Steering Wheel Grip State Control for Manual Driving Takeover

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Solution Overview

Problem

Conventional vehicle control systems incorrectly switch from automated driving to manual driving when the driver lightly places their hands on the steering wheel for preparatory action, rather than recognizing the intended preparatory action and maintaining automated driving.

Innovation Solution

The system includes a control system with a preparatory action request judging part, override action request judging part, steering wheel gripping state judging part, and action completion judging part, which differentiate between a nongripping state, a first gripping state, and a second gripping state, ensuring accurate determination of the driver's grip to prevent premature switching to manual driving.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the driver lightly places hands on the steering wheel for preparatory action, then the driver is prepared for immediate manual takeover, but the system incorrectly judges this as an override action and switches to manual driving

Engineering Contradiction:
Improveaccuracy of driver intent recognitionVSAvoiddriver's ability to perform preparatory action
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent segments the steering wheel gripping state into three distinct levels: nongripping state, first gripping state (light touch for preparatory action), and second gripping state (strong grip for override). This segmentation allows the system to differentiate between preparatory actions and genuine override intentions, resolving the contradiction by enabling both driver preparedness and accurate intent recognition.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the parameter of grip strength detection by introducing a torque sensor that measures the magnitude of torque applied to the steering wheel. By monitoring torque values and comparing them against predetermined thresholds, the system can distinguish between light preparatory touches and strong override grips, thereby improving reliability while maintaining ease of operation.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If the system uses a constant touched area threshold to detect override action, then the detection is simple, but it cannot distinguish between preparatory action and genuine override

Engineering Contradiction:
Improvesimplicity of detection systemVSAvoidprecision of override action detection
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent changes the detection parameter from simple touched area (binary contact detection) to torque magnitude (continuous measurement). This allows the system to measure the strength of the driver's grip, enabling precise differentiation between preparatory actions and genuine overrides while maintaining relatively simple system complexity through threshold-based comparison.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the conventional mechanical contact-based detection system with a torque sensing system that measures rotational force. This substitution enables more precise measurement of driver intent by capturing the mechanical torque applied to the steering wheel, improving detection precision without significantly increasing system complexity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Speed

If the system switches to manual driving when touched area exceeds threshold, then the response is immediate, but the switching occurs in states where the steering wheel is not firmly gripped

Engineering Contradiction:
Improveresponse speed of mode switchingVSAvoidsafety of manual driving transition
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The patent changes the switching criterion from binary touched area threshold to torque magnitude threshold. By requiring the driver to apply torque exceeding a predetermined threshold value, the system ensures that manual driving switching only occurs when the steering wheel is firmly gripped, improving safety while maintaining immediate response through real-time torque monitoring and threshold comparison.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements feedback by continuously monitoring torque sensor output and comparing it against the predetermined threshold. This real-time feedback mechanism allows the system to immediately detect when the driver applies sufficient grip strength for override, enabling fast and safe switching to manual driving only when appropriate conditions are met.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3352038B1Control system for vehicle
Publication Date: 2024.08.07 TOYOTA JIDOSHA KK
  • EP3352038B1 patent drawingFigure 1
  • EP3352038B1 patent drawingFigure 2~3
  • EP3352038B1 patent drawingFigure 4

AI summary

The automated driving control part 90 comprises a preparatory action request judging part 91 for judging if there is a request for preparatory action for manual driving, an override action request judging part 92 for judging if there is a request for override action to manual driving, a steering wheel gripping state judging part 93 for judging if the steering wheel gripping condition is a nongripping state, is a first gripping state, or is a second gripping state based on input information from the driver to the steering wheel, and an action completion judging part 94 for judging completion of the preparatory action and override action based on the steering wheel gripping state. The action completion judging part 94 judges that the preparatory action has been completed when there is a preparatory action request and when it is judged that the state is the first gripping state or the second gripping state and judges that the override action has been completed when there is an override action request and when it is judged that the state is the second gripping state.