• 소음진동
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• 제9권6호
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• pp.1247-1258
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• 1999

This paper presents vibration control of a CD-ROM(compact disc-read only memory) drive feeding system consisting of a new type of CD-ROM mount using an electro-rheologocal(ER) fluid. Chemically treated starch particles and silicon oil are used for EF fluid, and its field-dependent yield stresses are experimentally distilled under both the shear and the flow modes. On the basis of the yield stress, an appropriate size of ER CD-ROM mount adapted to conventional feeding system is designed and manufactured. Vibration isolation performance of the proposed mount is evaluated in the frequency domain and compared with that of conventional rubber mount. The ER CD-ROM mount is then installed to the drive feeding system and the system equation of motion is derived. The skyhook controller is then incorporated with the fuzzy technique to improve the performance of ER CD-ROM mount. A set of fuzzy parameters and control rules are obtained from a relation between vertical displacement and pitching motion of the feedng system. Followingthe formulation of the fuzzy-skyhook controller, computer simulation is undertaken in order to evaluate vibration suppression of the CD-ROM drive feeding system subjected to various excitations.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집B
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• pp.210-215
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• 2001

CD-ROM Drives Rotating high speed as 10000 rpm cause serious noise and vibration problems. At the high speed, dominant noise is Air Borne Noise produced from high-speed airflow and Structure Borne Noise produced from structural vibration. In this research, vibration and sound characteristics in CD-ROM Drive were studied by the use of experimental analysis and computational simulation. Sound intensity techniques and ODS(Operational Deflection Shape) techniques are applied to identify the acoustic noise source of CD-ROM drive. And Computational simulation using SYSNOISE is conducted for describing the noise behavior.

• 소음진동
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• 제7권3호
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• pp.393-399
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• 1997

This study proposes a methodology with which the optimal damper positions of the feeding system in a CD-ROM drive are determined to removal the harmful tilting vibration modes. For this purpose, vibration characteristics of the feeding system are identified by a theoretical modeling as well as vibration experiments. We perform the modal testings using the impact hammer and shaker; furthermore, we establish a vibration model due to the rigid-body motion. The analysis and experiments show that the feeding system has three rigid-body vibration modes in the low-frequency region and two of them come from the tilting modes. We show that the tilting modes can be removed by determining the damper positions.

• 유변학
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• 제11권2호
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• pp.97-104
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• 1999

본 연구에서는 전기장의 인가 유무에 따라 유체의 유변성질이 가역적으로 변화하는 ER(electro-rheological) 유체를 이용하여 CD-ROM(compact disc-read only memory) 마운트를 구성한 후 피딩 시스템의 진동제어를 수행하였다. 이를 위하여 우선 특수화학처리된 전분계 ER유체를 조성하였으며, 전단모드 및 유동모드하에서 전기장에 따른 항복응력을 실험적으로 도출하였다. 도출된 ER유체의 항복응력에 근거하여 복합모드형 CD-ROM 마운트를 설계, 제작하였다. 제작된 ER CD-ROM 마운트의 진동절연 특성을 주파수 영역에서 고찰하였으며 기존의 고무마운트 성능과 비교하였다. 나아가서 제안된 마운트를 장착한 정보저장기기 드라이브 피딩 시스템의 동적 모델링을 수행하였으며, 진동제어를 위한 스카이훅 제어기를 설계하였다. 컴퓨터 시뮬레이션을 통하여 여러 외란(가진) 조건에 따른 피딩 시스템의 진동제어 성능을 주파수 및 시간 영역에서 고찰하였다.

• 정보관리연구
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• 제21권2호
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• pp.9-23
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• 1990

CD-ROM기술(技術)의 개발(開發)은 불과 10년이 채 안되었지만 그동안 비약적 발전을 거듭하여 여러 응용분야(應用分野)에서 활용되고 있다. 서지데이터는 물론 수치(數値), 음성(音聲), 영(映) 화상(畵像) 데이터를 초록형(抄錄型) 또는 전문형(全文型)으로 수록하여 도서관은 물론 기업체(企業體), 정보기관(情報機關) 등에 제공(提供), 활용(活用)하여 도서관(圖書館) 직원(職員), 정보전문가(情報專門家), 일반이용자(一般利用者)들에게 정보검색(情報檢索) 훈련용(訓練用)으로 쓰일 수 있게 되었다. 한 개 디스크를 액세스하기 위해 한 대의 디스크드라이브와 한 대의 컴퓨터를 필요(必要)로 했던 것에서 탈피하여 현재는 한 대의 드라이브로 여러 장의 CD-ROM을 검색(檢索)할 수 있고, 동시에 여러 명의 이용자가 다양한 정보(情報)를 액세스할 우 있는 이상적인 시스템인 CD-ROM LAN이 가능하게 되었다. 따라서, 본고(本稿)에서는 CO-ROM의 기능(機能)과 종류(種類), 특성(特性), 시스템구성(構成)과 데이터블록, 제작과정(製作過程)과 표준화(標準化) 그리고 CD-ROM LAN에 대해 살펴보았다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 춘계학술대회논문집
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• pp.504-509
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• 2001

