Auto-Tuning of Digital PID Controllers Using Recursive Identification

Abstract

The paper deals with algorithms for auto-tuning of digital PID controllers. Tuning is based on the identification of process model parameters using the recursive least squares method (RLSM) with directional forgetting. The parameters of the PID controllers are designed on the basis of modified Ziegler-Nichols criterion for digital control loops and pole placement approach. The process is modelled as a regression model. The relations for setting procedures are given in the form of relatively simple formulas and flow diagrams. There has been developed the MATLAB-Toolbox ATC PID for desining, testing and simulating of auto-tuning digital PID controllers.