• Journal of Aerospace System Engineering
• /
• v.13 no.6
• /
• pp.43-51
• /
• 2019

The aircraft vertical acceleration from the excitation of the road surface in the taxing mode is a main factor with a negative effect on the boarding quality of pilots and passengers. In this paper, we propose an appropriate control method to improve the boarding quality of the MR damper landing gear. The proposed control method is Skyhook Control Type 2, which feeds the aircraft vertical acceleration back in addition to the aircraft vertical velocity. Since Skyhook Control Type 2 factors the velocity and acceleration of the upper mass, it can be expected to exceed the control performance of the existing Skyhook Control that factors only the upper mass velocity. For the simulation, the bumper type road surface was selected as a ground surface, and the landing gear model constructed with RecurDyn and the controller designed with Simulink were co-simulated. The control effect of Skyhook Control Type 2 was verified by comparing and analyzing the RMS and maximum value of the upper mass acceleration according to the taxing speed and control method.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.10 no.2 s.48
• /
• pp.83-90
• /
• 2006

In active vibration control of building, controller design considering both control input saturation of controller and parameter uncertainties of building is needed. In our previous research, we proposed a robust saturation controller which guarantees robust stability and control performance of the uncertain linear time-invariant system in the presence of control input saturation. In this paper, the availability of the robust saturation controller for the building with an active mass damper (AMD) system is verified through experimental tests. Experimental tests are carried oui using a two-story building model with a hydraulic-type AMD.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.28 no.6
• /
• pp.635-643
• /
• 2015

In this study, the experimental test results are given to confirm the control efficiency of the linear control algorithm used for designing the active mass dampers(AMD) which are supposed to be installed at Incheon international airport control tower. The comparison between the results from test and numerical analysis is conducted and it was observed that the AMD showed the control performance expected by the numerical model. The effects of the gain scheduling and constant-velocity signal added to the control signal calculated by the algorithm is identified through the observation that the AMD always show behavior within the given stroke limit without any loss of the desired control performance. The phase difference between the accelerations of the structure and the AMD were almost close to 90 degree, which implies that the AMD absorbed the structural energy effectively.

• Smart Structures and Systems
• /
• v.32 no.5
• /
• pp.281-295
• /
• 2023

The purpose of this study is to demonstrate and verify the application of phase-control absolute-acceleration-feedback active tuned mass dampers (PCA-ATMD) to multiple-degree-of-freedom (MDOF) building structures. In addition, servo speed control technique has been developed as a replacement for force control in order to mitigate the negative effects caused by friction and inertia. The essence of the proposed PCA-ATMD is to achieve a 90° phase lag for a structure by implementing the desired control force so that the PCA-ATMD can receive the maximum power flow with which to effectively mitigate the structural vibration. An MDOF building structure with a PCA-ATMD and a real-time filter forming a complete system is modeled using a state-space representation and is presented in detail. The feedback measurement for the phase control algorithm of the MDOF structure is compact, with only the absolute acceleration of one structural floor and ATMD's velocity relative to the structure required. A discrete-time direct output-feedback optimization method is introduced to the PCA-ATMD to ensure that the control system is optimized and stable. Numerical simulation and shaking table experiments are conducted on a three-story steel shear building structure to verify the performance of the PCA-ATMD. The results indicate that the absolute acceleration of the structure is well suppressed whether considering peak or root-mean-square responses. The experiment also demonstrates that the control of the PCA-ATMD can be decentralized, so that it is convenient to apply and maintain to real high-rise building structures.

• Smart Structures and Systems
• /
• v.11 no.5
• /
• pp.435-451
• /
• 2013

High-rise buildings are a common feature of urban cities around the world. These flexible structures frequently exhibit large vibration due to strong winds and earthquakes. Structural control has been employed as an effective means to mitigate excessive responses; however, structural control mechanisms that can be used in tall buildings are limited primarily to mass and liquid dampers. An attractive alternative can be found in outrigger damping systems, where the bending deformation of the building is transformed into shear deformation across dampers placed between the outrigger and the perimeter columns. The outrigger system provides additional damping that can reduce structural responses, such as the floor displacements and accelerations. This paper investigates the potential of using smart dampers, specifically magnetorheological (MR) fluid dampers, in the outrigger system. First, a high-rise building is modeled to portray the St. Francis Shangri-La Place in Philippines. The optimal performance of the outrigger damping system for mitigation of seismic responses in terms of damper size and location also is subsequently evaluated. The efficacy of the semi-active damped outrigger system is finally verified through numerical simulation.

