Ultrasonic Sensor Burst Drive Signal Segmentation for Reverberation Error Reduction
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Solution Overview
Problem
Conventional ultrasonic systems face erroneous wave determination due to reverberation effects when using burst drive signals, leading to incorrect identification of reflected waves and measured distances.
Innovation Solution
The ultrasonic system employs a burst drive signal with a first drive signal at the resonant frequency during sensor drive periods and a second drive signal at a different frequency outside the band pass filter's frequency range during interval periods, ensuring no waveform is generated during the interval period, thus preventing erroneous wave determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a burst drive signal is used to drive the sensor element, then the ultrasonic wave transmission efficiency is improved, but erroneous wave determination occurs due to reverberation effects
Solution Approach 1:
The drive signal is segmented into multiple bursts with interval periods between them. Each burst drives the sensor element to transmit ultrasonic waves, while the interval periods allow reverberation to subside. This segmentation resolves the contradiction by maintaining transmission efficiency through multiple bursts while preventing erroneous wave determination by spacing them appropriately.
Solution Approach 2:
The sensor element is driven periodically with burst signals separated by interval periods. The periodic driving at resonant frequency maintains transmission efficiency, while the interval periods create a temporal pattern that allows the system to distinguish between reverberation and actual reflected waves, thus improving wave determination accuracy.
2Reliability
If the interval period is lengthened to reduce reverberation interference, then wave determination accuracy is improved, but the measurement time increases
Solution Approach 1:
Instead of waiting for complete reverberation decay, the patent uses a partial waiting period that is sufficient to reduce interference to acceptable levels. The interval period is optimized to provide just enough time for reverberation to subside while maintaining efficient measurement cycles, thus improving wave determination accuracy without excessive time loss.
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 accurately determines the own wave, reducing errors in distance measurement by eliminating reverberation-induced interference and ensuring precise time-of-flight calculations.
Implementation Method 1
transmits an ultrasonic wave by driving a sensor element (piezoelectric element)
Implementation Method 2
measuring time TOF (Time Of Flight) until returning of a reflected wave
Implementation Method 3
a band pass filter (42) to which the received wave signal is input
Implementation Method 4
a first drive signal having a frequency within a frequency band of the band pass filter, and a second drive signal having a frequency different from a resonant frequency of the sensor element
Data Source
AI summary
A burst drive signal has a sensor drive period for transmitting a first drive signal, and an interval period provided between the sensor drive periods adjacent to each other, for transmitting a second drive signal. The first drive signal has a frequency within a frequency band of a band pass filter. The second drive signal has a frequency that is different from a resonant frequency of a sensor element and is outside the frequency band of the band pass filter.