• Title, Summary, Keyword: Motion response characteristic

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Inelastic Response Characteristic Analysis of Frame Structures Subjected to Near Fault Ground Motion (근거리지진을 받는 골조 구조물의 비탄성응답 특성 분석)

  • Han, Sung Ho;Shin, Jae Chul
    • Journal of The Korean Society of Civil Engineers
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    • v.26 no.2A
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    • pp.273-284
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    • 2006
  • In this study, After considering the general characteristic of Near Fault Ground Motion, the inelastic response spectrum is made to evaluate using the change of ductility and yield stiffness coefficient according to the inelastic behavior of structures which couldn't be examined through the elastic response spectrum. It is conducted to the elastic and inelastic time history analysis about the long period structure which could reflect the characteristic of Near Fault Ground Motion with the best and it is also examined the aspect of response distribution about the input data. Moreover, the response characteristic of structure is analyzed by investigating the plastic hinge for the purpose of grasp about the inelastic behavior of structure.

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A Study on Characteristics and Dynamic Response Spectrum of Near Fault Ground Motions (근거리지진의 특성과 동적응답스펙트럼에 관한 연구)

  • Bang, Myung-Seok;Han, Sung-Ho
    • Journal of the Korean Society of Safety
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    • v.20 no.3
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    • pp.143-151
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    • 2005
  • In this study, it is demonstrated that how the effect of the Near Fault Ground Motion affects the response of the structure. Considering the general characteristic of Near Fault Ground Motion the characteristics of Near Fault Ground Motions is analysed by elastic response spectrums, and the inelastic response spectrum is evaluated with the ductility and the yield strength to consider the inelastic behavior which couldn't be simulated through the elastic response spectrum. The result of this study shows that the effect of Near Fault Ground Motion should be considered in the long period range of long span structures but the domestic seismic design code was developed based on Far Fault Ground Motions, so the effects of Near Fault Ground Motions, which is very serious especially in large structures with a long period, are not considered. Therefore, the effect of the Near Fault Ground Motion has to be examined especially in the seismic performance evaluation of long period structure.

A Pilot Study on the Muscle Activities in Step Input Test as an Indicator of the Vehicle Characteristics

  • Kong, Yong-Ku;Jung, Myung-Chul;Lee, In-Seok;Hyun, Young-Jin;Kim, Chang-Su;Seo, Min-Tae
    • Journal of the Ergonomics Society of Korea
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    • v.32 no.3
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    • pp.217-227
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    • 2013
  • Objective: The purpose of this study was to analyze 'response time', 'peak response time' and 'overshoot value' for each muscle by applying the EMG signal to the vehicle response in ISO 7401 and to quantify the response of the driver according to vehicle characteristics by comparing vehicle characteristics and muscle responses of the driver. Background: The Open-loop test defined in international standards ISO 7401 is the only method for evaluating the performance of the vehicle. However, this test was focused only on mechanical responses, not driver's ones. Method: One skilled male driver(22 yrs. experience) was participated in this experiment to measure muscle activities of the driver in transient state. Then the seven muscle signals were applied to calculate 'response time', 'peak response time', and 'overshoot value'. Results: In the analyses of the EMG data, the effects of vehicle type and muscle were statistically significant on the 'response time' and 'peak response time'. Also, the effects of vehicle type, muscle, and lateral acceleration level were statistically significant on the 'overshoot value' in this study. According to the analyses of the vehicle motion data, vehicle motion variable(LatAcc, Roll, YawVel) was statistically significant on the 'response time' and vehicle type, vehicle motion variable, and lateral acceleration level were statistically significant on the 'peak response time', respectively. Conclusion: In the analyses of the 'response time' and 'overshoot value', the data of muscle activities(EMGs) was better index that could evaluate the vehicle characteristic and performance than the data of vehicle motion. In case of peak response time, both EMG and vehicle motion data were good index. Application: The EMGs data from a driver might be applicable as index for evaluation of various vehicle performances based on this study.

Optimal Motion Control of 3-axis SCARA Robot Using a Finite Jerk and Gain Tuning Based on $LabVIEW^{(R)}$ ($LabVIEW^{(R)}$ 기반 3축 스카라 로봇의 유한 저크 및 게인 동조를 이용한 최적 모션 제어)

  • Kim, J.H.;Chung, W.J.;Kim, H.G.;Lee, G.S.
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.17 no.3
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    • pp.40-46
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    • 2008
  • This paper presents the optimal motion control for 3-axis SCARA robot by using $LabVIEW^{(R)}$. Specifically, for optimal motion control of 3-axis SCARA robot, we study velocity profile based on finite jerk(the first derivative of acceleration) and optimal gain tunig based on frequency response method by using $LabVIEW^{(R)}$. The velocity optimization with finite jerk aims at generating the smooth velocity profile of robot. Velocity profile based on finite jerk is acquired and applied to 3-axis SCARA robot by using $LabVIEW^{(R)}$. DSA(Dynamic Signal Analyzer) for frequency response method is programed by using $LabVIEW^{(R)}$. We obtain the bode plot of transfer function about 3-axis SCARA robot by using DSA, and perform the gain tuning considering dynamic characteristic based on the bode plot. These experiments have shown that the proposed motion control can reduce vibration displacement and response error rate each 33.7% and 51.7% of 3-axis SCARA robot.