CD-ROM drive is improved in rotation speed up to 10,000 rpm. But Vibration and Noise are also increased simultaneously more and more. So many attempts are tried to reduce the unexpected effects. Most attempts are not enough to cover the increasement of Noise and Vibration. Merely availed tries are accumulated in many part and it makes the structure complicated. The Axiomatic approach could arrange the order of design and estimate the optimum design in good oder. In Axiomatic Approach, the composition is divided by Customer Requirement, Functional Requirement, Design Parameter and Design Matrix in large portion. This method also could show more effective way to design before making a prototype.

• 소음진동
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• 제8권3호
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• pp.533-541
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• 1998

Recently, optical disk drives are increasingly demanded to have higher speed as well as high information density, especially for applications like CD ROM drives. To this end, improvement of their optical pickup structure and control is recognized the very challenging issue. In this paper, the pickup is first analytically modelled in a plane to describe its coupled auto-focusing and auto-tracking motions. Subsequently, the model is linearized and combined with actuator dynamics for the auto-focusing system. With its unmeasurable parameters being estimated based on experimental data, an approximate I-DOF linear model is obtained neglecting the coupling term. To design the high speed and robust positional servo controller realistic design specifications are addressed, and H control method is employed based on the approximate model. Finally, taking the pickup in a commerical high speed CD ROM drive as an example performance of the designed controller is verified through realtime experiments.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1996년도 추계학술대회논문집; 한국과학기술회관, 8 Nov. 1996
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• pp.324-329
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• 1996

Vibration characteristics of the feeding system in a CD-ROM drive are identified by a theoretical modeling as well as vibration experiments. For this purpose, we establish a vibration model due to the rigid-body motion and perform the modal testings using the impact hammer and shaker. The analysis and experiments show that the feeding system has three rigid-body vibration modes in the low-frequency region and two of them come from the tilting modes. In order to remove the harmful tilting modes for the tracking servo control, a methodology to find the optimal positions of the dampers is also proposed in this study.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1997년도 추계학술대회논문집; 한국과학기술회관; 6 Nov. 1997
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• pp.438-444
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• 1997

Recently, optical disk drives are increasingly demanded to have higher speed as well as high information density, especially for applications like CD-ROM drives. To this end, improvement of their optical pick-up structure and control is recognized the very challenging issue. In this paper, the 2-D motion of the pick-up is first analytically modelled to identify the cause and effect of the troublesome cross coupling between auto-focusing and tracking directions. Subsequently, the overall system equations are derived to include the dynamics of the related components in the auto-focusing servo system. While its unmeasurable parameters being estimated by the least square error method, a simple but decent linear model can be obtained within its operating frequency range. To design the high speed and robust positional servo controller, the design specifications are detailed and H$\sub$.inf./ control method is employed based on the simple model. Using the pickup in a commercial 8 fold speed CD-ROM drive as an example, performance of the designed controller is verified by realtime experiments.

• 대한기계학회논문집B
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• 제28권1호
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• pp.66-71
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• 2004

Airborne contaminant particles are intruded into optical disk drive(ODD) due to the flow caused by disk rotation and can be adhered to objective lens, which causes read/write errors. Such a phenomenon can be a serious problem for high-density storage devices. The purpose of this paper is to understand the effect of particle contamination of objective lens in a CD-ROM drive on laser diode power and photo diode RF signal. The measurements of laser power and readout RF signal were carried out by using a laser power meter and a time interval analyzer, respectively. The parameters for estimating a readout-signal' distortion were its jitter and amplitude. Alumina(Al$_2$O$_3$) particles were used as test dust particles. The results show that the failure for data access happened as the degree of lens contamination was greater than 20％.