Browsing by Author "Zhu, J.M."
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Item Iterative Batch-to-Batch Input Profile Determination for Semi- Batch Processes.(1989) Zhu, J.M.; Zafiriou, E.; ISRPolymerization processes are very complex and high nonlinear. Their modeling often involves reaction mechanism analysis combined with empirical tests. Mismatch between the model and the industrial plant often exists and it can be the cause of bad performance when optimal input profiles computed for a particular model are applied to the actual plant. The approach followed in this paper is to directly modify the input profile from batch to batch, and it has been applied through computer simulations to the determination of the minimum-time temperature profile for the batch bulk polymerization of sqrene under modeling error. The results demonstrate that the approach has strong robustness characteristics and fast convergence properties.Item Optimal Control of Semi-Batch Processes in the Presence of Modeling Error(1990) Zafiriou, E.; Zhu, J.M.; ISRBatch processes are usually complex and highly nonlinear systems. Modeling error can be the cause of bad performance when optimal input profiles computed for a particular model are applied to the actual plant. The approach followed in this paper uses the available model and actual plant measurements to modify the operation of the next batch, without requiring the remodeling of the process. The effect of model error on the convergence of the iterative batch to batch input profile determination is investigated. The method is applied through computer simulations to the determination of the optimal feedrate profile for a cell mass production process. A model parameter update scheme is also proposed, based on the convergence analysis. This is applied to the determination of the optimal temperature profile of bulk polymerication of the optimal temperature profile of styrene.Item Optimal Feed Rate Profile Detamination for Fed-Batch Fermentations in the Presence of Model Plant Mismatch.(1989) Zafiriou, E.; Zhu, J.M.; ISRModelling error can be the cause of bad performance when optimal feed-rate profiles computed for a particular model are applied to the actual plant. This paper suggests the modification of the input trajectory from batch to batch, by using information from previous batches to modify the trajectories that are applied to the subsequent ones. The proposed approach does not require the remodeling of the process, but instead it redetermines the input profile directly, so that a steady improvement is accomplished from batch to batch.