• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.1
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• pp.219-224
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• 2016

The vibration control performance of a semi-active damper connected to adjacent buildings subjected to seismic loads was investigated. The MR damper was used as a semi-active control device. A fuzzy logic control algorithm was used for effective control of the adjacent buildings connected to the MR damper. In the buildings control coupled with a MR damper, the response reduction of one building results in an increase in the response in another building. Because of these conflict characteristics, multi-objective optimization is required. Therefore, a fuzzy logic control algorithm for the control of a MR damper was optimized using a multi-objective genetic algorithm. Based on numerical analyses, the semi-active fuzzy control of MR damper for adjacent coupled buildings can provide good control performance.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2003.05a
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• pp.177-181
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• 2003

PID(Proportional-Integral-Derivative)제어기는 제어악고리즘의 단순성과 실 현장에서의 강인성 등으로 산업용 보일러의 제어시스템서 주로 이용되어 왔다. 그러나 다중 루프를 가진 보일러 시스템에서는 루프간의 상호 간섭 영향 등으로 부하 변화에 따라 요구되는 증기(steam)압력, 증기 유량(steam flow)변화 등을 동시에 만족하도록 급수 유량, 연교 유량, 공기 유량 등을 PlH제어기만으로 제어하는 것은 어렵다. 본 연구에서는 보일러 시스템의 다목적 성능 최적화에 각각의 적합도 함수 $f_{a}$ , $f_{b}$, $f_{c}$를 정의하고 면역 알고리즘을 이용해 최적화를 구하고 그 결과에 대한 특성과 유효성을 검토하였다.다.다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.1
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• pp.6-13
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• 2002

This paper deals with the linear matrix inequality (LMI) design procedures for multi-objective Η$_2$/Η$_{\infty}$ controllers with pole-placement constraints for an inverted pendulum system modeled as convex polytopes to ensure the stabilizing regulator and tracking performances. Polytopic models with multiple linear time-invariant models linearized at some operating points are derived to design controllers overcoming the conservativeness such as a controller may have when it is designed for a model linearized at a single operating point. Multi-objective controllers are designed for polytopic models by the LMT design technique with convex algorithms. It is observed that the inverted pendulum controlled by any controller designed for each polytopic model is stabilizingly restored to the vertical angle position for initial values of larger tilt anlges.

• Journal of Korean Association for Spatial Structures
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• v.11 no.2
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• pp.89-99
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• 2011

In this study, a smart base isolation system has been proposed to reduce dynamic responses of a spacial structure subjected to seismic excitation. MR dampers and low damping elastomeric bearings were used to compose a smart base isolation system and its vibration control performance has been investigated compared to that of the optimally designed lead-rubber bearing (LRB) isolation system. Control performance of smart base isolation system depends on control algorithm. Fuzzy controller was used in this study to effectively control the spacial structure having a smart base isolation system. Dynamic responses of the spacial structure with isolation system is conflict with base drifts and thus these two responses are selected as objective functions to apply multi-objective genetic algorithm to optimization of fuzzy controller. Based on numerical simulation results, it has been shown that the smart base isolation system proposed in this study can drastically reduce base drifts and seismic responses of the example spacial structure in comparison with the optimally designed LRB isolation system.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.24 no.1
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• pp.69-78
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• 2011

In this study, an optimization method using multi-objective genetic algorithm(MOGA) has been proposed to develop a fuzzy control algorithm that can effectively control a smart tuned mass damper(TMD). A 76-story benchmark building subjected to wind load was selected as an example structure. The smart TMD consists of 100kN MR damper and the natural period of the smart TMD was tuned to the first mode natural period of the example structure. Damping force of MR damper is controlled to reduce the wind-induced responses of the example structure by a fuzzy logic controller. Two input variables of the fuzzy logic controller are the acceleration of 75th floor and the displacement of the smart TMD and the output variable is the command voltage sent to MR damper. Multi-objective genetic algorithm(NSGA-II) was used for optimization of the fuzzy logic controller and the acceleration of 75th story and the displacement of the smart TMD were used as objective function. After optimization, a series of fuzzy logic controllers which could appropriately reduce both wind responses of the building and smart TMD were obtained. Based on numerical results, it has been shown that the control performance of the smart TMD is much better than that of the passive TMD and it is even better than that of the sample active TMD in some cases.

