Ultrasonic Liquid Sensor Amplitude Ratio Drift Compensation

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Solution Overview

Problem

Existing methods for detecting properties of liquid media, such as disturbances, face inaccuracies due to signal noise ratio issues and drifts caused by temperature changes, particularly in ultrasonic pulse generation and reception.

Innovation Solution

The method involves generating and receiving ultrasonic pulses, calculating amplitude signal ratios between first and second echoes, and determining a property signal representing the liquid medium's properties, which includes compensating for disturbances like bubbles by using a calculator unit to adjust measurements and account for temperature drifts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If signal to noise ratio (SNR) is used to determine disturbances in the liquid medium, then detection capability is provided, but measurement accuracy deteriorates due to drift of pulse generator and receiver

Engineering Contradiction:

Improvedetection capabilityVSAvoidmeasurement accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

A reference echo is introduced as an intermediary element to mediate between the received echoes and the drift effects. The reference echo, stored in memory, serves as a stable reference that cancels out the drift components when comparing with subsequent echoes, thereby eliminating the trade-off between detection capability and measurement accuracy

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

A copy of the initial echo is created and stored in memory as a reference. This copied reference echo is then used for comparison with subsequent echoes to eliminate drift effects, allowing accurate disturbance detection without sacrificing measurement precision

Inventive Principle:

Principle #26Copying

2Reliability

If ultrasonic pulses are transmitted through the liquid medium to detect disturbances, then detection capability is improved, but measurement accuracy deteriorates due to temperature changes causing drift

Engineering Contradiction:

Improvedetection capabilityVSAvoidmeasurement accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The system implements feedback by continuously comparing subsequent echoes with the stored reference echo and using the difference signal to compensate for drift effects. This feedback mechanism maintains measurement accuracy despite temperature changes by actively correcting for drift in real-time

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

A reference copy of the initial echo is created and stored, then used for comparison with subsequent echoes to eliminate drift effects caused by temperature changes, enabling accurate disturbance detection

Inventive Principle:

Principle #26Copying

3Reliability

If amplitude signals of echoes are used to determine liquid medium properties, then detection capability is provided, but measurement accuracy deteriorates due to attenuation and transducer drifts

Engineering Contradiction:

Improvedetection capabilityVSAvoidmeasurement accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The reference echo amplitude serves as an intermediary reference value that mediates the comparison process. By comparing subsequent echo amplitudes against this stable reference, the system eliminates attenuation and drift effects, achieving both detection capability and measurement accuracy

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

A copy of the initial echo amplitude is stored as reference and used for comparison with subsequent echoes, eliminating the effects of attenuation and transducer drifts while maintaining detection capability

Inventive Principle:

Principle #26Copying

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 allows for accurate detection of disturbances and precise measurement of the liquid medium's properties, including speed of sound, even in the presence of bubbles, by correcting for attenuation and transducer drifts, thereby improving measurement reliability and accuracy.

Implementation Method 1

generating an ultrasonic pulse

Methodology Applied

Scientific EffectUltrasonic pulse generation: Ultrasound

Implementation Method 2

receiving a first echo and a second echo of the ultrasonic pulse transmitted through the liquid medium

Methodology Applied

Scientific EffectEcho reflection: Echo

Implementation Method 3

correcting for attenuation and transducer drifts

Methodology Applied

Scientific EffectUltrasonic attenuation: Acoustic Absorption

Data Source

PatentUS11346837B2Method and apparatus for detecting a property of a liquid medium, urea sensor system, computer program product and computer-readable storage medium

Publication Date: 2022.05.31 TE CONNECTIVITY NORGE AS

AI summary

A method for detecting a property of a liquid medium comprises generating an ultrasonic pulse, receiving a first echo and a second echo of the ultrasonic pulse transmitted through the liquid medium, and generating a first amplitude signal for the first echo and a second amplitude signal for the second echo. The method includes calculating an amplitude signal ratio between the first amplitude signal and the second amplitude signal and determining a property signal representing the property of the liquid medium.