• Journal of Korean Association for Spatial Structures
• /
• v.10 no.1
• /
• pp.103-110
• /
• 2010

In this study, the possibility of seismic response control of semi-active tuned mass damper (TMD) for spatial structures has been investigated. To this end, an arch structure was used as an example structure because it has primary characteristics of spatial structures and it is a comparatively simple structure. A TMD and semi-active TMD were applied to the example arch structure and the seismic control performance of them were evaluated based on the numerical simulation. In order to regulate the damping force of the semi-active TMD, groundhook control algorithm, which is widely used for semi-active control, was used. El Centro (1940) and Northridge (1994) earthquakes and harmonic ground motion were used for performance evaluation of passive TMD and semi-active TMD. Based on the analytical results, the passive TMD could effectively reduce the seismic responses of the arch structure and it has been shown that the semi-active TMD more effectively decreased the dynamic responses of the arch structure compared to the passive TMD with respect to all the excitations used in this study.

• Wind and Structures
• /
• v.21 no.5
• /
• pp.565-595
• /
• 2015

In recent years, high-rise buildings received a renewed interest as a means by which technical and economic advantages can be achieved, especially in areas of high population density. Taller and taller buildings are being built worldwide. These types of buildings present an asset and typically are built not to fail under wind loadings. The increase in a building's height results in increased flexibility, which can lead to significant vibrations, especially at top floors. Such oscillations can magnify the overall loads and can be annoying to the top floors' occupants. This paper shows that increased stiffness in high-rise buildings may not be a feasible solution and may not be used for the design for comfort and serviceability. High-rise buildings are unique, and a vibration control system for a certain building may not be suitable for another. Even for the same building, its behavior in the two lateral directions can be different. For this reason, the current study addresses the application of hybrid tuned mass and magneto-rheological (TM/MR) dampers that can work for such types of buildings. The proposed control scheme shows its effectiveness in reducing floors' accelerations for both comfort and serviceability concerns. Also, a dissipative analysis carried out shows that the MR dampers are working within the possible range of optimum performance. In addition, the design loads are dramatically reduced, creating more resilient and sustainable buildings. The purpose of this paper is to stimulate, shape, and communicate ideas for emerging control technologies that are essential for solving wind related problems in high-rise buildings, with the objective to build the more resilient and sustainable infrastructure and to optimally retrofit existing structures.

• Wind and Structures
• /
• v.6 no.5
• /
• pp.387-402
• /
• 2003

In the past decades, much effort has been made towards the study of single-mode-based vibration controls with dynamic energy absorbers such as single or multiple Tuned Mass Dampers(TMDs). With the increase of bridge span length and the tendency of the bridge cross-section being more slender and streamlined, multi-mode coupled vibrations as well as their controls have become very important for large bridges susceptible to strong winds. As a simple but effective device, the TMD system especially the semi-active one has become a promising option for such coupled vibration controls. However, despite various studies of optimal controls of single-mode-based vibrations with TMDs, research on the corresponding controls of the multi-mode coupled vibrations is very rare so far. For the development of a semi-active control strategy to suppress the multi-mode coupled vibrations, a comprehensive parametric analysis on the optimal variables of this control is substantial. In the present study, a multi-mode control strategy named "three-row" TMD system is discussed and the general numerical equations are developed at first. Then a parametric study on the optimal control variables for the "three-row" TMD system is conducted for a prototype Humen Suspension Bridge, through which some useful information and a better understanding of the optimal control variables to suppress the coupled vibrations are obtained. This information lays a foundation for the design of semi-active control.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.15 no.6 s.99
• /
• pp.712-717
• /
• 2005

This paper presents a system identification method for multi-input, multi-output (MIMO) systems, by which a rational polynomial transfer function model is identified from experimentally determined frequency response function data. Analytically determined information is incorporated in this method to obtain a more reliable model, even in the frequency range where the excitation energy is limited. To verify the suggested method, shaking table test for an actively controlled two-story, bench-scale building employing an active mass damper is conducted. The results show that the proposed method is quite effective and robust for system identification of MIMO systems.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.16 no.2 s.107
• /
• pp.207-213
• /
• 2006

In our previous research, we proposed a robust saturation controller which involves both control input saturation and structured real parameter uncertainties. This controller can analytically prescribed the upper and lower bounds of parameter uncertainties, and guarantee the closed-loop robust stability of the system in the presence of actuator's saturation. And the availability and the effectiveness of the proposed robust saturation controller were verified through numerical simulations. In this paper, we verify the robust stability of this controller through experimental tests. Expecially, we show unstable cases of other controllers in comparison with this controller. Experimental tests are carried out in the laboratory using a two-story test structure with a hydraulic-type active mass damper.