• 제목/요약/키워드: Nonlinear systems

검색결과 4,487건 처리시간 0.041초

비선형 비행 시스템을 위한 H 접근법 기반 적응 신경망 동적 표면 제어 (Adaptive Neural Dynamic Surface Control via H Approach for Nonlinear Flight Systems)

  • 유성진;최윤호
    • 제어로봇시스템학회논문지
    • /
    • 제14권3호
    • /
    • pp.254-262
    • /
    • 2008
  • In this paper, we propose an adaptive neural dynamic surface control (DSC) approach with $H_{\infty}$ tracking performance for full dynamics of nonlinear flight systems. It is assumed that the model uncertainties such as structured and unstrutured uncertainties, and external disturbances influence the nonlinear aircraft model. In our control system, self recurrent wavelet neural networks (SRWNNs) are used to compensate the model uncertainties of nonlinear flight systems, and an adaptive DSC technique is extended for the disturbance attenuation of nonlinear flight systems. All weights of SRWNNs are trained on-line by the smooth projection algorithm. From Lyapunov stability theorem, it is shown that $H_{\infty}$ performance nom external disturbances can be obtained. Finally, we present the simulation results for a nonlinear six-degree-of-freedom F-16 aircraft model to confirm the effectiveness of the proposed control system.

지연된 출력을 갖는 비선형 시스템의 상태 관측기 (A State Observer of Nonlinear Systems with Delayed Output)

  • 이성렬
    • 제어로봇시스템학회논문지
    • /
    • 제18권7호
    • /
    • pp.613-616
    • /
    • 2012
  • This paper proposes the state observer design for nonlinear systems with delayed output. It is shown that by considering a nonlinear term of error dynamics as an additional state variable, the nonlinear error dynamics with time delay can be transformed into the linear one with time delay. Sufficient conditions for existence of a state observer are characterized by linear matrix inequalities. Finally, an illustrative example is given in order to show the effectiveness of our design method.

Observers for nonautonomous discrete-time nonlinear systems

  • Nam, Kwanghee;Lee, Wonchang
    • 제어로봇시스템학회:학술대회논문집
    • /
    • 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 22-24 Oct. 1991
    • /
    • pp.1828-1832
    • /
    • 1991
  • We study the observer design problem for nonautonomous discrete-time nonlinear systems. We investigate the structure of nonautonomous discrete-time systems which are state equivalent to the nonlinear observer form and characterize their class. Necessary and sufficient conditions for the existence of an input independent (local) diffeomorphism axe derived which transforms multi-input, multi-output nonlinear systems into the nonlinear observer form.

  • PDF

Neural Model Predictive Control for Nonlinear Chemical Processes

  • Song, Jeong-Jun;Park, Sunwon
    • 한국지능시스템학회:학술대회논문집
    • /
    • 한국퍼지및지능시스템학회 1993년도 Fifth International Fuzzy Systems Association World Congress 93
    • /
    • pp.899-902
    • /
    • 1993
  • A neural model predictive control strategy combining a neural network for plant identification and a nonlinear programming algorithm for solving nonlinear control problems is proposed. A constrained nonlinear optimization approach using successive quadratic programming combined with neural identification network is used to generate the optimum control law for complex continuous chemical reactor systems that have inherent nonlinear dynamics. The neural model predictive controller (MNPC) shows good performances and robustness. To whom all correspondence should be addressed.

  • PDF

LYAPUNOV FUNCTIONS FOR NONLINEAR DIFFERENCE EQUATIONS

  • Choi, Sung Kyu;Cui, Yinhua;Koo, Namjip
    • 충청수학회지
    • /
    • 제24권4호
    • /
    • pp.883-893
    • /
    • 2011
  • In this paper we study h-stability of the solutions of nonlinear difference system via the notion of $n_{\infty}$-summable similarity between its variational systems. Also, we show that two concepts of h-stability and h-stability in variation for nonlinear difference systems are equivalent. Furthermore, we characterize h-stability for nonlinear difference systems by using Lyapunov functions.

뉴로 퍼지 시스템을 이용한 비선형 시스템의 IMC 제어기 설계 (Design of IMC for Nonlinear Systems by Using Adaptive Neuro-Fuzzy Inference System)

  • 김성호;강정규
    • 제어로봇시스템학회논문지
    • /
    • 제7권11호
    • /
    • pp.958-961
    • /
    • 2001
  • Control of Industrial processes is very difficult due to nonlinear dynamics, effect of disturbances and modeling errors. M.Morari proposed Internal Model Control(IMC) system that can be effectively applied to the systems with model uncertainties and time delays. The advantage of IMC is their robustness with respect to a model mismatch and disturbances. But it is difficult to apply for nonlinear systems. ANFIS(Adaptive Neuro-Fuzzy Inference System) which contains multiple linear models as consequent part is used to model nonlinear systems. Generally, the linear parameters in ANFIS can be effectively utilized to control a nonlinear systems. In this paper, we propose new ANFIS-based IMC controller for nonlinear systems. Numerical simulation results show that the proposed control scheme has good performances.

