw rate and yaw moment, and a front wheel steering angle correction device to adjust the steering angle and apply biased braking torque, thereby stabilizing the vehicle by correcting the steering angle and controlling braking on the outside turning wheel.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If the vehicle turns on a descent inclined road, then the side force on the front wheel increases due to load transfer, but the turning radius becomes smaller than intended and rollover risk increases

Engineering Contradiction:

Improveside force on front wheelVSAvoidvehicle stability

Core Design Contradiction:

ForceVSStability of the object's composition

Solution Approach 1:

The system applies preliminary counter-steering action by calculating a correction value for the steering angle based on detected vehicle state (yaw rate, steering angle, vehicle speed) and road conditions. This preliminary correction counteracts the excessive side force effect before it causes dangerous turning radius reduction, preventing rollover rather than reacting after instability occurs

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The system continuously monitors vehicle state parameters (yaw rate, steering angle, vehicle speed) and uses this feedback to dynamically calculate and adjust the steering angle correction value. This closed-loop feedback mechanism ensures the steering correction adapts to real-time conditions, maintaining vehicle stability despite varying load transfer effects on descent roads

Inventive Principle:

Principle #23Feedback

2Stability of the object's composition

If braking control is applied to stabilize the vehicle, then vehicle stability improves, but driver discomfort increases

Engineering Contradiction:

Improvevehicle stabilityVSAvoiddriver comfort

Core Design Contradiction:

Stability of the object's compositionVSEase of operation

Solution Approach 1:

The system performs preliminary steering angle correction before braking intervention is needed. By adjusting the steering angle proactively based on predicted vehicle behavior on descent roads, the system prevents instability from developing, thereby avoiding the need for braking control and maintaining driver comfort

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Instead of using the conventional approach of applying braking force to correct turning radius deviations, the system inverts the approach by correcting the steering angle itself. This alternative method achieves the same stability goal without the negative side effects of braking intervention on driver comfort

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentUS11014551B2Vehicle stability control system and method

Publication Date: 2021.05.25 HYUNDAI MOTOR CO LTD

AI summary

A vehicle stability control system and a vehicle stability control method which are capable of more improving lateral stability of a vehicle when the vehicle is turning on a descent inclined road, may enable the vehicle to turn along a turning trace intended by a driver through cooperative control of active front steering (AFS) control and an electronic stability control (ESC) when the vehicle is turning on the descent inclined road.