• 제목/요약/키워드: Park Disk

검색결과 1,031건 처리시간 0.037초

The Seek Control Design with Gain-Scheduling in Hard Disk Drives

  • Hwang, Eun-Ju;Hyun, Chang-Ho;Park, Mig-Non
    • International Journal of Fuzzy Logic and Intelligent Systems
    • /
    • 제11권1호
    • /
    • pp.65-70
    • /
    • 2011
  • The increased disk rotational velocity to improve the data transfer rate has raised up many serious problems in its servo control system which should control the position and velocity of a spot relative to a rotating disk. This paper proposes gain-scheduling-based track-seek control for single stage actuator of hard disk drives. Gain scheduling is a technique that can extend the validity of the linearization approach to a range of operating points and one of the most popular approaches to nonlinear control design. The proposed method schedules controller gains to improve the transient response and minimize overshoot during the functions of the read/write head positioning servomechanism for the seek control. The validity of the proposed method is demonstrated through stability analysis and simulation results.

철도 차량용 제동디스크의 열응력 해석 (Thermal Stress Analysis for a Ventilated Disk Brake of Railway Vehicles)

  • 이영민;박재실;석창성;이찬우
    • 한국정밀공학회:학술대회논문집
    • /
    • 한국정밀공학회 2005년도 춘계학술대회 논문집
    • /
    • pp.1617-1621
    • /
    • 2005
  • In this study, as a basic research to improve braking efficiency of a ventilated disk brake, we carried out a thermal stress analysis. From analysis result, we knew that a maximum mechanical stress by braking pressure and friction force is applicable to 5 percent of yield strength and has no effect on a fatigue life's decrease for brake disk material. While, a maximum thermal stress by frictonal heat is applicable to 43 percent of yield strength and locates on a friction surface. So, we have found that a thermal stress is the primary factor of crack initiation on a friction surface of disk brake

  • PDF

퍼지제어 기법을 이용한 아라고 원판 시스템의 위치 제어에 관한 연구 (The Position of an Arago Disk System using Fuzzy Logic Control Technique)

  • 문상익;조용석;박기헌
    • 대한전기학회:학술대회논문집
    • /
    • 대한전기학회 1999년도 하계학술대회 논문집 B
    • /
    • pp.709-711
    • /
    • 1999
  • In this paper, Fuzzy Logic Controller was Designed for the Degree control of Arago's disk system. Arago's disk system is an application of Arago's disk phenomenon which is the operating principle of induction motor. Since the Arago's disk system varies to stable region. maginally stable region, unstable region according to the degree of bar respectively, it is a sutable system which can be evaluate an efficiency of the system. While an existing controller which was designed using linearized system modeling could control the system on only one operating point, fuzzy logic controller has the advantage in showing good response for multi-operating points because it does not need system modeling.

  • PDF

형태의 변화에 따른 강압용 압전변압기의 유한요소해석 (Finite Element Analysis of Step-down Piezoelectric Transformer with Various Shape)

  • 정현호;박태곤;권오영
    • 한국전기전자재료학회:학술대회논문집
    • /
    • 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.2
    • /
    • pp.697-700
    • /
    • 2003
  • This paper presents design and analysis of step-down piezoelectric transformer for application to AC-adapters. These transformers are consist of rectangular type and disk type multilayered piezoelectric ceramic plate. This piezoelectric transformer operated in third thickness resonance vibration mode. Finite element methode(FEM) was used for analysing transformer. Vibration mode and electric field of piezoelectric transformer were simulated at resonance frequency. As results, rectangular type transformer's output voltage was higher than the disk type. But disk type transformer's current was lagger than rectangular type. These results are assumed that disk type transformer's mixed vibration mode influence transformer's output characteristics. From these results, we expect that disk type piezoelectric transformer is more adoptable than rectangular plate type piezoelectric transformer for AC adapters.

  • PDF

외란 검출기에 기반한 광디스크 시스템 제어기 설계 (Optical Disc System Controller Design Based on a Disturbance Detector)

  • 최병호;최가형;윤태성;박진배
    • 전기학회논문지
    • /
    • 제58권8호
    • /
    • pp.1595-1604
    • /
    • 2009
  • An Optical disk driver is used in many electronic products besides the computers. In particular, the demands are recently increased as an optical disk player/recorder in the mobile products such as camcorder, portable player or in the home theater appliances, etc. However, the more the mobility is emphasized, the more the optical disk player is exposed to the disturbance inputs. For reducing the possibility of malfunction of the optical disk, we propose a nonlinear controller using the disturbance detecting algorithm based on the Kalman filter. Actual experiments were executed to verify the performance of the proposed method. The proposed method controls the tracking error signal within ${\pm}0.1{\mu}m$.

