Electrostatic Occupant Detection System Noise Reduction
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Solution Overview
Problem
Existing electrostatic occupant detection systems generate noise when switching from a sine wave to a DC voltage or ground level, which can interfere with other electronic devices like radios during self-diagnosis and temperature correction.
Innovation Solution
The system gradually changes the amplitude or frequency of the sine wave when switching between occupant determination and diagnosis states, reducing noise frequencies and minimizing interference with other electronic devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sine wave is rapidly switched to DC voltage or ground level during self-diagnosis, then the diagnosis function can be performed, but noise is generated that adversely affects other electronic devices including radios
Solution Approach 1:
The patent applies the dynamics principle by making the sine wave amplitude changeable over time. During state transitions, the amplitude is dynamically adjusted from a normal level to zero level gradually rather than instantly, which reduces noise generation while maintaining the ability to perform diagnosis functions.
Solution Approach 2:
The patent changes the amplitude parameter of the sine wave signal during state transitions. By controlling the amplitude to gradually decrease to zero when switching from occupant determination state to self-diagnosis state, and gradually increase when switching back, the system reduces noise without compromising diagnostic capability.
2Object-generated harmful factors
If the sine wave amplitude is gradually changed during state switching, then noise is reduced, but the transition time between states increases
Solution Approach 1:
The patent applies partial action by implementing gradual amplitude change only during critical state transitions where noise would otherwise be generated, rather than continuously adjusting the amplitude. This selective approach reduces noise at transition moments while minimizing the impact on overall system response time.
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 effectively reduces noise generation when switching states, thereby restricting adverse effects on other electronic devices, such as radios, by smoothly attenuating or amplifying the sine wave amplitude or frequency.
Implementation Method 1
The electrostatic sensor outputs an electrical current or a voltage as an output value in accordance with an intensity of an electric field or a change in an electric filed generated by the electrode
Data Source
AI summary
An electrostatic occupant detection system includes an electrostatic sensor and an electronic control unit. The electronic control unit is switchable between an occupant determination state in which the electronic control unit outputs a sine wave having a constant amplitude and a diagnosis state in which the electronic control unit maintains a voltage of the electrostatic sensor at a constant level. The electronic control unit gradually changes at least one of an amplitude and a frequency of the sine wave either when the electronic control unit switches from the occupant determination state to the diagnosis state and/or when the electronic control unit switches from the diagnosis state to the occupant determination state.