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D.w.t. Rippin - One of the best experts on this subject based on the ideXlab platform.

  • Theory and application of the Modulating Function method—I. Review and theory of the method and theory of the spline-type Modulating Functions
    Computers & Chemical Engineering, 1993
    Co-Authors: Heinz A. Preisig, D.w.t. Rippin
    Abstract:

    Abstract The progress of research on Modulating Function methods and their applications over the period of 1954–1990 is summarized and analyzed herein. After introducing the concept of the Modulating Function method and defining the key properties of Modulating Functions the history of the method with its developments and applications is given. Applicable to nonlinear systems, the structure the models may have in terms of nonlinearities is explored in detail, which is followed by a discussion of the method in the framework of process identification. The second section introduces the analytically derived spline-type Modulating Functions and discusses in detail their specific properties.

  • Theory and application of the Modulating Function method—II. algebraic representation of Maletinsky's spline-type Modulating Functions
    Computers & Chemical Engineering, 1993
    Co-Authors: Heinz A. Preisig, D.w.t. Rippin
    Abstract:

    Abstract The complete algebraic representation of Maletinsky's spline-type modulation Function method is presented for arbitrary order. This result is extended to the cases of arbitrarily overlapping modulations running in parallel but with shifted phase. The equations for constant-length and different-length modulation are derived. In both cases it could be shown that the basic signal operations that are to be installed on-line are the same as for the “normal arrangement” suggested by Maletinsky. Additionally, the equation for the normalization factor was obtained. A short example demonstrates the power of the Modulating Function approach in system identification.

  • Theory and application of the Modulating Function method—III. application to industrial process, a well-stirred tank reactor
    Computers & Chemical Engineering, 1993
    Co-Authors: Heinz A. Preisig, D.w.t. Rippin
    Abstract:

    Abstract A dynamic model describing the energy dissipation in a poorly defined, industrial, well-stirred tank reactor is identified. A successive refinement approach is presented in which an initial simple model is refined in three stages: (i) the Modulating Function method is utilized for estimating the heat transfer parameters locally as a Function of time; (ii) the parameters, which, because of the modelling errors, change with changing operating conditions, are graphically correlated with the operating conditions; and (iii) the resulting nonlinear model is refined by introducing additional dynamic elements. Validation of the model was done by comparing the predicted steady-state heat losses with other experimental data.

Heinz A. Preisig - One of the best experts on this subject based on the ideXlab platform.

  • Theory and application of the Modulating Function method—I. Review and theory of the method and theory of the spline-type Modulating Functions
    Computers & Chemical Engineering, 1993
    Co-Authors: Heinz A. Preisig, D.w.t. Rippin
    Abstract:

    Abstract The progress of research on Modulating Function methods and their applications over the period of 1954–1990 is summarized and analyzed herein. After introducing the concept of the Modulating Function method and defining the key properties of Modulating Functions the history of the method with its developments and applications is given. Applicable to nonlinear systems, the structure the models may have in terms of nonlinearities is explored in detail, which is followed by a discussion of the method in the framework of process identification. The second section introduces the analytically derived spline-type Modulating Functions and discusses in detail their specific properties.

  • Theory and application of the Modulating Function method—II. algebraic representation of Maletinsky's spline-type Modulating Functions
    Computers & Chemical Engineering, 1993
    Co-Authors: Heinz A. Preisig, D.w.t. Rippin
    Abstract:

    Abstract The complete algebraic representation of Maletinsky's spline-type modulation Function method is presented for arbitrary order. This result is extended to the cases of arbitrarily overlapping modulations running in parallel but with shifted phase. The equations for constant-length and different-length modulation are derived. In both cases it could be shown that the basic signal operations that are to be installed on-line are the same as for the “normal arrangement” suggested by Maletinsky. Additionally, the equation for the normalization factor was obtained. A short example demonstrates the power of the Modulating Function approach in system identification.

  • Theory and application of the Modulating Function method—III. application to industrial process, a well-stirred tank reactor
    Computers & Chemical Engineering, 1993
    Co-Authors: Heinz A. Preisig, D.w.t. Rippin
    Abstract:

    Abstract A dynamic model describing the energy dissipation in a poorly defined, industrial, well-stirred tank reactor is identified. A successive refinement approach is presented in which an initial simple model is refined in three stages: (i) the Modulating Function method is utilized for estimating the heat transfer parameters locally as a Function of time; (ii) the parameters, which, because of the modelling errors, change with changing operating conditions, are graphically correlated with the operating conditions; and (iii) the resulting nonlinear model is refined by introducing additional dynamic elements. Validation of the model was done by comparing the predicted steady-state heat losses with other experimental data.

Jerome Jouffroy - One of the best experts on this subject based on the ideXlab platform.

