Steering Wheel Capacitive Divider for Skeleton Ground Fault Detection
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Solution Overview
Problem
Existing hands-off detection systems in semi-autonomous or fully autonomous vehicles rely on capacitance changes in the steering wheel, but fail to reliably detect defects in the skeletal connection between the steering wheel frame and ground, leading to unreliable hand recognition.
Innovation Solution
A steering wheel assembly with a capacitive voltage divider system comprising conductive layers and a skeletal capacitor, coupled to the vehicle's ground, allows for reliable detection of defects in the skeletal connection by measuring partial voltages, ensuring accurate hand detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional steering wheel with horn button is used, then the basic steering function is achieved, but bacteria can accumulate in the recesses and crevices of the horn button which cannot be reached by disinfectant sprays or wipes
Solution Approach 1:
The horn button is divided into a cap portion and a base portion that can be separated from each other. The cap portion can be removed from the base portion to allow access to the internal cavity for thorough disinfection, eliminating the problem of bacteria accumulation in inaccessible recesses.
2Reliability
If the horn button structure is simplified to enable disinfection, then disinfection effectiveness is improved, but the aesthetic appearance and tactile feedback may be compromised
Solution Approach 1:
The cap portion is designed to fit over the base portion in a nested configuration when assembled. This allows the horn button to maintain its conventional compact appearance and tactile feedback when closed, while enabling easy separation for disinfection of the internal cavity.
3Ease of manufacture
If the horn button is made as a single integrated piece, then manufacturing is simpler, but bacteria can accumulate in internal cavities that are inaccessible to disinfectants
Solution Approach 1:
The horn button is segmented into removable cap and base portions, allowing the internal cavity to be accessed for disinfection. The segmentation enables thorough cleaning while maintaining manufacturing feasibility through modular assembly.
Data Source
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Figure 2b
AI summary
The invention relates to a steering wheel arrangement (1) for a vehicle comprising a steering wheel device (2) wherein: the steering wheel device (2) has a steering wheel skeleton (3), a first conductive layer (6) and a second conductive layer (8); an inter-layer capacitor C_Layer_(12) is formed between the first conductive layer (6) and the second conductive layer (8); a skeleton capacitor C_Skeleton is formed between the second conductive layer (8) and the steering wheel skeleton (3); the steering wheel skeleton (3) can be and/or is coupled to an earth M of the vehicle via a skeleton connection (13); the inter-layer capacitor C_Layer_(12) and the skeleton capacitor C_Skeleton form a capacitive voltage divider for a voltage present at the first conductive layer (6); and a partial voltage can be sensed at the second conductive layer (8). The steering wheel arrangement also comprises an evaluation device (16), wherein the evaluation device (16) is designed to detect the partial voltage at the second conductive layer (8) and, on the basis of the detected partial voltage, assess the skeleton connection (13) to be OK or not OK.