• Title/Summary/Keyword: spring damper

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Equivalent Impedance Modelling and Frequency Characteristic Analysis of Linear Oscillatory Actuator System Considering Mass/spring System (질량/스프링 계를 고려한 리니어 왕복 액추에이터 시스템의 등가 임피던스 모델링과 주파수 특성 해석)

  • Jeong, Sang-Seop;Jang, Seok-Myeong
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.51 no.7
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    • pp.370-378
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    • 2002
  • As resent trends in structural construction have been to build taller and larger structures than any time in the past, they have had high flexibility and low damping that can cause large vibration response under severe environmental loading such as earthquakes, winds, and mechanical excitations. The damper with mass and spring is one approach to safeguarding the structure against excessive vibrations. In this paper, the lumped electrical circuit approach of mass/spring system is used to model the mechanical aspects according to the frequency. Therefore, the mass/spring system can be dealt with here and linked with the equivalent circuit of electric linear oscillatory actuator(LOA). Analysis models are two types of vibration control system, active mass damper(AMD) and hybrid mass damper(HMD). AMD consists of the moving coil LOA with mass only The LOA of HMD with mass and spring is composed of the fixed coil and the movable permanent magnet(PM) field part. The PM field part composed magnet modules and iron coke, is the damper marts itself. We Present the motional resistance and reactance of mass/spring system and the system impedance of AMD and HMD according to the frequency.

Seismic protection of the benchmark highway bridge with passive hybrid control system

  • Saha, Arijit;Saha, Purnachandra;Patro, Sanjaya Kumar
    • Earthquakes and Structures
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    • v.15 no.3
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    • pp.227-241
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    • 2018
  • The present paper deals with the optimum performance of the passive hybrid control system for the benchmark highway bridge under the six earthquakes ground motion. The investigation is carried out on a simplified finite element model of the 91/5 highway overcrossing located in Southern California. A viscous fluid damper (known as VFD) or non-linear fluid viscous spring damper has been used as a passive supplement device associated with polynomial friction pendulum isolator (known as PFPI) to form a passive hybrid control system. A parametric study is considered to find out the optimum parameters of the PFPI system for the optimal response of the bridge. The effect of the velocity exponent of the VFD and non-linear FV spring damper on the response of the bridge is carried out by considering different values of velocity exponent. Further, the influences of damping coefficient and vibration period of the dampers are also examined on the response of the bridge. To study the effectiveness of the passive hybrid system on the response of the isolated bridge, it is compared with the corresponding PFPI isolated bridges. The investigation showed that passive supplement damper such as VFD or non-linear FV spring damper associated with PFPI system is significantly reducing the seismic response of the benchmark highway bridge. Further, it is also observed that non-linear FV spring damper hybrid system is a more promising strategy in reducing the response of the bridge compared to the VFD associated hybrid system.

A Real-Time Collision-Free Trajectory Planning and Control for a Car-Like Mobile Robot (모바일 로봇의 충돌회피 알고리즘 개발)

  • Nguyen, Huu-Cong;Kim, Gi-Bok;Jo, Sang-young
    • Journal of the Korean Society of Industry Convergence
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    • v.18 no.2
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    • pp.99-109
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    • 2015
  • This study proposes a new approach to analyze the impedance and the elasticity of a serial chain of spring-damper system, areal-time collision-free trajectory generation algorithm is proposed. The reference points on a trajectory connected by the spring-damper system have a mechanism for self-position adjustment to solve a collision problem by the impedance, and the local adjustment of each reference point is propagated through the elasticity to a real robot at the end of the spring-damper system. As a result, the overall trajectory consisting of the reference points becomes free of collision with environmental obstacles and efficient having the shortest distance as possible. In this process,, the reference points connected by the spring-damper system take role of virtual robot as global guidance for a real robot, and a cooperative is carried out by the system of robots. A control technology is proposed to implement for mobile robot.

Effects of friction variability on a rolling-damper-spring isolation system

  • Wei, Biao;Wang, Peng;He, Xuhui;Zhang, Zhen;Chen, Liang
    • Earthquakes and Structures
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    • v.13 no.6
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    • pp.551-559
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    • 2017
  • A large number of isolation systems are designed without considering the non-uniform friction distribution in space. In order to analyze the effects of non-uniform friction distribution on the structural response of isolation system, this paper presented a simplified rolling-damper-spring isolation system and analyzed the structural responses under earthquakes. The numerical results indicate that the calculation errors related to the peak values of structural acceleration, relative displacement and residual displacement are sequentially growing because of the ignorance of non-uniform friction distribution. However, the influence rule may be weakened by the spring and damper actions, and the unreasonable spring constant may lead to the sympathetic vibration of isolation system. In the case when the friction variability is large and the damper action is little, the non-uniform friction distribution should be taken into consideration during the calculation process of the peak values of structural acceleration and relative displacement. The non-uniform friction distribution should be taken into full consideration regardless of friction variability degree in calculating the residual displacement of isolation system.

