• The Transactions of the Korean Institute of Electrical Engineers D
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• v.50 no.8
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• pp.361-366
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• 2001

This thesis proposes a fuzzy logic cross coupled controller for a multi axis servo system. The overall control system consists of three elements: the axial position controller, the speed controller, and a fuzzy logic cross coupled controller. In conventional multi axis servo system, the motion of each axis is controlled independently without regard to the motion of other axes, in which the contour error, defined as the shortest distance between the desired and actual contours is compensated only by the position error of each axis. This decoupled control approach may result in degraded contouring performance due to such factors as mismatch of axial dynamics and axial loop gains. In practice, such systems contain many uncertainties, Therefore, the multi axis servo system must receive and evaluate the motion of all axes for a better contouring accuracy. Cross coupled controller utilizes all axis position error information simultaneously to produce accurate contours. However the existing cross coupled controllers cannot overcome friction, backlash and parameter variation. Also, since it is difficult to obtain an accurate mathematical model of multi axis system, here we investigate a fuzzy logic cross coupled controller method. Some simulations and experimental results are presented to illustrate the performance of the proposed controller.

• Proceedings of the KSME Conference
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• 2000.11a
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• pp.607-611
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• 2000

Acoustic modal property of the vehicle passenger compartment is a very important factor which dominates vehicle interior noise in the low frequency range. In most real cars, trunk noise often transfers into the passenger compartment since the two cavities are acoustically coupled. This study identifies the major coupling path by examining the variation of the coupled acoustic modal frequencies and modes. An 1/2 size acryl compartment model is designed and manufactured for the measurement and analysis of coupled acoustic modes. Experimental result shows that package tray contributes to the coupling much more than the back seat and hole size of the package tray is an important design factor to control low frequency acoustic modes in the coupled system.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.5 s.98
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• pp.527-535
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• 2005

This paper explains a general coupling system in terms of the system parameters. impedance of a cavity or mobility of a structure. To easily access the mechanism of the structural-acoustic coupled system, a simple expression is derived. A general coupled equation is also derived of a general coupled problem constituted a flexible structure and an opening boundary in terms of vector and matrix notation, and is analyzed the coupling phenomena using the understanding acquired simple coupled system. The paper shows that the general coupled equation is expanded version of the simple coupled equation by some limiting checks. The paper also shows that the degree of coupling is proportioned to a stiffness of the acoustic system and a modal coupling coefficient, but is in inverse proportion to a mass of the structural system and the difference of the excitation frequency and resonant frequency of the acoustic or structural system.

• Journal of the Korea Institute of Military Science and Technology
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• v.11 no.4
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• pp.116-123
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• 2008

In this paper we study the performance of the measurement time-delay estimation of tightly-coupled GPS/INS(Global positioning system/Inertial Navigation system) system. Generally, the heading error estimation performance of loosely-coupled GPS/INS system using GPS's Navigation Solution is poor. In the case of tightly-coupled GPS/INS system using pseudo-range and pseudo-range rate, the heading error estimation performance is better. However, the time-delay error on the measurement(pseudo-range rate) make the heading error estimation performance degraded. So that, we propose the time-delay model on the measurement and compose the time-delay estimator. And we confirm that the heading error estimation performance in the case of measurement time-delay existence is similar with the case of no-delay by Monte-Carlo simulation.

• Earthquakes and Structures
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• v.16 no.1
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• pp.83-96
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• 2019

The seismic behavior of PRC coupling beam-hybrid coupled shear wall system is analyzed by using the finite element software ABAQUS. The stress distribution of steel plate, reinforcing bar in coupling beam, reinforcing bar in slab and concrete is investigated. Meanwhile, the plastic hinges developing law of this hybrid coupled shear wall system is also studied. Further, the effect of coupling ratio, section dimensions of coupling beam, aspect ratio of single shear wall, total height of structure and the role of slab on the seismic behavior of the new structural system. A fitting formula of plate characteristic values for PRC coupling beams based on different displacement requirements is proposed through the experimental date regression analysis of PRC coupling beams at home and abroad. The seismic behavior control method for PRC coupling beam-hybrid coupled shear wall system is proposed based on the continuous connection method and through controlling the coupling ratio, the roof displacement, story drift angle of hybrid coupled shear wall system, displacement ductility of coupling beam.

