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论文类型：期刊论文

发表时间：2020-07-01

发表刊物：JOURNAL OF THE FRANKLIN INSTITUTE-ENGINEERING AND APPLIED MATHEMATICS

收录刊物：SCIE

卷号：357

期号：11

页面范围：6571-6594

ISSN号：0016-0032

关键字：Optimal control computation; Nonlinear dynamical system; Total variation; Parallel optimization; Fed-batch fermentation

摘要：In this paper, an optimal minimal variation control in the fed-batch fermentation of glycerol bio-conversion to 1,3-propanediol (1,3-PD) caused by Klebsiella pneumonia (K. pneumonia) is considered. In fed-batch process, it is required for the concentration of 1,3-PD to satisfy a quality constraint (i.e., the concentration of 1,3-PD at the terminal time is to reach a critical value), and furthermore, the cost associated with the change of the control signal must also be taken into account. It is formulated as an optimal control problem in which the total variation of the control signal is taken as the cost function, while the feeding rates of glycerol and alkali and the switching instants are taken as decision variables. The optimal control problem is subject to the quality constraint and certain continuous state inequality constraints. To handle the continuous state inequality constraints, the optimal control problem is approximated as a sequence of nonlinear programming subproblems. Because of the nature of the optimal control problem, which is highly complicated, a parallel algorithm is proposed to solve these subproblems based on genetic algorithm and the gradients of the constraint functions with respect to decision variables. From extensive simulation studies, it is observed that the obtained optimal feeding rates and switching instants are highly satisfactory. (C) 2020 The Franklin Institute. Published by Elsevier Ltd. All rights reserved.