• 한국생산제조학회지
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• 제23권4호
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• pp.385-391
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• 2014

A control system for ultrasonic spray pyrolysis deposition was developed that can coat a large size glass panel with a transparent conductive oxide. It consists of several ultrasonic atomizer devices to cover a large area and a host computer for individually controlling the devices. The sub-controller in an ultrasonic atomizer device can adjust the flow rate of the atomized conductive oxide gas by setting the flow rate of the solution and regulating the level of the solution in the tank. To construct a feedback control loop for level regulation, a level sensor that utilized an infrared distance sensor and an electric circuit for adjusting the ultrasonic oscillator were developed. The host program was also developed, which can monitor and control the sub-controllers. A proportional-integral controller was developed for a simplified model, and its operation was verified through an experiment.

• 한국염색가공학회지
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• 제9권4호
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• pp.28-38
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• 1997

Peach skin fabrics were washed by the general and ultrasonic washing systems using different conditions. The physical properties of the washed fabrics were estimated. The following results were obtained through experimental data and their analysis. The tensile properties were changed due to fabric running speed and washing methods. The lower the running speed, the higher the extensibility and resilience and the lower the linearity and tensile energy. In the general washing method, the extensibility and resilience had lower values than those of the ultrasonic washing method and the linearity and tensile energy had the higher values than those of the ultrasonic washing system. The bending properties, bending moment and histeresis, were estimated. These values were generally lower in the ultrasonic washing system than those of the general washing system. The faster the washing speed, the higher the value of hysterisis. The shear properties were affected by the fabric running speed and washing methods. Shear stiffness and hysteresis of shear forces increased according to the increase of the fabric running speed. The values were higher in the general washing system than those of the ultrasonic washing system. The compressional energy was affected by the fabric running speed. The higher the fabric speed the higher the compressional energy. The ultrasonic washing system had lower compressional energy than the general washing system. The higher the running speed, the lower the coefficient of friction and geometrical roughness. The values of geometrical roughness were infienced by the removal of the sizing agent. The higher the remaining sizing agent, the higher the fabric weight and the thicker the thickness of fabric.

• Journal of Positioning, Navigation, and Timing
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• 제9권4호
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• pp.387-395
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• 2020

Accuracy of an integrated Global Positioning System (GPS) / Inertial Navigation System (INS) relies heavily on the visibility of GPS satellites. Especially, its accuracy is dramatically degraded in urban canyon due to signal obstructions due to large structures. In this paper, we propose a new integrated positioning system that effectively combines INS, GPS, ultrasonic sensor, and barometer in GPS-denied environments. In the proposed system, the ultrasonic sensor provides velocity information along the forward direction of moving vehicle. The barometer output provides height information compensated for the pressure variation due to fast vehicle movements. To evaluate the performance of the proposed system, an experiment was carried out by mounting the proposed system on a test car. By the experiment result, it was confirmed that the proposed system bears good potential to maintain positioning accuracy in harsh urban environments.

• 동력기계공학회지
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• 제17권5호
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• pp.100-111
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• 2013

Indoor real-time positioning for multiple targets is required to realize human-robot symbiosis. This study firstly presents positioning accuracy on an autonomous mobile robot controlled by 3-D coordinates that is obtained by a real-time indoor positioning system with spread spectrum (SS) ultrasonic signals communicated by code-division multiple access. Although many positioning systems have been investigated, the positioning system with the SS ultrasonic signals can measure identified multiple 3-D positions in every 70 ms with noise tolerance and error within 100 mm. This system is also robust to occlusion and environmental changes. However, thus far, the positioning errors in an autonomous mobile robot, controlled by these systems using the SS ultrasonic signals, have not been evaluated as an experimental study. Therefore, a positioning experiment for trajectory control is conducted using an autonomous mobile robot and our positioning system. The effectiveness of this positioning method for robot self-localization is shown, from this experiment, because the average control error between the target position and the robot's position at 29 mm is obtained.

• Composites Research
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• 제29권5호
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• pp.288-292
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• 2016

본 연구에서는 전영역 초음파전파영상화 시스템이라 불리는 새로운 초음파전파영상화 장치를 소개한다. 본 시스템은 비파괴적으로 구조를 2 축 선형 이동 스테이지 기반으로 검사한다. 일치된 초음파 센싱과 가진 레이저 빔이 구조를 스캔하며 동시에 펄스-에코 모드 레이저 초음파를 수집한다. 이 과정은 스캔영역만큼 큰 두께 방향의 전영역 초음파를 생성하는 것을 가능하도록 한다. 본 시스템을 사용하여 실제로 운용 중인 알루미늄 허니콤 구조 기반의 CN-235의 도색된 샌드위치 조종면를 검사 및 평가하고 구조 검사 결과로써 전영역 초음파전파 영상을 소개하였으며 기존 초음파 탐상 기법의 결과와 비교하여 성능 및 민감도를 검증하였다.

