• Title/Summary/Keyword: Track dynamic analysis

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The Development and Performance Analysis of Beam Rotating Actuator for Multi-Beam Disk Drive (다중빔 광디스크용 빔 회전 구동기의 제작과 특성평가)

  • Kim, Byeong-Jun;Kim, Su-Hyeon;Gwak, Yun-Geun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.12
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    • pp.3026-3032
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    • 2000
  • To enhance the effective data transfer rate the multi-beam optical disk drive is presented. The Beam rotating actuator is necessary for putting multi-beam on more than one track. Ray tracing was also executed for real system set-up. The beam Rotating Actuator is made up of piezoelectric material, high stiffness wire hinge and dove prism. The actuator has about 1kHz natural frequency and suitable operational range. The dynamic equation for the actuator is derived for the control real system.

A Study on the Optimization of the Alignment Considering the Ride Comfort in the Case of the Superimposition of Vertical and Horizontal Curves (종곡선/평면곡선 경합 시 승차감을 고려한 선형최적화에 관한 연구)

  • Um, Ju-Hwan;Yang, Sin-Chu;Choi, Il-Yoon
    • Proceedings of the KSR Conference
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    • 2010.06a
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    • pp.1943-1950
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    • 2010
  • Superimposition of horizontal and vertical curves may hamper the ride comfort and the running stability of train and largely affect the maintenance cost. However, in many cases, it's not easy to make a track plan because of the fixed points (bridge, tunnel, turnout, catenary system, etc.) to be avoided due to the geographic conditions or to be passed for utilization of existing structures. In this study, when the horizontal and vertical curves are superimposed, in order to optimize the horizontal curve in aspect of the ride comfort, the object function $P_{CT}$ was developed and verified by vehicle dynamic analysis. Also, the solution algorithm for simplified evaluation method was presented.

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Dynamic Field Test of High-Speed Railway Bridge Considering Temperature (온도를 고려한 고속철도 교량의 진동 실험)

  • Choi, Eun-Suk;Chin, Won-Jong;Lee, Jung-Woo;Kang, Jae-Yoon;Kwark, Jong-Won;Kim, Byung-Suk
    • Proceedings of the KSR Conference
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    • 2007.11a
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    • pp.1392-1394
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    • 2007
  • By the examination of data collected by long-term measuring system on high-speed railway bridges, it has been known that the atmospheric temperature may affect the responses of maximum deflection and acceleration of bridge deck. Collected data show a tendency by seasonal factor to that, by the decrease of temperature, the response of acceleration of bridge deck increases, and the response of deflection decreases. To trace the cause of this tendency, parametric analysis on the stiffness of bridge bearing and track ballast has been performed, and the in-site measurement has been achieved in high-speed railway line to understand seasonal influences.

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Dynamic Behavior Analysis for HDD Spindle Motors with Rotor Eccentricity (HDD 스핀들 구동용 BLDC 전동기의 편심을 고려한 동적 거동 해석)

  • 김태종;김경태;황상문
    • Journal of KSNVE
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    • v.10 no.6
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    • pp.977-984
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    • 2000
  • Vibration of disk drive spindle is one of the major limiting factors in achieving higher track densities in hard disk drives. Vibration of a BLDC motor is a coupled phenomenon between mechanical characteristics and magnetic origins through the motor air-gap. In this paper, radial magnetic forces for symmetric and asymmetric BLDC motor are calculated with respect to the various rotor eccentricity using analytic method. Based on the results of the radial magnetic forces, transient whirl responses of the spindle motor are analyzed using finite element and transfer matrices. Results show that an asymmetric motor has a worse effects on unbalanced magnetic forces and vibration when mechanical and magnetic coupling exists.

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Robust Current Tracking Control of Switched Reluctance Motors (Switched Reluctance Motor의 견실한 전류추적 제어기 설계)

  • Kim, Chang-Hwan
    • Journal of Institute of Control, Robotics and Systems
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    • v.7 no.3
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    • pp.218-228
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    • 2001
  • The switched reluctance motor(SRM) has been increasingly used in high-performance servo applications such as electric vehicles, aircraft, and direct-drive robots. The dynamic equations of SRMs are, however, highly nonlinear and this makes it difficult to control SRMs with high performance. In this paper, we propose a new robust current tracking controller for SAMs which can compensate the nonlinear characteristics of SRM(i.e., back-emf and inductance) completely and hence shows perfect tracking performance even with an arbitrary small current control loop gain. Furthermore, even in case that there exist some model uncertainties, our current controller guarantees that the stator currents can track the reference current commands with sufficiently small tracking errors. In order to justify our work, we present the tracking performance analysis and some simulation results.

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An Analytic Technique for Making a Linear Model of a Hydraulic Mount (유체 봉입 마운트 선형 모형의 해석적 구성 기법)

  • Lee, Jun-Hwa;Kim, Kwang-Joon;Won, Kwang-Min;Kang, Koo-Tae
    • Proceedings of the KSME Conference
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    • 2001.06b
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    • pp.410-415
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    • 2001
  • Hydraulic mounts have been used as an alternative to the conventional rubber mounts for they can provide more desirable stiffness and damping properties which may vary with frequency and excitation amplitude. Although a lumped-parameter non-linear model of the hydraulic mount developed by a simple fluid dynamic analysis can be successfully used for representing the inertia track dynamics, a linear model is still preferred. In this paper, an analytic technique for making a linear model of the hydraulic mount is proposed.

