A differential-analyzer study of certain nonlinearly damped servomechanisms

A servomechanism must hold its error or the difference between input and output, to as small a value as possible. If a large error appears as a result of a rapid change in the value of an input position signal, then high acceleration and high output speed are desirable, and these in turn are favored by a low damping ratio. When the error is near zero, the speed should be reduced rapidly so that overshoot does not occur, and this requires a high damping ratio. Thus the use of nonlinear damping which has some inverse relationship to the error has been proposed by several investigators.1¿5