Flow Rate Sensor Signal Processing for Heating State Switching Accuracy
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Solution Overview
Problem
The measurement accuracy of physical quantity detection devices degrades after a heating state is switched or after a flow rate is changed, as described in PTL 1.
Innovation Solution
A physical quantity detection device that includes a flow rate measuring element with a heating element, a heating element control unit for switching the heating element between heat generation and suppression states, and a signal processing unit with a buffer and frequency analysis block. The signal processing unit processes measured flow rate values using the main frequency calculated by the frequency analysis block, particularly when events such as sudden changes in measured values or heating state switches occur.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If frequency analysis is continuously performed to maintain measurement accuracy, then measurement precision is improved, but power consumption increases
Solution Approach 1:
The patent applies periodic action by performing frequency analysis only at specific intervals or trigger events rather than continuously. The signal processing unit executes frequency analysis on the measured value when predetermined conditions are met, such as when the measured value changes beyond a threshold or at predetermined time intervals, thereby reducing computational load and power consumption while maintaining measurement accuracy when needed.
2Speed
If frequency analysis is performed frequently to track rapid changes, then response speed is improved, but computational complexity increases
Solution Approach 1:
The patent applies dynamics by making the frequency analysis execution dynamic and adaptive based on the state of the measured value. The system adjusts the frequency of analysis according to whether the measured value is changing rapidly or stabilizing, using predetermined thresholds and time intervals to dynamically determine when analysis is necessary, thus optimizing response speed while minimizing unnecessary computational 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 solution reduces accuracy degradation after switching the heating state or changing the flow rate, by stabilizing the output period and reducing power consumption in the frequency analysis process.
Implementation Method 1
a flow rate measuring element (602) that includes a heating element (608) and measures a flow rate of a measurement target gas
Data Source
AI summary
It is possible to reduce a degradation in accuracy after switching of a heating state or after change of the flow rate.A physical quantity detection device includes a flow rate measuring element which is equipped with a heating element and measures a flow rate of a measurement target fluid; a heating element control unit which switches a control state of the heating element to one of a heat generation state or a heat generation suppression state; and a signal processing unit which includes a buffer and a frequency analysis block, and processes a measured value of the flow rate measuring element, using a main frequency calculated by the frequency analysis block, in which the measured value for a past predetermined period is recorded in the buffer, the frequency analysis block calculates the main frequency by performing a frequency analysis of the measured value recorded in the buffer, when an occurrence of an event is detected, the signal processing unit performs a calculation, using the main frequency calculated immediately before for a predetermined period from the occurrence of the event, and the event is a sudden change in the measured value and switching of the control state performed by the heating element control unit.