Browsing by Author "Gu, Da-Wei"

Now showing 1 - 3 of 3
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    Kolmogorov-Chaitin complexity of digital controller implementations.
    (Springer Science Business Media, 2006-07-01T00:00:00Z) Whidborne, James F.; McKernan, John; Gu, Da-Wei
    The complexity of linear, fixed-point arithmetic digital controllers is investigated from a Kolmogorov-Chaitin perspective. Based on the idea of Kolmogorov-Chaitin complexity, practical measures of complexity are developed for statespace realizations, parallel and cascade realizations, and for a newly proposed generalized implicit state-space realization. The complexity of solutions to a restricted complexity controller benchmark problem is investigated using this measure. The results show that from a Kolmogorov-Chaitin viewpoint, higher-order controllers with a shorter word-length may have lower complexity and better performance, than lower-order controllers with longer word-length.
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    Optimal Controller and Filter Realisations using Finite-precision, Floating- point Arithmetic.
    (Taylor & Francis, 2005-06-01T00:00:00Z) Whidborne, James F.; Gu, Da-Wei; Wu, Jun; Chen, Sheng
    The problem of reducing the fragility of digital controllers and filters implemented using finite-precision, floating-point arithmetic is considered. Floating-point arithmetic parameter uncertainty is multiplicative, unlike parameter uncertainty resulting from fixed-point arithmetic. Based on first- order eigenvalue sensitivity analysis, an upper bound on the eigenvalue perturbations is derived. Consequently, open-loop and closed-loop eigenvalue sensitivity measures are proposed. These measures are dependent upon the filter/ controller realization. Problems of obtaining the optimal realization with respect to both the open-loop and the closed-loop eigenvalue sensitivity measures are posed. The problem for the open-loop case is completely solved. Solutions for the closed-loop case are obtained using non-linear programming. The problems are illustrated with a numerical example.
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    Robust controller design using h-infinity loop-shaping and the method of inequalities
    (IEEE, 1994-12-01) Whidborne, James F.; Postlethwaite, I.; Gu, Da-Wei
    A new approach to robust controller design is proposed. By using plant-weighting functions as the design parameters, the approach combines the method of inequalities with robust stabilization of normalized coprime factor descriptions of the weighted plant to design explicitly for closed-loop performance and stability robustness. A procedure for the design of robust two degree-of-freedom controllers is presented and is illustrated on a high-purity distillation column example