• 한국기계가공학회지
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• 제17권2호
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• pp.15-21
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• 2018

In this paper, a detection and warning system is proposed for the remaining kids in a school bus. For detecting the remaining kids, an ultrasonic sensor is used. The basic experiments of the ultrasonic sensor are performed, and a modified ultrasonic sensor is proposed. Also, the appropriate location of the ultrasonic sensor is proposed by considering various sitting positions. Based on the above kid detection system, a warning algorithm is designed. Using the above detection and warning system, experiments are performed. From the experimental results, it is found that the proposed system, based on the modified ultrasonic sensor, can detect the remaining kids in a school bus. The proposed system can also give an appropriate warning signal.

• 제어로봇시스템학회논문지
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• 제17권12호
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• pp.1240-1247
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• 2011

The localization of mobile robot in environment is a major concern in mobile robot navigation. So, many kinds of localization techniques have been researched for several years. Among them, the positioning system using ultrasound has received attention. Most of these ultrasonic positioning systems to synchronize the transmitters and receivers are used for RF (Radio Frequencies). However, due to the use of RF, the interference problems can not be avoided and the performance of radio frequencies directly affects the positioning performance. So we proposed the ultrasonic positioning system without synchronizing RF. The proposed system is based on existing USAT (Ultrasonic Satellite System) adopted infrastructure transmitting type, and consists of transmitter and receiver synchronizing modules instead of the radio frequency transmitters and receiver. The ultrasonic transmitters and receivers are synchronized individually by the transmitter and receiver synchronizing modules. In order to calculate the bias between the transmitter and receiver synchronizing modules, new positioning algorithm similar to GPS was proposed. The positioning performance of the improved USAT without synchronizing RF and the validity of the proposed positioning algorithm are verified and evaluated by experiments.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계학술대회논문집
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• pp.959-962
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• 2005

In the semiconductor and optical industry. a new transport system which can replace the conventional transport system is required. The Transport systems are driven by the magnetic field and conveyer belts. The magnetic field may damage semiconductor and the contact force may scratch the optical lens. The ultrasonic wave driven system can solve these problems. In this semiconductor and optical industry, the non-contact system is required for reducing the damages. The ultrasonic transportation is the solution of the problem. In this paper, the ultrasonic levitation system for levitation object are proposed. The 3D vibration profiles of the beam are measured by Laser Scanning Vibrometer for verifying the vibration characteristics of the system and the amplitudes of the beam and the levitation heights of object are measured fore evaluating the performance.

• 한국정밀공학회지
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• 제30권11호
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• pp.1121-1128
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• 2013

Ultrasonic grinding system is that the ultrasonic vibration by ultrasonic actuator is applied on conventional grinding system during grinding process. The Ultrasonic vibration with a frequency of over 20kHz can reduce grinding forces and increase surface quality, material removal rate (MRR) and grinding wheel life. In addition, ultrasonic vibration assisted grinding can be used for the materials that are difficult to cut. In this paper, methodology for ultrasonic tools is studied based on finite element method, and in turn the ultrasonic tools are designed and fabricated. It is found that the ultrasonic tool can vibrate with a frequency of 20kHz and amplitude of $25{\mu}m$. In order to verify the machining performance, the grinding experiment is performed on titanium alloy. By applying ultrasonic vibration, the grinding force and temperature are reduced and MRR is increased compared with the conventional grinding.

• 산업기술연구
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• 제27권B호
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• pp.97-101
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• 2007

We have developed a Edge Position Controller (EPC) using a ultrasonic sensor and applied to a fabric machine as a web guide system. Hardware devices composed of a ultrasonic transmitter-receiver sensor module and microprocessor-based sensor signal processing system are developed to realize the proposed system. We evaluated the control characteristics of the EPC and the performance of the system was good enough to apply the actual system.

