Electrostatic Grip Detection Steering Wheel Sensor

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Solution Overview

Problem

Conventional electrostatic grip detection devices for steering wheels face challenges in power consumption and detecting gripping around the entire circumference, as heating elements are often only placed where the driver's hand is in contact, leading to incomplete detection.

Innovation Solution

An electrostatic grip detection device with a heater wire and sensor wire integrated into the base material around the entire circumference of the steering wheel, where the sensor wire has one end open to prevent electric current flow, allowing for reduced power consumption and accurate detection of gripping through changes in electrostatic capacitance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If heating elements are placed only where the driver's hand is in contact, then power consumption is reduced, but gripping detection around the entire circumference becomes incomplete

Engineering Contradiction:
Improvepower consumptionVSAvoidgripping detection completeness
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The heating element is divided into multiple independent heating sections arranged around the steering wheel circumference. Each section can be independently controlled, allowing the system to activate only the sections where gripping is detected, thus reducing overall power consumption while maintaining complete coverage capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The sensor wire serves dual functions: it acts as both a sensing element for gripping detection and as a heating element when activated. This multi-functionality eliminates the need for separate heating components, reducing system complexity and power consumption while maintaining detection completeness around the entire circumference.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If heating elements are placed around the entire circumference, then gripping detection completeness is improved, but power consumption increases

Engineering Contradiction:
Improvegripping detection completenessVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The heating sections are activated periodically or on-demand based on detection needs rather than continuously. The control unit activates specific heating sections only when gripping is detected in those areas, enabling complete circumference coverage capability while minimizing actual power consumption through selective, intermittent operation.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

Different sections of the steering wheel are treated differently - heating is applied locally only where needed for detection rather than uniformly across the entire circumference. The control unit determines which local sections require heating based on detection requirements, optimizing power usage while maintaining detection completeness.

Inventive Principle:
Principle #3Local quality

3Measurement precision

If the sensor wire is electrically connected to the heater wire, then the sensor can utilize the heater wire's electrostatic capacitance for detection, but electric current flows through the sensor wire causing increased power consumption

Engineering Contradiction:
Improvedetection sensitivityVSAvoidpower consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The sensor wire is electrically isolated from the heater wire by introducing an insulating layer between them. This extraction of the sensor function from the heating function allows the sensor to detect electrostatic capacitance changes of the heater wire without being part of the heating circuit, thereby eliminating current flow through the sensor while maintaining detection sensitivity.

Inventive Principle:
Principle #2Taking out (Extraction)

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

The solution effectively suppresses power consumption while enabling comprehensive gripping detection around the entire circumference of the steering wheel, enhancing sensitivity and accuracy by adjusting the pattern density and thickness of the sensor and heater wires.

Implementation Method 1

senses a change in electrostatic capacitance of at least one of the heater wire and the sensor wire

Methodology Applied
Scientific EffectElectrostatic capacitance: Capacitance

Implementation Method 2

a heater wire (11), a sensor wire (13)

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP3153379B1Electrostatic grip detection device
Publication Date: 2019.11.06 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
  • EP3153379B1 patent drawingFigure 1
  • EP3153379B1 patent drawingFigure 2
  • EP3153379B1 patent drawingFigure 3

AI summary

An electrostatic grip detection device includes a base material, a heater wire, a sensor wire, and a detection unit. The heater wire is formed in the base material. The sensor wire is formed in the base material, and has a first end electrically connected to the heater wire and a second end opened. The detection unit is electrically connected to at least one of the heater wire and the sensor wire, and senses a change in electrostatic capacitance of at least one of the heater wire and the sensor wire.