A Study on the Positioning Characteristic of Aerostatic Stage (공기베어링 스테이지의 이송특성 연구)

  • 황주호;박천홍;송창규;김중천
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.668-671
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    • 2000
  • An aerostatic stage has frictionless behavior, so it has a advantage of investigation into driven mechanism such as ballscrew. In this paper, fur investigating positioning characteristic of ballscrew and feedback device in aerostatic stage, we compare the positioning characteristic between full-closed(laser scale) and semi-closed(encoder) system. Experimental results show that the aerostatic stage has a 10nm micro step response and repeatability is improved up to 1.00${\mu}{\textrm}{m}$ using laser scale. We confirm the laser scale compensate error motion of ballscrew, so acquire 1.12${\mu}{\textrm}{m}$ positioning accuracy.

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Thermal Characteristic Analysis of a High-Speed Horizontal Machining Center with Built-in Motor and Linear Motors (내장형 모터와 리니어 모터를 적용한 초고속 수평형 머시닝센터의 열 특성 해석)

  • 김석일;조재완
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • pp.416-423
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    • 2004
  • This paper presents the thermal characteristic analysis of a high-speed horizontal machining center with spindle speed of 50,000rpm and feedrate of 120m/fin. The spindle system is designed based on the built-in motor, angular contact ceramic ball bearings, oil-air lubrication and oil-jacket cooling method. The X-axis and Y-axis feeding systems are composed of the linear motors and linear motion guides, and the Z-axis feeding system is composed of the servo-motor, ball screw and linear motion guides. The thermal characteristics such as the temperature distribution, temperature rise, thermal deformation and step response, are estimated based on the finite element model of machining center and the heat generation rates of heat sources related to the machine operation conditions. Especially, the thermal time constant assessed from the step response function is introduced as an index of thermal response characteristics.

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Thermal Characteristic Analysis of a High-Speed Horizontal Machining Center with Built-in Motor and Linear Motors (내장형 모터와 리니어 모터를 적용한 초고속 수평형 머시닝센터의 열 특성 해석)

  • Kim Seok-ll;Cho Jae-Wan
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.13 no.5
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    • pp.30-37
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    • 2004
  • This paper presents the thermal characteristic analysis of a high-speed horizontal machining center with spindle speed of 50,000rpm and feedrate of 120m/min. The spindle system is designed based on the built-in motor, angular contact ceramic ball bearings, oil-air lubrication and oil-jacket cooling method. The X-axis and Y-axis feeding systems are composed of the linear motors and linear motion guides, and the Z-axis feeding system is composed of the servo-motor, ball screw and linear motion guides. The thermal characteristics such as the temperature distribution, temperature rise, thermal deformation and step response, are estimated based on the finite element model of machining center and the heat generation rates of heat sources related to the machine operation conditions. Especially, the thermal time constant assessed from the step response function is introduced as an index of thermal response characteristics.

Dynamic Analysis of NFR Slider (NFR 슬라이더의 동특성 분석)

  • 안채헌;임경화
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.586-591
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    • 2001
  • Dynamic analysis using impulse responses is formulated to estimate effect of slider rail shape on dynamic responses. Impulse responses are obtained on numerical nonlinear model including rigid motion of slider and fluid motion of air bearing under the slider. Dynamic characteristics of slider motion are evaluated by utilizing the decay ratio of impulse responses and modal frequencies from frequency response functions. The dynamic characteristics of the developed NFR(Near Field Recording) slider are checked by comparing those of HDD sider(Nutcracker). Also, sensitivities of slider position conditions and rotation speed on the dynamic characteristics are investigated. The researches show that the utilized method is a good indicator of designing the better slider.

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A Position Control System of SRM using Digital Hysteresis Controller (디지털 히스테리시스 제어기를 이용한 SRM의 위치제어시스템)

  • Baik Won-Sik;Kim Nam-Hun;Choi Kyeong-Ho;Kim Dong-Hee;Kim Min-Huei;Hwang Don-Ha
    • Proceedings of the KIPE Conference
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    • pp.41-45
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    • 2001
  • This paper presents an implementation of motion control system of Switched Reluctance Motor (SRM) using digital hysteresis controller by TMS320F240 DSP. SRM position control system possess several advantages over other motors, including high efficiency, simple structure, low cost, and four-quadrant operation at a wide speed range, especially for the servo drive systems with precision, stability and fast response characteristics in the industrial applications. In the suggested motion control system, position control using digital hysteresis controller is developed, and is evaluated using experimental testing. The developed system for cost reduction and high-performance by fully digital controller is shown a good response characteristic of motion control results.

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A multiple scales method solution for the free and forced nonlinear transverse vibrations of rectangular plates

  • Shooshtari, A.;Khadem, S.E.
    • Structural Engineering and Mechanics
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    • v.24 no.5
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    • pp.543-560
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    • 2006
  • In this paper, first, the equations of motion for a rectangular isotropic plate have been derived. This derivation is based on the Von Karmann theory and the effects of shear deformation have been considered. Introducing an Airy stress function, the equations of motion have been transformed to a nonlinear coupled equation. Using Galerkin method, this equation has been separated into position and time functions. By means of the dimensional analysis, it is shown that the orders of magnitude for nonlinear terms are small with respect to linear terms. The Multiple Scales Method has been applied to the equation of motion in the forced vibration and free vibration cases and closed-form relations for the nonlinear natural frequencies, displacement and frequency response of the plate have been derived. The obtained results in comparison with numerical methods are in good agreements. Using the obtained relation, the effects of initial displacement, thickness and dimensions of the plate on the nonlinear natural frequencies and displacements have been investigated. These results are valid for a special range of the ratio of thickness to dimensions of the plate, which is a characteristic of the Multiple Scales Method. In the forced vibration case, the frequency response equation for the primary resonance condition is calculated and the effects of various parameters on the frequency response of system have been studied.