• 조명전기설비학회논문지
• /
• 제27권7호
• /
• pp.95-100
• /
• 2013

In this paper, we propose an active controller for high-speed pantograph in order to improve the transient response. Electrical power is delivered from a catenary to the train via a pantograph and thus it is very important to regulate the contact force between catenary and pantograph. By regarding the catenary displacement as an unknown disturbance input and analyzing the frequency response from the disturbance to contract force. we present an active controller that utilizes the lead compensator and resonant controller. It is shown by the computer simulation that the substantial improvement in transient response can be achieved by the proposed controller.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2001년도 추계학술대회논문집 I
• /
• pp.229-234
• /
• 2001

A practical and effective semi-active on-off control law is developed for vibration attenuation of a natural, multi-degree-of-freedom suspension system, when its operational response mode is available. It does not need the accurate system parameters and dynamics of semi-active actuator. It reduces the total vibratory energy of the system including the work done by external disturbances and the maximum energy dissipation direction of the semi-active control device is tuned to the operational response mode of the structure. The effectiveness of the control law is illustrated with a three degree-of-freedom excavator cabin model.

• Smart Structures and Systems
• /
• 제12권2호
• /
• pp.157-179
• /
• 2013

We present an approach, based on the state dependent Riccati equation, for designing non-collocated seismic response control strategies for buildings accounting for physical constraints, with particular attention to force saturation. We consider both cases of active control using general actuators and semi-active control using magnetorheological dampers. The formulation includes multi control devices, acceleration feedback and time delay compensation. In the active case, the proposed approach is a generalization of the classic linear quadratic regulator, while, in the semi-active case, it represents a novel generalization of the well-established modified clipped optimal approach. As discussed in the paper, the main advantage of the proposed approach with respect to existing strategies is that it allows to naturally handle a broad class of non-linearities as well as different types of control constraints, not limited to force saturation but also including, for instance, displacement limitations. Numerical results on a typical building benchmark problem demonstrate that these additional features are achieved with essentially the same control effectiveness of existing saturation control strategies.

• 한국지진공학회논문집
• /
• 제9권6호
• /
• pp.75-90
• /
• 2005

사장교의 효과적 지진응답제어를 위하여 MR 감쇠기를 이용한 준능동 퍼지 제어기법을 제시하였다. 제시하는 방법은 MR 감쇠기의 응답정보만을 이용한 퍼지추론 과정을 통하여 준능동 제어를 수행하는 방법으로서, 능동제어이론에 기반한 기존 준능동 제어기법과 달리, 별도의 능동제어기를 설계할 필요가 없는 간단한 구조로서 구성될 수 있다. 제시한 제어기법의 제어성능을 평가하기 위해 사장교 벤치마크 문제에 적용하였으며 기존 준능동 제어기법들과의 성능비교를 통하여 그 효율성을 평가하였다. 제어성능을 비교한 결과, 제시하는 준능동 퍼지 제어기법은 주탑의 전단력 및 휨모멘트, 데크의 수평변위, 그리고 케이블 장력 등의 상충하는 지진응답들을 동시에 효과적으로 제어함으로써 지진응답제어에 매우 효율적인 제어전략이 될 수 있음을 보였다.

• 한국공간구조학회논문집
• /
• 제10권1호
• /
• pp.103-110
• /
• 2010

본 연구에서는 지진하중을 받는 대공간 구조물의 지진응답을 저감시키기 위하여 준능등 동조질량제어장치(STMD)를 이용한 제어기법의 가능성을 검토하여 보았다. 이를 위하여 대공간구조물의 기본적인 동적특성을 가지고 있으며 동시에 가장 간단한 구조이기도 한 아치 구조물에 일반적인 TMD 및 STMD를 설치하여 지진응답 제어성능을 평가하였다. STMD의 감쇠력을 조절하기 위해서 널리 사용되고 있는 준능동 제어알고리즘인 그라운드혹(groundhook) 제어기법을 이용하였다. STMD 및 수동 TMD의 성능검토를 위하여 조화지반가속도와 El Centro (1940) 및 Northridge (1994) 지진하중을 사용하였다. 해석결과 수동 TMD에 의해서 아치구조물의 지진응답을 효과적으로 저감시킬 수 있었으며 STMD를 사용하면 수통 TMD 보다 더욱 우수한 응답저감효과를 얻을 수 있는 것을 확인하였다.

