Moisture Sensing with Temperature Compensation
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Solution Overview
Problem
Existing methods for sensing moisture on surfaces, such as those used in vehicle windshield systems, fail to accurately account for temperature variations, leading to false positives or negatives in moisture detection, which can result in unnecessary wiper operation or missed moisture removal.
Innovation Solution
A method that involves transmitting a vibrational wave to a substrate, detecting its vibrations, and compensating for phase shifts caused by temperature to provide a more accurate measurement of moisture, independent of temperature fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature compensation is not incorporated in the moisture estimation system, then the system is simpler, but the measurement precision deteriorates due to false positives or negatives caused by temperature variations
Solution Approach 1:
The patent segments the phase shift measurement into two independent components: temperature-induced phase shift and moisture-induced phase shift. By measuring temperature separately and calculating its effect on phase shift, the system isolates the moisture detection component, thereby improving measurement precision without requiring a completely new system architecture.
Solution Approach 2:
Temperature acts as an intermediary variable that mediates between the physical environment and the phase shift measurement. By introducing temperature as a separate measurement parameter and using it to compensate for its effect on phase shift, the system eliminates temperature's harmful influence while preserving the moisture detection capability.
2Reliability
If temperature compensation is implemented, then the reliability improves by eliminating false positives or negatives, but the device complexity increases due to additional temperature sensing and calculation requirements
Solution Approach 1:
The system implements feedback by continuously monitoring temperature and using this information to adjust the moisture detection threshold or interpretation. The temperature measurement feeds back into the phase shift analysis, allowing the system to dynamically compensate for temperature effects and maintain reliable operation across varying environmental conditions.
Solution Approach 2:
The patent changes the operational parameters of the moisture detection system by introducing temperature as an additional measured parameter. Instead of relying solely on phase shift, the system now considers both temperature and phase shift, changing the detection paradigm from single-parameter to multi-parameter analysis, which improves reliability.
3Measurement precision
If phase shift is used to determine moisture amount, then the sensing method is simple, but the measurement precision deteriorates because temperature effects cannot be distinguished from moisture effects
Solution Approach 1:
The patent segments the total phase shift into distinct components attributable to temperature and moisture respectively. By measuring temperature independently and calculating its contribution to phase shift, the system separates the two effects mathematically, making it possible to accurately determine moisture amount without interference from temperature variations.
Solution Approach 2:
Temperature measurement serves as an intermediary that enables the differentiation between temperature-induced and moisture-induced phase shifts. This additional measurement acts as a key that unlocks the ability to distinguish between the two sources of phase shift, resolving the detection difficulty.
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 the accuracy of moisture sensing, ensuring the wiper system operates only when necessary, regardless of temperature, thereby improving the robustness and reliability of the moisture detection system.
Implementation Method 1
transmitting a transmitter signal to generate a vibrational wave and propagating the vibrational wave to vibrate the substrate
Implementation Method 2
compensating for a phase shift between the transmitter signal and the receiver signal attributable to the temperature of the substrate
Data Source
AI summary
A method for determining an amount of moisture on a surface of a substrate includes a step of transmitting a transmitter signal to generate a wave. The transmitter signal has a first phase. The wave is propagated to vibrate the surface. Vibrations in the surface are detected and converted into a receiver signal. The receiver signal has a second phase different than the first phase. The method includes the step of sensing the temperature of the substrate. The amount of moisture on the surface is computed based on a phase shift between the transmitter signal and the receiver signal that has been compensated to account for surface temperature.