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Parameter Systems (parameter + system)

Distribution by Scientific Domains
Engineering81%

Kinds of Parameter Systems

  • distributed parameter system
    		•

    Selected Abstracts

    Robust force control of a flexible arm with a nonsymmetric rigid tip body

    JOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 5 2001
    Yoshifumi Morita
    In this article, we discuss modeling and robust control of bending and torsional vibrations and contact force of a flexible arm with a nonsymmetric rigid tip body. By using Hamilton's principle and the Lagrange multiplier method, dynamic equations of the constrained flexible arm are derived. Since the flexible arm has the nonsymmetric tip body, the bending and torsional vibrations are coupled. As the obtained boundary conditions of the distributed parameter system are nonhomogeneous, we introduce a change of variables to derive homogeneous boundary conditions. By using the eigenvalues and the correpsonding eigenfunctions related to the distributed parameter system, we derive a finite-dimensional modal model. To compensate for the spillover instability, we construct robust controllers of an optimal controller with a low-pass property and an H, controller. Some experiments have been carried out to show the effectiveness of the proposed robust controllers. © 2001 John Wiley & Sons, Inc. [source]

    Dynamic optimization of the methylmethacrylate cell-cast process for plastic sheet production

    AICHE JOURNAL, Issue 6 2009
    Martín Rivera-Toledo
    Abstract Traditionally, the methylmethacrylate (MMA) polymerization reaction process for plastic sheet production has been carried out using warming baths. However, it has been observed that the manufactured polymer tends to feature poor homogeneity characteristics measured in terms of properties like molecular weight distribution. Nonhomogeneous polymer properties should be avoided because they give rise to a product with undesired wide quality characteristics. To improve homogeneity properties force-circulated warm air reactors have been proposed, such reactors are normally operated under isothermal air temperature conditions. However, we demonstrate that dynamic optimal warming temperature profiles lead to a polymer sheet with better homogeneity characteristics, especially when compared against simple isothermal operating policies. In this work, the dynamic optimization of a heating and polymerization reaction process for plastic sheet production in a force-circulated warm air reactor is addressed. The optimization formulation is based on the dynamic representation of the two-directional heating and reaction process taking place within the system, and includes kinetic equations for the bulk free radical polymerization reactions of MMA. The mathematical model is cast as a time dependent partial differential equation (PDE) system, the optimal heating profile calculation turns out to be a dynamic optimization problem embedded in a distributed parameter system. A simultaneous optimization approach is selected to solve the dynamic optimization problem. Trough full discretization of all decision variables, a nonlinear programming (NLP) model is obtained and solved by using the IPOPT optimization solver. The results are presented about the dynamic optimization for two plastic sheets of different thickness and compared them against simple operating policies. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source]

    Adaptive control of continuous time stochastic systems

    INTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING, Issue 5 2002
    T.E. Duncan
    Abstract Some problems and solutions of adaptive control problems for continuous time stochastic systems are described. A solution is given to the adaptive linear quadratic Gaussian control problem under the natural assumptions of controllability and observability. The effects of sampling and numerical differentiation on a least-squares estimation algorithm are described. Adaptive control problems for non-linear stochastic systems and linear stochastic distributed parameter systems are briefly described. Copyright © 2002 John Wiley & Sons, Ltd. [source]

    Identification and adaptive control of some stochastic distributed parameter systems

    INTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING, Issue 6 2001
    B. Pasik-Duncan
    Abstract An important class of controlled linear stochastic distributed parameter systems is that with boundary or point control. A survey of some existing adaptive control problems with their solutions for the boundary or the point control of a partially known linear stochastic distributed parameter systems is presented. The distributed parameter system is described by an analytic semigroup with cylindrical white noise and a control that occurs only on the boundary or at discrete points. The unknown parameters in the model appear affinely in both the infinitesimal generator of the semigroup and the linear transformation of the control. The noise in the system is a cylindrical white Gaussian noise. Strong consistency is verified for a family of least-squares estimates of the unknown parameters. For a quadratic cost functional of the state and the control, the certainty equivalence control is self-optimizing, that is the family of average costs converges to the optimal ergodic cost. Copyright © 2001 John Wiley & Sons, Ltd. [source]

