The Comparation And Analysis Of PID Control Methods For Resistance Furnace

The temperature control system itself has the characteristics of large inertia, pure time-delay and is difficult to build an accurate mathematical model. The traditional PID control method can't meet the control require for this kind of controlled plant. This paper uses the resistance furnace as the research plant, finds a suitable PID control method for the resistance furnace through the comparison of several PID control methods and achieves the control effect such as small overshoot and short setting time.Firstly, the paper expounds the advantages and disadvantages of the traditional PID control and uses the Smith compensator to improve it. The difficulty of PID control method is how to set the suitable PID parameters. The paper attempts to use the ZN critical ratio degree method to set the PID parameters. Considering the fuzzy control can get good dynamic performance, the paper uses the adaptive fuzzy PID control to give an online real-time adjustment for the PID parameters to make up for defect of fixed PID parameters. On the basis of this, this paper put forwards a fuzzy and PID double model control method based on Smith compensator. This method combines the good robustness of fuzzy control with the advantage of high steady precision of PID control. At the same time, the paper improves the switching method from the fuzzy control to the PID control.This paper gives a simulation analysis of different control method by using the Matlab Fuzzy Toolbox and Simulink Toolbox. The simulation results show that the overshoot and adjust time of PID control method can't meet the requirements. When using the adaptive fuzzy PID control method. The anti-interference ability of the system is not good, when using the fuzzy and PID double model control method based on Smith compensator. The dynamic response of the system and the steady precision have been greatly improved and have strong anti-interference ability. According to the system's requirements, this paper designs a control system of the resistance furnace using King view platform. Experiments prove that the fuzzy and PID double model control method based on Smith compensator has good control effect on the nonlinear system with large inertia and lag.