p r, T.

idea of v ive ro l A survey of more than 11,000 controllers in the refining, large number of papers have also appeared, see e.g. [17– systems with poor robustness [1]. Ziegler and Nichols presented two methods, a step response method and a frequency response method. In this paper we will ized by two parameters obtained from the step response. where PID control is appropriate? When is derivative integral gain subject to a constraints on the maximum sensitivity. The method, called MIGO (M-constrained integral gain optimization), worked very well for PI control. In [33] the method was used to find simple tuning rules for PI control called AMIGO (approximate MIGO). The same approach is used for PID control i