• Journal of the Korean Solar Energy Society
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• v.32 no.5
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• pp.59-67
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• 2012

In this study,the compact type solar thermal and ground coupled heat pump hybrid system for space heating/cooling and hot water supply has been developed. This hybrid system was installed in Zero Energy Solar House(ZeSH) in KIER for the demonstration. The thermal performance and operational characteristics of this hybrid system were analysed especially. The results are as follows. (1) This hybrid system was designed in order to address the existing disadvantages of solar thermal/ground coupled heat pump system. For this design, all parts except solar collector and ground coupled heat pump were integrated into a single product in a factory. The compact type unit includes two buffer tanks, an expansion tank, pumps, valves, a controller, etc. This system has an advantage of easy installation with simple plumbing work even in narrow space. (2) The thermal charging and discharging time of the buffer tanks and its characteristics by ground coupled heat pump, and heat pump COP according to geo-source temperature and buffer storage temperature have been studied. This system was found to meet well to the heat load without any other auxiliary heating equipment. (3) The operating hours of the ground coupled heat pump as a backup device of solar thermal can be reduced significantly by using solar heat. It was also found that the minimum heating water supply setting temperature and maximum cooling water supply setting temperature make an influence on the heat pump COP. The lower heating water and the higher cooling water temperature, the higher COP. In this respect, the hybrid system's performance can be improved in ZeSH than conventional house.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.5
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• pp.1383-1391
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• 1996

The steady-state response for a coupled structure-acoustic-cavity systme has been investigated by numerical technique using a directly coupled finite element method(FEM) and Boundary Element Method(BEM) model. The Laplace tranformed matrix equations for the structure and the acoustic cavity are coupled directly satisfying the necessary equilibrium and compatibility conditions. The coupled FEM-BEM code is verified by comparing its prediction for an example with known analytical, numerical and experimental results. The example involves a coupled structure-acoustic-cavity system which is a box-type cavity with one end as experimentally excited pinned-pinned plate.

• The Transactions of the Korean Institute of Power Electronics
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• v.27 no.4
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• pp.348-355
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• 2022

A bipolar DC distribution system suffers from an imbalance in voltages when asymmetric loads are connected at the outputs. Dedicated voltage balancers are required to address the imbalance in bipolar voltage levels. However, additional components eventually increase the cost and decrease the efficiency and power density of the system. Therefore, to deal with the imbalance in output voltages without adding any extra components, this study presents a coupled inductor-based voltage balancing technique with a dual-output CLL resonant converter. The proposed coupled inductor does not require extra magnetic components to balance the output voltages because it is the result of resonant inductors of the CLL tank circuit. It can also avoid complex control schemes applied to voltage balancing. Moreover, with the proposed coupled inductor, the CLL converter acquires good features including zero voltage and zero current switching. Detailed analysis of the proposed coupled inductor is presented with different load conditions. A 3.6-kW hardware prototype was built and tested to validate the performance of the proposed coupled inductor-based voltage balancing technique.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.30 no.4
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• pp.351-361
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• 2017

Reinforced concrete(RC) structural walls are major lateral load-resisting structural member in building structures. Generally these RC structural walls are coupled with each other by the coupling beams and slabs, and therefore they behave as RC coupled structural wall system. In the design of these coupled structural wall systems, member forces are calculated using elastic structural analysis. These elastic analysis methodologies for the design of coupled structural wall system was not reasonable because it can not consider their ultimate behavior and assure economic feasibility. Performance based design and moment redistribution method to solve these problems is regarded as a reasonable alternative design method for RC coupled structural wall system. However, it is not verified under various design parameters. In this study, nonlinear analysis of RC coupled structural wall system was performed according to various design parameters such as reinforcement ratio, ultimate concrete strain and wall height. Based on analysis results, design considerations for coupled RC structural wall system was proposed.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.877-882
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• 2005

The definition of multi-coupled operation is that coupled two trainsets is able to be operated one trainset identically. That is to say, the one driver, coupled two trainsets can operate the traction and braking system, control vehicle doors, phanto-graph, HVAC and passenger room lighting system etc, such as one trainset controlling. This study will provide high speed train design engineer with introducing multi-coupled operation system electrically and presentation automatic complex coupler mechanism, and then this paper will be applied to design next generation high speed train system such as Jun-la/Ho-nam line