Vehicle Door Entrapment Detector Vibration Filtering
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Solution Overview
Problem
Existing door entrapment detectors for vehicle doors suffer from inaccurate detection due to false signals triggered by vehicle vibrations, leading to reduced accuracy in identifying actual door entrapment.
Innovation Solution
A door entrapment detection system that includes an obtainment unit, a detection signal generation unit, and a determination unit, which reduces the effect of vehicle vibrations on the output signal by filtering frequency components and adjusts threshold values based on vehicle travel state, thereby improving detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pressure switch detects deformation of an elastic member on the door leading edge, then door entrapment can be detected, but false detection occurs due to vehicle vibration signals
Solution Approach 1:
A vibration countermeasure unit is introduced as an intermediary component between the pressure switch and the door entrapment determination logic. This unit processes the output signal from the pressure switch by counting threshold-exceeding signals within a predetermined time window, effectively filtering out high-frequency vibration noise while preserving genuine entrapment detection capability.
Solution Approach 2:
The system changes the temporal parameter of signal evaluation by introducing a time window mechanism. Instead of responding to instantaneous pressure switch signals, the vibration countermeasure unit accumulates and counts threshold-exceeding signals over a predetermined period, transforming the detection criterion from immediate response to time-averaged evaluation, thereby distinguishing genuine entrapment from transient vibrations.
2Measurement precision
If the detection sensitivity is increased to detect actual entrapment, then detection accuracy improves, but false positive rate increases due to vibration
Solution Approach 1:
The vibration countermeasure unit implements a feedback mechanism by continuously monitoring the pressure switch output and adjusting the detection decision based on the count of threshold-exceeding signals within the time window. This feedback loop enables the system to maintain high detection sensitivity while automatically compensating for vibration interference through signal accumulation analysis.
Solution Approach 2:
The system applies periodic evaluation by counting signals within a predetermined time window rather than responding to individual instantaneous signals. This periodic action transforms the detection process into a rhythmic evaluation cycle, allowing the system to distinguish between transient vibration events and sustained entrapment conditions that persist across multiple measurement cycles.
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 system effectively limits erroneous door entrapment detection caused by vehicle vibrations, enhancing the accuracy of door entrapment detection by filtering out vibration frequencies and adapting threshold values to the vehicle's travel state.
Implementation Method 1
a detection sensor detecting deformation of an elastic member attached to a leading edge of the door
Implementation Method 2
an output signal from a detection sensor detecting deformation of an elastic member when the vehicle is traveling includes a frequency component of vibration of the vehicle
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A door entrapment detector (1) is configured to detect whether or not a door (30) for opening and closing an entrance of a vehicle is in an entrapment state. The door entrapment detector (1) includes an obtainment unit (11) obtaining an output signal from a detection sensor (53, 54) that detects deformation of elastic members (51, 52) attached to a leading edge of the door (30), a detection signal generation unit (12) performing a process for reducing an effect of vibration that is caused by traveling of the vehicle and included in the output signal obtained by the obtainment unit (11) to generate a detection signal, and a determination unit (13) determining whether or not the door (30) is in an entrapment state based on the detection signal generated by the detection signal generation unit (12).