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학술대회 Enlarging the Short Range Detection Limit using Input Shaping Technique in Low Damping Ultra-Sonic Transducers
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이성규, 염우섭
International Congress on Sound and Vibration (ICSV) 2017, pp.1-6
17HS2300, 신체기능의 이상이나 저하를 극복하기 위한 휴먼 청각 및 근력 증강 원천 기술 개발, 신형철
Recently, detecting short range are required increasingly in surround imaging for smart cars. It is required to detect the close obstacles or image around the smart car within a couple of wavelength of driving frequency. In paper, the input shaping technique (IST) in low damping ultrasonic transducer is proposed for enlarging the short range detection limit when the pulse-echo ultrasonic imaging is applied. For high efficient and high sensitive sensing the ultrasonic signal, the transducer should have low damping characteristics. However, with low damping characteristics, it is difficult to detect the short range because slow decaying signal. IST is to generate a command to make zero residual vibra-tion of transducer, so that pulse signal is generated with only one cycle of natural frequency of trans-duce. The transducer can receive the echo signal after one cycle of pulse to enlarge the range of detection limit. In this experiment, the 25 kHz ultrasonic transducer is used for smart car application. When the 10V pulse input is applied to the transducer, the acoustic signal lasts more than 20 cycles. It is required to wait more than 800 micro second for the transducer to change into receive mode. Especially, when the obstacle is soft, it is required to wait more time because of weak echo signal. With conventional method, it is not easy to detect less than 150 mm due to the coupling effect of pulse signal. Through IST method, the pulse signal is controlled to have several cycle. After giving 3cycles of input for 120 micro second, the transducer is changed into received mode and detects the echo signal of the obstacle positioned at 100mm. The echo signal is converted to digital with 2.5Msps, so that the potential res-olution would be about 0.5 mm. These results are quite enough for smart car application to have precise surround image.
KSP 제안 키워드
Acoustic signal, Conventional methods, Coupling effects, Damping characteristics, Detection limit, Echo signal, High sensitive, Input shaping technique, Natural frequency, Pulse-echo, Range detection