• International Journal of Control, Automation, and Systems
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• v.4 no.6
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• pp.775-781
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• 2006

An intelligent optimization method for designing Fractional Order PID(FOPID) controllers based on Particle Swarm Optimization(PSO) is presented in this paper. Fractional calculus can provide novel and higher performance extension for FOPID controllers. However, the difficulties of designing FOPID controllers increase, because FOPID controllers append derivative order and integral order in comparison with traditional PID controllers. To design the parameters of FOPID controllers, the enhanced PSO algorithms is adopted, which guarantee the particle position inside the defined search spaces with momentum factor. The optimization performance target is the weighted combination of ITAE and control input. The numerical realization of FOPID controllers uses the methods of Tustin operator and continued fraction expansion. Experimental results show the proposed design method can design effectively the parameters of FOPID controllers.

• Journal of the Korean Institute of Intelligent Systems
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• v.4 no.2
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• pp.35-40
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• 1994

Fuzzy logic controllers are often found to behave better than PI controllers. One of the major reasons for this is that the fuzzy logic inferences used can produce nonlinear type controllers. For some applicatioins, howeveer, linear fuzzy logic controllers also perofrm better than PI controllers. In this paper, we examine linear fuzzy logic controllers to show that the truncation effects of the fuzzy logic controllers make them perform much better than the PI controllers. In terms of a performance index we used, the truncation effects reduced the index value by up to 80% for examples we studied.

• Journal of the Korea Safety Management & Science
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• v.11 no.4
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• pp.153-159
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• 2009

This study was conducted in search of the acceptance level of air traffic services from domestic airlines pilot's perspective in comparison with male controllers and female controllers. Pilots responded to the questionnaire that female ATC controllers are of significance to male controllers in terms of pronunciation, accuracy of English grammar, attitude and kindness. Besides, The ICAO aviation English proficiency level four test revealed that female controllers were found superior to male controllers in terms of rating scales of holistic descriptors.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.55 no.12
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• pp.667-673
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• 2006

Programmable electronic interlocking system plays key role in railway operation and is closely related to railway accidents, in which the programmable electronic controller of interlocking system may become sources. Redundant digital controllers are adopted as the interlocking controllers to prevent the accidents from the controllers being out of order. The redundant digital controllers being fault tolerant are realized through dual or triplex controllers. In this paper, we calculated safety and availability of the redundant digital controllers using Markov models, demonstrated key part to determine the availability ana the safety.

• International Journal of Control, Automation, and Systems
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• v.6 no.4
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• pp.495-505
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• 2008

This paper describes modeling Voltage Sourced Inverter (VSI) type Flexible AC Transmission System (FACTS) controllers and control methods for power system dynamic stability studies. The considered FACTS controllers are the Static Compensator (STATCOM), the Static Synchronous Series Compensator (SSSC), and the Unified Power Flow Controller (UPFC). In this paper, these FACTS controllers are derived in the current injection model, and it is applied to the linear and nonlinear analysis algorithm for power system dynamics studies. The parameters of the FACTS controllers are set to damp the inter-area oscillations, and the supplementary damping controllers and its control schemes are proposed to increase damping abilities of the FACTS controllers. For these works, the linear analysis for each FACTS controller with or without damping controller is executed, and the dynamic characteristics of each FACTS controller are analyzed. The results are verified by the nonlinear analysis using the time-domain simulation.

• Journal of Drive and Control
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• v.14 no.3
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• pp.50-57
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• 2017

Recently, methods of verification for electro-hydraulic servo controllers are various and the required number of testing controllers is continuously increasing in some specific systems. In this study, a PCB-based electronic simulator of hydraulic actuators is designed and developed to simplify test set-up for controllers and to facilitate alteration for characteristics of the simulator. Several features to reduce required time and manpower for verifying controllers are described. Especially, the simulator is considerably efficient to examine some controllers for different hydraulic actuators in a test. Response characteristics of the simulator are compared with those of real actuators to demonstrate validity of this method. Results reveal utilizing the designed simulator for inspecting controllers is equally effective as using hydraulic actuators.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.1392-1395
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• 1996

Nonlinear PID controllers have increasingly used in current industrial practice because it is robust and is easy to operate. Little guideline and tuning method, however, has been recommended for the nonlinear PID controllers while a lot of result is available for the linear PID controllers. Application guideline and tuning formulae are presented for error square type nonlinear controllers, which are most popular currently, are presented.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1992.10a
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• pp.192-197
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• 1992

The position error in multi-axis machine tools are due to many elements, such as the static friction, servo lag, a nonlinear disturbance, the gain mismatch between multi-axis controllers. In the work, modeling for the plant was carried out through the velocity response by the step input signal. Digital PI controllers, LQ optimal controllers and feedforward controllers are designed for a high tracking performance based on the model. The results of experimentation showed that the controllers worked properly.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1998.10a
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• pp.411-419
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• 1998

In this paper the steady-state genetic algorithm is applied for the optimal design of fuzzy PID controllers. Basically the structure of the discussed fuzzy PID controller is extended from the conventional fuzzy PI and PD controllers where only a two-dimensional rule base of the fuzzy PID controller are designed simultaneously. Simulations results shows the superior performance of this optimal designed fuzzy PID controllers to the optimal designed conventional fuzzy PI and PD controllers.

• Journal of Electrical Engineering and Technology
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• v.7 no.5
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• pp.664-671
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• 2012

This paper presents the application of Unified Power Flow Controller (UPFC) in order to simultaneous control of power flow and voltage and also damping of Low Frequency Oscillations (LFO) at a Single-Machine Infinite-Bus (SMIB) power system installed with UPFC. PI type controllers are commonly used controllers for UPFC control. But for the sake of some drawbacks of PI type controllers, the scope for finding a better control scheme still remains. In this regard, in this paper the new IP type controllers are considered as UPFC controllers. The parameters of these IP type controllers are tuned using Genetic Algorithms (GA). Also a stabilizer supplementary controller based UPFC is considered for increasing power system damping. To show the ability of IP controllers, this controller is compared with classical PI type controllers. Simulation results emphasis on the better performance of IP controller in comparison with PI controller.