Research On Modeling And Control Of Boiling Sugar Crystallization Process

The sugar industry is an important branch of human food processing industry, the main process is boiling sugar crystallization in the sugar industry. The most important thing in the process of boiling sugar crystallization is controlling the oversaturation. Because the sugar boiling crystallization process is a complex physical and chemical of change, and the mutual coupling between the influence of various parameters of the sugar boiling process, and its time varying and nonlinear are very obvious, so it is difficult to establish the mathematics model of boiling sugar crystallization process, also increased the difficulty of designing control method.This paper introduces the process of boiling sugar crystallization process, as well as factors affecting the crystallization mechanism and the influencing factors of crystallization process, and analyzed the current saturation measurement technology. Combined with the actual production conditions, select RF instrument as super saturation detection instrument. The actual living conditions and the control method considering the limitations of the case, combined with the actual situation of temperature and oversaturation degree brix as variable model of boiling sugar crystallization process. According to the actual investigation and study, combined with the existing theoretical results and the actual production experience, collecting a lot of data, using multiple regression analysis to establish the boiling crystallization process oversaturation model, and has carried on the related inspection, after inspection, fully verify the effectiveness, the validity of the model. The model also can be used as the basis of other control algorithms or other discipline research.Aiming at the time-varying, nonlinear oversaturation model, according to the actual situation of the representative region in the oversaturation, state space transformation. In order to be able to restore the true boiling scene environment, and enhance the applicability of the control system, the state equation of boiling sugar crystallization and brix and temperature were introduced with uncertain parameters to reflect the time varying model, based on determining the object and on the Lyapunov stability theory, the adaptive law of the state variables. Based on the model reference adaptive control system design.In order to better reflect the actual production situation, in the design of the adaptive control system, not only to consider the parameters of controlled object, also introduced three different interference, instantaneous interference, in a certain period of time the interference and the whole interference to more realistic simulation of the production conditions of sucrose crystallization process. It can be seen from the simulation results, on the basis of the model reference adaptive control system designed by Lyapunov stability theory can make the output of controlled object quickly reaches a steady state and well tracks the reference model output, and can effectively inhibit the process of modeling uncertainties, as well as a variety of interference may exist in actual production.