• Title/Summary/Keyword: Non-linear System

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Design of Rotary Inverted Pendulum applying an Embedded System and Implementation by PID (Embeded system을 적용한 Rotary Inverted Pendulum 설계 및 PID에 의한 구현)

  • 김영춘;김정훈;김영탁;김동한
    • Proceedings of the IEEK Conference
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    • 2002.06e
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    • pp.5-8
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    • 2002
  • In this paper, we applied a PC interface and an embedded system in order to design a non-linear system and implement the PID algorithm as our control one. We used the inverted pendulum, one of the most generally used non-linear system models, to control uncertain factors in the environment. This paper showed how to use this non-linear system model to control the factors completely as well as to understand the PID algorithm. Furthermore, this paper applied and understood the embedded system.

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Approximate Response of a Non-linear Vibration Isolation System Using the Harmonic Balance Method (하모닉 밸런스법을 이용한 비선형 진동절연 시스템의 근사적 응답)

  • Lee, Gun-Myung
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.17 no.6
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    • pp.124-129
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    • 2018
  • A non-linear vibration isolation system which is composed of a non-linear spring and a linear damper was proposed in past research. When the support of the isolation system is excited harmonically, the response component of the isolation system mass at the excitation frequency has been calculated approximately using the harmonic balance method. The response was approximated by a single mode, and the result was compared with a numerical result which is assumed as an accurate one. Next, the response was approximated by two modes, and the result was compared with the former one.

Effectiveness of non-linear fluid viscous dampers in seismically isolated buildings

  • Guler, Elif;Alhan, Cenk
    • Earthquakes and Structures
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    • v.17 no.2
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    • pp.191-204
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    • 2019
  • Near-field earthquake records including long-period high-amplitude velocity pulses can cause large isolation system displacements leading to buckling or rupture of isolators. In such cases, providing supplemental damping in the isolation system has been proposed as a solution. However, it is known that linear viscous dampers can reduce base displacements in case of near-field earthquakes but at the potential expense of increased superstructure response in case of far-field earthquakes. But can non-linear dampers with different levels of non-linearity offer a superior seismic performance? In order to answer this question, the effectiveness of non-linear viscous dampers in reducing isolator displacements and its effects on the superstructure response are investigated. A comparison with linear viscous dampers via time history analysis is done using a base-isolated benchmark building model under historical near-field and far-field earthquake records for a wide range of different levels of non-linearity and supplemental damping. The results show that the non-linearity level and the amount of supplemental damping play important roles in reducing base displacements effectively. Although use of non-linear supplemental dampers may cause superstructure response amplification in case of far-field earthquakes, this negative effect may be avoided or even reduced by using appropriate combinations of non-linearity level and supplemental damping.

Vibration of Non-linear System under Random Parametric Excitations by Probabilistic Method (불규칙 매개변수 가진을 받는 비선형계의 확률론적 진동평가)

  • Lee, Sin-Young
    • Journal of the Korean Society for Precision Engineering
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    • v.23 no.12 s.189
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    • pp.72-79
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    • 2006
  • Vibration of a non-linear system under random parametric excitations was evaluated by probabilistic methods. The non-linear characteristic terms of a system structure were quasi-linearized and excitation terms were remained as they were An analytical method where the square mean of error was minimized was used An alternative method was an energy method where the damping energy and restoring energy of the linearized system were equalized to those of the original non-linear system. The numerical results were compared with those obtained by Monte Carlo simulation. The comparison showed the results obtained by Monte Carlo simulation located between those by the analytical method and those by the energy method.

Vibration Evaluation of Non-linear System under Random Excitations by Probabilistic Method (불규칙 가진을 받는 비선형계의 확률론적 진동평가)

  • Lee Sin-Young
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2006.05a
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    • pp.113-114
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    • 2006
  • Vibration of a non-linear system under random excitations was evaluated by probabilistic methods. The non-linear characteristic terms of a system structure were quasi-linearized and excitation terms were remained as they were. An analytical method where the square mean of error was minimized was used. An alternative method was an energy method where the damping energy and restoring energy of the linearized system were equalized to those of the original non-linear system. The numerical results were compared with those obtained by Monte Carlo simulation. The comparison showed the results obtained by Monte Carlo simulation located between those by the analytical method and those by the energy method.

