• Journal of the Institute of Electronics Engineers of Korea SC
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• v.46 no.2
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• pp.52-60
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• 2009

This paper proposes a digital controller for a nonlinear multi-input/multi-output(MIMO) system with time-delayed input. A nonlinear system with multi-input time delay is discretized using Taylor's discretization method, and the discretized system can be converted into a general nonlinear system. Consequently, general nonlinear controller synthesis can be applied to the discretized time-delay system We adopted MAC controller synthesis and verified the performance of the proposed method by conducting computer simulations. The results of the simulation showed that the proposed controller synthesis performs well and the proposed method is useful for controlling a nonlinear time-delay system.

• Journal of the Korean Institute of Telematics and Electronics
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• v.19 no.6
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• pp.67-79
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• 1982

The stability of general pulse-width modulation system with Gaussian random disturbance was discussed . General system is divided into nonlinear and linear elements using the conventional describing function method. The concept of the equivalent admittance was used to find the transfer characteristic of the nonlinear element of the system. In this paper the self-sustained oscillation condition in the autonomous system was derived and the results was analyzed with computer simulation.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.185-190
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• 1991

In this paper, we present a method of analising a system with nonlinear parameter by pole sensitivity defined by the rate of pole movement with respect of non-linear parameter variation. Pole sensitivity give us not only the rate of pole movement but also the directional information. We present a method of design of a state feedback for a system with nonlinear system parameter by considering the pole sensitivity and show that the suggested method guarantee the stability robustness for a system with nonlinear parameter, parameter perturbation and urimodelled dynamics.

• Korean Journal of Mathematics
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• v.24 no.2
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• pp.181-198
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• 2016

In this work, we suggest a new system of generalized nonlinear regularized nonconvex variational inequalities in a real Hilbert space and establish an equivalence relation between this system and fixed point problems. By using the equivalence relation we suggest a new perturbed projection iterative algorithms with mixed errors for finding a solution set of system of generalized nonlinear regularized nonconvex variational inequalities.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.53 no.9
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• pp.630-637
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• 2004

In this paper, we present a local reduced-order observer for a class of nonlinear systems that have full robust relative degree. The proposed observer utilizes the coordinate change which transforms a nonlinear system into an approximate normal form. The proposed reduce order observer is applied to a ball and beam system, and simulation results show that substantial improvement in the performance was achieved compared with the jacobian linearization observers.

• Journal of IKEEE
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• v.11 no.1 s.20
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• pp.1-14
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• 2007

In this paper, a design of an integral augmented nonlinear optimal variable structure system(INOVSS) is presented for the prescribed output control of uncertain MIMO systems under persistent disturbances. This algorithm basically concerns removing the problems of the reaching phase and combining with the nonlinear optimal control theory. By means of an integral nonlinear sliding surface, the reaching phase is completely removed. The ideal sliding dynamics of the integral nonlinear sliding surface is obtained in the form of the nonlinear state equation and is designed by using the nonlinear optimal control theory, which means the design of the integral nonlinear sliding surface and equivalent control input. The homogeneous $2{\upsilon}(\kappa)$ form is defined in order to easily select the $2{\upsilon}$ or even $(\kappa)-form$ higher order nonlinear terms in the suggested sliding surface. The corresponding nonlinear control input is designed in order to generate the sliding mode on the predetermined transformed new surface by means of diagonalization method. As a result, the whole sliding output from a given initial state to origin is completely guaranteed against persistent disturbances. The prediction/predetermination of output is enable. Moreover, the better performance by the nonlinear sliding surface than that of the linear sliding surface can be obtained. Through an illustrative example, the usefulness of the algorithm is shown.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.2551-2554
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• 2003

In this paper, we describe the nonlinear character for a friction control. The nonlinear character of friction control is inherent in mechanical system, which has gained more and more interest. The modeling and compensation of nonlinear friction are difficult tasks for precise motion control. This paper is performance evaluation of nonlinearities and mechanical compliance exists together with friction control system.

• Journal of Electrical Engineering and Technology
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• v.10 no.4
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• pp.1843-1850
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• 2015

Controlling nonlinear systems with linear feedback control methods can lead to chaotic behaviors. Order increase in system dynamics due to integral control and control parameter variations in PID controlled nonlinear systems are studied for possible chaos regions in the closed-loop system dynamics. The Lur’e form of the feedback systems are analyzed with Routh’s stability criterion and describing function analysis for chaos prediction. Several novel chaotic systems are generated from second-order nonlinear systems including the simplest continuous-time chaotic system. Analytical and numerical results are provided to verify the existence of the chaotic dynamics.

• 제어로봇시스템학회:학술대회논문집
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• 1987.10b
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• pp.346-351
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• 1987

In this study, digital simulation with nonlinear modeling is carried out to analyse the performance of a hydraulic servomotor system developed for the position control of a large inertia. Nonlinear element, such as nonlinear pressure flow relationships of servovalve, valve spool limits, nonlinear friction, and backlash and resilience of gear system are included in the simulation along with the dynamic characteristics of variable delivery pump compensation mechanism. Simulation results are compared with experimental results for both step and sinusoidal inputs. Independent of input magnitude, both results are in good agreement with minor differences in detail.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2001.06a
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• pp.125-128
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• 2001

In this paper, We proposed the nonlinear controller and observer design for a ball and beam system. Unfortunately, for the ball and beam system, the control coefficient is zero whenever the angular velocity or ball position are zero. Therefore, the relative degree of the ball and beam system is not well defined. The presented the nonlinear controller and observer design is based on the approximation input-output feedback linearization. And we verified that the proposed nonlinear controller and observer scheme is the feasible through a computer simulation.