진동신호분석을 통한 광디스크 드라이브의 고장원인분석 (Failure Analysis of Optical Disk Drives Using the Vibration Signal Analysis)

  • 박영필;신창호;정진태
    • 대한기계학회논문집A
    • /
    • 제29권7호
    • /
    • pp.1028-1034
    • /
    • 2005
  • In this paper, the failure analysis of an optical disk drive is carried out and the limit ranges of the misalignment f3r the higher performance are presented. Since optical disks are removable from optical disk drive, the translational and angular misalignments, which causes read/write errors, always exist. Therefore, the limit ranges of the misalignment should be investigated. For this reason, the failure analysis by the vibration analysis is studied. The influences of the misalignment are tested by the aging test. And the limit ranges of the misalignment are proposed for the reliability of optical disk drives.

하드디스크 드라이브 내부 유동에 의한 액추에이터의 진동 저감을 위한 수치해석 연구 (The Numerical Simulation of the Airflow for Reducing Vibrations of an Actuator in HDDs)

  • 박재현;유진규;임윤철
    • 대한기계학회:학술대회논문집
    • /
    • 대한기계학회 2003년도 추계학술대회
    • /
    • pp.664-669
    • /
    • 2003
  • Recently, the recording density of hard disk drives has improved at an annual percentage rate of 100%. Therefore for faster access, higher disk rotational speeds will be required. The influence of the airflow produced by the rotation of a disk on the positioning accuracy has become a serious topic of research and the aerodynamic aspect of hard disk drives is now quite considerable with the increases in recording density and higher rotational speeds. Unsteady airflow in an actual hard disk drive is numerically simulated by using LES(Large Eddy Simulation) technique, we could predicted and aerodynamic mechanism that was related actuators' surroundings in HDD. At a result, with modifying the various shapes of the E-block and Damper, we estimated the characteristic of the influence of airflow in HDDs.

  • PDF

철도 차량용 제동디스크의 피로수명평가 (Fatigue Life Assessment for a Brake Disk of Railway Vehicles)

  • 석창성;박홍선;허용;김재훈;이영민
    • 한국정밀공학회:학술대회논문집
    • /
    • 한국정밀공학회 2006년도 춘계학술대회 논문집
    • /
    • pp.385-386
    • /
    • 2006
  • A brake disk in railway vehicle is safety part. Requirements not only in performance but also in comfort, serviceability and working lifetime are high and rising. In this study, we carried out fatigue test and thermal stress analysis. To determine a pressure distribution, contact pressure analysis precede thermal stress analysis. Especially, characteristics of the brake disk were analyzed in considering intial velocity, and thickness of a frictional plate. Form the comparing the results of experiment and FEM analysis, fatigue characteristic and fatigue life assessment ok a brake disk of railway vehicle were performed.

  • PDF

제동 디스크 소재의 강도평가 (Strength Assessment of the Brake Disk material)

  • 이영민;최정훈;허용;박재실;석창성;최경진
    • 한국철도학회:학술대회논문집
    • /
    • 한국철도학회 2004년도 추계학술대회 논문집
    • /
    • pp.497-502
    • /
    • 2004
  • In this study, we compared the strength of a material used in the A-type disk brake with that in the B-type. From tensile test results, it has been found that the strength of the B-type disk brake is higher than that of the A-type. The microstructure observation and chemical analysis were conducted to determine the cause of the difference between the strength of A and B types of disk brake materials. From the experimental results, it has been confirmed that the difference in the strength between the two types of disk brake is due to the difference in the shape of graphite.

  • PDF

Discrimination of Intervertebral Disk Extrusion from Protrusion with MR Imaging

  • Kim, Jee-Young;Jee, Won-Hee;Ha, Kee-Yong;Park, Chun-Kun;Cho, So-Hee;Byun, Jae-Young
    • 대한자기공명의과학회:학술대회논문집
    • /
    • 대한자기공명의과학회 2002년도 제7차 학술대회 초록집
    • /
    • pp.138-138
    • /
    • 2002
  • To determine the accuracy of magnetic resonance (MR) imaging for discrimination between intervertebral disk extrusion versus protrusion. MR images of 80 patients who had MR imaging of the spine and confirmed as intervertebral disk extrusion or protrusion were retrospectively reviewed by an experienced musculoskeletal radiologist. A 1.5-T scanner was used. After review of medical records, MR findings of disk extrusion and protrusion were compared using the chi-square test. Intraobserver agreement for differentiation of disk extrusion from protrusion was calculated by using coefficient.

  • PDF