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STABILITY AND BIFURCATION IN A DIFFUSIVE PREY-PREDATOR SYSTEM : NON-LINEAR BIFURCATION ANALYSIS

  • Bhattacharya, Rakhi;Bandyopadhyay, Malay;Banerjee, Sandip
    • Journal of applied mathematics & informatics
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    • v.10 no.1_2
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    • pp.17-26
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    • 2002
  • A stability analysis of a non-linear prey-predator system under the influence of one dimensional diffusion has been investigated to determine the nature of the bifurcation point of the system. The non-linear bifurcation analysis determining the steady state solution beyond the critical point enables us to determine characteristic features of the spatial inhomogeneous pattern arising out of the bifurcation of the state of the system.

Quasi-linearization of non-linear systems under random vibration by probablistic method (확률론 방법에 의한 불규칙 진동 비선형 계의 준선형화)

  • Lee, Sin-Young;Cai, G.Q.
    • Proceedings of the KSME Conference
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    • 2008.11a
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    • pp.785-790
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    • 2008
  • Vibration of a non-linear system under random parametric excitations was evaluated by probablistic methods. The non-linear characteristic terms of a system were quasi-linearized and excitation terms were remained as they were given. An analytical method where the square mean of error was minimized was ysed. An alternative method was an energy method where the damping energy and rstoring energy of the linearized system were equalized to those of the original non-linear system. The numerical results were compared with those obtained by Monte Carlo simulation. The comparison showed the results obtained by Monte Carlo simulation located between those by the analytical method and those by the energy method.

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Performance analysis of Binary Clipping PW-CDMA against non-linear distortion over Flat fading Channel (Flat 페이딩 채널환경에서 비선형 왜곡에 대한 Binary Clipping PW-CDMA 성능 분석)

  • 김현욱;안치훈;옥경준;정준엽;김동구
    • Proceedings of the IEEK Conference
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    • 2003.11c
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    • pp.297-301
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    • 2003
  • The binary clipping PW/CDMA system is considered. This system can be constructed with effective cost. leading to reduce the influence of the non-linear amplifier because of converting multi-level signals into constant envelope signals. In addition, the clipping method which is to clip out signal amplitude at some level when multi-level signals are converted into constant envelope signals is used. The multi-level signals are clipped at 1 and -1 to limit the extension of bandwidth and to maintain the bandwidth after clipping. In this paper, the performance of the binary clipping PW/CDMA system with the non-linear amplifier analyzed by simulation over AWGN and flat fading channels respectively. The binary clipping PW/CDMA system with the non-linear amplifier is 2.2dB and 0.9dB better than conventional DS/CDMA system over the flat fading channels when the number of users are 9 and 17 respectively.

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A Study on the State Space Identification Model of the Dynamic System using Neural Networks (신경회로망을 이용한 동적 시스템의 상태 공간 인식 모델에 관한 연구)

  • 이재현;강성인;이상배
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • 1997.10a
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    • pp.115-120
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    • 1997
  • System identification is the task of inferring a mathematical description of a dynamic system from a series of measurements of the system. There are several motives for establishing mathematical descriptions of dynamic systems. Typical applications encompass simulation, prediction, fault diagnostics, and control system design. The paper demonstrates that neural networks can be used effective for the identification of nonlinear dynamical systems. The content of this paper concerns dynamic neural network models, where not all inputs to and outputs from the networks are measurable. Only one model type is treated, the well-known Innovation State Space model(Kalman Predictor). The identification is based only on input/output measurements, so in fact a non-linear Extended Kalman Filter problem is solved. Even for linear models this is a non-linear problem without any assurance of convergence, and in spite of this fact an attempt is made to apply the principles from linear models, an extend them to non-linear models. Computer simulation results reveal that the identification scheme suggested are practically feasible.

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Dynamic Analysis of a Geometrical Non-linear Plate (기하학적 비선형성을 갖는 평판의 동특성 해석)

  • 임재훈;최연선
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2003.11a
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    • pp.498-503
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    • 2003
  • Dynamic analysis of a plate with non-linearity due to large deformation is performed in the study. There have been many researches about the non-linear dynamic behavior of plates examining by means of theoretical or numerical analyses. But it is important how exactly model the actual system. In this respect, the Continuous-Time system identification technique is used to generate non-linear models, for stiffness and damping terms, to explain the observed behaviors with single mode assumptions for the simplicity after comparing the experimental results with the numerical results of a linear plate model.

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