Ultrasonic Sensor Burst Signal Frequency Adaptation

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Solution Overview

Problem

Ultrasonic sensors face a drop in transmission/reception sensitivity due to environmental changes such as mud, rain, snow, and temperature variations, which affect the proper vibration frequency of the piezoelectric element, leading to reduced detection accuracy.

Innovation Solution

An ultrasonic sensor system that adjusts the burst wave frequency to match the reverberation frequency by integrating and processing the reverberation signal, using a signal processing circuit to count pulse signals and adjust the frequency to maximize signal strength, thereby maintaining sensitivity despite environmental changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the sending frequency is set to the proper vibration frequency of the piezoelectric element, then transmission/reception sensitivity is enhanced, but the sensitivity drops when environmental changes cause the proper vibration frequency to shift

Engineering Contradiction:
Improvetransmission/reception sensitivityVSAvoidfrequency adaptation to environmental changes
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent implements feedback by detecting the reverberation frequency of the piezoelectric element and using this information to automatically adjust the sending frequency. The signal processing circuit measures the reverberation frequency and feeds this back to the burst signal generating circuit, which then adjusts the sending frequency to match the current proper vibration frequency of the piezoelectric element, ensuring optimal sensitivity despite environmental changes

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent changes the parameter of sending frequency dynamically based on environmental conditions. By detecting shifts in the piezoelectric element's proper vibration frequency caused by environmental factors (temperature, moisture, etc.) and adjusting the sending frequency accordingly, the system maintains optimal transmission/reception sensitivity across varying operating conditions

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If multiple frequency detection and adjustment mechanisms are implemented, then frequency accuracy is improved, but device complexity increases

Engineering Contradiction:
Improvefrequency measurement accuracyVSAvoidsignal processing circuit complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The signal processing circuit performs multiple functions using a unified approach: it detects the reverberation signal, measures the reverberation frequency, and provides this information for sending frequency adjustment. This multi-functional design achieves accurate frequency measurement without requiring separate dedicated circuits for each function, thereby limiting the increase in device complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 system automatically corrects the burst wave frequency to maintain transmission/reception sensitivity, enhancing detection accuracy and extending the sensor's operational range.

Implementation Method 1

the proper vibration frequency of an piezoelectric element with a view to amplifying the sent ultrasonic vibration

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

an ultrasonic sensor that transmits and receives ultrasonic waves

Methodology Applied
Scientific EffectPiezoelectric effect: Converse Piezoelectric Effect

Implementation Method 3

the time that elapses after ultrasonic waves are sent until waves reflected from an object are received is used to determine the presence/absence of an obstacle

Methodology Applied
Scientific EffectAcoustic wave reflection: Reflection

Implementation Method 4

waves are sent at a frequency equal to the proper vibration frequency of an piezoelectric element with a view to amplifying the sent ultrasonic vibration

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP3244230B1Ultrasonic sensor and burst signal control method
Publication Date: 2022.03.30 ROHM CO LTD
  • EP3244230B1 patent drawingFigure 1
  • EP3244230B1 patent drawingFigure 2
  • EP3244230B1 patent drawingFigure 3A~3C

AI summary

An ultrasonic sensor 1000 has a transmission/reception processing circuit 100, and the transmission/reception processing circuit 100 has a burst signal transmission circuit 1 that generates and transmits burst signals S0, and a signal processing circuit 7 that processes reception signals received by a piezoelectric element 4. The signal processing circuit 7 verifies the reverberation frequency of the reverberation signals of ultrasonic signals (reception signals) reflected to the piezoelectric element 4 from a subject, and on the basis of the verified reverberation frequency and reverberation time of the reception signals, adjusts the frequency of the burst signals S0 to be substantially equal to the reverberation frequency, said burst signals being to be generated by the burst signal transmission circuit 1.