• Proceedings of the KIEE Conference
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• 대한전기학회 2001년도 추계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.85-87
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• 2001

Linear motor damper(LMD) for vibration control of structure is consisted of the NdFeB permanent magnets with high specific energy as the stator, a coil-wrapped nonmagnetic hollow rectangular structure and an iron core as a pathway for magnetic flux. The active mass of LMD is 1.5 ton and consisted of permanent magnet and iron yoke. In this paper, LMD system is manufactured and tested for dynamic characteristics and frequency response.

• The Journal of Korea Robotics Society
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• 제17권3호
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• pp.347-352
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• 2022

The paper presents how to update impedance control parameters for dual-arm manipulators using EMG signals and motions of the operator. Since the hand motions of the dual-arm are modeled to be the mass-spring-damper system in this paper, the impedance parameter update method is an important issue to reflect the operator's force. However, task space inertia to be used as the mass parameter goes to infinity if the manipulator approaches a kinematic singularity. To alleviate this issue, the impedance (stiffness and damping) parameters are divided with a diagonal element of the task space inertia. Also, the stiffness and damping matrices are updated using the normalized EMG signals captured from the operator's forearm. Through this process, the motion of the dual-arm manipulator is more stabilized even though it approaches the kinematic singularity.

• Journal of the Korean Society of Hazard Mitigation
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• 제5권3호
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• pp.23-28
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• 2005

This study defined engineering mechanism and compensation method to establish reference pressure of smoke control zone with atmospheric pressure that is compensated for temperature. The reliable pressure differential sensor was developed by establishing the specifications, algorithms and constructing engineering data. The development of pressure differential sensor can cut down number of processes, manufacturing and installation cost by removing pressure measurement pipe established separately for non smoke control zone, and improve the accuracy of pressure differential by embedding pressure measurement ports for non smoke control zone. More correct and reliable pressure differentials can be obtained by the central control rather than the existent individual control. This will provide the basics and the flexibility to the integral smoke control system and accordingly improve the performance of disaster prevention.

• Journal of the Earthquake Engineering Society of Korea
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• 제12권2호
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• pp.53-67
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• 2008

In this study, seismic control performance of friction dampers installed in a reinforced concrete shear wall-moment frame system, of which main lateral force resisting system is a shear wall, is investigated. Three configurations of friction dampers are investigated. One is a diagonal brace type reinforcing the shear wall directly, another is a diagonal brace type reinforcing the moment frame without the shear wall, and the other one is a vertical boundary element type installed at both ends of the shear wall. In addition, various levels of the total friction force and its distribution methods are examined. Time history analysis considering material nonlinearity is conducted for seismic loads increased by the enhanced design code compared to the initial design loads, and energy dissipation, lateral loads and structural member damages are analyzed. As a result, the shear wall-reinforcing diagonal brace type with the total friction force of 30 % of the reference friction force gives the best performance on the whole, and the distribution methods of the friction force do not have remarkable difference in effects. Also, concentrated installation in adjacent four stories shows just a little compromised control performance compared to the entire story installation.

• Advances in concrete construction
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• 제13권5호
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• pp.385-394
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• 2022

Recently, an increasing number of cutting-edged studies have shown that designing a smart active control for real-time implementation requires piles of hard-work criteria in the design process, including performance controllers to reduce the tracking errors and tolerance to external interference and measure system disturbed perturbations. This article proposes an effective artificial-intelligence method using these rigorous criteria, which can be translated into general control plants for the management of civil engineering installations. To facilitate the calculation, an efficient solution process based on linear matrix (LMI) inequality has been introduced to verify the relevance of the proposed method, and extensive simulators have been carried out for the numerical constructive model in the seismic stimulation of the active rigidity. Additionally, a fuzzy model of the neural network based system (NN) is developed using an interconnected method for LDI (linear differential) representation determined for arbitrary dynamics. This expression is constructed with a nonlinear sector which converts the nonlinear model into a multiple linear deformation of the linear model and a new state sufficient to guarantee the asymptomatic stability of the Lyapunov function of the linear matrix inequality. In the control design, we incorporated H Infinity optimized development algorithm and performance analysis stability. Finally, there is a numerical practical example with simulations to show the results. The implication results in the RMS response with as well as without tuned mass damper (TMD) of the benchmark building under the external excitation, the El-Centro Earthquake, in which it also showed the simulation using evolved bat algorithmic LMI fuzzy controllers in term of RMS in acceleration and displacement of the building.

