Research And Application Of Reactor Temperature Control System Based On LabVIEW

The reactor is a common reaction vessel used in the field of chemical production. As the control object, the reactor has the characteristics of time-variable, nonlinear, pure time-delay, big inertia, as a result, the precise mathematical model is difficult to be established and conventional PID control is also hard to achieve the control requirements because of the complicated parameter tuning and time-consuming human tuning. This thesis analyzes the principles of PID and fuzzy control algorithm based on the combination of the two to explore the temperature control system, applies the method of fuzzy self-adaptive PID controller by the ues of fuzzy rules to adjust parameters online, and the switching control method between fuzzy control and PID control which takes advantages of the quickness of fuzzy controller and the high-precision of PID controllerFirstly, this thesis introduces the current research state of virtual instrument technology and temperature control system. Then, the traditional PID control, fuzzy control technology and fuzzy self-adaptive PID algorithm are discussed, and the advantages and disadvantages of various control strategies are further analyzed, on basis of that, a switching controller between fuzzy self-adaptive PID and fuzzy control is designed well and the system’s implementation method is elaborated with details. The system consists of solid-state relays, thermocouples, data acquisition cards and computers. And software part of it is to constuct the fuzzy controller with PID controller by using fuzzy logic toolbox of the LabVIEW2011software platform (Fuzzy Logic for G Toolkit), ultimately in order to expose the functionality including temperature data acquisition, display, storage, system alarms and report query and so on, by Lab VIEW software programming,The results show that the temperature control system proposed in this paper based on the switching of fuzzy self-adaptive PID and fuzzy control has the characteristics of small overshoot, short adjusting time, no-shock. On the other hand the control system is also easy to operate, friendly interface and easy to maintain, so that the system is suitable for the actual control of reaction kettle temperature. In all, the research has a broad prospect and application in chemical production.