• 전기학회논문지
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• 제58권10호
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• pp.2071-2078
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• 2009

In this paper, we proposed a non-contact respiration measurement system with ultrasonic proximity sensor. Ultrasonic proximity sensor approach of respiration measurement which respiration signatures and rates can be derived in real-time for long-term monitoring is presented. 240 kHz ultrasonic sensor has been applied for the proposed measurement system. The time of flight of sound wave between the transmitted signal and received signal have been used for a respiration measurement from abdominal area. Respiration rates measured with the ultrasonic proximity sensor were compared with those measured with standard techniques on 5 human subjects. Accurate measurement of respiration rate is shown from the 50 cm measurement distance. The data from the method comparison study is used to confirm the performance of the proposed measurement system. The current version of respiratory rate detection system using ultrasonic can successfully measure respiration rate. The proposed measurement method could be used for monitoring unconscious persons from a relatively close range, avoiding the need to apply electrodes or other sensors in the correct position and to wire the subject to the monitor. Monitoring respiration using ultrasonic sensor offers a promising possibility of non-contact measurement of respiration rates. Especially, this technology offers a potentially inexpensive implementation that could extend applications to consumer home-healthcare and mobile-healthcare products. Further advances in the sensor design, system design and signal processing can increase the range of the measurement and quality of the rate-finding for broadening the potential application areas of this technology.

• 한국음향학회지
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• 제16권2호
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• pp.5-9
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• 1997

본 논문에서는 chirp 신호를 초음파 신호처리 시스템에 입력시킬 때 반사신호의 진폭을 최대로 얻기위한 chirp 신호의 대역폭을 결정하는 방법을 연구하였다. 초음파 신호처리 시스템에서 반사신호의 S/N 비는 초음파의 전파시에 발생하는 감쇠와 산란에 의하여 매우 낮게된다. Chirp 신호를 사용한 펄스 압축기술은 초음파 반사시스템의 S/N 비를 증가시킬 수 있는 방법중 하나이다. 시뮬레이션 및 실험결과, chirp 신호의 펄스폭이 넓을수록 출력이 증가하였고 동일한 펄스폭과 주어진 초음파시스템의 대역폭에 대한 최대출력은 chirp 신호의 대역폭이 초음파시스템의 대역폭 보다 1.15배 클 때 얻어짐을 확인하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 합동 추계학술대회 논문집 정보 및 제어부문
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• pp.411-413
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• 2002

In this paper we researched about the ultrasonic cane which aids the blind to walk. We used ultrasonic in recognizing the object and implemented pulse counting method in measuring the distance. The distance measuring system consists of transmitter unit, receiver unit and micro-processor. We used broadband ultrasonic sensors in transmitter unit and receiver unit. The blind is able to recognize the distance between obstacles and himself as it used a vibration system.

• 한국전자통신학회논문지
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• 제8권5호
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• pp.725-731
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• 2013

본 논문은 시뮬레이션을 통해 다수의 초음파 발신부로부터 순차적으로 발생되는 초음파를 공간 내에서 자유롭게 움직이는 여러개의 이동형 개체들에 각각 장착된 초음파 수신부가 수신하여 각 개체의 위치를 스스로 계산할 수 있는 시스템을 제안한다. 이 시스템은 적절한 위치에 고정 장착된 3개 이상의 초음파 발신부에 의해 정의되는 공간 내에서 움직이는 개체가 자신들의 위치를 스스로 추정 가능하게 하기 때문에 공간 내에 존재하는 개체 수에 제안을 받지 않는 다는 장점이 있다. 따라서 본 기술은 다 개체 시스템의 위치 제어 및 모션 포착 기술에 효과적으로 응용이 가능하다.

• 소성∙가공
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• 제13권3호
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• pp.253-261
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• 2004

The machining technology for the brittle materials such as ceramics are applied to the fields of MEMS(micro electromechanical system) by the progress of new machining technologies such as Etching, Diamond machining, Micro drilling, EDM(Electro discharge machining), ECDM(Electro discharge machining), USM(Ultrasonic machining), LBM(Laser beam machining), EBM(Electron beam machining). Especially, the USM technology can be applied to the dieletric brittle materials such as silicon, borosilicate glass, silicon nitride, quartz and ceramics with high aspect ratio. The micro machining system with machining force controlled position servo is developed in this paper and the optimized ultrasonic machining algorithm is constructed by the force controlled position servo control. The load cell is adapted in the force measuring and the servo control algorithm, suit for the ultrasonic machining characteristics, is estabilished with using the PID auto-tunning functions at the PMAC system which is generally adapted in the field of robot industries. The precision force signal amplifier is constructed with high precision operational amplifier AD524. The vacuum adsorption chuck which is made of titanum and internal flow line is engraved, is used in the workpiece fixing. The mahining results by USM shows that there are some deviation between the force command and the actual machining force that the servo control algorithm should be applied in the machining procedures. Therefore, the constant force controlled position servo system is developed for the micro USM system and by the examination machining process in USM, the stable USM system is realized by tracking the average value of machining force.