Steering Wheel Electrode Layout for Accurate Rim Grip Detection
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Solution Overview
Problem
Existing steering devices struggle to accurately detect the presence of a hand gripping the annular rim part of a steering wheel due to the orientation of the electrode, leading to potential inaccuracies in determining driver engagement.
Innovation Solution
The steering device incorporates annular rim parts with electrodes positioned in the spoke parts, including first electrode portions facing the rim part and second electrode portions facing the driver, allowing for accurate detection of hand presence through induced electric force lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a plate-like electrode is provided in the spoke part with its plane facing the driver, then the electrode can detect hand contact with the spoke part, but it cannot accurately detect hand gripping on the annular rim part
Solution Approach 1:
The electrode is divided into multiple electrode portions (first electrode portion and second electrode portion) with different orientations. The first electrode portion faces the rim part while the second electrode portion faces the driver, allowing each segment to detect hand contact in different locations and orientations, thereby achieving both accurate spoke part detection and rim part detection.
Solution Approach 2:
The electrode configuration transitions from a single-plane plate-like structure to a multi-dimensional arrangement with electrode portions extending in different directions (radially outward and axially). This dimensional expansion allows the electrode to generate electric force lines in multiple directions, enabling detection of hand contact both on the spoke part and on the radially outward rim part.
2Reliability
If the electrode is oriented to face the driver for detecting spoke part contact, then driver engagement can be detected, but hand gripping on the rim part cannot be accurately detected
Solution Approach 1:
The electrode is segmented into multiple portions with different facing directions. The second electrode portion maintains the original orientation to face the driver for reliable spoke part contact detection, while the first electrode portion is added to face the rim part, ensuring both detection functions operate simultaneously with high reliability and precision.
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
This configuration enables precise detection of hand contact or approach to both the rim and spoke parts, enhancing traffic safety by ensuring accurate determination of driver engagement.
Implementation Method 1
The sensor device described in Patent Document 1 detects, based on a change in the capacitance of an electrode provided in a spoke part of the steering wheel, that a hand of the driver is in contact with or has approached the steering wheel.
Implementation Method 2
a line of electric force induced around the electrode passes perpendicularly to the electrode
Data Source
AI summary
A steering device 1 accepts steering operations by a driver and comprises: an annular rim 20; a hub 23 located on the inner side of the rim 20; spokes 25L, 25R which extend radially from the hub 23 and which are connected to a rim inner circumference 21 of the rim 20; electrode devices 55L, 55R provided in the spokes 25L, 25R, respectively; and a steering control device 4 that detects a change in the electrostatic capacitance between the electrode devices 55L, 55R and a ground connection. The electrode device 55L comprises a first electrode 56L having flat parts 561L, 562L, 563L directed toward the rim 20 and the electrode device 55R comprises a first electrode 56R having flat parts 561R, 562R, 563R directed toward the rim inner circumference 21.