Four Water Mixed System Modeling And Predictive Control

Hybrid system is a system that contains continuous dynamic part and discrete logic dynamic part interacting with each other.In the industry process, hybrid system with continuous variables and discrete variables is widespread, it is very difficult to describe the dynamic behavior of such systems using the traditional control theory, so we requires the establishment of a new control theory. The four tank is a typical hybrid systems with constraints that discrete event is tank structure mutation and valve switch. In this paper, using the mixed logic dynamic system control theory to research the modeling and control problem of a four tank.the main contents are:(1) the conventional control of the four tank hybrid system is studied. The JX-300XP DCS as control platform, it is difficult to get better control effect from the operation result of applying double PID control strategy in the four tank system.(2)The mixed logic dynamic model of the four tank hybrid system is studied, analyzed the MLD model structure, elaborated several typical hybrid system modeling process, summed up the steps of establishing the mixed logic dynamic model and got the MLD model of four tank hybrid system.(3) The predictive control of hybrid systems based on MLD form is studied. The predicted control is extended to mixed logic dynamic systems, researched the predicted control based on the quadratic norm and∞norm performance indicators, explored the stability of the system and verified the effectiveness of the two algorithms, designed the model predictive control based on the∞norm of four tank hybrid systems.(4) The application of prediction strategy for four tank DCS system is studied. To complete the MATLAB control of field devices, the paper put forward an application of OPC communication. On the platform of JX-300X DCS, MATLAB predictive control strategy is applied to the actual hybrid systems.