Flow Rate Sensor Correction Device for Linearity Error Reduction
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Solution Overview
Problem
Flow rate sensors often exhibit poor linearity in their relationship between sensor output values and actual flow rates, leading to errors in flow rate measurement across the entire range of sensor output values.
Innovation Solution
A correction device and method that adjusts the sensitivity coefficient of the flow rate sensor by calculating a corrected flow rate characteristic function using a function correction value based on the outputted flow rate value from the sensor, allowing the flow rate sensor to match the sensitivity-adjusted actual flow rate characteristic function, thereby reducing flow rate errors over the entire range of sensor output values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a standard flow rate characteristic function f(x) is used to convert sensor output values to flow rate values, then the flow rate sensor can operate with a predetermined relationship between sensor output and flow rate, but flow rate errors occur when the actual flow rate characteristic function F(x) has poor linearity
Solution Approach 1:
The patent applies parameter changes by introducing a sensitivity correction value m that modifies the sensitivity coefficient of the flow rate sensor. This correction parameter adjusts the relationship between sensor output values and actual flow rates, transforming the poor linearity in F(x) into improved linearity in the sensitivity-adjusted function, thereby reducing flow rate errors across the entire measurement range
2Measurement precision
If the sensitivity coefficient of the flow rate sensor is adjusted to improve linearity, then flow rate errors are reduced over the entire range, but the device complexity increases due to additional correction calculations
Solution Approach 1:
The patent changes the sensitivity coefficient by introducing a sensitivity correction value m, which transforms the actual flow rate characteristic function F(x) into a sensitivity-adjusted function with improved linearity. This parameter adjustment reduces flow rate errors across the entire measurement range while maintaining operational simplicity
Solution Approach 2:
The patent creates a corrected flow rate characteristic function g(x) by copying and modifying the standard flow rate characteristic function f(x). The correction is applied through multiplication by a function correction value n, which is determined based on the sensitivity correction value m and the span point characteristics, thereby obtaining a new function that accurately represents the sensor's actual behavior
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
The solution effectively reduces flow rate errors by converting the actual flow rate characteristic function with poor linearity to a sensitivity-adjusted function with improved linearity, ensuring accurate flow rate measurements across the entire range of sensor output values.
Implementation Method 1
a sensor mechanism M1 that outputs an output signal FI on the basis of a thermal conductivity difference between a sensor and a flowing fluid
Data Source
AI summary
In order to reduce a flow rate error over the entire range of a sensor output value even when the relationship between the sensor output value and a flow rate value is poor in linearity, a flow rate sensor correction device includes: a sensitivity setting part adapted to set a sensitivity coefficient on the basis of an initial value and a sensitivity correction value and adjust the sensitivity of the flow rate sensor; a function calculation part adapted to calculate a corrected flow rate characteristic function on the basis of a function correction value, which is determined on the basis of the flow rate value, and a standard flow rate characteristic function; and a function modification part adapted to make a function storage part store, as a flow rate characteristic function, a final flow rate characteristic function based on the corrected flow rate characteristic.