• Journal of the Korean Institute of Intelligent Systems
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• 제24권3호
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• pp.245-250
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• 2014

Addiction can be largely divided into two categories. One is called medium addiction in which medium itself causes an addiction. Another is called cause addiction that brings addiction through combination of sensitive self and latent personal action. The medium addiction involves addiction phenomena directly caused by illegal drugs, alcohol and various other chemicals. The cause addiction is dependent on personal sensitivities as a sensitive problem of personal and includes cyber addictions such as shopping, work, game, internet, TV, and gambling. In this paper we propose two-dimensional addiction model that are equivalent to using an R-L-C series circuit of Electrical circuit and a Spring-Damper-mass of mechanical system. We also organize a Duffing equation that is added a nonlinear term in the proposed two-dimensional addiction model. We represent periodic motion and chaotic motion as time series and phase portrait according to parameter's variation. We confirm that among parameters chaotic motion had addicted state and periodic motion caused by change in control coefficient had pre-addiction state.

• Wind and Structures
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• 제7권4호
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• pp.251-264
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• 2004

The effects of a class of nonlinear Tuned Mass Dampers on the aeroelastic behavior of SDOF systems are investigated. Unlike classical linear TMDs, nonlinear constitutive laws of the internal damping acting between the primary oscillator and the TMD are considered, while the elastic properties are keept linear. The perturbative Multiple Scale Method is applied to derive a set of bifurcation equations in the amplitude and phase and a parametric analysis is performed to describe the postcritical scenario of the system. Both cubic- and van der Pol-type dampings are considered and the dependence of the limit-cycle amplitudes on the system parameters is studied. These new results, compared with the previously obtained bifurcation scenario of a SDOF aeroelastic oscillator equipped with a linear TMD, show a detrimental effect on the maximum limit-cycle amplitude reduction of the nonlinear TMD. However, the analyses evidence that in the parameter region away from the perfect tuning condition the nonlinear connection can be used to tune the system with an enhancement of the limit-cycle amplitude reduction.

• Transactions of the Korean Society of Automotive Engineers
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• 제9권6호
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• pp.186-194
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• 2001

To meet the challenge of testing increasingly complex automotive control systems, the real-time hardware-in-the-loop(HIL) simulation technology has been developed. In this paper, a strategy for evaluation of semiactive suspension systems using real-time HIL simulation is presented. A multibody vehicle model is adopted to simulate vehicle dynamic motions accurately. Accuracy of the vehicle simulation results is compared to that of the real vehicle field test and proven to be very accurate. The controller and stepping motor to adjust semi-active damper stage are equipped as external hardwares and connected to the real-time computer which has vehicle dynamic model. Open and closed loop test methods are used to evaluate a controlled suspension system and the system's operations are verified it is found that the proposed evaluation methods can be used well for the verification of semi-active suspension systems.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 한국해양공학회 2004년도 학술대회지
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• pp.29-34
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• 2004

Numerical and experimental studies on pipeline laying for intake Deep Ocean Water are carried out. In the numerical study, an implicit finite difference algorithm is employed for three-dimensional pipe equations. Fluid non-linearity and bending stiffness are considered and solved by Newton-Raphson iteration. Seabed is modeled as elastic foundation with linear spring and damper. Top tension and general configuration of pipeline at a depth are predicted. It is found that control for tension to prevent being large curvature of pipeline is needed on th steep seabed and, it should be considered 23.5 ton of tension at a top of pipe on the process of pipeline laying at 400m of water depth The largest top tension of pipe on condition of the beam sea during pipe laying is shown from the experiment. The results of this study can be contributed to the design of pipeline laying for upwelling deep ocean water.

• Wind and Structures
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• 제2권3호
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• pp.151-171
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• 1999

In its 90 years of life, the Tuned Mass Damper have found application in many fields of engineering as a vibration reducing device. The evolution of the theory of TMDs is briefly outlined in the paper. A generalised mathematical linear model for the analysis of the response of line-like structures with TMDs is presented. The system matrices of the system including the TMDs are written in the state space as a function of the mean wind speed. The stability of the system can be analysed and the Power Spectral Density Function of any response parameter calculated, taking into account an arbitrary number of modes of vibration as well as an arbitrary number of TMDs, for any given PSDF of the excitation. The procedure can be used to optimise the number, position and mechanical properties of the damping devices, with respect to any response parameter. Due to the stationarity of the excitation, the method is well suited to structures subjected to the wind action. In particular the procedure allows the calculation of the onset galloping wind speed and the response to buffeting, and a linearisation of the aeroelastic behaviour allows its use also for the evaluation of the response to vortex shedding. Finally three examples illustrate the suggested procedure.