Design And Use Of GA-Fuzzy PID Controller

PID control is one of the developed firstly control strategies. Up to now, PID control and improved PID control strategies have been widely used in industrial control system for its simple structure and strong robustness. The performance of controller directly influences the qualities of producing process and products. Therefore, tuning parameters of PID controller is the most important step in the control system design. With the quick development of computer technology and the penetration of intelligence computations in automatic control field, they support new ways and approaches for tuning parameters of PID controller.Fuzzy control simulates the human thinking, which is able to deal with the imprecise and nonlinear information in the objective world. At the same time, it possesses the ability of anti-jamming. In this thesis, fuzzy control is used to produce the change of parameters of PID controller, which makes PID controller self-adaptive and robust. On the basis of the basic fuzzy PID control, GA algorithm, which is from the intelligent behavior of the natural beings, is applied to tuning and optimizing parameters of PID controller. The related theory analysis and convergence proof are done. Then, vague set using measures of similarity reasoning makes up the defaults, in order to getting the final outputs of the controller.Based on tuning parameters of the GA algorithm, the embedded self-tuning PID controller is designed. In the hardware, the master control chip is LPC2214, which has 8 channel 10-bit A/D converter and 256KB embedded fast Flash ROM. Because of less on-chip RAM, SRAM is expanded. Besides, D/A converter, keyboard and LCD displayer are adopted. In the software, the process of transplanting the embedded real-time operating system, namely uC/OS-II, on LPC2214 is introduced in detail. Based on uC/OS-II, realize the GA-fuzzy PID controller by dividing the application into several tasks with modularization.At last, the designed GA-fuzzy PID controller is made into high-density beer dilution system.