Research Of Temperature Control In Biological Fermentation Process

Biological fermentation is a kind of complex biochemical process.The temerature had remarkable influence on biolgical fermentation process. However, the controlled object usually exist serious delay and nonlinear phenomenon ,so the conventional control arithmetic is difficult to reach the required control quality. The paper takes the ferment device as controlled plant, the combination feasibility and mode of Smith predictor and fuzzy control about temperature of biolgical fermentation are studied. The main research work and contribution of this dissertation are as follows:1.The Subject introductionThe paper analyses the characters of biological fermentation process,and do a lot of research in the reasons why so many bad temperature control performance in fermentation process. At last, we make a conclusion about the various ways of temperature control and development status.2.The nonliner division fuzzy-Smith controllerFor lack of an accurate model for temperature with large time delay in fermentation processes, the traditional PID control is difficult to acquire satisfying result. As for some nonlinear systems which don't possess accurate models, the fuzzy control based on expert system can overcome the adverse effects caused by large time delay to some extent, but it easily cause oscillation to the long time delay system. Aiming at large delay system in fermentation process, an adaptive smith control method with nonliner division of fuzzy linguistic variable based on fuzzy immune control is proposed. In this method, the adaptive Smith predictor can improve the control performance and enhance the system robustness and immunity, and the fuzzy immune control can improve system response time and control precision,.The research results obtained from the temperature control system demonstrate the effectiveness of Nonliner division fuzzy-Smith controller.3. Temperature control systemIn this chapter,we introduce the equipment's control structure,basic function of FG-3000,and the characteristics of the upper and lower computer.Though the temperature'sheps reponse curve in steady state obtain the temperature model of FG-3000.4. The experimental of temperature control in biolgical fermentationTaking traditional PID control,Smith predictive control and improved fuzzy control in the fermentation device.The results show that improved fuzzy control is better than others control algorithm in response speed and overshot.