• 제어로봇시스템학회논문지
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• 제5권2호
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• pp.200-207
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• 1999

In this paper, a precise sensitivity measurement system of ultrasonic transducer in the frequency range from 1 MHz to 15 MHz, which can implement the reciprocity principle is constructed. All of the elements of this system such as the ultrasonic preamplifier, ultrasonic absorber, water tank, water degassing system, and four-axes translator and reflector are constructed. For the performance evaluation of the calibration system, a standard hydrophone precisely calibrated from PTB(Physikalisch Technische Bundesanstalt) in Germany are used. And the system parameters which affected the evaluation of the measurement accuracy and the reproducibility in various measuring conditions are considered. The measurement uncertainty of the calibration system is estimated within $\pm$ 2.0㏈.

• 한국염색가공학회지
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• 제12권3호
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• pp.207-217
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• 2000

A new, high-efficiency ultrasonic fabric washing machine was developed to be an energy-efficient washing machine and to enhance fabric washing quality in washing processes of the dyeing and finishing process in the textile industry. This system is composed of ultrasonic wave generator, air blowing nozzle, torque motor for fabric tension control, and enclosed washing bath, multi-tube type exchanger, noiseless heater, air cylinder, expander roller, mangle upper and lower rollers, bend bar, dancer, shower spray nozzle, and solenoid valve, and so on. These elements are synergised for fabric washing. One of the very important principles is the low tension fabric running system. For an efficient washing effect, a counter flow system is also adopted. The new system also adopts the dancer and torque motor to control fabric tension and prevent fabric creasing. Shower spray nozzle, counter flow and overflow apparatus, and air-blowing apparatus are adopted to enhance the fabric washing effect. In this study, peach yoryu, exter, and moss crepe fabrics were washed by the general and ultrasonic washing systems under different conditions respectively. The washing efficiency was affected by the fabric running speed and characteristics of fabrics. Size content after washing increased with increasing the fabric running speed. The values in the general washing system were higher than those of the ultrasonic washing system. The changes of conductivity in the ultrasonic and the cooling bath were affected by the running time under the ultrasonic generating. The values of conductivity decreased as the experimental time passed.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 추계학술대회 논문집
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• pp.415-418
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• 2005

In the semiconductor and optical industry, a new transport system which can replace the conventional transport systems is required. The transport systems are driven by the magnetic field and conveyer belts. The magnetic field may damage semiconductor and the contact force may scratch the optical lens. The ultrasonic wave driven system can solve these problems. In this semiconductor and optical industry, the non-contact system is required fur reducing the damages. The ultrasonic transportation is the solution of the problem. In this paper, the ultrasonic levitation system fur levitating object are proposed. The 3D vibration profiles of the beam are measured by Laser scanning Vibrometer fur verifying the vibration characteristics of the system and the amplitudes of the beam and the levitation heights of object are measured for evaluating the performance.

• 비파괴검사학회지
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• 제33권2호
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• pp.232-240
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• 2013

This paper presents recent advances in damage visualization algorithms of laser generated ultrasonic propagation imaging(UPI) system. An effective damage evaluation method is required to extract correct information from raw data to properly characterize anomalies present in structure. A temporal-reference free imaging system provides easy and rapid defect inspection capability with less computational complexity. In this paper a number of methods such as ultrasonic wave propagation imaging(UWPI), anomalous wave propagation imaging(AWPI), ultrasonic spectral imaging(USI), wavelet ultrasonic propagation imaging(WUPI), variable time window amplitude mapping(VTWAM), time point adjustment(TPA), time of flight and amplitude mapping(ToF&Amp) and ultrasonic wavenumber imaging(UWI) are discussed with instances of successful implementation on various structures.

• 한국분무공학회지
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• 제8권4호
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• pp.1-8
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• 2003

The objective of this study is to investigate experimentally atomization characteristics for differently made an ultrasonic twin-fluid nozzle. A spray system, an ultrasonic system, and three different type(Nozzle type, Tube type, Conventional type)are made and tested by applied with ultrasonic energy. In this investigation, the measurement and calculation of spray droplet are to analyze the effects of ultrasonic energy on the agricultural atomization system. Through the measurement of suray angle, spray column using, high speed camera and PDA, it is found that nozzle type is highest efficiency than that of tube type and conventional type. It was found that the ultrasonic energy increased the atomization efficiency of spray droplets about 9% respectively and spray angle was wide spray.