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Continuous-time Systems (continuous-time + system)

Distribution by Scientific Domains
Engineering76%

Kinds of Continuous-time Systems

  • nonlinear continuous-time system
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    Selected Abstracts

    Fuzzy scheduling strategy for generalized switched server systems and its robustness over system heterogeneity

    INTERNATIONAL JOURNAL OF INTELLIGENT SYSTEMS, Issue 3 2009
    Xingxuan Wang
    Generalized switched server system, a discretely controlled continuous-time system, in which N tanks are used to represent N parallel entities, respectively, can be employed to address a class of load-balancing problems. A tank-pair model is a system that consists of two tanks and a single input single output controller, which regulates the inflows of the two tanks to acquire the two uniform levels under the specified inflow constraints. According to a quantized observation of the N tank levels, some discrete events are generated, and based on certain event feedback strategy, switching the location of the tank-pair can control all the N tanks in a time-sharing manner to acquire the N levels uniformity. Different from some existing scheduling strategies, this study proposes a fuzzy scheduling strategy (FSS) for such generalized switched server systems. Special measures are taken to reduce the N -inputs two-outputs fuzzy inference to a two-inputs one-output one, which greatly facilitates fuzzy scheduler design. Simulation results show that the proposed FSS strategy outperforms over the three existing scheduling strategies as a whole, and they also show that the proposed FSS strategy demonstrates high robustness over system heterogeneity. © 2009 Wiley Periodicals, Inc. [source]

    Observer design for nonlinear discrete-time systems: Immersion and dynamic observer error linearization techniques

    INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 5 2010
    Jian Zhang
    Abstract This paper focuses on the observer design for nonlinear discrete-time systems by means of nonlinear observer canonical form. At first, sufficient and necessary conditions are obtained for a class of autonomous nonlinear discrete-time systems to be immersible into higher dimensional observer canonical form. Then a method called dynamic observer error linearization is developed. By introducing a dynamic auxiliary system, the augmented system is shown to be locally equivalent to the generalized observer form, whose nonlinear terms contain auxiliary states and output of the system. A constructive algorithm is also provided to obtain the state coordinate transformation. These results are an extension of their counterparts of nonlinear continuous-time systems to nonlinear discrete-time systems (Syst. Control Lett. 1986; 7:133,142; SIAM. J. Control Optim. 2003; 41:1756,1778; Int. J. Control 2004; 77:723,734; Automatica 2006; 42:321,328; IEEE Trans. Automat. Control 2007; 52:83,88; IEEE Trans. Automat. Control 2004; 49:1746,1750; Automatica 2006; 42:2195,2200; IEEE Trans. Automat. Control 1996; 41:598,603; Syst. Control Lett. 1997; 31:115,128). Copyright © 2009 John Wiley & Sons, Ltd. [source]

    On stabilization of nonlinear systems under data rate constraints using output measurements

    INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 6 2006
    C. De Persis
    Abstract We present a contribution to the problem of semi-global asymptotic stabilization of nonlinear continuous-time systems under data rate constraints when only output measurements are available. We consider systems which are uniformly observable and we point out that the design of an ,embedded-observer' decoder and a controller which semi-globally stabilize this class of systems under data-rate constraints requires an appropriate choice of the observer gain and the data rate. Copyright © 2006 John Wiley & Sons, Ltd. [source]

    Output regulation of discrete-time linear plants subject to state and input constraints

    INTERNATIONAL JOURNAL OF ROBUST AND NONLINEAR CONTROL, Issue 8 2003
    Guoyong Shi
    Abstract Discrete-time output regulation of linear systems with state and/or input constraints on magnitude is considered. Structural properties of linear plants are identified under which the so-called constrained semi-global and global output regulation problems are solvable. As in the case of continuous-time systems, an important aspect of our development is a taxonomy of constraints showing a clear relationship between the constraint types and the output regulation results. Solvability conditions are developed for semi-global and global output regulation problems. Appropriate regulators are constructed for problems that are solvable. Copyright © 2003 John Wiley & Sons, Ltd. [source]

    Fault detection in nonlinear continuous-time systems with uncertain parameters

    AICHE JOURNAL, Issue 9 2008
    Youdong Lin
    Abstract In model-based fault diagnosis for dynamic systems with uncertain parameters, an envelope of all fault-free behaviors can be determined from the model and used as a reference for detecting faults. We demonstrate here a method for generating an envelope that is rigorously guaranteed to be complete, but without significant overestimation. The method is based on an interval approach, but uses Taylor models to reduce the overestimation often associated with interval methods. To speed fault detection, a method that uses bounded-error measurement data and a constraint propagation procedure is proposed for shrinking the envelope. Several fault detection scenarios involving nonlinear, continuous-time systems are used to evaluate this approach. © 2008 American Institute of Chemical Engineers AIChE J, 2008 [source]