• 한국지능시스템학회논문지
• /
• 제25권5호
• /
• pp.495-501
• /
• 2015

해상에서 운용되는 함정은 다양한 위협에 둘러싸여 있는데 그중에서도 가장 위협적인 것은 다양한 환경과 플랫폼에서 발사가 가능한 대함미사일이다. 대함미사일은 함정의 레이더나 전자전 장비에 대하여 회피 기능까지 보유하고 있어 함정에 치명적인 피해를 줄 수 있다. 대함미사일에 의한 함정에 직접적인 피해를 줄이는 능동기만기는 대함미사일이 함정 대신 기만기를 추적하도록 유인하여 함정의 생존성을 높이는 장비로써 대함미사일 방어에 효과적인 방법이다. 본 논문에서 제안 기법은 해상 환경에서 함정의 능동기만기를 사용하여 대함미사일에 대응하기 위해 시뮬레이션 방법론인 DEVS (Discrete Event System Specification)를 적용하여 능동기만기의 효과적인 운용 시간을 검증한다. 이를 위해 함정, 대함미사일, 그리고 능동기만기를 각각 모델링하고 정의된 모델을 결합하여 시뮬레이션을 수행하였다. 시뮬레이션 수행을 통해 도출된 결과는 수동형 기만기, 체공 고정형 기만기, 그리고 이동형 능동기만기 중에서 이동형 능동기만기의 운용 시간 우수성을 검증했고, 대함미사일로부터 함정 방어를 위한 이동형 능동기만기의 운용 시간에 따른 방어구역을 추정하였다.

• Structural Engineering and Mechanics
• /
• 제42권2호
• /
• pp.211-228
• /
• 2012

Present study deals with the development of finite element based solution methodology to investigate active control of dynamic response of delaminated composite shells with piezoelectric sensors and actuators. The formulation is based on first order shear deformation theory and an eight-noded isoparametric element is used. A coupled piezoelectric-mechanical formulation is used in the development of the constitutive equations. For modeling the delamination, multipoint constraint algorithm is incorporated in the finite element code. A simple negative feedback control algorithm coupling the direct and converse piezoelectric effects is used to actively control the dynamic response of delaminated composite shells in a closed loop employing Newmark's time integration scheme. The validity of the numerical model is demonstrated by comparing the present results with those available in the literature. A number of parametric studies such as the locations of sensor/actuator patches, delamination size and its location, radius of curvature to width ratio, shell types and loading conditions are carried out to understand their effect on the transient response of piezoceramic delaminated composite shells.

• Smart Structures and Systems
• /
• 제8권3호
• /
• pp.239-252
• /
• 2011

In this study, the performances of a passive tuned mass damper (TMD) and a semi-active TMD (STMD) were evaluated in terms of seismic response control of elastic and inelastic structures under seismic loads. First, elastic displacement spectra were obtained for damped structures with a passive TMD and with a STMD proposed in this study. The displacement spectra confirmed that the STMD provided much better control performance than passive TMD and the STMD had less stroke requirement. Also, the robustness of the TMD was evaluated by off-tuning the frequency of the TMD to that of the structure. Finally, numerical analyses were conducted for an inelastic structure of hysteresis described by the Bouc-Wen model. The results indicated that the performance of the passive TMD whose design parameters were optimized for an elastic structure considerably deteriorated when the hysteretic portion of the structural responses increased, and that the STMD showed about 15-40% more response reduction than the TMD.

• Structural Engineering and Mechanics
• /
• 제44권2호
• /
• pp.127-138
• /
• 2012

The composite materials may be exposed to environmental (thermal or hygral or both) condition during their service life. The effect of environmental condition is usually adverse from the point of view of design of composite structures. In the present research study the effect of hygrothermal condition on the design of laminated composite structures is investigated. The active fiber composite (AFC) which may be utilized as actuator or sensor is considered in the present analysis. The sensor layer is used to sense the level of response of the composite structures. The sensed voltage is fed back to the actuator through the controller. In this study both displacement and velocity feedback controllers are employed to reduce the response of the composite laminate within acceptable limit. The Newmark direct time integration scheme is employed along with modal superposition method to improve the computational efficiency. It is observed from the numerical study that the laminated composite structures become weak in the presence of hygrothermal load. The response of the structure can be brought to the acceptable level once the AFC layer is activated through the feedback loop.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2003년도 춘계학술대회 논문집
• /
• pp.447-450
• /
• 2003

This paper concerns on application of active magnetic bearing(AMB) system to levitate the elevation axis of an electro-optical sight mounted on moving vehicles. In such a system. it is desirable to retain the elevation axis within the predetermined air-gap while the vehicle is moving. A disturbance compensation control is proposed to reduce the base motion response. In the consideration of the uncertainty of the system model, a filtered-x least-mean-square(FXLMS) algorithm is used to estimate adaptively the frequency response function of the feedforward control which cancels disturbance responses. The frequency response function is fitted to an optimal feedforward control. Experimental results demonstrate that the proposed control reduces the air-gap deviation to 27.7% that by feedback control alone.