Vehicle Motion Control for Split-Friction Road Handling

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Solution Overview

Problem

Vehicles face challenges in safely navigating roads with treacherous conditions characterized by varying friction levels, leading to longer stopping distances, stability issues, and increased risk of accidents, especially when encountering tracks and patches with different friction characteristics.

Innovation Solution

A vehicle system that detects and evaluates road friction conditions, adjusts vehicle motion to avoid low-friction areas, and creates a map of treacherous sections accessible to multiple vehicles, enabling improved handling and safety through strategic driving maneuvers and differential braking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the vehicle drives on tracks or patches with different friction characteristics, then the vehicle can maintain its intended path, but the stopping distance increases and stability deteriorates

Engineering Contradiction:
Improvevehicle stabilityVSAvoidstopping distance
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The system performs preliminary detection of road friction conditions using cameras and sensors to identify tracks and patches with different friction characteristics before the vehicle encounters them. This allows the vehicle to proactively adjust its motion and braking strategy, maintaining stability while preparing for appropriate stopping distances in advance of entering low-friction zones.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system applies different braking forces to different wheels based on the local friction conditions detected in specific road areas. By identifying which wheels are on tracks or patches with different friction characteristics, the system can independently control brake pressure for each wheel, optimizing both stopping distance and vehicle stability for each local condition.

Inventive Principle:
Principle #3Local quality

2Device complexity

If the vehicle uses conventional braking systems in split-mu conditions, then the braking system is simple, but the vehicle experiences stability problems and longer stopping distances

Engineering Contradiction:
Improvebrake system complexityVSAvoidvehicle stability
Core Design Contradiction:
Device complexityVSStability of the object's composition

Solution Approach 1:

The system continuously monitors road friction conditions using cameras and sensors, and uses this feedback to dynamically adjust brake pressure distribution across different wheels. The feedback loop detects when wheels are on tracks or patches with different friction characteristics and automatically modifies braking forces to maintain vehicle stability, enabling sophisticated control without requiring complex hardware modifications.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The braking system transitions from static, uniform brake pressure application to dynamic, adaptive brake pressure control. The system continuously adjusts brake forces based on real-time detection of friction conditions, allowing the braking characteristics to change dynamically as the vehicle moves across different road surfaces, thereby maintaining stability in split-mu conditions.

Inventive Principle:
Principle #15Dynamics

3Device complexity

If the vehicle does not detect road friction variations, then the detection system is simple, but the vehicle cannot adjust motion appropriately leading to safety issues

Engineering Contradiction:
Improvedetection system complexityVSAvoiddriving safety
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The system uses cameras and optical sensors as intermediary devices to detect road friction conditions indirectly by analyzing visual characteristics of tracks and patches. These intermediary sensors capture images of the road surface, and image processing algorithms identify friction variations without requiring direct physical contact with the road, enabling safe detection of treacherous conditions while keeping the detection system relatively simple.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3546312B1Method and system for handling conditions of a road on which a vehicle travels
Publication Date: 2025.01.15 POLESTAR PERFORMANCE
  • EP3546312B1 patent drawingFigure 1
  • EP3546312B1 patent drawingFigure 2
  • EP3546312B1 patent drawingFigure 3

AI summary

The embodiments herein relate to a method performed by a vehicle system for handling conditions of a road on which a vehicle (100) travels. The vehicle system detect that a first part (105) of the road has a first condition which is different from a second condition (108) of a second part of the road. The vehicle system estimates friction of the first part (105) and evaluates the estimated friction. The vehicle system determines that the vehicle's motion should be adjusted when a result of the evaluation indicates that the estimated friction of the first part (105) of the road affects the vehicle's expected motion, and initiates adjustment of the vehicle's motion on the road as determined.