• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1989년도 한국자동제어학술회의논문집; Seoul, Korea; 27-28 Oct. 1989
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• pp.1069-1074
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• 1989

A discrete-time learning control for robotic manipulators is studied using its pulse transfer function. Firstly, discrete-time learning stability condition which is applicable to single-input two-outputs systems is derived. Secondly, stability of learning algorithm with position signal is studied. In this case, when sampling period is small, the algorithm is not stable because of an unstable zero of the system. Thirdly, stability of algorithm with position and velocity signals is studied. In this case, we can stabilize the learning control system which is unstable in learning with only position signal. Finally, simulation results on the trajectory control of robotic manipulators using the discrete-time learning control are shown. This simulation results agree well with the analytical ones.

• 제어로봇시스템학회논문지
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• 제4권5호
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• pp.579-584
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• 1998

This paper presents an efficient algorithm which determines the parameters of discrete PID controller. The proposed algorithm is an algebraic method to obtain controller parameters using ROM(Reduced Order Model), which can not only make design procedure simple but also reduce the computational burden required for controller implementation. Also, by solving a set of linear equations based on least squares method, the proposed method can make the controller design procedure systematic. Simple examples are given to demonstrate the effectiveness of our method when compared with widely-used conventional method.

• 대한전기학회논문지
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• 제45권3호
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• pp.407-414
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• 1996

In this paper we consider the variable structure control for a class of discrete-time uncertain multivariable systems where the nominal system is linear. Discrete-time switching dynamics are introduced so that a new type of state trajectories called sliding mode may exist on the sliding surface by state feedback. The quantitative analysis for the matched uncertainties will show that every response of the system with the proposed switching dynamics is bounded within small neighborhoods of the state-space origin. Also, by the similarity transformation it will be shown that the eigenvalues of the closed-loop systems are composed of those of the subsystems which govern the range-space dynamics and null-space dynamics. It will be also shown that ideal sliding mode can be obtained in the absence of uncertainties due to one-step attraction to the sliding surface regardless of initial position of states. (author). 12 refs., 2 figs.

• Journal of Information Processing Systems
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• 제12권4호
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• pp.754-764
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• 2016

The exhaustive list of sparsification methods for a digital image suffers from achieving an adequate number of zero and near-zero coefficients. The method proposed in this paper, which is known as the Discrete Rajan Transform Sparsification, overcomes this inadequacy. An attempt has been made to compare the simulation results for benchmark images by various popular, existing techniques and analyzing from different aspects. With the help of Discrete Rajan Transform algorithm, both lossless and lossy sparse representations are obtained. We divided an image into $8{\times}8-sized$ blocks and applied the Discrete Rajan Transform algorithm to it to get a more sparsified spectrum. The image was reconstructed from the transformed output of the Discrete Rajan Transform algorithm with an acceptable peak signal-to-noise ratio. The performance of the Discrete Rajan Transform in providing sparsity was compared with the results provided by the Discrete Fourier Transform, Discrete Cosine Transform, and the Discrete Wavelet Transform by means of the Degree of Sparsity. The simulation results proved that the Discrete Rajan Transform provides better sparsification when compared to other methods.

• 조명전기설비학회논문지
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• 제24권12호
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• pp.193-200
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• 2010

In this paper, the eigenvalue sensitivity analysis is calculated in the power system which is including both generator controllers such as Exciter, PSS and thyristor controlled FACTS devices in transmission lines such as TCSC. Exciter and PSS are continuously operating controllers but TCSC has a switching device which operates non-continuously. To analyze both continuous and non-continuous operating equipments, the RCF method one of the numerical analysis method in discrete time domain is applied using discrete models of the power system. Also the eigenvalue sensitivity calculation algorithm using state transition equations in discrete time domain is devised and applied to a sampled system. As a result of simulation, the eigenvalue sensitivity coefficients calculated using discrete system models in discrete time domain are changed periodically and showed different values compared to those of continuous system model in time domain by the effect of periodic switching operations of TCSC.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1987년도 정기총회 및 창립40주년기념 학술대회 학회본부
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• pp.439-443
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• 1987

This paper presents a method for constructing model of manufacturing processes for simulation and design of the discrete control logic. The models represent the discrete vent evolution of the system as well as features of the underlying continues processes, for applications such as discrete parts manufacture and assembly, the process is decomposed into operations and for each operation the required resources and associated discrete resource slates are Identified. The structure of the discrete-level control is modeled by modified Perti nets which are synthesized from single resource activity cycles. Construction of nets provides discrete control logic with guaranteed properties based on extended Petri nets theory, for illustration, the proposed method is applied to the high-level discrete control of a two-robotic assembly cell.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.430-433
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• 1997

In this paper, an intervalwise receding horizon control (IRHC) is proposed which stabilizes linear continuous and discrete time-varying systems each other by means of a feedback control stemming from a receding horizon concept and a minimum quadratic cost. The results parallel those obtained for continuous [4],[9] and discrete time varying system [5],[15] each other.

• 한국시뮬레이션학회논문지
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• 제3권1호
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• pp.75-88
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• 1994

Discrete event modeling is finding ever more application to anlysis and design of complex manufacturing, communication, computer systems, etc. This paper shows how packet network systems may be advantageously represented as DEVS (Discrete Event System Specification) models by employing System Entity structure / Model base (SES/MB) framework developed by Zeigler. DEVS models and network structure representations support a strong basis for performance analysis of packet network systems. This approach is illustated in a typical packet network example with several routing strategies.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국내학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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• pp.836-841
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• 1993

For a class of discrete-time nonlinear systems, an iterative learning control method is proposed and a sufficient condition is derived for the convergence of the output error. The proposed method is shown to be less sensitive to modelling errors and the uniform boundedness of the output error is guaranteed even in the presence of initial state errors. It is illustrated by simulations that the actual output converges to a desired output within the tolerance bound and convergence performance is improved by the presented method.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1993년도 한국자동제어학술회의논문집(국내학술편); Seoul National University, Seoul; 20-22 Oct. 1993
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• pp.189-194
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• 1993

This paper presents an ARW(Anti-Reset Windup) method for discrete-time control systems with saturation nonlinearites. The method is motivated by the concept of the equilibrium point. The design parameters of the ARW scheme is explicitly derived by minimizing a reasonable performance index. The proposed method is closely related with the singular perturbed theory. The proposed method is applicable to any open-loop stable plants with saturation nonlinearities whose controllers are determined a priori by some design technique.