The Application Research On Fuzzy PID Control In Three-tank Water System Control

Three water-tank system imitates the popular process control system in industry,and its has some characteristics as: it is a heavy inertia, non-linear and strong coupled system. It has pratical significance to analyse and control the Three-tank water system. The flux law is adopted to bring forward the mathmetical model of the Three-tank water system. The mathmatical model of the system is studyed. Aiming to its non-linear, strong coupled characteristics, a decoupling method for non-linear dynamic system is applicated to the system. Its advantage is that absolute decoupling for the nominal responses of system outputs can be implemented for this kind of system which takes a non-linear compensation way.In the article,the PID controller of the conventional control theory is introduced. Several familiar upswing PID controllers are analysed, and their advantages and disavantages are pointed out. The intelligent control theory is investigated, mainly points out the fuzzy control theory and its arithmetic. A controller which combined both the conventional and fuzzy theory—self adjusting fuzzy PID controller is introduced and analysed.In the end, Digital PID and Fuzzy PID control methods are taken into the system based on the decoupling, and simulations are taken in MATLAB. The result proves the efficiency of decoupling method, shows that the system has stronger anti-disturbance characteristic and some other predominances under the control of Fuzzy PID than that of Digital PID.