Lateral Control Apparatus for Vehicle Platoon String Stability

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Solution Overview

Problem

Existing vehicle platoon systems face string instability issues due to error propagation, where lateral displacements are amplified downstream, potentially causing vehicles to leave their lanes, especially in decentralized platoons without specialized infrastructure.

Innovation Solution

An apparatus and method for lateral control of a host vehicle in a platoon using sensors to acquire and filter control signals and lateral errors, implementing a control algorithm that ensures string stability by filtering these signals and relaying information within the platoon to maintain stable vehicle following without direct vehicle-to-vehicle communication.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If decentralized platoon control is implemented without specialized infrastructure, then ease of operation and adaptability are improved, but string stability deteriorates due to error propagation

Engineering Contradiction:
Improveadaptability to unmodified roadsVSAvoidstring stability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent implements feedback by having each vehicle receive and process control signals from preceding vehicles. The control signal u_i includes lateral error information that is fed back into the control algorithm of following vehicles, allowing them to adjust their positioning to compensate for upstream errors and maintain platoon stability.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent introduces an intermediary communication system that transmits control signals between vehicles. This intermediary mechanism allows error correction information to be propagated through the platoon without requiring direct sensor contact between all vehicles, resolving the stability issue while maintaining decentralized operation on unmodified roads.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If lateral error information is transmitted from preceding vehicles, then control accuracy is improved, but error propagation throughout the platoon increases

Engineering Contradiction:
Improvelateral error detection accuracyVSAvoiderror propagation
Core Design Contradiction:
Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The patent changes the parameter representation by transforming raw lateral error measurements into corrected control signals that include compensation factors. The control signal u_i is modified to account for upstream errors, effectively changing the error propagation dynamics from amplification to damping through parameter transformation.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If automated lateral control is implemented, then driver comfort and safety are improved, but system complexity increases

Engineering Contradiction:
Improvedriver comfortVSAvoidcontrol algorithm complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent segments the control system into modular components: sensor modules for detecting lateral position, communication modules for exchanging control signals, and control algorithm modules for processing information. This segmentation allows the complex automated control function to be implemented through simple, standardized modules that maintain driver comfort while managing system complexity.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP2685338B1Apparatus and method for lateral control of a host vehicle during travel in a vehicle platoon
Publication Date: 2018.04.11 VOLVO CAR CORP
  • EP2685338B1 patent drawingFigure 1
  • EP2685338B1 patent drawingFigure 2
  • EP2685338B1 patent drawingFigure 3

AI summary

Embodiments herein relate to an apparatus and method for lateral control of a host vehicle (F) during travel in a vehicle platoon. The apparatus comprises: means for acquiring a control signal u and a lateral error ε relative to a target vehicle (L) of a preceding vehicle (T) travelling in the vehicle platoon; filter means (F1) for filtering the received lateral error ε; filter means (F2) for filtering the received control signal u; and controller means (C) for executing a control algorithm for actuating lateral control of the host vehicle (F).