• 제목/요약/키워드: mass damper

검색결과 628건 처리시간 0.023초

반능동 현가시스템용 자기동조 게인조절형 스카이훅 제어기의 구현 및 실험 (Self-Tuning Gain-Scheduled Skyhook Control for Semi-Active Suspension Systems: Implementation and Experiment)

  • 홍경태;허창도;홍금식
    • 제어로봇시스템학회논문지
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    • 제8권3호
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    • pp.199-207
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    • 2002
  • In this paper, a self-tuning gain-scheduled skyhook control for semi-active suspension systems is investigated. The dynamic characteristics of a continuously variable damper including electro-hydraulic pressure control valves is analyzed. A 2-d.o.f. time-varying quarter-car model that permits variations in sprung mass and suspension spring coefficient is considered. The self-tuning skyhook control algorithm proposed in this paper requires only the measurement of body acceleration. The absolute velocity of the sprung mass and the relative velocity of the suspension deflection are estimated by using integral filters. The skyhook gains are gain-scheduled in such a way that the body acceleration and the dynamic tire force are optimized. An ECU prototype is discussed. Experimental results using a 1/4-ear simulator are discussed. Also, a suspension ECU prototype targeting real implementation is provided.

모달 파라미터를 이용한 동적 시스템의 운동 방정식 구성 (Constructing Equations of Motion for a Dynamic System from Modal Parameters)

  • 황우석
    • 한국항공우주학회지
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    • 제35권1호
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    • pp.40-45
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    • 2007
  • 구조물의 모달 해석 또는 모달 시험은 구조물의 동적 특성을 나타내는 모달 파라미터들을 구하는 과정이다. 모달 파라미터에는 고유 진동수, 감쇠율, 진동 모드의 세 가지 값들이 있다. 본 연구에서는 시스템의 개발과정에서 당연히 수행되는 모달 해석의 결과인 모달 파라미터를 활용하여 시스템 방정식을 구하는 방법에 대한 연구를 수행하였다. 상태 방정식의 고유치와 고유 벡터의 상관관계로부터 물리적 시스템 행렬인 질량, 감쇠, 강성 행렬을 각각 구하는 방법을 개발하였다. 간단한 질량-스프링-댐퍼 시스템과 외팔보에 대한 수치 예제를 통하여 개발된 방법의 유용성과 정확도를 검증하였다

진동대실험에 의한 동조액체기둥감쇠기의 동적특성 (Dynamic Characteristics of Tuned Liquid Column Dampers Using Shaking Table Test)

  • 민경원;박은천
    • 한국소음진동공학회논문집
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    • 제19권6호
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    • pp.620-627
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    • 2009
  • Shaking table test was carried out to obtain dynamic characteristics of TLCDs with uniform and non-uniform sections for both horizontal and vertical tubes. The input to the table is harmonic acceleration with constant magnitude. The output is horizontal dynamic force which is measured by load cell installed below the TLCD. Transfer functions are experimentally obtained using the ratio of input and output. Natural frequency, the most important design factor, is compared to that by theoretical equation for TLCDs with five different water levels. System identification process is performed for experimentally obtained transfer functions to find the dynamic characteristics of head loss coefficient and effective mass of TLCDs. It is found that their magnitudes are larger for a TLCD with non-uniform section than with uniform section and natural frequencies are close to theoretical ones.

