Inductive Door Handle Resonant Frequency Detection
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Solution Overview
Problem
Existing vehicle door handle detection systems using capacitive sensors are prone to false detections due to environmental conditions such as humidity, salt, rain, and metallic surfaces, leading to unreliable user presence detection and potential safety issues like untimely door openings or lockings.
Innovation Solution
The system incorporates an inductive sensor with a mobile electrode and a resonant oscillating circuit, where the mobile electrode moves upon user contact, varying the capacitance and resonance frequency to accurately detect user intention, and uses threshold comparisons and duration calculations to validate locking or unlocking actions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If capacitive sensors are used for user presence detection, then the detection system can identify user approach and contact, but false detections occur due to environmental conditions such as humidity, salt, rain, and metallic surfaces
Solution Approach 1:
The patent changes the detection parameter from direct capacitive coupling (sensitive to environmental factors) to resonant frequency measurement. By measuring the resonant frequency of an LC circuit formed by the electrode and ground, the system detects user presence through frequency shifts caused by capacitance changes, which are less susceptible to environmental interference like humidity and salt.
Solution Approach 2:
The patent replaces the direct capacitive sensing mechanism with an inductive sensing mechanism using a coil and mobile electrode. This substitution creates an LC resonant circuit where the detection is based on electromagnetic resonance rather than direct capacitive coupling, making the system immune to the harmful environmental factors that affect traditional capacitive sensors.
2Ease of operation
If capacitive sensors detect user presence, then automatic locking and unlocking can be triggered, but safety issues arise from untimely door openings or lockings due to false detections
Solution Approach 1:
The patent implements a feedback mechanism where the resonant frequency is continuously monitored and compared against threshold values. The system only triggers locking or unlocking actions when the frequency shift exceeds predetermined thresholds, providing feedback validation that prevents false detections from causing unsafe automatic door operations.
Solution Approach 2:
The patent requires a significant frequency shift (exceeding threshold values) to trigger detection, rather than responding to minimal capacitive changes. This partial action approach ensures that only genuine user presence causes detection, filtering out minor environmental variations that would otherwise trigger false automatic operations.
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 approach significantly reduces false detections, providing a robust and reliable method for user presence detection, immune to environmental interference and suitable for various vehicle configurations, ensuring safe and accurate door operation.
Implementation Method 1
a resonant oscillating circuit, where the mobile electrode moves upon user contact, varying the capacitance and resonance frequency to accurately detect user intention
Implementation Method 2
varying the capacitance and resonance frequency to accurately detect user intention
Implementation Method 3
The system incorporates an inductive sensor with a mobile electrode and a resonant oscillating circuit
Data Source
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AI summary
The present invention relates to a method for detecting the intention to lock or unlock a motor vehicle door by a user, by a detection device (D') incorporated in a handle (10), the invention proposing that the method comprises the continuous measurement of the resonant frequency (F) of said detection device (D') and comparison of said successively measured resonant frequency (F) with a first threshold (F1) representing the approach of the user and with a second threshold (F2), greater than the first threshold (F1), representing the contact of the user, the intention by the user to lock or unlock the door of the vehicle only being confirmed if a time between the passage from the resonant frequency below the first threshold and the passage of the resonant frequency above the second threshold is less than a predetermined time. The invention also relates to an associated detection device.