Heinz Unbehauen - One of the best experts on this subject based on the ideXlab platform.

  • Batch scheme recursive Hartley Modulating Functions identification of nonlinear continuous-time Hammerstein model
    1999 European Control Conference (ECC), 1999
    Co-Authors: S. Daniel-berhe, Heinz Unbehauen
    Abstract:

    In this contribution, a new batch scheme recursive Hartley Modulating Functions identification approach is developed to estimate the parameters of a nonlinear continuous-time Hammerstein model. The method is implemented by moving a fixed window size of time series data forward at each sampling instance. A new transformation is formulated for the Hartley Modulating Function (HMF) which is suitable for recursive Hartley spectra computations. Once the initial sequential batch data is measured, the algorithm computes the required input-output Hartley transforms then updates recursively the sequential Hartley transforms and spectra for each coming sample of input-output signals. Hence, this will update the regressand vector and regression matrix of the system HMF model. After that, a least squares algorithm is employed to estimate recursively parameters of the linear dynamic system and the static nonlinear element. The batch scheme recursive algorithm developed here offers significant reductions in the computation of numerical Hartley integration compared to the nonrecursive implementation of the HMF-method [4]. In this paper, the numerical Hartley integration is based on a stair-case approximation and updated as a fixed window size which is shifted one step forward every sampling instant. Simulation studies are provided to illustrate the performance of the proposed algorithm.

  • Bilinear continuous-time systems identification via Hartley-based Modulating Functions
    Automatica, 1998
    Co-Authors: S. Daniel-berhe, Heinz Unbehauen
    Abstract:

    Abstract This paper highlights the relevance and merits of the Hartley Modulating Functions (HMF) method for the identification of bilinear continuous-time (BCT) systems from recorded input and noise-contaminated output data and it provides an insight into parameter estimation of a wider range of nonlinear systems in practice. The methodology replaces the I/O-differential equation representing the dynamic system behavior by the Hartley spectrum equation. As a result it involves the known derivatives of the Modulating Function instead of the derivatives of the input and noisy output data by applying integral transformation to signals. A frequency weighted least-squares algorithm is also applied in the identification and a normalized root mean square criterion is used to investigate some computational considerations and the bias of the estimates. Results of the simulation studies demonstrate the appropriateness of the approach and its efficiency.

L. Sani - One of the best experts on this subject based on the ideXlab platform.

  • Modulating Functions for identification and modeling of ZVS class E 2 resonant converters
    Industrial Electronics 2002. ISIE 2002. Proceedings of the 2002 IEEE International Symposium on, 2002
    Co-Authors: Alessandro Balestrino, A. Landi, Ottorino Bruno, L. Sani
    Abstract:

    Aim of the paper is to build mathematical models of class E2 resonant DC/DC converters from input-output data. Among the various identification techniques, the Modulating Functions were chosen, due to their capability for revealing converter dynamics even in case of fast time constants. Each obtained model was tested around its working point: an accurate analysis was performed by varying both the number of pole-zeroes and the window width for identification. Extensive Spice simulations were run for an exhaustive and accurate evaluation of the models proposed. Preliminary results from experimental tests confirm the simulated ones. As a relevant conclusion, the Modulating Function method for identification and modelling reveals its effectiveness even in the critical case of resonant converters, where all traditional averaging techniques fail.

  • Parameter identification of continuous systems with multiple-input time delays via Modulating Functions
    IEE Proceedings - Control Theory and Applications, 2000
    Co-Authors: Alessandro Balestrino, A. Landi, L. Sani
    Abstract:

    The identification of continuous systems with multiple-input delays is discussed. A batch algorithm for parametric identification of both multiple time delays and unknown parameters is proposed using the Modulating Function approach. If the unknown delay is expressed as a linear combination of a bank of known delays, it is proven that the distribution of the identified coefficients is a sampling centred on the unknown delays; the result is then extended to the multiple delay case. The Modulating Function method guarantees a continuous-time approach and robustness for a high value of noise-to-signal ratio. Simulation results are included to illustrate the proposed technique.

  • Identification of Hammerstein systems with input/output time delay via Modulating Functions
    IFAC Proceedings Volumes, 2000
    Co-Authors: Alessandro Balestrino, A. Landi, L. Sani
    Abstract:

    Abstract Hammerstein processes are represented by a static nonlinear element followed by a dynamic linear system. This paper proposes the application of Modulating Function method to identify Hammerstein models, in the hypothesis of a nonlinear element approximated by a polynomial Function. The linear dynamic system can include the presence of unknown time delays. The use of the Modulating Function method guarantees a continuous-time approach and robustness for high value of the noise-to-output signal ratio (NSR).