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- Nonlinear dynamical system; optimal control; continuous state constraint; smoothing approximation; fed-batch fermentation (1)
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- Optimal switching control · Control parametrization · Time scaling transform · Heuristic approach · Fed-batch fermentation (1)
Articles 1 - 4 of 4
Full-Text Articles in Physical Sciences and Mathematics
Optimal Switching Control Of A Fed-Batch Fermentation Process, Chongyang Liu, Zhaohua Gong, Enmin Feng, Hongchao Yin
Optimal Switching Control Of A Fed-Batch Fermentation Process, Chongyang Liu, Zhaohua Gong, Enmin Feng, Hongchao Yin
Chongyang Liu
Considering the hybrid nature in fed-batch culture of glycerol biconversion to 1,3-propanediol (1,3-PD) by Klebsiella pneumoniae, we propose a state-based switching dynamical system to describe the fermentation process. To maximize the concentration of 1,3-PD at the terminal time, an optimal switching control model subject to our proposed switching system and constraints of continuous state inequality and control function is presented. Because the number of the switchings is not known a priori, we reformulate the above optimal control problem as a two-level optimization problem. An optimization algorithm is developed to seek the optimal solution on the basis of a heuristic approach …
Nonlinear Dynamical Systems Of Fed-Batch Fermentation And Their Optimal Control, Chongyang Liu, Zhaohua Gong, Enmin Feng, Hongchao Yin
Nonlinear Dynamical Systems Of Fed-Batch Fermentation And Their Optimal Control, Chongyang Liu, Zhaohua Gong, Enmin Feng, Hongchao Yin
Chongyang Liu
In this article, we propose a controlled nonlinear dynamical system with variable switching instants, in which the feeding rate of glycerol is regarded as the control function and the moments between the batch and feeding processes as switching instants, to formulate the fed-batch fermentation of glycerol bioconversion to 1,3-propanediol (1,3-PD). Some important properties of the proposed system and its solution are then discussed. Taking the concentration of 1,3-PD at the terminal time as the cost functional, we establish an optimal control model involving the controlled nonlinear dynamical system and subject to continuous state inequality constraints. The existence of the optimal …
Modeling And Parameter Identification Involving 3-Hydroxypropionaldehyde Inhibitory Effects In Glycerol Continuous Fermentation, Zhaohua Gong, Chongyang Liu, Yongsheng Yu
Modeling And Parameter Identification Involving 3-Hydroxypropionaldehyde Inhibitory Effects In Glycerol Continuous Fermentation, Zhaohua Gong, Chongyang Liu, Yongsheng Yu
Chongyang Liu
Mathematical modeling and parameter estimation are critical steps in the optimization of biotechnological processes. In the 1,3-propanediol (1,3-PD )production by glycerol fermentation process under anaerobic conditions, 3-hydroxypropionaldehyde (3-HPA) accumulation would arouse an irreversible cessation of the fermentation process. Considering 3-HPA inhibitions to cells growth and to activities of enzymes, we propose a novel mathematical model to describe glycerol continuous cultures. Some properties of the above model are discussed. On the basis of the concentrations of extracellular substances, a parameter identification model is established to determine the kinetic parameters in the presented system. Through the penalty function technique combined with an …
Optimal Control Of A Fed-Batch Fermentation Involving Multiple Feeds, Chongyang Liu, Zhaohua Gong, Zhaoyi Huo, Bangyu Shen
Optimal Control Of A Fed-Batch Fermentation Involving Multiple Feeds, Chongyang Liu, Zhaohua Gong, Zhaoyi Huo, Bangyu Shen
Chongyang Liu
A nonlinear dynamical system, in which the feed rates of glycerol and alkali are taken as the control functions, is first proposed to formulate the fed-batch culture of 1,3-propanediol (1,3-PD) production. To maximize the 1,3-PD concentration at the terminal time, a constrained optimal control model is then presented. A solution approach is developed to seek the optimal feed rates based on control vector parametrization method and improved differential evolution algorithm. The proposed methodology yielded an increase by 32.17% of 1,3-PD concentration at the terminal time.