MULTILOOP PI CONTROLLER TUNING FOR INTERACTING MULTIVARIABLE PROCESSES

A trial-and-error method that is a variation of Ziegler-Nichols tuning has been employed in the past for field tuning of PID controllers. Th is method is now extended for tuning of multiloop PI controllers. The Nyquist array method is refined to determine ultimate gains for multil oop tuning. The proposed method is simple to use and simulation result s show that it avoids sluggish responses and unbalanced responses betw een loops that occur with other tuning methods such as BLT and sequent ial autotuning. (C) 1998 Elsevier Science Ltd. All rights reserved.