• Journal of Institute of Control, Robotics and Systems
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• v.4 no.2
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• pp.203-208
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• 1998

This paper presents an adaptive fuzzy controller using an neural network and adaptation algorithm. Reference-model following neuro-fuzzy controller(RMFNFC) is invesgated in order to overcome the difficulty of rule selecting and defects of the membership function in the general fuzzy logic controller(FLC). RMFNFC is developed to tune various parameter of the fuzzy controller which is used for the discrete nonlinear system control. RMFNFC is trained with the identification information and control closed loop error. A closed loop error is used for design criteria of a fuzzy controller which characterizes and quantize the control performance required in the overall control system. A control system is trained up the controller with the variation of the system obtained from the identifier and closed loop error. Numerical examples are presented to control of the discrete nonlinear system. Simulation results show the effectiveness of the proposed controller.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.2
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• pp.303-311
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• 2012

In this study, we introduce a dynamic process model as well as the design methodology of optimized fuzzy controller for its efficient application to vacuum production system to produce a semiconductor, solar module and display and so on. In a vacuum control field, PID control method is widely used from the viewpoint of simple structure and preferred performance. But, PID control method is very sensitive to the change of environment of control system as well as the change of control parameters. Therefore, it's difficult to get a preferred performance results from target system which has a complicated structure and lots of nonlinear factors. To solve such problem, we propose the design methodology of an optimized fuzzy PID controller through a following series of steps. First a dynamic characteristic of the target system is analyzed through a series of experiments. Second the process model is built up and its characteristic is compared with real process. Third, the optimized fuzzy PID controller is designed using genetic algorithms. Finally, the fuzzy controller is applied to target system and then its performance is compared with that of other conventional controllers(PID, PI, and Fuzzy PI controller). The performance of the proposed fuzzy controller is evaluated in terms of auto-tuned control parameters and output responses considered by ITAE index, overshoot, rise time and steady state time.

• The Transactions of the Korean Institute of Power Electronics
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• v.5 no.5
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• pp.475-483
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• 2000

This paper describes designs about the power system of KITSAT-4 satellite. The KITSAT-4 power system is mainly composed of power stage and control stage. The power stage is a 200〔W〕 buck converter and control stages are hardware controller and software controller The hardware controller is PPT(Peak Power Tracker), battery voltage controller and software controller is battery current controller and direct duty controller. So the operation of power system has many advantages in that it can select controller according to reliable control and precise control. The controller design methods are presented and the small signal analyses are performed to verify system stability.

• Journal of Institute of Control, Robotics and Systems
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• v.7 no.5
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• pp.399-406
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• 2001

This paper presents a dynamic modeling and a sliding mode controller for the high-speed/high-accuracy position control system. The selected target system is the wire bonder assembly which is used in the semiconductor assembly process. This system is a reciprocating one around the pivot point that consists of VCM(voice coil motor) as an actuator and transducer horn as a bonding tool. For the modeling elements, the sys-tem is divided into electrical circuit, magnetic circuit and mechanical system. Each system is modeled using the bond graph method and united into the full system. Two major aims are considered in the design of the controller. The first one is that the horn must track the given reference trajectory. The second one is that the controller must be realizable by using the DSP board. Computer simulation and experimental results show that the designed sliding mode controller provides better performance than the PID controller.

• Journal of Power System Engineering
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• v.21 no.6
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• pp.101-109
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• 2017

The pneumatic driving system has advantages such as high output power per weight and low heat generation rate. However, it is difficult to control the position because of its strong non-linearity such as large friction forces compared to driving force, and heat transfer characteristics that change during operation. Therefore, in order to achieve the control objectives, a robust controller should be designed considering modeling error and model uncertainty. In this paper, a sliding mode controller is designed to improve the position control performance of pneumatic cylinder driving system. Experimental results show that the designed controller achieves the designed control objectives even if the model of the cylinder driving system, such as the initial pressure inside the cylinder and the initial position of the piston is changed.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.10 no.3
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• pp.26-30
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• 2001

Controller refinement scheme to improve the performance of a conventional system automatically in frequency domain is proposed. The controller automatic tuning method features using experimental frequency responses of the conventional closed-loop system, the conventional controller, and the improved closed-loop system, instead of poorly modeled plant due to non-linearities and disturbances. The improved closed-loop system characteristics is automatically acquired by the con-ventional closed-loop system characteristics and the proposed performance index in system bandwidth. And the proper controller is realized by least squares approximation in frequency domain. To testify the usefulness of the approach, the path tracking control of robot arm is performed. Experimental results and analytic results are well-matched.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10a
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• pp.52-55
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• 1996

In this paper, we consider the decentralized reduced-order H$_{\infty}$ controller for the general plant. Simplifying method is suggested for the general plant with the decentralized controller structure. When the controller is reconstructed for the original system, the decentralizability of the controller for the transformed system is generally destroyed with the older method. We solve this problem. For the simplified system, the structure of the decentralized controller is suggested..

• The Transactions of the Korean Institute of Electrical Engineers
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• v.39 no.5
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• pp.485-493
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• 1990

The idea of expert control is to incorporate a rule based expert system in a feedback control system. In this paper, we present some heuristic rules based on relay experiment for the choice of controller structure and the setting of the controller parameters. Heuristic rules are used as an element of the feedback loop in an auto-tuning PID controller. The algorithms are coded in a form which is as pure as possible and the heuristic logic is implemented with the rules. This paper reports an implementation of an expert controller on microcomputer-based system, including an industrial programmable controller.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1862-1865
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• 2005

We have a plan to design a controller for electron beam manufacturing system. At first, we designed a controller for SEM. The controller consists of five parts (power source, beam controller, scanning controller, optic controller and main controller). Beam controller supplies pulse wave for generating high voltage and can monitor the status of high voltage instrument through emission current. Optic controller controls focus, spot size and image shift. Main controller transmits variables from operating program to each part and monitors the status of peripheral device.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.11
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• pp.1663-1668
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• 2017

A BLDC motor with higher number of phases has several advantages, compared to the conventional three-phase BLDC motors. It can reduce the commutation torque ripple and the iron loss without increasing the voltage per phase and increase the reliability and power density. Higher number of phases increase the torque-per-ampere ratio for the same machine volume and output power by widening the electrical conduction period. In this paper, the proposed seven-phase BLDC motor drive system is made into several functional modular blocks, so that it can be easily extended to other ac motor applications: back-EMF block, hysteresis current control block, pwm inverter block, phase current block, and speed/torque control block. Also in a system of BLDC motor drive, the PI controller has been widely used in the speed controller because of the simple implementation. To obtain a good speed response in a general drive system using the PI controller, the high bandwidth of a controller is established. therefore, in this paper, a Fuzzy controller is applied to the 7-phase BLDC motor drive system in order to improve the speed control performance. The Fuzzy controller is compared with a conventional PI controller through the experiment with respect to speed dynamic responses. These experimental results show that the Fuzzy controller of the 7-phase BLDC motor drive system is superior over the conventional PI controller. The algorithm using the Fuzzy controller can improve a comfortable ride in the field of high performance 7-phase BLDC motor drive applications.