ROBUST SELF-TUNING PID CONTROLLER

Abstract

New algorithm of digital self-tuning controller (STC PID) has been derived in this paper. The parameters of this controller are designed on the basis of modified Ziegler-Nichols criterion for digital control loops. The process is modelled as a controlled regression of the third order and its parameters estimated using the recursive least squares method (RLSM) with the LD decomposition and with directional forgetting is applied. The algorithm is suitable for automatic setting of digital PID controllers for control the deterministic processes or for adaptive control of stochastic processes.