An Improvement of the Stability of Plane Journal Bearing using Leaf Spring Damper (겹판스프링댐퍼를 이용한 저어널베어링의 안정성 향상)

  • 김종수;최영준;제양규
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2000.06a
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    • pp.87-92
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    • 2000
  • In order to improve the instability of Plane journal bearing, it is introduced the leaf spring damper(LSD). The effects of dynamic characteristics of LSD on the stability of a plane journal bearing were investigated theoretically. The improvements on the stability of a plane journal bearing with LSD. are compared with the results of a floating ring journal bearing and of journal bearing without LSD. It found that a plane journal bearing with LSD will be an effective way in the improvement on the stability of rotor system.

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Effects of Asymmetry of Bearing Damper Stiffness on the Stability of Rotors (베어링 지지댐퍼 강성의 비대칭이 회전체 동특성에 미치는 영향)

  • 제양규
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.14 no.6
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    • pp.463-469
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    • 2004
  • In order to improve the instability of journal bearings, the leaf spring dampers (LSD) are introduced. The effects of LSD on the stability of journal bearings are investigated theoretically The stability of the journal bearing with LSD are compared with the results of the journal bearing without LSD. And the effects of the asymmetry of the stiffness of the leaf spring damper on the stability of rotors are also investigated.

An Improvement of the Stability of Plane Journal Bearing using Leaf Spring Damper (겹판스프링댐퍼를 이용한 저어널베어링의 안정성 향상)

  • 김종수;최영준;제양규
    • Tribology and Lubricants
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    • v.17 no.3
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    • pp.179-184
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    • 2001
  • In order to improve the instability of plane journal bearing, it is introduced the leaf spring damper(LSD). The effects of dynamic characteristics of LSD on the stability of a plane Journal bearing were investigated theoretically. The improvements on the stability of a plane journal bearing with LSD are compared with the results of a floating ring journal bearing and of journal bearing without LSD. It found that a plane journal bearing with LSD will be an effective way in the improvement on the stability of rotor system.

Effects of Asymmetry of Bearing Damper Stiffness on the Stability of Rotors (베어링 지지댐퍼 강성의 비대칭이 회전체 동특성에 미치는 영향)

  • 제양규
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2003.05a
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    • pp.100-106
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    • 2003
  • In order to improve the instability of a plane journal bearing, the leaf spring dampers (LSD) are introduced. The effects of LSD on the stability of a plane journal bearing are investigated theoretically. The stability of a plane journal bearing with LSD are compared with the results of a plane journal bearing without LSD. And the effects of the asymmetry of the stiffness of the leaf spring damper on the stability of rotors are also investigated.

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Optimum Design of Suspension on Impulse to AGV (AGV가 받는 충격량에 대한 현가장치의 최적설계)

  • 김재헌;최환도;김중완;전언찬
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.05a
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    • pp.361-365
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    • 2002
  • This research is presented for optimizing the coefficients of spring and damper by impulse which is applied to AGV when the two containers are loaded on AGV. The suspension is estimated to the condition that two containers, initial velocity of container, initial height of container and maximum of suspension stroke. The coefficients of spring and damper are calculated numerically through Newmark method uses finite difference expansions. The procedure of calculation is applied by one DOFs of mass-spring-damper system. The coefficients of spring and damper have large value as increase of height or decrease of stroke. The result of calculation is shown in graph and the investigation is used AGV design.

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Optimum Design of Suspension in Loading Container on Trailer (컨테이너 상차 시 트레일러 현가장치의 최적설계)

  • Kim, Jae-Heon;Hong, Do-Kwan;Kim, Joong-Wan;Jeon, Un-Chan;Ahn, Chan-Woo
    • Proceedings of the KSME Conference
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    • 2001.11a
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    • pp.710-715
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    • 2001
  • This research is presented for optimizing the coefficients of spring and damper by impact load which is applied to a trailer when the containers are loaded up trailer. The procedure utilize the condition that two containers, initial velocity of container, initial height of container and maximum of suspension stroke. The coefficients of spring and damper are calculated numerically through Newmark method uses finite difference expansions. The procedure of calculation is applied by one DOFs of mass-spring-damper system. The coefficients of spring and damper have large value as increase of height or decrease of stroke. The result of calculation is investigated and is used AGV design.

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