Active Roll Stabilization Torque Control for Vehicle Understeer

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Solution Overview

Problem

Existing active roll stabilization systems for two-axle vehicles struggle to balance driving stability and agility, particularly due to understeering tendencies at lower speeds and the need for varying torque distribution between axles, which existing systems fail to address efficiently.

Innovation Solution

An electric motor-based active roll stabilization system that introduces a basic torque only when the vehicle is stationary or moving slowly, and increases torque during cornering to counteract understeering, using a learned 'zero position' and considering driving speed, yaw rate, and lateral acceleration to adjust the torque applied by the split anti-roll bar.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an active roll stabilization system applies greater torque to counteract rolling motion, then driving stability is improved, but energy consumption increases

Engineering Contradiction:
Improvedriving stabilityVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system dynamically adjusts the torque applied by the electric motor based on real-time driving conditions including vehicle speed, lateral acceleration, and yaw rate. The control unit modulates the anti-roll bar torque to provide stabilization only when necessary, rather than maintaining constant torque, thereby improving driving stability while minimizing unnecessary energy consumption.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the operational parameters of the anti-roll bar by adjusting the torque level according to detected driving states. When lateral acceleration and yaw rate indicate cornering conditions, the system increases torque application; when these parameters indicate straight-line driving, the system reduces or eliminates torque application, optimizing the balance between stability and energy usage.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If an active roll stabilization system applies greater torque to improve driving agility, then understeering tendency is reduced, but driving stability deteriorates

Engineering Contradiction:
Improvedriving agilityVSAvoiddriving stability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The system dynamically modulates the torque applied to the anti-roll bar based on real-time detection of vehicle state parameters including speed, lateral acceleration, and yaw rate. This dynamic adjustment allows the system to provide enhanced agility during cornering while maintaining stability during straight-line driving, resolving the contradiction between agility and stability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system applies different torque characteristics to the anti-roll bar depending on the specific driving condition detected. During cornering maneuvers, higher torque is applied to reduce understeer and improve agility; during straight-line driving, lower or zero torque is applied to maintain stable behavior, creating locally optimized performance for each driving scenario.

Inventive Principle:
Principle #3Local quality

3Reliability

If an active roll stabilization system continuously applies torque to maintain stability, then driving behavior remains predictable, but energy consumption increases

Engineering Contradiction:
Improvedriving predictabilityVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system employs periodic assessment of driving conditions through sensors that continuously monitor vehicle speed, lateral acceleration, and yaw rate. Based on this periodic evaluation, the control unit activates or deactivates torque application to the anti-roll bar, creating a rhythm of engagement and disengagement that maintains predictability when needed while conserving energy during normal driving.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system uses its own sensor data and control algorithms to autonomously determine when torque application is necessary. The electronic control unit self-regulates the anti-roll bar torque based on detected driving states, eliminating the need for continuous external intervention or constant energy input, thereby maintaining predictability while reducing energy consumption.

Inventive Principle:
Principle #25Self-service

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

This approach reduces energy consumption and enhances driving agility by dynamically adjusting torque based on driving conditions, maintaining stability and ease of control, similar to a passive system when not needed, while preventing understeer and promoting oversteer when necessary.

Implementation Method 1

the electric motor arranged between the halves of the anti-roll bar can twist them against one another and in doing so generates at least one basic torque

Methodology Applied
Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Implementation Method 2

a passive roll stabilization system with a anti-roll bar with a comparable spring rate

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP2772374B1Operating method for a single-axle roll stabilization system of a two-axle, two-track vehicle
Publication Date: 2018.06.06 BAYERISCHE MOTOREN WERKE AG

AI summary

The method involves setting an electromotor in a driving condition in which an understeering of the vehicle is undesired. The nominal border moment is introduced into the stabilizer halves, such that the basic torque is adjusted when the basis angle between the two stabilizer halves is held active without the action of driving dynamic forces on the substrate in the vehicle transverse direction. The basis angle between the two stabilizer halves is determined according to start-up of the vehicle by the electronic control unit in corresponding operating mode.