Applied Research, The Plc-based Fuzzy Control

In recent years, the development of intelligent control field is rapid. There is an issue that to apply the intelligent control theory timely. Fuzzy Control is a computer control method which based on fuzzy logic. It is an important branch of the intelligent control. As easy to use, good control effect, fuzzy control is widely used in various control systems, in particular, the model uncertainty, nonlinear, large time delay control system. Fuzzy control theory is not only theoretical, but also has a large number of practical applications.PLC is widely used in industrial control presently. For common control task, the PLC with conventional PID algorithm has good performance, but it is hard to deal with the complex tasks. To enhance the control performance of PLC, the PLC manufacturer developed some intelligent control modules, such as fuzzy control module. These modules have enhanced the control performance of PLC, However there are many problem of them, such as privacy technologies, lack of flexibility, poor versatility, expensive and so on. Taking into account these issues, this paper proposes to use the software method to implement low-cost fuzzy control on PLC.This paper has studied the basic theory and system design of fuzzy control, and research status; the fuzzy PID control, and fuzzy self-tuning PID control to improve the fuzzy control. and analyze the shortcoming of the look-up table method, make a line interpolation algorithm improvement on the look-up table method. has studied the fuzzy control on PLC and completed the design and simulation of FLC by MATLAB. and completed the overall design and detailed design fuzzy control system of DC motor rotation speed, has implemented fuzzy algorithm in STEP7-Micro/WIN which IDE for S7-200 PLC, has compared the performance of fuzzy control with PID control.The research results shows that software implement of fuzzy control on PLC can be used for industrial application. The way has lower cost, be more flexible, and better portability compared to hardware implement method. Fuzzy control has a faster response and a better robustness than PID control.