Experimental study on a new damping device for mitigation of structural vibrations under harmonic excitation

  • Alih, Sophia C.;Vafaei, Mohammadreza;Ismail, Nufail;Pabarja, Ali
    • Earthquakes and Structures
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    • 제14권6호
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    • pp.567-576
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    • 2018
  • This manuscript introduces a new damping device which is composed of a water tank and a pendulum. The new damping device can be tuned to multiple frequencies. In addition, it has a higher energy dissipation capacity when compared with the conventional Tuned Liquid Dampers (TLDs). In order to evaluate the efficiency of this new damping device a series of free vibration and forced vibration tests were conducted on a scaled down single-story one-bay steel frame. Two different configurations were studied for the mass of the pendulum that included a completely and a partially submerged mass. It was observed that the completely submerged configuration led to 44% higher damping ratio when compared with the conventional TLD. In addition, the completely submerged configuration reduced the peak displacement response of the structure 1.6 times more than the conventional TLD. The peak acceleration response of the structure equipped with the new damping device was reduced twice more than the conventional TLD. It was also found that, when the excitation frequency is lower than the resonance frequency, the conventional TLD performs better than the partially submerged configuration of the new damping device.

파워 어시스트 시스템을 위한 이동 머니퓰레이터의 제어 (Control of Mobile Manipulators for Power Assist Systems)

  • 이형기;성영휘;정명진
    • 대한전기학회논문지:시스템및제어부문D
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    • 제49권2호
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    • pp.74-80
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    • 2000
  • In this paper, we present a control method of mobile power assist systems. Most of mobile power assist systems have a heavy base for preventing easy tumbling, so continual movement of the base during operations causes high energy consumption and gives the high risk of human injury. Furthermore, the slow dynamics of the base limits the frequency bandwidth of the whole system. Thus we propose a cooperation control method of the mobile base and manipulator, which removes the unnecessary movements of the base. In our scheme, the mobile base does not move until the center of gravity(C.G) of the system goes outside a safety region. When C.G. reaches the boundary of the safety region, the base starts moving to recover the manipulator's initial configuration. By varying the parameters of a human impedance controller, the operator is warned by a force feedback that C.G. is on the marginal safety region. Our scheme is implemented by assigning a nonlinear mass-damper-spring impedance to the tip of the manipulator. Our scheme is implemented by a nonlinear mass-spring impedance to the tip of the manipulator. The experimental results show the efficacy of the proposed control method.

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A wireless decentralized control experimental platform for vibration control of civil structures

  • Yu, Yan;Li, Luyu;Leng, Xiaozhi;Song, Gangbing;Liu, Zhiqiang;Ou, Jinping
    • Smart Structures and Systems
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    • 제19권1호
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    • pp.47-56
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    • 2017
  • Considerable achievements in developing structural regulators as an important method for vibration control have been made over the last few decades. The use of large quantities of cables in traditional wired control systems to connect sensors, controllers, and actuators makes the structural regulators complicated and expensive. A wireless decentralized control experimental platform based on Wi-Fi unit is designed and implemented in this study. Centralized and decentralized control strategies as sample controllers are employed in this control system. An optimal control algorithm based on Kalman estimator is embedded in the dSPACE controller and the DSP controller. To examine the performance of this control scheme, a three-story steel structure is developed with active mass dampers installed on each floor as the wireless communication platform. Experimental results show that the wireless decentralized control exhibits good control performance and has various potential applications in industrial control systems. The proposed experimental system may become a benchmark platform for the validation of the corresponding wireless control algorithm.

Dynamic properties of a building with viscous dampers in non-proportional arrangement

  • Suarez, Luis E.;Gaviria, Carlos A.
    • Structural Engineering and Mechanics
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    • 제55권6호
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    • pp.1241-1260
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    • 2015
  • Any rational approach to define the configuration and size of viscous fluid dampers in a structure should be based on the dynamic properties of the system with the dampers. In this paper we propose an alternative representation of the complex eigenvalues of multi degree of freedom systems with dampers to calculate new equivalent natural frequencies. Analytical expressions for the dynamic properties of a two-story building model with a linear viscous damper in the first floor (i.e. with a non-proportional damping matrix) are derived. The formulas permit to obtain the equivalent damping ratios and equivalent natural frequencies for all the modes as a function of the mass, stiffness and damping coefficient for underdamped and overdamped systems. It is shown that the commonly used formula to define the equivalent natural frequency is not applicable for this type of system and for others where the damping matrix is not proportional to the mass matrix, stiffness matrix or both. Moreover, the new expressions for the equivalent natural frequencies expose a novel phenomenon; the use of viscous fluid dampers can modify the vibration frequencies of the structure. The significance of the new equivalent natural frequencies is expounded by means of a simulated free vibration test. The proposed approach may offer a new perspective to study the effect of viscous dampers on the dynamic properties of a structure.