    Rejection of persistent-bounded disturbances in linear time-delay systems by output-feedback

    OPTIMAL CONTROL APPLICATIONS AND METHODS, Issue 4 2010
    Magdi S. Mahmoud
    Abstract In this paper, the problem of persistent-bounded disturbance rejection of linear continuous-time systems with time-varying delays is investigated using the tools of invariant set analysis and Lyapunov-function methodology. We derive less conservative sufficient conditions on robust attractor for time-delay systems in terms of strict linear matrix inequalities (LMIs) to guarantee the desired ,1 -performance. A robust output-feedback controller is designed and the associated gain is determined using strict LMIs. The developed results are tested on two representative time-delay examples. Copyright © 2009 John Wiley & Sons, Ltd. [source]

    Unified approach for Euler,Lagrange equation arising in calculus of variations

    OPTIMAL CONTROL APPLICATIONS AND METHODS, Issue 6 2004
    D. S. Naidu
    Abstract We address the development of a unified approach for the necessary conditions for optimization of a functional arising in calculus of variations. In particular, we develop a unified approach for the Euler,Lagrange equation, that is simultaneously applicable to both shift (q)-operator-based discrete-time systems and the derivative (d/dt)-operator-based continuous-time systems. It is shown that the Euler,Lagrange results that are now obtained separately for continuous- and discrete-time systems can be easily obtained from the unified approach. An illustrative example is given. Copyright © 2005 John Wiley & Sons, Ltd. [source]

    Multi-objective state feedback control for linear delay systems

    ASIAN JOURNAL OF CONTROL, Issue 4 2010
    Wei Xie
    Abstract This paper provides new linear matrix inequalities (LMI)-based formulae for mixed H2/H, state-feedback synthesis of linear continuous-time systems with state delays of any size. The proposed delay-independent LMI-based conditions enable us to parameterize a memoryless state-feedback controller without involving the Lyapunov variables in the formula. Compared with previous results based on a common Lyapunov variable, the proposed formula provides less conservative results. Copyright © 2010 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society [source]

    A new tracking controller for discrete-time SISO non minimum phase systems,

    ASIAN JOURNAL OF CONTROL, Issue 1 2010
    Mohsen Ruzbehani
    Abstract A new tracking controller for discrete-time Single Input Single Output (SISO) non-minimum phase (NMP) systems is presented. In the proposed method, after cancelation of poles and cancelable zeros of the system, the controller adds some NMP zeros to compensate the effect of NMP zero (zeros) of the system. As a result, the phase of the overall transfer function will be almost linear and its magnitude approaches unity for all frequencies. The method can be applied even to the systems with complex conjugate NMP zeros. As well, it is applicable to the systems for which the conventional methods cannot properly be used. Furthermore, a generalization of method to continuous-time systems is another given result. Several examples are provided to illustrate the effectiveness of the method. Copyright © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society [source]

    Observers for a class of nonlinear systems with time-delay,

    ASIAN JOURNAL OF CONTROL, Issue 6 2009
    Lei Zhou
    Abstract In this paper, the issue of observer designs for a class of nonlinear continuous-time systems with time-delay is addressed, where the nonlinear function is not necessarily Lipschitz. It is shown that both full-order and reduced-order observers can be obtained by means of the same linear matrix inequality. A numerical example is presented to show the effectiveness of the proposed approach. Copyright © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society [source]

    Network-based robust H, control of continuous-time systems with uncertainty,

    ASIAN JOURNAL OF CONTROL, Issue 1 2009
    Xun-Lin Zhu
    Abstract This paper studies the problem of robust H, control for continuous-time networked control systems (NCSs). A new type of Lyapunov functionals is exploited to derive sufficient conditions for guaranteeing the robust exponential stability and H, performance of the considered system. It is shown that the new result is less conservative than the existing corresponding ones. Meanwhile, a method of eliminating redundant variables to reduce computational complexity is given, which is also applied to design state feedback H, controllers, and the design condition is given in terms of solutions to a set of linear matrix inequalities (LMIs). Numerical examples are given to illustrate the effectiveness of the proposed methods. Copyright © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society [source]

    Convergence and Robustness of Iterative Learning Control For Strongly Positive Systems

    ASIAN JOURNAL OF CONTROL, Issue 1 2002
    Daniel Andres
    ABSTRACT In this paper, we consider the convergence and robustness of a general iterative learning control scheme for a class of systems which we term "strongly positive". The analysis is made in the framework of Hilbert-space theory. Thus the results are valid for discrete-time as well as continuous-time systems which may be time-variant or time-invariant. For the special case of continuous linear time-invariant systems which are defined over the Hilbert-space of square integrable functions, we will give a characterization of strongly positive systems in the frequency domain. [source]