  • PDF

Robust Nonlinear H$\infty$ FIR Filtering for Time-Varying Systems

  • Ryu, Hee-Seob;Son, Won-Kee;Kwon, Oh-Kyu
    • Transactions on Control, Automation and Systems Engineering
    • /
    • 제2권3호
    • /
    • pp.175-181
    • /
    • 2000
  • This paper investigates the robust nonlinear H$_{\infty}$ filter with FIR(Finite Impulse Response) structure for nonlinear discrete time-varying uncertain systems represented by the state-space model having parameter uncertainty. Firstly, when there is no parameter uncertainty in the system, the discrete-time nominal nonlinear H$_{\infty}$ FIR filter is derived by using the equivalence relationship between the FIR filter and the recursive filter, which corresponds to the standard nonlinear H$_{\infty}$ filter. Secondly, when the system has the parameter uncertainty, the robust nonlinear H$_{\infty}$ FIR filter is proposed for the discrete-time nonlinear uncertain systems.

  • PDF

입력지연을 갖는 이산 시간 비선형 시스템의 제어 (Control of Discrete Time Nonlinear Systems with Input Delay)

  • 이성렬
    • 제어로봇시스템학회논문지
    • /
    • 제18권6호
    • /
    • pp.509-512
    • /
    • 2012
  • This paper presents the state feedback control design for discrete time nonlinear systems where there exists a time delay in input. It is shown that under some boundedness condition, the time delay nonlinear systems can be transformed into the time delay linear systems with time varying parameters. Sufficient conditions for existence of stabilizing state feedback controller are characterized by linear matrix inequalities. Finally, an illustrative example is given in order to show the effectiveness of our design method.

뉴로 퍼지 시스템을 이용한 비선형 시스템의 IMC 제어기 설계 (Design of IMC Controller for Nonlinear Systems by Using Adaptive Neuro-Fuzzy Inference System)

  • 강정규;김정수;김성호
    • 제어로봇시스템학회:학술대회논문집
    • /
    • 제어로봇시스템학회 2000년도 제15차 학술회의논문집
    • /
    • pp.236-236
    • /
    • 2000
  • Control of Industrial processes is very difficult due to nonlinear dynamics, effect of disturbances and modeling errors. M.Morari proposed Internal Model Control(IMC) system that can be effectively applied to the systems with model uncertainties and time delays. The advantage of IMC systems is their robustness with respect to a model mismatch and disturbances. But it was difficult to apply for nonlinear systems. Adaptive Neuro-Fuzzy Inference System which contains multiple linear models as consequent part is used to model nonlinear systems. Generally, the linear parameters in neuro-fuzzy inference system can be effectively utilized to identify a nonlinear dynamical systems. In this paper, we propose new IMC design method using adaptive neuro-fuzzy inference system for nonlinear plant. Numerical simulation results show that proposed IMC design method has good performance than classical PID controller.

  • PDF

A Method for Separating Volterra Kernels of Nonlinear Systems by Use of Different Amplitude M-sequences

  • Harada, Hiroshi;Nishiyama, Eiji;Kashiwagi, Hiroshi;Yamaguchi, Teruo
    • 제어로봇시스템학회:학술대회논문집
    • /
    • 제어로봇시스템학회 1998년도 제13차 학술회의논문집
    • /
    • pp.271-274
    • /
    • 1998
  • This paper describes a new method for separation of the Volterra kernels which are identified by use of M-sequence. One of the authors has proposed a method for identification of Volterra kernels of nonlinear systems using M-sequence and correlation technique. When M-sequence are applied to a nonlinear systems, the cross-correlation function between the input and the output of the nonlinear systems includes cross-sections of high-order Volterra kernels. However, if various order Volterra kernels exixt on the obtained cross-correlation function, it is difficult to separate the Volterra kernels. In this paper, the authors show that the magnitude of Volterra kernels is maginified by the amplitude of M-sequence according to the order of Volterra kernels. By use of this property, each order Volterra kernels is obtained by solving linear equations. Simulations are carried out for some nonlinear systems. The results show that Volterra kernels can be separated in each order successfully by the proposed method.

  • PDF