Effectiveness of design procedures for linear TMD installed on inelastic structures under pulse-like ground motion

  • Quaranta, Giuseppe;Mollaioli, Fabrizio;Monti, Giorgio
    • Earthquakes and Structures
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    • 제10권1호
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    • pp.239-260
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    • 2016
  • Tuned mass dampers (TMDs) have been frequently proposed to mitigate the detrimental effects of dynamic loadings in structural systems. The effectiveness of this protection strategy has been demonstrated for wind-induced vibrations and, to some extent, for seismic loadings. Within this framework, recent numerical studies have shown that beneficial effects can be achieved by placing a linear TMD on the roof of linear elastic structural systems subjected to pulse-like ground motions. Motivated by these positive outcomes, closed-form design formulations have been also proposed to optimize the device's parameters. For structural systems that undergo a near-fault pulse-like ground motion, however, it is unlikely that their dynamic response be linear elastic. Hence, it is very important to understand whether such strategy is effective for inelastic structural systems. In order to provide new useful insights about this issue, the paper presents statistical results obtained from a numerical study conducted for three shear-type hysteretic (softening-type) systems having 4, 8 and 16 stories equipped with a linear elastic TMD. The effectiveness of two design procedures is discussed by examining the performances of the protected systems subjected to 124 natural pulse-like earthquakes.

Wave energy converter by using relative heave motion between buoy and inner dynamic system

  • Cho, I.H.;Kim, M.H.;Kweon, H.M.
    • Ocean Systems Engineering
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    • 제2권4호
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    • pp.297-314
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    • 2012
  • Power-take-off through inner dynamic system inside a floating buoy is suggested. The power take-off system is characterized by mass, stiffness, and damping and generates power through the relative heave motion between the buoy and inner mass (magnet or amateur). A systematic hydrodynamic theory is developed for the suggested WEC and the developed theory is illustrated by a case study. A vertical truncated cylinder is selected as a buoy and the optimal condition of the inner dynamic system for maximum PTO (power take off) through double resonance for the given wave condition is systematically investigated. Through the case study, it is seen that the maximum power can actually be obtained at the optimal spring and damper condition, as predicted by the developed WEC theory. However, the band-width of high performance region is not necessarily the greatest at the optimal (maximum-power-take-off) condition, so it has to be taken into consideration in the actual design of the WEC.

Structural Design of High-Rise Building in Toranomon-Azabudai Project (A Block)

  • Kazumasa, Okabe;Kai, Toyama;Takuya, Furuta;Jyunichi, Yamashita;Hiroki, Mukai;Takahiro, Goseki;Shingo, Masuda;Dai, Shimazaki;Yusuke, Miyagi;Yuji, Ozawa
    • 국제초고층학회논문집
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    • 제11권3호
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    • pp.157-170
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    • 2022
  • This paper explains about structural planning and structural design of the high-rise building in Toranomon-Azabudai Project (A Block) which is now under construction. The building is about 330 meters high, has 4.2 aspect ratio, and the outline of the building has shallow curve. We adopted seismic response control structure. The building is a steel rigid frame structure with braces, and it has enough stiffness to obtain its primary natural period to be less than about seven seconds, in consideration of wind response, seismic response and inhabitability for the wind shaking. In terms of business continuity plan, the building has a high seismic performance; value of story drift angle shall be 1/150 or less and members of the building remain almost undamaged while or after a large earthquake. Active mass dumper shall be installed at the top of the building to improve inhabitability while strong wind is blowing.