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Design of a Rubber Mount for Vibration Reduction in a Slim Optical Disk Drive (슬림형 광디스크 드라이브의 방진마운트 설계)

  • Kim, Kug-Weon;Kim, Nam-Woong
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.16 no.6
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    • pp.103-109
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    • 2007
  • With the increase of track density, high rotational speed and the compatibility for various media in optical disk drives, the effective design to vibration reduction is very important for robust operation. Especially when a slim optical disk drive for a notebook PC is excited by a mass-unbalanced disk, internal vibration and its transmission to external case bring about severer problem than that of conventional one. In this paper a design process of a rubber mount in a slim optical disk drive for vibration reduction is presented. The characteristics of rubbery materials - hyper-elastic and visco-elastic - are measured with standard specimens. The static stiffness of a rubber mount was calculated by FEM and the dynamic stiffness is predicted with the static stiffness and the impedance test data of the standard specimen. The transmissibility tests are performed for the purpose of verification of the design process.

An Evaluation on Derailment according to Running Safety of Next-Generation High Speed Train (HEMU-430X) (차세대 고속열차(HEMU-430X)의 주행 안전에 따른 탈선평가)

  • Sim, Kyung-Seok;Park, Tae-Won;Lee, Jin-Hee;Jeong, Gi-Beom
    • Journal of the Korean Society for Railway
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    • v.15 no.4
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    • pp.343-351
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    • 2012
  • With the cooperation of many research institutes and railway companies, the next generation high speed train is under development for many years. To confirm the safety requirement of the developed high speed train, multibody dynamic analysis is implemented. Through this analysis, railway derailment and lateral guiding force simulation was evaluated according to UIC code 518 OR for international railway vehicle. Test results were compared by limit value of safety criteria. Safety evaluation results, according to international standards, would provide basic reference data of ensuring safety speed and track radius curve. The safety of the train at the maximum speed is verified by numerical analysis results.

Analysis of Influence on Derailment due to Primary Spring Aging (축상스프링 노화에 따른 탈선안전도 영향 분석)

  • Hur, Hyunmoo;Shin, Yujeong;You, Wonhee;Park, Joonhyuk
    • Journal of the Korean Society for Railway
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    • v.20 no.3
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    • pp.320-328
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    • 2017
  • In order to analyze the influence on derailment safety according to the aging of primary rubber springs widely applied to railway vehicles, characteristic tests were carried out on aged primary rubber spring samples. To analyze the effect of primary rubber spring aging on derailment safety, a vehicle dynamic analysis was carried out. The results of the vertical characteristics test for the rubber spring specimens with 17 years of service life revealed that the displacement restoration function was degraded due to rubber aging and the spring stiffness significantly increased. The results of the running dynamic analysis simulating the twist track running in accordance with the EN14363 standard, compared with the normal vehicle model (Case 1), showed that the derailment coefficient and the wheel unloading of the vehicle model (Case 2) using the aging primary spring characteristic increased, and the derailment safety was degraded. IN particular, it was found that the derailment safety due to the reduction of the wheel load is weak in the transient section where a steep slope change occurs.

Story-based Information Retrieval (스토리 기반의 정보 검색 연구)

  • You, Eun-Soon;Park, Seung-Bo
    • Journal of Intelligence and Information Systems
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    • v.19 no.4
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    • pp.81-96
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    • 2013
  • Video information retrieval has become a very important issue because of the explosive increase in video data from Web content development. Meanwhile, content-based video analysis using visual features has been the main source for video information retrieval and browsing. Content in video can be represented with content-based analysis techniques, which can extract various features from audio-visual data such as frames, shots, colors, texture, or shape. Moreover, similarity between videos can be measured through content-based analysis. However, a movie that is one of typical types of video data is organized by story as well as audio-visual data. This causes a semantic gap between significant information recognized by people and information resulting from content-based analysis, when content-based video analysis using only audio-visual data of low level is applied to information retrieval of movie. The reason for this semantic gap is that the story line for a movie is high level information, with relationships in the content that changes as the movie progresses. Information retrieval related to the story line of a movie cannot be executed by only content-based analysis techniques. A formal model is needed, which can determine relationships among movie contents, or track meaning changes, in order to accurately retrieve the story information. Recently, story-based video analysis techniques have emerged using a social network concept for story information retrieval. These approaches represent a story by using the relationships between characters in a movie, but these approaches have problems. First, they do not express dynamic changes in relationships between characters according to story development. Second, they miss profound information, such as emotions indicating the identities and psychological states of the characters. Emotion is essential to understanding a character's motivation, conflict, and resolution. Third, they do not take account of events and background that contribute to the story. As a result, this paper reviews the importance and weaknesses of previous video analysis methods ranging from content-based approaches to story analysis based on social network. Also, we suggest necessary elements, such as character, background, and events, based on narrative structures introduced in the literature. We extract characters' emotional words from the script of the movie Pretty Woman by using the hierarchical attribute of WordNet, which is an extensive English thesaurus. WordNet offers relationships between words (e.g., synonyms, hypernyms, hyponyms, antonyms). We present a method to visualize the emotional pattern of a character over time. Second, a character's inner nature must be predetermined in order to model a character arc that can depict the character's growth and development. To this end, we analyze the amount of the character's dialogue in the script and track the character's inner nature using social network concepts, such as in-degree (incoming links) and out-degree (outgoing links). Additionally, we propose a method that can track a character's inner nature by tracing indices such as degree, in-degree, and out-degree of the character network in a movie through its progression. Finally, the spatial background where characters meet and where events take place is an important element in the story. We take advantage of the movie script to extracting significant spatial background and suggest a scene map describing spatial arrangements and distances in the movie. Important places where main characters first meet or where they stay during long periods of time can be extracted through this scene map. In view of the aforementioned three elements (character, event, background), we extract a variety of information related to the story and evaluate the performance of the proposed method. We can track story information extracted over time and detect a change in the character's emotion or inner nature, spatial movement, and conflicts and resolutions in the story.