教師著作
Permanent URI for this collectionhttp://rportal.lib.ntnu.edu.tw/handle/20.500.12235/31268
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Item Digital redesign of uncertain interval systems based on time-response resemblance via particle swarm optimization(2008-06-27) Chen-Chien Hsu; Geng-Yu LinIn this paper, a novel design approach based on time-response resemblance of the closed-loop system via particle swarm optimization is proposed to improve performance of the redesigned digital system for continuous-time uncertain interval systems. The design rationale of the proposed approach is to derive a digital controller for the redesigned digital system so that step response sequences corresponding to the extremal sequence energy closely match those of their continuous counterpart under the perturbation of the plant parameters. By suitably formulating the design problem as an optimization problem, an evolution framework incorporating three PSOs (particle swarm optimizations) is presented to derive a set of optimal parameters for the digital controller. Computer simulations have shown that time responses of the redesigned digital system having an interval plant have a better resemblance to their continuous-time counter part in comparison those obtained using existing open-loop discretization methods.Item Digital redesign of uncertain interval systems via a hybrid particle swarm optimizer(Inderscience, 2008-07-01) Chen-Chien Hsu; Chun-Hwei KaoIn this paper, a hybrid optimiser incorporating particle swarm optimisation (PSO) and an enhanced NM simplex search method is proposed to derive an optimal digital controller for uncertain interval systems having an interval plant based on frequency-response resemblance. By combining the uncertain plant and controller, extremal systems for the redesigned digital system and its continuous counterpart can be obtained as the basis for comparison. The design problem is then formulated as an optimisation problem of an aggregated error function in terms of frequency-response deviation between the redesigned digital system and its continuous counterpart, and subsequently optimised by the proposed optimiser to obtain an optimal set of parameters for the digital controller. Thanks to the performance of the proposed hybrid optimiser, frequency envelope of the redesigned digital system using the digital controller evolutionarily derived by the proposed approach bare a better resemblance to its continuous-time counterpart in comparison to those obtained using existing open-loop discretisation methods.