The Experts below are selected from a list of 63 Experts worldwide ranked by ideXlab platform

J. Lardies - One of the best experts on this subject based on the ideXlab platform.

  • MODAL PARAMETER ESTIMATION AND MODEL ORDER SELECTION OF A RANDOMLY VIBRATING SYSTEM
    Mechanical Systems and Signal Processing, 1998
    Co-Authors: J. Lardies
    Abstract:

    Abstract A vibrating system was excited by a random force and only the multi-output responses were measured. A state-space modelling of the sensors output was then considered, which consisted of the state equation and the observation equation. The modal parameters were obtained from the transition Matrix of the vibrating system. Three methods for transition Matrix determination are presented using shift property of a block Hankel Matrix of the covariances, calculated from the data and using a shift property of the observability Matrix and of the Controllability Matrix. The order of the state-space system is obtained from a test which is based on the ratio of the determinants of the innovations covariance matrices of the process, from the models of two different sizes. This test exploits the distributional properties of the canonical correlation coefficients. A numerical example illustrates the procedure for identifying the order and parameters of a vibrating system.

Joseph Lardies - One of the best experts on this subject based on the ideXlab platform.

  • Modal parameter identification by an iterative approach and by the state space model
    Mechanical Systems and Signal Processing, 2017
    Co-Authors: Joseph Lardies
    Abstract:

    The problem of estimating a spectral representation of exponentially decaying signals from a set of sampled data is of considerable interest in several applications such as in vibration analysis of mechanical systems. In this paper we present a nonparametric and a parametric method for modal parameter identification of vibrating systems when only output data is available. The nonparametric method uses an iterative adaptive algorithm based in the formation of a two dimensional grid mesh, both in frequency and damping domains. We formulate the identification problem as an optimization problem where the signal energy is obtained from each frequency grid point and damping grid point. The modal parameters are then obtained by minimizing the signal energy from all grid points other than the grid point which contains the modal parameters of the system. The parametric approach uses the state space model and properties of the Controllability Matrix to obtain the state transition Matrix which contains all modal information. We discuss and illustrate the benefits of the proposed algorithms using a numerical and two experimental tests and we conclude that the nonparametric approach is very time consuming when a large number of samples is considered and does not outperform the parametric approach.

Martine Olivi - One of the best experts on this subject based on the ideXlab platform.

  • Lossless scalar functions: boundary interpolation, Schur algorithm and Ober's canonical form
    2008
    Co-Authors: Martine Olivi, Bernard Hanzon, Ralf L.m. Peeters
    Abstract:

    In Ober (1987) a balanced canonical form for continuous-time lossless systems was presented. This form has a tridiagonal dynamical Matrix A and the useful property that the corresponding Controllability Matrix K is upper triangular. In this paper, a connection is established between Ober's canonical form and a Schur algorithm builts from angular derivative interpolation conditions. It provides a new interpretation of the parameters in Ober's form, as interpolation values at infinity, and a recursive construction of the balanced realization.

  • Canonical lossless state-space systems: Staircase forms and the Schur algorithm
    Linear Algebra and its Applications, 2007
    Co-Authors: Ralf L.m. Peeters, Bernard Hanzon, Martine Olivi
    Abstract:

    A new finite atlas of overlapping balanced canonical forms for multivariate discrete-time lossless systems is presented. The canonical forms have the property that the Controllability Matrix is positive upper triangular up to a suitable permutation of its columns. This is a generalization of a similar balanced canonical form for continuous-time lossless systems. It is shown that this atlas is in fact a finite sub-atlas of the infinite atlas of overlapping balanced canonical forms for lossless systems that is associated with the tangential Schur algorithm; such canonical forms satisfy certain interpolation conditions on a corresponding sequence of lossless transfer matrices. The connection between these balanced canonical forms for lossless systems and the tangential Schur algorithm for lossless systems is a generalization of the same connection in the SISO case that was noted before. The results are directly applicable to obtain a finite sub-atlas of multivariate input-normal canonical forms for stable linear systems of given fixed order, which is minimal in the sense that no chart can be left out of the atlas without losing the property that the atlas covers the manifold.

Ralf L.m. Peeters - One of the best experts on this subject based on the ideXlab platform.

  • Lossless scalar functions: boundary interpolation, Schur algorithm and Ober's canonical form
    2008
    Co-Authors: Martine Olivi, Bernard Hanzon, Ralf L.m. Peeters
    Abstract:

    In Ober (1987) a balanced canonical form for continuous-time lossless systems was presented. This form has a tridiagonal dynamical Matrix A and the useful property that the corresponding Controllability Matrix K is upper triangular. In this paper, a connection is established between Ober's canonical form and a Schur algorithm builts from angular derivative interpolation conditions. It provides a new interpretation of the parameters in Ober's form, as interpolation values at infinity, and a recursive construction of the balanced realization.

  • Canonical lossless state-space systems: Staircase forms and the Schur algorithm
    Linear Algebra and its Applications, 2007
    Co-Authors: Ralf L.m. Peeters, Bernard Hanzon, Martine Olivi
    Abstract:

    A new finite atlas of overlapping balanced canonical forms for multivariate discrete-time lossless systems is presented. The canonical forms have the property that the Controllability Matrix is positive upper triangular up to a suitable permutation of its columns. This is a generalization of a similar balanced canonical form for continuous-time lossless systems. It is shown that this atlas is in fact a finite sub-atlas of the infinite atlas of overlapping balanced canonical forms for lossless systems that is associated with the tangential Schur algorithm; such canonical forms satisfy certain interpolation conditions on a corresponding sequence of lossless transfer matrices. The connection between these balanced canonical forms for lossless systems and the tangential Schur algorithm for lossless systems is a generalization of the same connection in the SISO case that was noted before. The results are directly applicable to obtain a finite sub-atlas of multivariate input-normal canonical forms for stable linear systems of given fixed order, which is minimal in the sense that no chart can be left out of the atlas without losing the property that the atlas covers the manifold.

Wenhui Dou - One of the best experts on this subject based on the ideXlab platform.