Hands-On Rim Detection Using Dual-Current Capacitance Sensing
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Solution Overview
Problem
The switched capacitor method used in hands-on detection devices struggles with responsiveness due to long measurement times when detecting bare hands, while increasing current to shorten measurement times complicates accurate identification between hands-off, gloved, and bare-hand states.
Innovation Solution
Implementing a hands-on detection device and computer program that utilize two modes with different currents for hands-on detection, allowing for appropriate mode selection to improve both the speed and accuracy of determining hands-on or hands-off states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the current used for charging is increased to shorten the measurement time, then the speed of hands-on detection is improved, but the measurement precision deteriorates because the hands-off measurement value and glove wearing measurement value become closer and harder to distinguish
Solution Approach 1:
The patent applies dynamics by making the measurement current variable rather than fixed. The control unit dynamically adjusts the measurement current based on the detected capacitance value: using a first current value for initial measurement and switching to a second, larger current value when bare hand detection is identified. This dynamic adjustment allows the system to optimize between speed and precision depending on the detection scenario.
Solution Approach 2:
The patent changes the parameter of measurement current from a static value to multiple variable values. By implementing at least two different current values (first current and second current) and selectively switching between them based on detection needs, the system can adapt the measurement parameters to achieve both fast response and accurate differentiation between hands-off and bare hand states.
2Measurement precision
If the measurement time is extended to improve measurement precision for bare hand detection, then the accuracy of determination is improved, but the productivity deteriorates due to lack of responsiveness
Solution Approach 1:
The system dynamically adjusts measurement duration based on the detected state. For hands-off and gloved hand detection, shorter measurement times suffice. For bare hand detection, the system extends measurement time or switches to alternative measurement modes to ensure accurate differentiation, thereby optimizing productivity across different operational scenarios.
Solution Approach 2:
The system performs preliminary measurement with a first current value to quickly assess the capacitance state. Based on this preliminary result, it determines whether further extended measurement with a second current value is necessary, avoiding unnecessary long measurement times for cases where bare hand detection is not suspected.
3Device complexity
If a single current value is used for hands-on detection, then the device complexity is reduced, but the adaptability deteriorates because the system cannot optimally handle different gripping conditions (bare hand, gloved hand, hands-off)
Solution Approach 1:
The detection device achieves multi-functionality by using a single measurement unit that can operate with multiple current values. This universal approach allows the same hardware to adaptively handle different detection scenarios (hands-off, gloved hand, bare hand) by switching between first and second current values, avoiding the need for separate dedicated circuits for each condition.
Solution Approach 2:
The system enhances adaptability by changing the measurement current parameter based on detection needs. The control unit selects between first and second current values depending on the gripping condition, allowing the same physical device to optimally respond to varied conditions without increasing hardware complexity.
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 enables simultaneous improvements in the speed and accuracy of hands-on detection, addressing the issues of long measurement times and accurate identification in existing technologies.
Implementation Method 1
a contact detection sensor that uses a switched capacitor method that captures events other than the object of detection, which is a human hand coming into contact with or approaching a door handle, as noise
Data Source
AI summary
A hands-on detection device and a computer program that can simultaneously improve the speed of determining hands-on or hands-off and the accuracy of such determination.A hands-on detection ECU that performs hands-on detection of the rim part by passing a current through a sensor electrode provided on the rim part, hands-on detection being performed using two modes in which the current for the hands-on detection is different.