• 한국생산제조학회지
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• 제25권6호
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• pp.486-491
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• 2016

Disturbance/vibration reduction is critical in many applications using machine vision. The off-focusing or blurring error caused by vibration degrades the machine performance. In line with this, real-time disturbance estimation and avoidance are proposed in this study instead of going with a more familiar approach, such as the vibration absorber. The instantaneous motion caused by the disturbance is sensed by an attitude heading reference system module. A periodic vibration modeling is conducted to provide a better performance. The algorithm for vibration avoidance is described according to the vibration modeling. The vibration occurrence function is also proposed, and its parameters are determined using the genetic algorithm. The proposed algorithm is experimentally tested for its effectiveness in the vision inspection system.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 추계학술대회논문집
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• pp.94-99
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• 2000

When operating NC lathe, gear box which is equipped with gear train and spindle sometimes generates loud noise and excessive vibrations. In order to identify their causes, In this study, torsional and lateral vibration characteristics including critical speeds of the gear train-spindle system are first analyzed by using torsional and lateral vibration models of the gear train and shafts. Natural frequencies and modes of the gear box structure are also analyzed by impulse hammer test. Furthermore, measured vibration and noise signals are analyzed and compared with theoretical analysis results. At last it is concluded that the cause of the excessive mise and vibration is the resonance between gear meshing frequency including its side bands, shaft bending and torsional vibration frequencies, and the natural frequencies of th gear box structure. Consequently the noise and vibration levels are greatly reduced by avoiding resonance between them through the redesign of the gear module.

• Journal of international Conference on Electrical Machines and Systems
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• 제2권1호
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• pp.97-103
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• 2013

This paper describes the characteristics of Electronic Throttle Controller (ETC) module in BLDC motor without the hall sensor for detecting a rotor position. The proposed ETC control system, which is mainly consisted of a BLDC motor, a throttle plate, a return spring and reduction gear, has a position sensor with an analogue voltage output on the throttle valve instead of BLDC motor for detecting the rotor position. So the additional commutation information is necessarily needed to control the ETC module. For this, the estimation method is applied. In order to improve and obtain the high resolution for the position control, it is generally needed to change the gear ratio of the module or the electrical switching method etc. In this paper, the 3-phase switching between successive commutations is adapted instead of the 2-phase switching that is conventionally used. In addition, the position control with a variable PI gain is applied to improve a dynamic response during a transient period and reduce vibration at a stop in case of matching position reference. The mentioned method can be used to estimate the commutation state and operate the high-precision position control for the ETC module and the high response characteristics. The validity of the proposed method is examined through the experimental results.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 춘계학술대회논문집
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• pp.217-220
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• 2005

Zero tail type mini excavator is small in size and capacity compared with medium or large excavator. Therefore noise and heat problems are major issues in design due to layout of each components such as engine and hydraulic module. It is necessary to assure reduction of noise and vibration in construction machine, due to be enforced regulation for high noise construction machinery at home and abroad. The objective of this study is to provide basic data which is apply to predict noise effect in detail design stage by estimating noise of cabin for zero tail type mini excavator.

• 한국소음진동공학회논문집
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• 제17권8호
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• pp.673-682
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• 2007

Recently the trend of automobile industry is that IQS evaluation index against a sensitivity quality is increasing. To reduce rattle noise due to speaker sound at low frequencies, it is required the advanced technology analysis process of body structure. This paper optimized the design parameters of package tray panel according to the theoretical background about robust design and suggested the design guideline for resonance avoidance and the reduction of vibrational sensitivity considering the excitation frequency of woofer speaker. And this paper described the design process of a door module panel through the sensitivity analysis in case of the door speaker excitation. Finally, the analysis of the quality deviation using mother car is suggested to guarantee the stable characteristics of vehicle vibration in the early stage of vehicle development. These improvements can lead to shortening the time needed to develop better vehicles.

• 한국구조물진단유지관리공학회 논문집
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• 제17권2호
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• pp.21-32
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• 2013

본 논문에서는 건축물의 실시간 피드백 진동제어를 위한 기초연구로써, 자체 기술력을 바탕으로 개발된 무선 가속도센서 시스템 및 프로토타입 (Prototype) AMD 시스템을 결합하여 피드백 진동제어 시스템을 구성하고, 모형 건축물을 대상으로 구성된 제어시스템의 기초성능을 평가하고자 하였다. 이를 위하여 본 논문에서는 우선 MEMS 센서 소자 및 블루투스 통신 모듈 기반의 무선 가속도 센서 유닛, 실시간 가속도 응답획득 및 제어법칙에 근거한 제어출력을 구현하도록 구성한 운영프로그램 등을 개발하였다. 또한 AC 서보모터를 이용해 기동되도록 설계한 프로토타입 AMD 및 모터 드라이버 시스템을 구성하였다. 마지막으로 이를 이용해 실시간 피드백 진동제어 시스템을 구성하였고, 2층 모형 건축물을 대상으로 실험실 규모의 진동제어 실험을 수행하여 목적된 구조물의 진동저감 효과를 정량적으로 분석하였다. 실험의 결과, 모형 구조물의 1차 및 2차 공진주파수 그리고 랜덤주파수 등의 실험조건에서 명확한 진동저감의 효과를 확인할 수 있었으며, 종국적으로 본 논문에서 개발한 무선 가속도센서 시스템 및 AMD 시스템이 향후 여타 구조물의 진동제어를 위한 효과적인 수단으로 응용될 수 있는 가능성을 확인하였다.

