• Journal of Power Electronics
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• v.9 no.4
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• pp.567-574
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• 2009

A linear transfer function for the output current control of frequency-controlled resonant inverters is proposed in this paper. The circuit of resonant inverters can be transformed into two coupled circuits through the complex phasor transform. The circuits consist of cross-coupled power sources and passive elements. The circuits are used to induce the state space equation, which is transformed into the $4^{th}$ order cross-coupled transfer function. The $4^{th}$ order cross-coupled transfer function is modeled into a $2^{nd}$ order linear transfer function based on a behavior analysis of the pole and zero locations that facilitate a simple and intuitive linear transfer function. The feasibility and validity of the proposed linear transfer function were verified by simulation and experiment.

• Journal of the Korean Mathematical Society
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• v.32 no.3
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• pp.447-459
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• 1995

A fundamental problem is to construct linear systems with given transfer functions. This problem has a well known solution for unitary linear systems whose state spaces and coefficient spaces are Hilbert spaces. The solution is due independently to B. Sz.-Nagy and C. Foias [15] and to L. de Branges and J. Ball and N. Cohen [4]. Such a linear system is essentially uniquely determined by its transfer function. The de Branges-Rovnyak construction makes use of the theory of square summable power series with coefficients in a Hilbert space. The construction also applies when the coefficient space is a Krein space [7].

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.57 no.3
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• pp.215-224
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• 2008

In this paper, we introduced a linear motor-based transfer system with an active pid controller which can be replaced with an automated guided vehicle (AGV) for the port automation. This system, which is named LMCTS(liner motor-based container transfer system), is based on PMLSM (permanent magnetic linear synchronous motor) which basically consists of stator modules on the rail and shuttle car. Therefore more progressive and adaptive control mechanisms should be required to control a system with large variation of container weight, the difference of each characteristic of stator modules, a stator module's trouble etc. We introduced an active control mechanism with an online tuning scheme using modified evolutionary strategy. Some computer simulations are implemented to assess the robustness of the proposed system.

• Coupled systems mechanics
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• v.11 no.2
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• pp.107-119
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• 2022

The aim of the work presented in this paper is development of numerical model for prediction of temperature distribution in pavement according to the measured meteorological parameters, with introduction of non-linear heat transfer coefficient which is a function of temerature difference between the air and the pavement. Developed model calculates heat radiated from the pavement back in the air, which is an important part of the heat trasfer process in the open air surfaces. Temperature of the pavement surface, heat radiation together with many meteorological parameters were measured in series during two years in order to validate the model and calibrate model parameters. Special finite element method for temperature heat transfer towards the soil together with the time integration scheme are used to solve the governing equation. It is proved that non-linear heat transfer coefficient, which is a function of time and temperature difference between the air and the pavement, is required to decribe this phenomena. Proposed model includes heat tranfer coefficient callibration for specific climate region, through the iterative inverse procedure.

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.396-401
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• 2001

Heat transfer analysis of a iron core type linear motor for surface mounting device applications was considered in this study. In order to avoid the complex conjugate problem a fluid flow regime and a solid regime were considered separately. First, film coefficients of the moving parts were evaluated from computational fluid dynamic analysis and those of the stationary parts from the existing empirical or analytic correlations. And then, by applying them, internal and external temperatures of the linear motor pal1s were computed through finite element analysis. Both computation and measurement were carried out with respect to motor driving power. The measurement did not exhibit a linear temperature variation trend with respect to motor power while the computation revealed a linear correlation. Nonetheless, the computations agreed with the measurements within an error range of 20%. It indicates that an adequate heat transfer model for the reciprocative coil assembly may help more exact prediction.

• Journal of the Korean Society for Precision Engineering
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• v.32 no.5
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• pp.405-413
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• 2015

This paper presents the motion accuracy simulation considering loads such as workpiece weight, cutting force, cogging force of a linear motor, and force caused by misalignment and runout error of a ballscrew in linear motion units. The transfer function method is basically utilized to estimate 5-DOF motion errors, together with the equilibrium equations of force and moment on the table. The transfer function method is modified in order to consider clearance changed according to the loads in the double sided hydrostatic/aerostatic bearings. Then, the analytic model for predicting the 5-DOF motion errors is proposed with the modified transfer function method. Motion errors were simulated under different loading conditions in the linear motion units using hydrostatic, aerostatic, and linear motion bearings, respectively. And the proposed analytic model was verified by comparing the estimated and measured motion errors.

• Journal of Navigation and Port Research
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• v.28 no.6
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• pp.541-548
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• 2004

In the maritime container terminal. LMCTS (Linear Motor-based Container Transfer System) is horizontal transfer system for the yard automation, which In., been proposed to take the place of AGV (Automated Guided Vehicle). The system is based on PMLSM (Permanent Magnetic Linear Synchronous Motor) that is consists of stator modules on the rail and shuttle car (mover). Because of large variant of mover's weight by loading and unloading containers, the difference of each characteristic of stator modules, and a stator module's trouble etc. LMCTS is considered as that the system is changed its model suddenly and variously. In this paper, we will introduce the softcomputing method of a multi-step prediction control for LMCTS using DR- FNN (Dynamically-constructed Recurrent Fuzzy Neural Network). The proposed control system is used two networks for multi step prediction Consequently, the system has an ability to adapt for external disturbance, detent force, force ripple, and sudden changes by loading and unloading the container.

• Journal of Korean Institute of Industrial Engineers
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• v.16 no.2
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• pp.81-89
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• 1990

Transfer pricing mechanism is applied to the problem of input buffer size in the context of interfacing a flexible manufacturing system with multiple following production lines. The size of the input buffers can be determined economically by using non-linear transfer pricing either in a decentralized organization or in a centralized organization. Under the certain conditions, input buffer size determined from this non-linear transfer pricing is more economical than the traditional economic lot size model. The benefit comes from transferring part of FMS' inventory to the following production lines. And this non-linear transfer pricing makes sense if the FMS' unit inventory holding cost is high enough.

• Structural Engineering and Mechanics
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• v.62 no.4
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• pp.443-453
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• 2017

The performance of bolted side-plated (BSP) beams is affected by the degree of transverse partial interaction, which is a result of the interfacial slip caused by transverse shear transfer between the bolted steel plates and the reinforced concrete beams. However, explicit formulae for the transverse shear transfer profile have yet to be derived. In this paper, a simplified piecewise linear shear transfer model was proposed based on force superposition principle and simplification of shear transfer profiles derived from a previous numerical study. The magnitude of shear transfer was determined by force equilibrium and displacement compatibility condition. A set of design formulae for BSP beams under several basic load cases was also derived. Then the model was verified by test results. A worked example was also provided to illustrate the application of the proposed design formulae. This paper sheds some light on the shear force transfer mechanism of anchor bolts in BSP beams, and offers a practical method to evaluate the influence of transverse partial interaction in strengthening design.

• Journal of the Semiconductor & Display Technology
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• v.7 no.3
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• pp.11-16
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• 2008

The authors investigated an overhead shuttle (OHS) system for automatic transferring the liquid crystal display (LCD) panels. The constructed tracks of OHS system include the linear and curve regions and have been installed on the ceiling to transfer the cassette of LCD glass along the closed-loop and open-loop tracks. In this study, the OHS system was implemented by a proposed linear motor to solve encoder installation and the system cost problems of the long distance transfer system. In addition, we utilized a new algorithm of the position detection and a new control algorithm for driving linear motor. The newly developed control algorithm was demonstrated from both a computer simulation and an experimentation, indicating that the highly reliable and speedy transfer system can enhance the LCD panel productivity of commercial OHS system.