• Journal of the Korean Society of Propulsion Engineers
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• v.1 no.2
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• pp.67-73
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• 1997

This paper shows the development status of attitude control thruster for KOMPSAT(Korea Multi-Purpose Satellite). Hanwha Corp. has manufactured and delivered 1.0 lbf monopropellant thrusters under the technology transfer of TRW Co. in U.S.A regarding design, analysis and manufacturing of MRE-1 thruster These thrusters will be installed to KOMPSAT which is scheduled to be launched in July 1999. Monopropellant thrusters can provide reliable and cost-effective means of propulsive control for middle class satellite and maneuvering control systems. Some information concerning with system specification, performance analysis/simulations and manufacturing process has been introduced in this paper.

• Journal of Korean Association for Spatial Structures
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• v.10 no.4
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• pp.93-102
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• 2010

In this study, a smart sky-bridge composed of MR damper and FPS has been proposed and vibration control performance of a smart sky-bridge for the connected buildings was investigated. To this end, 10-story and 20-story building structures connected by a smart sky-bridge were selected as example structures and El Centro and Kobe earthquakes, which have near and far fault ground motion characteristics respectively, were used for time history analyses. In order to effectively control the smart sky-bridge, fuzzy logic controller was developed and multi-objective genetic algorithm was used to optimize fuzzy logic controllers. Based on optimization results, it has been seen that there is a trade-off between seismic responses of 10-story and 20-story buildings and a suite of Pareto optimal solutions of fuzzy logic controllers for seismic response control can be obtained by multi-objective genetic algorithm. It is shown from numerical study that seismic responses of adjacent buildings can be efficiently controlled by using a smart sky-bridge.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.26 no.1
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• pp.69-77
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• 2013

When structural design of a tall building is conducted, reduction of wind-induced lateral displacement is one of the most important problem. For this purpose, additional dampers and vibration control devices are generally considered. In this process, control performance of additional devices are usually investigated for optimal design without variation of characteristics of a structure. In this study, multi-objective integrated optimization of structure-smart control device is conducted and possibility of reduction of structural resources of a tall building with additional smart damping device has been investigated. To this end, a 60-story diagrid building structure is used as an example structure and artificial wind loads are used for evaluation of wind-induced responses. An MR damper is added to the conventional TMD to develop a smart TMD. Because dynamic responses and the amount of structural material and additional smart damping devices are required to be reduced, a multi-objective genetic algorithm is employed in this study. After numerical simulation, various optimal designs that can satisfy control performance requirement can be obtained by appropriately reducing the amount of structural material and additional smart damping device.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10a
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• pp.235-237
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• 2003

다목적실용위성 2호(KOMPSAT-2)에서는 위성자세 제어를 담당하고 있는 RDU(Remote Drive Unit)의 성능 향상를 위하여 80386 CPU와 함께 80387 Coprocessor를 장착하여 임무수행을 담당한다. 다목적실용위성 1호(KOMPSAT-1)에서는 수치연산을 위하여 상용소프트웨어인 PACLIB를 사용하여 수치연산을 80C186을 이용한 에뮬레이션 방식으로 수행하였지만, 2호기에서는 실질적인 코프로세서를 이용한 수치연산을 수행하게 된다. 본 논문에서는 다목적실용위성 2호에서 사용되는 80387 코프로세서의 초기화 과정과 예외사항 발생시 처리 방법, 80387 코프로세서를 이용한 수치연산 함수 구현 및 libtary 구성 방법에 대하여 설명한다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.6
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• pp.61-71
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• 2003

In the study of control technique for a turbojet engine model, the Takagi-Sugeno fuzzy logic controller has been designed based on the model identification by the well designed PI controlled system through T-S neuro-fuzzy inference system. To enhance this designed controller, those procedures are proposed that certainty factors are adopted to each rule of objective groups which are classified by the fuzzy C-Means algorithm and the satisfaction degrees are matched to meet the objectives. This proposed technique shows its feasibility by upgrading performances of the previously well-designed T-S fuzzy controller.