Adaptive Steering Torque Overlay for Lane Keeping Aid

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Solution Overview

Problem

Existing lane keeping aid systems struggle to adapt steering wheel torque overlays effectively across various driving conditions, including straight driving, entering, exiting, and cutting road curves, and do not adequately account for driver steering input.

Innovation Solution

A method and system that measure applied steering wheel torque and determine a scaling factor to adapt the controller torque overlay, allowing for a corrective steering wheel torque overlay that takes into account vehicle and road parameters, and adjusts based on driver input and driving scenarios, using a scaling curve with a dead zone and break points to optimize torque application.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a static regulator for angle deviation is used with a fixed characteristic curve, then the control system is simple to implement, but it cannot adapt to various driving conditions (straight driving, road curves, entering/exiting/cutting curves)

Engineering Contradiction:
Improveadaptability to various driving conditionsVSAvoidcomplexity of torque overlay adaptation system
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies dynamics by transforming the static characteristic curve into a dynamic one that adapts to different driving conditions. The system determines a scaling factor based on current driving conditions (straight driving, road curves, entering/exiting/cutting curves) and applies this factor to the base torque overlay, allowing the torque characteristic to change dynamically while maintaining a relatively simple system structure.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of torque overlay by introducing a scaling factor that modifies the base torque overlay according to driving conditions. Instead of creating entirely different control systems for each condition, the system adjusts the torque parameter through the scaling factor, achieving adaptability with minimal complexity increase.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If the characteristic curve is widened asymmetrically when cornering to allow cutting corners, then cornering performance is improved, but the system does not account for driver steering input torque

Engineering Contradiction:
Improveease of cornering operationVSAvoidresponsiveness to driver steering input
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The patent applies feedback by measuring the driver's steering input torque and using this information to adjust the scaling factor. The system continuously monitors the driver's steering torque and incorporates this feedback into the torque overlay calculation, ensuring the system responds appropriately to driver intentions while maintaining ease of cornering operation.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts the torque overlay based on real-time driver input by determining the scaling factor as a function of driver steering torque. This dynamic adjustment allows the system to maintain ease of operation during cornering while simultaneously being responsive to driver intentions.

Inventive Principle:
Principle #15Dynamics

3Ease of operation

If a scaling factor is determined as a function of driver steering torque with a dead zone and break points, then steering comfort is improved under diverse conditions, but the control system complexity increases

Engineering Contradiction:
Improvesteering comfortVSAvoidcomplexity of scaling factor determination
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent changes the torque parameter through a scaling factor that is determined based on driver steering torque with specific characteristics (dead zone, break points). This approach improves steering comfort by providing appropriate torque characteristics across different operating ranges while keeping the implementation relatively simple through parameter-based control.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system applies partial action by introducing a dead zone in the scaling factor determination, where small variations in driver torque do not trigger torque overlay changes. This partial responsiveness improves steering comfort by filtering out minor fluctuations while still responding to significant driver inputs.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP2591983B1Method and system for adaptation of a steering wheel torque overlay of a lane keeping aid system
Publication Date: 2018.01.10 VOLVO CAR CORP
  • EP2591983B1 patent drawingFigure 1~2
  • EP2591983B1 patent drawingFigure 3~4
  • EP2591983B1 patent drawingFigure 5

AI summary

The present disclosure relates to a method for adaptation of a steering wheel torque overlay of a lane keeping aid system in a vehicle (2), the method comprising: a) requesting a controller steering wheel torque overlay Tr from a controller (22), b) measuring an applied steering wheel torque Ta applied on a steering wheel (10) of the vehicle (2), c) determining a scaling factor α as a function of the applied steering wheel torque Ta, d) determining a corrective steering wheel torque overlay Tc based on the controller torque overlay Tr multiplied by the scaling factor α. The disclosure further relates to a system (20) for adaptation of a steering wheel torque overlay and to a lane keeping aid system (18) comprising such a system (20). In addition, the disclosure refers to a vehicle comprising such a lane keeping aid system (18).