A Study Of Ultrasonic Biological Treatment System Modeling And H∞ Control

The ultrasonic biological treatment technology is a green technology without pollution. During the period of the production process, the biomass and the cells are sensitive to the ultrasonic frequency and power, and the ultrasound can damage the biomass and the cells. When the stability of the ultrasonic frequency and power is getting worse, the impurity content will be becoming higher, even the biological activity of the extracts will be becoming weeker. In this paper, based on the control theory, we study on model analysis and control strategy, respectively. Therefore, this article has theory and academic value. The work of this thesis includes:(1)For the ultrasonic biological treatment system, the objective is to improve the performance for the robustness of ultrasonic biological treatment system, which includes a transducer mechanism portion and an ultrasonic extraction portion. The two parts mainly study on model analysis and control strategy, respectively.(2)For the transducer mechanism of the ultrasonic biological treatment systems, the objective is to establish a differential equation model of piezoelectric transducer, the equivalent circuit model of piezoelectric transducer vocal and the piezoelectric transducer forced vibration equation were compared. Taking into account the inverter, rectifier process, we obtain a state space model of piezoelectric transducer.(3) For the ultrasonic extraction of this biological treatment systems, we establish an input-output model through analyzing the relation between ultrasonic power and parameters in ultrasonic extraction process. In addition, the kinetic model has been obtained by using the second Fick’s law.(4) In order to improve the acquaintance for the robustness of ultrasonic biological treatment system, we establish a predictive model based on the theory of Markov jump under the uncertainty and the disturbances among the ultrasonic biological treatment system. According to the model, the control law has been studied. Finally, many simulations have been performed to prove the validity of the control law.In summary, this paper mainly studies on model analysis and control strategy by control theroy, and the simulation results show the proposed control strategies are effective.