Flow Rate Control Apparatus Using Weighted Average Estimation
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Solution Overview
Problem
Existing flow rate control systems experience noise amplification and delays due to time differential pressure measurements, leading to unstable valve flow rates, especially in steady-state conditions.
Innovation Solution
A flow rate control apparatus that includes a fluid resistor, a downstream side valve, a pressure sensor, and a valve flow rate estimation part using a weighted average calculation based on resistor flow rate, conversion flow rate, and a changeable weighting factor to estimate the valve flow rate, reducing noise and adjusting delay.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the time differential value of pressure is used to estimate the valve flow rate, then the control delay is reduced, but noise is amplified leading to unstable flow rate control
Solution Approach 1:
The patent changes the parameter of weighting factor dynamically based on flow rate conditions. When flow rate changes rapidly, a smaller weighting factor is used to prioritize responsiveness. When flow rate is stable, a larger weighting factor is used to reduce noise impact. This adaptive parameter adjustment resolves the contradiction between reducing control delay and maintaining flow rate stability.
Solution Approach 2:
The patent introduces dynamic adjustment of the weighting factor in the weighted average calculation based on real-time flow rate conditions. The system transitions from a static estimation approach to a dynamic one where the estimation parameters adapt to changing operating conditions, allowing the system to optimize between response speed and noise reduction continuously.
2Measurement precision
If the flow rate sensor is positioned upstream of the downstream side valve, then the measured flow rate is obtained, but a time delay occurs in the measured flow rate with respect to the actual flow rate through the valve
Solution Approach 1:
The patent introduces pressure as an intermediary parameter to estimate the valve flow rate indirectly. Instead of directly measuring flow rate at the valve position, the system uses pressure differential measurements combined with flow rate sensor data to calculate the valve flow rate through a weighted average estimation, eliminating the need for direct physical measurement at the delayed location.
Solution Approach 2:
The patent replaces direct mechanical flow rate measurement at the valve position with a computational estimation system using pressure sensors and algorithms. This substitution allows the system to obtain valve flow rate information without the time delay inherent in physical sensor placement upstream of the valve.
3Device complexity
If a fixed weighting factor is used in the weighted average calculation, then the calculation is simple, but the system cannot adapt to different flow rate conditions and target values
Solution Approach 1:
The patent makes the weighting factor dynamic by adjusting it based on the relationship between target flow rate and actual flow rate. When the target flow rate is large relative to actual flow rate, a smaller weighting factor is used for faster response. When the target flow rate is small, a larger weighting factor is used for noise reduction. This dynamic adaptation maintains calculation simplicity while significantly improving system versatility.
Solution Approach 2:
The patent changes the weighting factor parameter based on operating conditions rather than using a fixed value. This parameter adaptation allows the system to optimize performance across different flow rate scenarios without requiring complex algorithms, maintaining computational efficiency while enhancing adaptability.
Data Source
AI summary
In order to provide a flow rate control apparatus capable of reducing noise while reducing delay, the flow rate control apparatus includes: a fluid resistor provided in a flow path; a downstream valve provided downstream of the fluid resistor; and a downstream pressure sensor provided between the fluid resistor and the downstream valve. The apparatus calculates a resistor flow rate through the fluid resistor; the time change amount of the downstream pressure; on the basis of the resistor flow rate, the difference between the resistor flow rate and the time change amount of the downstream side pressure, and a weighting factor, calculates a weighted average to estimate a valve flow rate through the downstream valve; and, on the basis of the deviation between a set flow rate and the valve flow rate, controls the downstream side valve, in which the weighting factor is configured to be changeable.