There are two primary ways to go about selecting the P.I .D. gains. Either the operator uses a trial and error or an analytical approach. Using a trial and error approach relies significantly on the operator’s own prior experience with other servo systems. The one significant downside to this is that there is no
physical insight into what the gains mean and there is no way to know if the gains are optimum by any
definition. However, for decades this was the approach most commonly used. In fact, it is still used
today for low performance systems usually found in process control. To address the need for an analytical approach, Ziegler and Nichols [1] proposed a method based on their many years of industrial control experience. Although they originally intended their tuning method for use in process control, their technique can be applied to servo control. Their procedure basically boils down to these two steps.