Research Of Intelligent PID And Its Application In The Water Level Control

PID control is widely used in industrial process control systems for its simple structure and good adaptability.However,with the rapidly development of manufacturing level and science technology,the modem control systems become more complicated and systematic,and it is difficult for conventional PID control to obtain the satisfied control quality.Intelligent Control,as a brand-new field of automatic control,provides such complex uncertain problem a new way with its advanced and innovative thought.In recent years,intelligent PID combined by intelligent control and PID control is so attractive and has been effectively used in actual production,which shows the broad development prospect.The paper select two major branches of intelligent control—fuzzy control and neural network control for study.The former is robust and good at dealing with the structural knowledge without the object's precise mathematic model,while the latter has the primary advantage of self-learning,approaching any arbitrary function and parallel processing.On the Basis of introducing basic principle and parameters tuning methods of PID control in detail, about how to effectively integrate fuzzy control,neural network with traditional PID control is explored positively and several control projects are also summed up.The paper focuses on fuzzy self-tuning PID and PID based on improved BP neural network which get the most extensive application.Capabilities of tracking targets, anti-disturbance,fitting to changing process model and other aspects are studied by simulation based on MATLAB/Simulink.The simulation curves show that both control methods are obviously superior to conventional PID.Finally,the specific method using Intelligent PID control in typical industrial processes—level system is studied.Based on the Nanjing University process control laboratory CS4000 experimental device,select the dual-capacity water tank as the object,and consider the below water tank level as the control goal.PID,fuzzy self-tuning PID strategy are adopted separately to control water tank level in real-time.It analyses the respective control quality thoroughly.Both the simulation and the experimental result indicate that fuzzy self-tuning PID can control water tank level effectively and show strong robustness and good dynamic performance characteristics.