    On-line robust parameter identification for parabolic systems

    INTERNATIONAL JOURNAL OF ADAPTIVE CONTROL AND SIGNAL PROCESSING, Issue 6 2001
    M. A. Demetriou
    Abstract In this paper a robust scheme for the adaptive parameter identification of parabolic distributed parameter systems is developed. Results from the finite-dimensional treatment of the parameter projection method and , (sigma) modifications to the standard adaptation rules are extended to infinite-dimensional systems. For the class of systems under study, modifications to these standard parameter adaptation rules were deemed necessary in order to account for the additional mathematical subtleties that arise when dealing with infinite-dimensional systems. Copyright © 2001 John Wiley & Sons, Ltd. [source]

    Impact of deposit ageing on thermal fouling: Lumped parameter model

    AICHE JOURNAL, Issue 2 2010
    Edward.
    Abstract The thermal and hydraulic performance of heat exchangers can be seriously impaired by the formation of fouling deposits on the heat transfer surfaces. The thermal effect of fouling can be complicated when the deposit is subject to ageing, represented here as a change in deposit thermal conductivity (but not thickness) over time. In this article, we revisit the ageing concept for crude oil fouling proposed by Nelson (Refiner Nat Gas Manufacturer. 1934;13:271,276, 292,298), using a numerical model incorporating first order kinetics to generate quantitative comparisons of different ageing rates. Results are reported for lumped parameter systems (which also simulate point measurement methods commonly used in laboratory testing) that demonstrate that ageing can have a substantial influence on the rate of heat transfer and hence on the surface temperature and rate of fouling. Rapid ageing (compared with the rate of deposition) does not pose problems, but slow ageing, or the use of constant heat fluxes in experiments, can lead to modified thermal fouling behavior. It is concluded that deposit ageing dynamics should be considered alongside deposition rate dynamics when interpreting experimental fouling data and when modeling fouling behavior in support of heat exchanger design or operation. © 2009 American Institute of Chemical Engineers AIChE J, 2010 [source]

    Reduced-order suboptimal control design for a class of nonlinear distributed parameter systems using POD and ,,D techniques

    OPTIMAL CONTROL APPLICATIONS AND METHODS, Issue 3 2008
    Radhakant Padhi
    Abstract A new computational tool is presented in this paper for suboptimal control design of a class of nonlinear distributed parameter systems (DPSs). In this systematic methodology, first proper orthogonal decomposition-based problem-oriented basis functions are designed, which are then used in a Galerkin projection to come up with a low-order lumped parameter approximation. This technique has evolved as a powerful model reduction technique for DPSs. Next, a suboptimal controller is designed using the emerging ,,D technique for lumped parameter systems. This time domain control solution is then mapped back to the distributed domain using the same basis functions, which essentially leads to a closed form solution for the controller in a state-feedback form. We present this technique for the class of nonlinear DPSs that are affine in control. Numerical results for a benchmark problem as well as for a more challenging representative real-life nonlinear temperature control problem indicate that the proposed method holds promise as a good optimal control design technique for the class of DPSs under consideration. Copyright © 2007 John Wiley & Sons, Ltd. [source]

    Stochastic Response of a Continuous System with Stochastic Surface Irregularities to an Accelerated Load

    PROCEEDINGS IN APPLIED MATHEMATICS & MECHANICS, Issue 1 2003
    C.A. Schenk
    The problem of calculating the second moment characteristics of the response of a general class of nonconservative linear distributed parameter systems with stochastically varying surface roughness, excited by a moving concentrated load, is investigated. In particular the case of an accelerated load is discussed. The surface roughness is modeled as a Gaussian stationary second order process. For the stochastic representation of the surface roughness a orthogonal series expansion of the covariance kernel, the so called Karhunen-Loéve expansion, is applied. The resulting initial/boundary value problem is transformed by eigenfunction expansion into the modal state space. Second moment characteristics of the response are determined numerically by direct integration using a Runge-Kutta method. [source]

    Construction of 2D isomorphism for 2D H, -control of Sturm-Liouville systems

    ASIAN JOURNAL OF CONTROL, Issue 2 2010
    Boe-Shong Hong
    Abstract This work makes possible that H, -loopshaping has a 2D version for the Sturm-Liouville class of distributed parameter systems. Here, the Laplace integral is composite of a Galerkin projection to transform the underlying dynamics, both spatially distributed and temporally varying, into pure algebra, so that any technique of classical control becomes applicable to spatio-temporal analyses and syntheses. Accompanied by this Laplace-Galerkin transform and its inverse are Fourier-Galerkin transforms that constitute a pair of geometrical isomorphism between space-time domain and mode-frequency domain. Based on the isomorphism, Small Gain Theorem and H, -loopshaping can expand on 2D version in terms of mode-frequency responses. Copyright © 2010 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society [source]