教師著作
Permanent URI for this collectionhttp://rportal.lib.ntnu.edu.tw/handle/20.500.12235/31268
Browse
3 results
Search Results
Item 結合局部搜尋之多目標並行處理粒子群聚最佳化法及其在不確定間隔系統數位控制之應用(3/3)(行政院國家科學委員會, 2009-07-31) 許陳鑑連續時間間隔系統(continuous-time interval systems)之數位控制(digital control)係一 不易藉由傳統方法處理的問題，為了替這種系統進行數位模擬(digital simulation)或是數 位設計(digital design)，在數位化(discretization) 的過程中會導致數位模型係數為不確定 參數之非線性函數，而且有嚴重地指數函數耦合情況，這使得原系統之間隔結構(interval structure)在數位化的過程中喪失殆盡；同時，在數位化的過程中也會額外引進一獨立變 數-取樣時間 (sampling period)，使得數位控制系統之分析及設計更加困難。這些複雜的 問題至少包含：連續時間間隔系統之數位建模 (discrete modelling)、等效數位模型最小 相條件 (minimum-phase criteria)、數位控制器之設計(Digital redesign of continuous systems with improved suitability)、數位化再設計之性能評估(Performance evaluation of redesigned digital system for uncertain interval systems)等。有鑑於這些問題所要處理的函 數大都為高度非線性耦合(nonlinear coupling) 之non-convex 函數，傳統最佳化方法將無 法有效解決此一問題，特別是在處理高階的間隔系統時尤其困難，因此，本計劃即針對 該些問題提出可能之解決方案，作法上係藉由對不確定參數作適當的邊界跳脫 (overbounding)，將求取等效數位模型、最小相取樣時間範圍、穩定取樣時間範圍、以及 數位化再設計之適合度評估等問題，規劃形成複數個最佳化的問題，再利用所提出具有 並行處理能力的通用型(general-purpose)、嵌設有改良式NM 區域搜尋法、以及加入多目 標最佳化處理機制等功能之粒子群聚最佳化法之研究成果為基礎，發揮其全域最佳化、 概念簡單、容易實現、高運作效能等優點、具備並行處理能力之優勢，以改善粒子群聚 最佳化法的演化過程較為耗時的問題，提升其運算效能，以有效解決上述不確定連續時 間間隔系統在數位控制之分析及設計上之諸多問題，方便使用者應用離散時間領域中關 於強健控制之既有方法，進行後續之的分析與設計。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.