连续发酵非线性混杂动力系统的切换最优控制

发布时间：2018-05-04 05:54

本文选题：连续发酵 + 1　；参考：《鲁东大学》2017年硕士论文

【摘要】：本文针对一类微生物连续发酵甘油生产1,3-丙二醇(1,3-PD)问题,建立了不同层次非线性切换系统.基于提出的灵敏度函数和鲁棒性指标,令终端时刻产物1,3-PD的产量最大是性能指标,建立了不同的最优控制模型,并进一步构造了优化算法求解.所得数值结果表明该项研究可以为实际发酵过程提供重要参考.本文的研究工作现概括如下:1.综合考虑胞内胞外物质浓度的变化,提出了一个包含16种切换模式的切换系统描述连续发酵过程.因部分系统参数依赖于决策变量,讨论了系统状态关于参数和决策变量的灵敏度,并得到了含有切换的梯度公式.基于灵敏度,建立了最优控制模型,并应用序列二次规划法求解.数值结果表明,依据所得最优流加策略,可以有效提高终端时刻1,3-PD的浓度.2.因部分系统参数依赖于决策变量,提出了系统状态的鲁棒指标.以稳态时刻1,3-PD的产率最大为性能指标,以甘油的流加速率及初始浓度为决策变量建立了优化模型.通过近似光滑逼近法,原问题转化成了数学规划问题,并构造了含有切换的数值优化算法寻找上述问题的最优数值解.最终得到了比较满意的流加策略,参数值以及切换时刻与切换序列.3.根据dha调节子的遗传调节,建立了一个由14维动力学方程描述的非线性切换系统.我们的目标是通过优化决策变量即甘油流加速率和初始浓度得到目标产物即终端时刻1,3-PD的浓度最大.鉴于部分未知的系统参数依赖于决策变量,提出了鲁棒性指标的定量表达,并基于鲁棒性指标建立了最优控制模型.基于精确罚函数法与单纯形搜索法构造了有效的算法求解上述问题.通过数值模拟得到了最优的流加策略和状态轨线。
[Abstract]:In this paper, a nonlinear switching system of different levels is established for the production of 1k3- propanediol by continuous fermentation of glycerol by microorganism. Based on the proposed sensitivity function and robustness index, the maximum output of terminal product 1 / 3-PD is the performance index. Different optimal control models are established, and the optimization algorithm is further constructed. The numerical results show that this study can provide an important reference for the actual fermentation process. The research work of this paper is summarized as follows: 1. Considering the change of extracellular concentration, a switching system consisting of 16 switching modes was proposed to describe the continuous fermentation process. Because some system parameters depend on decision variables, the sensitivity of system state on parameters and decision variables is discussed, and a gradient formula with switching is obtained. Based on sensitivity, the optimal control model is established and solved by sequential quadratic programming. The numerical results show that, according to the optimal flow addition strategy, the concentration of 1 / 3-PD at the end time can be increased effectively. Because some system parameters depend on decision variables, a robust index of system state is proposed. The optimal model was established with the maximum yield of 1 ~ 3-PD at steady state as the performance index and the flow acceleration rate and initial concentration of glycerol as decision variables. By using the approximate smooth approximation method, the original problem is transformed into a mathematical programming problem, and a numerical optimization algorithm with switching is constructed to find the optimal numerical solution of the above problem. Finally, satisfactory stream addition strategy, parameter value, handover time and handover sequence. 3 are obtained. According to the genetic regulation of dha regulator, a nonlinear switching system is established, which is described by 14 dimensional dynamic equations. Our goal is to obtain the maximum concentration of the target product, I. e., the terminal time 1 / 3-PD, by optimizing the decision variables, that is, the glycerol flow rate and the initial concentration. In view of the fact that some unknown system parameters depend on decision variables, a quantitative representation of robustness index is proposed, and an optimal control model based on robustness index is established. Based on the exact penalty function method and simplex search method, an effective algorithm is constructed to solve the above problems. The optimal flow addition strategy and state trajectory are obtained by numerical simulation.
【学位授予单位】：鲁东大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ923;O232

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