Vehicle Door Handle Sensing With Capacitive-Inductive Confirmation
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Solution Overview
Problem
Existing vehicle door handle detection systems using capacitive and inductive sensors suffer from false detections due to environmental conditions and metal surfaces, leading to unreliable user presence detection, which can result in unwanted vehicle operations such as door opening or locking.
Innovation Solution
A combined capacitive and inductive sensor system where an amagnetic metal target moves under user contact, with independent measurement circuits for each sensor, ensuring reliable detection by confirming user intention through simultaneous signals from both sensors, and an elastically deformable member to support the electrode for improved flexibility and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If capacitive sensors are used for detecting user approach, then the detection range is extended, but false detections increase due to environmental conditions and metal surfaces
Solution Approach 1:
The patent combines capacitive sensors and inductive sensors into a single detection system. The capacitive sensor detects user approach by measuring capacitance changes, while the inductive sensor confirms the detection by measuring inductance changes when the user contacts the amagnetic metal target. This merging of two different sensing mechanisms allows the system to maintain extended detection range while eliminating false detections through cross-validation.
Solution Approach 2:
The amagnetic metal target serves as an intermediary element between the user and the inductive sensor. When the user contacts the handle, the target moves under the electrode, mediating the interaction and enabling the inductive sensor to detect the contact through changes in inductance. This intermediary allows reliable contact detection without the false positives that plague capacitive-only systems.
2Ease of operation
If capacitive sensors are used for detecting user contact, then the system responds to user presence, but false detections occur in humid or salty environments
Solution Approach 1:
The system merges capacitive and inductive sensing to overcome environmental limitations. The capacitive sensor provides sensitive user presence detection, while the inductive sensor with amagnetic metal target provides robust contact confirmation that is insensitive to humidity and salt. Together, they enable reliable operation in challenging environmental conditions.
Solution Approach 2:
The system uses feedback from both capacitive and inductive measurements to validate user intent. The capacitive sensor provides initial detection feedback, and the inductive sensor provides confirmation feedback. Only when both sensors agree does the system trigger unlocking, creating a robust feedback mechanism that eliminates false detections in humid or salty environments.
3Device complexity
If a single sensor type is used, then the device complexity is reduced, but detection reliability decreases
Solution Approach 1:
The patent merges capacitive and inductive sensor systems into an integrated detection device. The capacitive sensor measures capacitance changes for approach detection, while the inductive sensor measures inductance changes for contact confirmation. This merging increases reliability through multi-modal sensing while maintaining manageable complexity through integrated circuit board mounting and shared control electronics.
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 provides robust and reliable detection of user intention to lock or unlock, reducing false detections and ensuring safety and efficiency in vehicle operation, particularly in systems that perform unlocking and opening, while maintaining an inconspicuous design.
Implementation Method 1
a capacitive sensor for detecting an approach of the user and/or contact of a hand of the user toward/with the handle or the frame
Implementation Method 2
an inductive sensor with an amagnetic metal target that is capable of moving under the action of the hand of the user
Implementation Method 3
the target being associated with a coil placed in an oscillating circuit comprising at least one capacitor and having a specific resonant frequency
Data Source
AI summary
A device for detecting an intention of a user to lock or unlock an opening element of a motor vehicle includes a capacitive sensor and incorporates an inductive sensor with an amagnetic metal target moving under the action of the hand of the user on the handle or the frame, the target being associated with a coil placed in an oscillating circuit being connected to an inductive measurement circuit detecting the intention of the user to lock or unlock the opening element. The intention is only confirmed when detected by both the capacitive and inductive sensors, the target of the inductive sensor being borne by the electrode of the capacitive sensor and a member supporting the electrode being elastically deformable under the action of the user on the handle or the frame, the inductive and capacitive measurement circuits being independent of each other.