The Research Of Parameter Self-tuning PID Control System Of Liquid-level Based On Flex Factor

In the conventional self-tuning fuzzy PID controller design, the quantizing factor and scale factor is fixed, when the control system approaches gradually to the zero error, the initial input of a given fuzzy partition domain makes it rough, it is difficult to obtain higher control accuracy. To solve this problem, the PID parameters self-tuning control approach based on the flex factor is presented in this paper. On the one hand, the method introduced the idea of variable domain, so that the basic domain of the fuzzy controller's input and output stretches changes with the control criteria at a certain time, with adaptive capacity, which improves performance of the fuzzy PID control. On the other hand, the genetic algorithm was used to optimize the parameters of flex factor, so as to achieve the purpose of optimizing the fuzzy controller. And then comparing with PID control and the conventional fuzzy PID control method, simulation results show that the control system using this method is more speed, adaptive and robust.A Network control system consisting of the A3000 process-control system, SIMATIC S7-200 and PC/PPI Programming cable is introduced as an experimental platform, and then the control algorithm and human-computer interface (HMI) are developed using MATLAB language and the KingView configuration software respectively. Then the PID parameters self-tuning control approach based on flex factor is applied to the real-time control for a liquid-level system, and it achieved better control effect. The experiment results prove the validity and feasible of the variable domain fuzzy self-tuning PID controller.