• 한국막학회:학술대회논문집
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• 한국막학회 1997년도 심포지움시리즈 Jan-97 수처리용 분리막 기술 및 응용
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• pp.87-109
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• 1997

Reverse osmosis(R/O), ultrafiltration(UF) and microfiltration (MF) processes are widely used for water treatment. In the seminar, characteristics of typical membrane modules including tubular, hollow fiber, plate and frame and spiral wound types will be discussed in detail. The design methods based on hydrodynamics for hollow fiber and spiral wound modules will be introduced analytically. Concentration polarization (CP) and membrane fouling mechnism as well as the techniques for CP reduction will be handled. The CP control techniques contain chemically modified membrane surface, pretreatment of feed water, operation of low trans-membrane pressure, chemical or physical cleaning methods and artificial production of various fluid turbulences near the membrane surface, etc. In especially, the recent commercial membrane modules for CP control including module rotation, vibration and Taylor or Dean vortex system will be introduced and discussed in detail.

• 한국전자통신학회논문지
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• 제12권5호
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• pp.899-906
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• 2017

본 논문은 다세대 공동 주택에서 윗층과 아래층 간에 발생하는 층간 소음을 줄일 수 있도록 도와주는 층간소음 방지 시스템을 제안하고 있다. 제안하는 시스템에서는 오픈소스 컨트롤러 중 하나인 아두이노 보드에 소리 감지 센서와 진동 감지 센서를 연결하여 층간 소음으로 판단하는 소리와 진동을 입력 받고 이를 고속 푸리에 변환을 이용하여 주파수 대역에서의 신호 분석을 수행한다. 특정 주파수 대역의 신호 크기가 구조물의 투과 손실을 고려한 기준을 넘을 때에는 LCD화면에 경고 메시지를 보내고 휴대폰으로 이메일 또는 메시지를 전송하도록 하였다. 이를 통해 시스템은 사용자가 소음 발생 상황을 인지하여 스스로 주의할 수 있도록 돕는다. 시스템 검증을 위한 실험에서 제안하는 시스템은 외부 입력 신호에서 130 Hz~1040 Hz의 대역 성분 추출을 수행하였으며, 추출된 신호의 크기와 투과 손실의 차이 값이 45 dB를 초과할 경우 기기의 연결된 디스플레이와 Wi-Fi로 연결된 모바일 기기에 현재 소음이 발생하고 있음을 공지하는 동작을 수행하였다.

• 소성∙가공
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• 제18권7호
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• pp.538-543
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• 2009

The cowl cross bar of an automobile is a frame component that is installed inside the cockpit module to provide a guide surface, to which functional components for electricity and air condition are attached. In the recent years, the geometries of cowl cross bars are getting more complex in order to meet the demands of a wide variety of embedded functional components and the reduced weight of frame parts with enhanced mechanical and noise/vibration characteristics. There for, welding processes between tubes with different diameters are widely conducted while the welded parts are experiencing various problems such as undermined appearance, low production efficiency and poor mechanical characteristics. Therefore, this paper seeks to develop an one-piece forming process which eliminate welding process for the cowl cross bar by applying the tube drawing process. However, it was predicted that a conventional tube drawing can not be applied directly to the current part since the area reduction ratio of the drawing process reaches 51.7% which exceeds the general limiting value. Therefore, in this study, a combined drawing process which adds a compressive force to a tensile force of the conventional drawing process was proposed and 2-stage drawing process was designed by using CAE analyses. In addition, drawing tryouts were carried out by using the manufactured combined drawing machine in order to verify the designed process.

• 한국생산제조학회지
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• 제20권4호
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• pp.502-508
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• 2011

In this paper, we proposed vertical feeding mechanism for a slide parts feeder using the slide type method. This parts feeder of the slide type method have been proposed to suppress the dust generation from the feeding objects. The proposed parts feeder mechanism is composed with the casing hopper, the vertical feeding unit, the in-line feeder and linear shooter unit. And, these mechanisms did modularity through optimum design by means of mechanical and dynamical analysis using the RecurDyn(multi-body dynamics) analysis module. Also were carried out the virtual prototype using the 3-D CAD program. And it had been manufactured as the prototype of the slide parts feeder. The field test for validation of performance was performed directly at the inspection line of bolt and screw. In the field test, this slide parts feeder showed an efficiency of about 1.2 times the bowl feeder. It also showed an epoch reduction in the dust generation compared to the vibration bowl feeder. So this slide parts feeder will be applied useful in the vision inspection system for a screw and bolt.