Variably damped servomechanisms

THE SPEED of response is one of the most important characteristics of a large class of servomechanisms. A variety of methods and criteria for determining the speed of response exists. One of these criteria is the length of time between the application of a step of input to the servo and the time when the output corresponds to the new input, within a specified tolerance. This length of time is usually referred to as the settling time. Fig. 1 shows the settling time of a typical underdamped servo. In most applications, the designer desires to obtain as small a settling time as possible, i.e., he will design the servo with the highest possible speed of response.