• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 학술회의 논문집 정보 및 제어부문 A
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• pp.255-258
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• 2003

It is hard to centrol the wheeled mobile robot because of uncertainty of modeling, non-holonomic constraint and so on. To solve the problems, we design the controller of wheeled mobile robot based on fuzzy-neural network algorithm. In this paper, we should research the problem of classical controller for path-tracking algorithm and design of Fuzzy-Neural Network algorithm controller. Classical controller acquired different control value according to change of initial position and direction. In this control value having very difficult and having acquired a lot of trial and error Fuzzy is implemented to adaptive adjust control value by error and change of error and neural network is implemented to adaptive adjust the control gain during the optimization. The computer simulation shows that the proposed fuzzy-neural network controller is effective.

• 대한전기학회논문지
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• 제41권2호
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• pp.199-208
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• 1992

MIESF(Modified Integral Error and State Feedback) controller suggested in order to control the processes with time delay is the control scheme that combines Smith predictor and IESF(Integral Error and State Feedback). This control scheme has better performance than the conventional PID controller incorporating Smith predictor with respect to the robustness and control performance for the modelling error. MIESF controller can be simply designed by pole assignment algorithm. BUT in such a case, it is difficult to find proper poles which gurantee robustness with respect to process parameter uncertainties. In order to solve the aforementioned difficulties, we suggest a new design method for MIESF controller and show the validity of the proposed design method.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 학술대회 논문집 전문대학교육위원
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• pp.106-109
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• 2003

The repeatability error creeps in every corner of mechanical design as mechanical design becomes diverse and complicated. Inkjet printing has inherent repeatability error problem due to its nature of seamless incremental image synthesis of partial images. Without the calibration for the repeatability error realization of high print quality or enhancement of other printing performance could be impaired. Printer designers have met this recurrent problem even before the inception of inkjet print device and contrived various solutions as their own intelectual proprietary. Also, it is a trend to perform necessary calibration without painstaking human intervention. To come up with another useful and proprietary solution has become an important ingredient in inkjet printer design. This paper presents such a solution developed at Digital Printing Division of Samsung Electronics Company.

• 대한전자공학회논문지TC
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• 제42권11호
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• pp.13-20
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• 2005

현대의 디지털통신기기나, 오디오/비디오 전자기기엔 항상 비바이나리 에러정정복부호기가 사용되는데 그중 필수적으로 사용되는 Reed-Solomon 복부호화기기의 설계에 대해 기술했다. 2,3 symbol RS 복호기설계법을 설명 후, 새로운 RS 부호화기의 설계법을 제시한다. 각각의 복부호화기기의 동작여부를 예를들어 test해보고 잘 동작함을 확인했다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1997년도 춘계학술대회논문집
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• pp.179-182
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• 1997

One-step inverse methods based on deformation theory causes some amount of error. The amount of error is generally increased as the deformation path is more complex. As a remedy, a new three dimensional multi-step inverse method is introduced for optimum design of blank shapes and strain distributions from desired final shapes. The approach extends a one-step inverse method to a multi-step inverse method in order to reduce the amount of error. The algorithm developed is applied to square cup drawing to confirm its validity by demonstrating reasonably accurate numerical results.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집A
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• pp.548-553
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• 2000

A new design of cylindrical capacitive sensor(CCS) for the displacement measurement of precision active magnetic bearing(AMB) spindle is presented in this paper. This research is motivated by the problem that existing 4-segment CCS is still sensitive to the $3^{rd}$ harmonic component of the geometric errors of a rotor. The procedure of designing new CCS starts from the modeling and error analysis of CCS. The angular size of CCS is set up as a design parameter, and new 8-segment CCS is introduced to possess an arbitrary angular size. The optimum geometry of CCS to minimize the effect of geometric errors is determined through minimum norm approach. Experimental results with test rotors have confirmed the improvement in geometric error suppression.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 B
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• pp.537-540
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• 1998

This thesis deals with the design problem of the state estimator for digital servo system. Digital servo system has input time delay, which depends on the size of control algorithm. The delayed input is a factor that brings out the state estimation error. So, in order to reduce this state estimation error of the system, we proposes a state estimator in which the delayed input of the system is considered. At first, a discrete-time state-space model is established accounting for the delayed input. Next, the state estimator is designed based on this model. we employ Kalman filter algorithm in design of the state estimator. The performance of proposed state estimator is exemplified via some simulations and experiment for servo system. And robustness of the proposed estimator to modelling error by variation of the system parameter is also shown in these simulations.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 B
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• pp.992-994
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• 1995

FLC has a good performance for complication system or unknown model by using human linguistic method but many part control design are based on expert knowledge or trial-error method and it is difficult to prove stability and robustness of controller. In this paper we improve this problem by setting fuzzy rules by dividing phase plane of error and rate of error change by switching surface. We can guarantee the stability in nonlinear system, and also in fuzzy PID type controller the complexity of controller design is increased by increasing the number of input variables and defining more range of operation if we want performance of more specific rules, thus we need to fine the method to decrease the number of control rules used in FLC design. In this paper the algorithm is validated by simulation using conventional FLC and proposed method.

• Journal of Communications and Networks
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• 제14권2호
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• pp.199-205
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• 2012

This work investigates the progressive linear precoder design for packet retransmissions in multi-input multi-output (MIMO) systems with multiple codewords and automatic repeat request (ARQ) bundling feedback. Assuming perfect channel state information, a novel progressive linear ARQ precoder is proposed in the perspective of minimizing the packet error rate. We devise the ARQ precoder by combining power loading and sub channel pairing between current retransmission and previous transmissions. Furthermore, we extend the design to the case that the channel estimation error exists. Numerical results show that the proposed scheme can improve the performance of MIMO ARQ systems significantly regardless of the channel estimation error.

• 대한전기학회논문지:전력기술부문A
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• 제48권5호
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• pp.607-614
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• 1999

This paper deals with the design problem of the state estimator for servo system. The servo system has input time delay which depends on the computational time of control algorithm. The delayed input is a factor that brings out the state estimation error. So in order to reduce the state estimation error of the system, we propose a state estimator in which the delayed input of the system is considered. For this purpose, discrete time state space model is established accounting for the delayed input and a state estimator is designed based on this model. Kalman filter algorithm is employed in the design of the state estimator. The proposed estimator is used in the speed control of servo system with delayed input. Performance of the proposed state estimator is exemplified via simulations and experiments for servo system. Also, robustness of the proposed estimator to modeling error by variation of the system parameters is also shown in simulations.