First-order Plus Dead-time Unstable Processes Using PID Controllers

PID control is currently one of the most widely used method in the field of industrial control. In recent years, scholars in and abroad are still studying on the PID control, it has emerged a large number of new methods and combined with other smart methods. In this thesis, methods of tuning parameter for the PID controller have been classified, conducting a detailed analysis of all types, from which some of the characteristics of PID parameter tuning and experience have been summed up. And also through the analysis of the first-order time-delay non-steady state process system With a PID controller, the controller parameters and delay parameters on the system stability of the region have been determined.The thesis analyzes the formula for the characteristic equation of the feedback control of the FOPDT unstable closed-loop system, and proposes a method of D-partition, which can determine settings of the controller parameters with a fixed order times and the structure as well as the time delay. Such method primarily embodies the analytic expression of D-partition boundary. And the thesis also uses the D-partition to derive the formula of P, PI, PD and discusses the stable ability of the FOPDT non-stable system controlled by PID, which proves the conductivity of the D-partition to build a stable set of controller parameters. This method has a strong ability in the stable region of the FOPDT unstable system with PID control.