• International Journal of Control, Automation, and Systems
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• v.6 no.2
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• pp.194-203
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• 2008

Iterative learning control (ILC) is a simple and effective method for the control of systems that perform the same task repetitively. ILC algorithm uses the repetitiveness of the task to track the desired trajectory. In this paper, we propose a PID (proportional plus integral and derivative) type ILC update law for control discrete-time single input single-output (SISO) linear time-invariant (LTI) systems, performing repetitive tasks. In this approach, the input of controlled system in current cycle is modified by applying the PID strategy on the error achieved between the system output and the desired trajectory in a last previous iteration. The convergence of the presented scheme is analyzed and its convergence condition is obtained in terms of the PID coefficients. An optimal design method is proposed to determine the PID coefficients. It is also shown that under some given conditions, this optimal iterative learning controller can guarantee the monotonic convergence. An illustrative example is given to demonstrate the effectiveness of the proposed technique.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.7
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• pp.1777-1786
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• 1996

This paper describes theories and implementation techniques of a digital high-definition television(HDTV) modem based on 32-QAM for terrestrial broadcasting. We proposed a digital demodulation scheme and a symbol timing recovery structure based on the band edge component maximization(BECM) method. The adaptive equalizer has 256 complex taps to remove the multipath of delays ranging from -2.mu.s~+24.mu.s with a new T/2-spaced blind equalization algorithm. computer simulation results reveal that the proposed algorithm outperforms other conventional blind equalization algorithm a digital HDTV modem with 4.91MHz symobol rate is implemented by utilizing the proposed algorithms. All processings for modem operations such as demodulation, estimation of symbol timing phase error, adaptive equalization, and carrier recovery except IF signal processing and sampling phase control part of the AD converter are done in digital domain. Especially, the carrier recovery loop can track a carrier offset of upto .+-.350KHz.

• KIEE International Transaction on Systems and Control
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• v.2D no.2
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• pp.108-114
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• 2002

This paper describes the design of a robust adaptive controller for a nonlinear dynamical system with unknown nonlinearities. These unknown nonlinearities are approximated by multilayered neural networks (MNNs) whose parameters are adjusted on-line, according to some adaptive laws far controlling the output of the nonlinear system, to track a given trajectory. The main contribution of this paper is a method for considering input constraint with a rigorous stability proof. The Lyapunov synthesis approach is used to develop a state-feedback adaptive control algorithm based on the adaptive MNN model. An overall control system guarantees that the tracking error converges at about zero and that all signals involved are uniformly bounded even in the presence of input saturation. Theoretical results are illustrated through a simulation example.

• The Transactions of the Korean Institute of Power Electronics
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• v.25 no.1
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• pp.29-36
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• 2020

In this study, a variable step algorithm is proposed on the basis of the perturb and observe method. The proposed algorithm can follow the maximum power point (MPP) quickly when solar irradiance changes rapidly. The proposed technique uses the voltage change characteristic at the MPP when the environment changes because of insolation or temperature. The MPP is tracked through the voltage control using a variable step method. This method determines the sudden change of solar irradiance by setting the threshold value and operates in fast tracking mode to track the MPP rapidly. When the operation point reaches the MPP, the mode switches to the variable step mode to minimize the steady state error. In addition, the output disturbance is decreased through the optimization of the control method design. The performance of the proposed MPPT algorithm is verified through simulation and experiment.

• Proceedings of the KIEE Conference
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• 1996.11a
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• pp.46-48
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• 1996

In almost all the servo systems, especially for the robot manipulators and numerical control systems, there are resonance effects and nonlinear frictions which should be considered in designing servo controllers. In this paper to compensate friction and track the step-input without steady-state error, the original system is augmented with an integrator and employes $\mu$-Controller design method $\mu$-Controller design method enables to meet not only performance requirements but robust stabilities simultaneously. And there may exist a limit cycles due to interaction between integrator and nonlinear friction. With describing function method, the possibility of limit cycle is checked.

• Journal of the Korea Institute of Military Science and Technology
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• v.9 no.2 s.25
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• pp.77-86
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• 2006

Usually, a tracking-gate of the tracker is used to track the target radar signal in the active ECM system. In this paper, we propose the feed-back tracking-gate filtering method. The designed method applies a tracking-gate of the tacker to the ECM system's receiver as a rejection or pass filter selected by the receiver's purpose, and the specific target signals can be passed or rejected though this tracking-gate filter. Thus, the number of input signals within the receiver's search band is minimized owing to this filter except the target signals. In conclusion, the EW equipment's reaction time can be reduced and the error value about the target signals can be lower than the previous methods'.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.235-237
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• 2017

We suggest a way to improve the performance of a target distance estimation algorithm using Kalman Filter to compensate for the error that occurs when the target track information over the Combat Radio Network is lost.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.11a
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• pp.790-795
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• 2000

디스크마다 일정영역을 할당하여 위치정보를 기록하는 임베디드 서보방식 하드디스크는 데이터가 저장되는 데이터 영역사이에서 스핀들 런아웃, 공진과 디스크 플러터 등에 의하여 Gaussian 분포를 가지는 트랙에서 벗어나는 오차를 가지게 된다. 더높은 저장밀도와 빠른 기록속도를 요구함에 따라서 디스크의 회전속도가 올라감에 의한 디스크 면진동에 의한 헤드 위치오차가 중요하게 대두되고 있다. 본 연구에서는 헤드위치 오차량을 계산하기 위하여 고속탐색이 가능한 수정된 Barasch의 수치해석법, 유한요소법, 그리고 실험을 통하여 적용가능성을 확인하였으며 같은 드라이브내에서 디스크의 사이즈를 바꿈에 의한 디스크 동특성의 해석과 변환율을 이용하여 오류가 발생할 수 있는 트랙 벗어남과 저장밀도의 상관관계를 살펴보았다.

• Journal of the Korea Society of Computer and Information
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• v.7 no.3
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• pp.49-55
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• 2002

This paper proposes speaker recognition algorithm which includes both the pitch parameter and the fuzzy. This study proposes a pitch detection method for the peak and valley pitch detection function by means of comparing spectra which utilizes the transform characteristics between time and frequency. It measures the similarity to the original spectrum while arbitrarily varying the period in the time domain. It heavily weights the error due to the changing characteristics of the phonemes, while it is strong against noise. In this paper, makes reference pattern using membership function and performs vocal track recognition of common character using fuzzy pattern matching in odor to include time variation width for non-linear utterance time.

• Journal of the Korea Society of Computer and Information
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• v.5 no.3
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• pp.51-57
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• 2000

This paper proposes speaker recognition algorithm which includes both the pitch and the fuzzy. This study proposes a pitch detection method for the peak and valley pitch detection function by means of comparing spectra which utilizes the transform characteristics between time and frequency. It measures the similarity to the original spectrum while arbitrarily varying the period in the time domain. It heavily weights the error due to the changing characteristics of the phonemes, while it is strong against noise. In this paper, makes reference pattern using membership function and performs vocal track recognition of common character using fuzzy pattern matching in order to include time variation width for non-linear utterance time.