Tuning Fork Viscometer Dynamic Feedback Gain Control

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Solution Overview

Problem

Conventional viscometers face challenges in achieving high response speed for high viscosity and low shear rate measurements, leading to slow response times and inability to obtain continuous smooth measurement graphs.

Innovation Solution

The tuning fork vibration viscometer is enhanced with a gain control mechanism that dynamically adjusts feedback gain based on viscosity oscillations, allowing for improved response speed and continuous measurement graphs by using ceramic or metal vibrators and an electromagnetic drive system with a microcontroller for precise amplitude and gain control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional feedback control is used for high viscosity measurements, then measurement stability is maintained, but response time becomes excessively long

Engineering Contradiction:
Improvemeasurement stabilityVSAvoidresponse time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The feedback gain is made dynamic rather than fixed. The controller automatically adjusts the feedback gain based on the measured viscosity value, using higher gain for low viscosity measurements and lower gain for high viscosity measurements. This dynamic adaptation allows the system to achieve both fast response and stable measurement across different viscosity ranges.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The feedback gain parameter is changed according to the measurement conditions. The system divides the measurement range into multiple viscosity ranges and assigns different feedback gain values to each range. This parameter change strategy optimizes the control response for each specific measurement scenario, resolving the contradiction between speed and stability.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If fixed feedback gain is used, then system complexity is reduced, but measurement accuracy across different viscosity ranges deteriorates

Engineering Contradiction:
Improvecontrol system complexityVSAvoidviscosity measurement accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The feedback gain transitions from a static fixed value to a dynamic value that changes based on measured viscosity. This dynamic approach maintains relatively simple system architecture while significantly improving measurement precision across the full viscosity range by adapting control parameters to measurement conditions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

Different feedback gain parameters are applied to different viscosity ranges. The system automatically selects appropriate gain values based on the measured viscosity magnitude, enabling high measurement precision without requiring complex manual configuration or multiple dedicated systems.

Inventive Principle:
Principle #35Parameter changes

3Speed

If high feedback gain is applied, then response speed improves, but measurement stability deteriorates causing oscillations

Engineering Contradiction:
Improveresponse speedVSAvoidmeasurement stability
Core Design Contradiction:
SpeedVSStability of the object's composition

Solution Approach 1:

The feedback gain is dynamically adjusted based on the actual measurement conditions. For low viscosity measurements where fast response is needed, higher gain is applied. For high viscosity measurements where stability is critical, lower gain is applied. This dynamic adaptation prevents oscillations while maintaining appropriate response speed for each measurement scenario.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The feedback gain parameter is changed according to viscosity ranges. By dividing the measurement range and assigning appropriate gain values to each range, the system achieves optimal balance between response speed and stability for each specific measurement condition, avoiding the oscillations caused by uniformly high gain.

Inventive Principle:
Principle #35Parameter changes

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 significantly reduces response time across all viscosity ranges, enabling continuous smooth measurement graphs even at high viscosities and low shear rates, thereby improving measurement accuracy and efficiency.

Implementation Method 1

a magnet 10a and an electromagnetic coil 10b for vibrating the vibrators 3 and 3

Methodology Applied
Scientific EffectElectromagnetic drive: Electromagnetic Induction

Implementation Method 2

a displacement detection sensor 11 for detecting an amplitude of the vibrators 3 and 3

Methodology Applied
Scientific EffectDisplacement detection: Displacement

Implementation Method 3

By utilizing a proportional relationship between a driving current to be applied to the electromagnetic coil 10b and a viscosity of the sample 4

Methodology Applied
Scientific EffectViscous damping: Viscous Damping

Data Source

PatentEP3156781B1Method and device for measuring physical properties of fluid
Publication Date: 2020.08.05 A&D CO LTD
  • EP3156781B1 patent drawingFigure 1
  • EP3156781B1 patent drawingFigure 2
  • EP3156781B1 patent drawingFigure 3

AI summary

Provided are a method and device for improving a response speed in a measurement of viscosity of a fluid and obtaining a continuous smooth measurement graph. A viscometer includes a machine part that generates a shear rate in a sample, a machine drive, a shear rate changing means that outputs a target shear rate of the machine part, and a displacement detection sensor that measures displacement of the machine part, and performs feedback control to control a driving force of the machine drive so that an output value of the displacement detection sensor corresponds to the target shear rate and measures a viscosity of a sample, wherein a feedback gain is simply set for each measurement according to an optimum design or target shear rate.