• Journal of the Korean Society for Precision Engineering
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• v.16 no.6
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• pp.166-175
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• 1999

This paper describes a design and performance evaluation of robust controller which overrides unstable motion and pulls out quickly after water entry of underwater vehicle dropped from aircraft or surface ship. We use 6-DOF equation for model of motions and assume parameter uncertainty to reflect the difference of real motion from modelled motion equation. we represent a nonlinear system with uncertainty as Takagi and Sugeno's(T-S) fuzzy models and design controller stabilizing them. The fuzzy controller utilizes the concept of so-called parallel distributed compensation (PDC). Finally, we confirm stability and performance of the controller through computer simulation and hardware in the loop simulation (HILS).

• Journal of the Korean Society of Industry Convergence
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• v.12 no.1
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• pp.43-50
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• 2009

The manufacturing process of the semiconductor is guided by the controller, which is supposed to sense the unexpected shocks and/or vibrations to shutdown the hard disk and the whole system in order to prevent the malfunction. This feature of controller would shutdown the system due to the instability of the controller itself as well as the instability of the manufacturing system. And consequently will cause significant losses. In this study the structure of a controller has been investigated to find ways to suppress the vibrations from the structure. The frequency response test and the computer simulation has been implemented to find the structure with improved stability. The result of the study shows that the relatively simple design alterations can eliminate most of the vibrations.

• Proceedings of the KIEE Conference
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• 1998.07b
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• pp.455-457
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• 1998

This paper designs a noise controller for the small cavity using Coefficient Diagram Method(CDM). In the small cavity system, there exist nonlinear characteristics such as uncertain-time delay and parameter variation. In the controller design of nonlinear system with uncertainty need to the higher order controller or complexity computation. The coefficient diagram is convenient implementation of the control system design method, that is utilized as a vehicle to collectively express the important features of the system and an improved version Kessler's standard form and the Lipatov stability condition of a constitutes the theoretical basis. Simultaneously, it is provided a desired specification, such as the robustness, the stability, faster response, and lower order controller. A simulation of the system with the proposed controller shows sufficient noise cancelation in small cavity.

• Journal of the Korean Institute of Intelligent Systems
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• v.10 no.3
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• pp.260-269
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• 2000

The fuzzy and state-feedback control systems have been applied in various areas from non-linear to linear systems. A Fuzzy controller is endowed with control rules and membership function that are constructed on the knowledge of expert, as like intuition and experience. but It is very difficult to obtain the exact values which are the membership function and consequent parameters. though apply back-propagation algorithm to the system, the convergence time a much. Besides, the state-feedback system is most widely used in industry due to its simple control structure and easily able to design the controller. but it is weak in complex system of higher degree and non-linear. In this paper presents the design of a fuzzy switching mode, it these two controllers work at different operation conditions, the advantages of both controller can be retained and the disadvantages can be removed. Between the Fuzzy and the State-feedback controlles, the good outputs are selected by the switching mode. Moreover it is powerful in complex system of higher degree and non-linear. In these sense compared with the state-feedback controller, the performance of the proposed controller was improvedin the section of linearization.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.12
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• pp.2069-2074
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• 2016

This paper presents a methodology based on evolutionary optimization for simultaneously optimizing design parameters of controller and components of plant. Genetic programming(GP) based bond graph model generation is adopted to open-ended search for the plant. Also GP is applied to represent the controller with a unified method. The formulations of simultaneous plant-controller design optimization problem and the description of solution techniques based on bond graph are derived. A feasible solutions for a plant/controller design using the simultaneous optimization methodology is illustrated.

• Journal of Institute of Control, Robotics and Systems
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• v.12 no.9
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• pp.850-855
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• 2006

This is concerned with the development and design of automatic maneuvering system using Differential Global Positioning System(DGPS). To achievement of autonomous maneuvering controller for giant ship, first, we investigated automatic maneuvering controller using DGPS in motor car. The sensors are configured with DGPS and digital compass. We calculated velocity and steering angle of motor car based on sensor signal. To design the controller, we derived the bicycle model and developed critically damped controller. The critically damped controller can be tracing previously appointed position in the fastest time. We are used a laptop computer to realize and the control algorithm is programmed by visual basic software. The obtained experimental results from developed system show unmanned motor car is good tracing planed positions. Hence, the system is looking forward to use the autonomous maneuvering control fur giant ship.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.3
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• pp.247-256
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• 1999

In this paper, a methodology for optimal design of PID controller using the modified genetic algorithm has been proposed to improve the transient stability at system fault in HVDC transmission system, mathematical model preparation for stability analysis, and supplementary signal control by an optimal PID controller using the modified genetic algorithm(MGA). The propriety was verified through computer simulations regarding transient stability. It means that the application of MGA-PID controller in HVDC transmission system can contribute the propriety to the improvement of the transient stability in HVDC transmission system and the design of MGA-PID controller has been proved indispensible when applied to HVDC transmission system.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.179-184
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• 2008

This paper presents the design of the feed forward controller to improve on the non-interference control performance of a single PWM converter in parallel for high-speed trains. The feed forward controller is designed to minimize the interference generated by converter switching in parallel operation of PWM converters. The gain value of the feed forward controller is calculated by inductance values of the input transformer. However, it is difficult to decide this gain value exactly because inductance values are changed by the operation condition of an input transformer. In this paper, the proposed design of feed forward controller can exactly decide the gain value using the leakage inductances estimated by detecting the variation of input current. the validity of the proposed feed forward controller is proved through the simulation results.

• Journal of Power Electronics
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• v.4 no.3
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• pp.152-160
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• 2004

This paper presents analysis, modeling, and design of a low-harmonic, isolated, active-clamped SEPIC for future avionics applications. Simpler converter dynamics, high switching frequency, zero voltage-Transition-PWM switching, and a single-layer transformer construction result. This paper describes complete design of a digital controller for a high-frequency switching power supply. Guidelines for the minimum required resolution of the analog-to-digital converter, the pulse-width modulator, and the fixed-point computational unit is derived. A design example based on a SEPIC converter operating at the high switching frequency is presented. The controller design is based on direct digital design approach and standard root-locus techniques.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.1
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• pp.1-5
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• 2002

A common way to design a digital control system is to design an analog controller first and discretize it for digital implemention. In this paper, optimal digital controller design is studied within the framework of sampled -data control theory. In particular, multirate discretization of analog controller is considered using an Η$_2$optimality criterion. Solutions are obtained via multirate H2 optimization with a causality constraint due to the multirate structure. In design example, the comparison of the proposed methods is made with the conventional discretization methods, and demonstrate the superiority of the multirate design method.