Capacitive Sensor Array Gesture Recognition via Temporal Analysis
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing capacitive sensor systems for actuating vehicle tailgates are prone to false triggering due to the inability to differentiate between human gestures and other movements, leading to malfunction and reduced recognition accuracy.
Innovation Solution
A capacitive sensor arrangement with spatially offset, elongated sensor electrodes and a control and evaluation circuit that records and compares the time sequences of capacitance changes to distinguish between valid and invalid actuation gestures by analyzing the response and fall times of the electrodes, ensuring symmetry and consistency in signal patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single capacitive sensor electrode is used to detect object approach, then the device complexity is reduced, but the measurement precision deteriorates due to inability to differentiate between human gestures and other movements
Solution Approach 1:
The sensor system is segmented into multiple sensor electrodes (first sensor electrode and second sensor electrode) arranged at different spatial positions. Each electrode independently detects capacitance changes, and the control unit evaluates the combined signals to differentiate between valid human gestures and invalid movements, thereby improving measurement precision without excessive complexity increase
Solution Approach 2:
The patent introduces a temporal dimension by evaluating the time sequence of capacitance changes from multiple electrodes. The control unit analyzes whether capacitance changes occur in a specific temporal pattern consistent with human gestures, adding time-based discrimination capability that improves gesture recognition accuracy
2Area of stationary object
If the sensor electrodes are arranged to cover a larger detection area, then the detection capability is improved, but the reliability deteriorates due to increased false triggering from animals or objects
Solution Approach 1:
The detection area is segmented into multiple zones monitored by different sensor electrodes positioned at different locations. The control unit requires a specific spatio-temporal pattern of capacitance changes across multiple electrodes to validate an actuation request, which allows covering a larger detection area while filtering out false triggers from animals or rolling objects that do not produce the characteristic human gesture pattern
Solution Approach 2:
The control unit continuously monitors capacitance changes from multiple electrodes and provides feedback evaluation by comparing the detected pattern against expected human gesture patterns. This feedback mechanism enables the system to distinguish between valid actuation requests and false triggers, maintaining reliability across an expanded detection area
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 enhances detection accuracy by differentiating between intended human gestures and unintended movements, reducing false actuations and improving the reliability of tailgate operation.
Implementation Method 1
detects a change in the capacitance of the sensor electrode arrangements compared to a reference potential
Implementation Method 2
evaluates at least one parameter of a current or voltage curve that is dependent on the periodic charging and discharging of the sensor electrode
Data Source
Figure 1A~1B
Figure 2A~2B
AI summary
A sensor array for the detection of movement gestures on a motor vehicle, wherein two sensor electrode arrays (2, 3) are arranged at spatially offset positions on the motor vehicle, wherein the sensor electrodes (2, 3) are designed as elongate electrode arrays. The sensor array comprises at least one control and evaluation device (5) which is coupled to the sensor electrode arrays and detects a change in the capacitance of the sensor electrode arrays. One of the sensor electrode arrays (2) is longer than the other (3). The longer sensor electrode array (2) is deformed in the direction of the shorter sensor electrode array (3) in the region of the sections protruding horizontally over the shorter sensor electrode array (3). The control and evaluation device is designed to detect a time sequence of capacitance values for each of the sensor electrode arrays (2, 3). The times when each sensor array responds and stops responding are recorded, and the time difference between the times when the sensor electrode arrays respond (response time difference) and the time difference between the times when the sensor electrodes stop responding (drop-out time difference) are compared when assessing whether an actuation event has been recorded by the control and evaluation device (5).