基于动态数据交换技术的海洋蛋白酶发酵过程GD-FNN软测量

    Soft sensor of generalized dynamic fuzzy neural network for marine protease fermentation process based on dynamic data exchange

    • 摘要: 为实现微生物发酵过程中关键生物参数(菌体浓度、基质浓度、产物浓度等)的实时显示与存储,该文结合MATLAB与WinCC各自的优势,提出了一种基于动态数据交换(dynamic data exchange,DDE)技术的广义动态模糊神经网络(generalized dynamic fuzzy neural network,GD-FNN)软测量方法。以海洋蛋白酶发酵过程为研究对象,通过MATLAB编程,建立发酵过程GD-FNN软测量模型,获得生物参数的预测值;以Excel软件为中间桥梁,利用DDE技术实现MATLAB与上位机WinCC之间的实时数据通讯,最终获得了生物参数的实时显示与存储。应用结果表明,利用GD-FNN所建立的生物参数软测量模型具有很高的预测精度,所得的最大均方根误差为0.4266,最大平均绝对误差为0.2552,满足系统测量的精度要求;同时通过DDE技术连接MATLAB与WinCC,编程效率高,实现方便,通用性强。该研究为发酵过程的优化控制以及工业化生产提供了依据。

       

      Abstract: Abstract: The crucial biological variables (such as biomass concentration, substrate concentration, and product concentration, and so on) of the microbial fermentation process are difficult to measure online, which has a great influence on the quality of fermentation production. In this paper, a soft sensing method based on a generalized dynamic fuzzy neural network (GD-FNN) was proposed. The configuration software windows control center (WinCC) possesses the advantages of powerful practicality and flexible configuration. A complex interactive graphical interface can be generated by WinCC, but its ability to perform data processing is weak. So it is unable to achieve soft sensor modeling of biological parameters and estimate the value of biological parameters by WinCC. MATLAB is professional software for mathematical analysis and engineering operations. It has the characteristic of powerful data processing capabilities and an open application programming interface, but direct data communication can not be realized between MATLAB and the industrial control equipment. In order to solve this problem, combining MATLAB with WinCC to achieve respective advantage, taking Excel as the middle bridge, the real-time communication between MATLAB and WinCC was established by dynamic data exchange (DDE,DDE is the message mechanism based on Windows, two Windows applications carry on DDE Conversation through mutual transfer DDE message, and thus complete the data request, response, and transmission).Finally the real-time display and monitoring of crucial biological variables was realized. In this paper, the typical microbial fermentation process (the marine protease fermentation process) was taken as an example. First, in MATLAB, a soft sensor model based on GD-FNN(The algorithm of GD-FNN was based on an elliptical basis function. In the algorithm, fuzzy ε-completeness was used as the distribution mechanism of on-line parameters, the importance of fuzzy rules and input variables were evaluated, and this algorithm which has salient advantages in the aspect of learning efficiency and performance was established by using the training sample set for the fermentation process. The established model was verified by the test sample set. Second, the real-time collection data was transferred from configuration software WinCC to Excel by DDE technology. The data of Excel was called by MATLAB programming, and crucial biological parameters were predicted by the established model and the value transferred back to Excel. Finally, the real-time display and monitoring of the biological parameters were realized by DDE settings and the friendly human-machine interface of WinCC, and the intelligent monitoring system of a marine protease fermentation process based on WinCC was established. The application results showed that the prediction accuracy of soft sensor modeling based on GD-FNN is higher,and connecting MATLAB and WinCC by DDE technology has the characteristic of efficient programming, convenient use, and good general performance. The real-time monitoring was processed by WinCC for the marine protease fermentation process, which met the requirements of optimal control of the marine protease fermentation process and enhanced the automation level of the fermentation process and improved the product yield and economic benefit. These lay the foundation for the industrial production of a marine protease fermentation process.

       

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