Piecewise linear servomechanisms

LINEAR servomechanisms have found widespread application primarily because of their inherent simplicity. This simplicity is reflected both in the physical structure of an approximately linear system and in its analysis. It is well known that the performance of a nonlinear servomechanism may be considerably better than that of a comparable linear one. Second-order systems may be investigated semianalytically by the phase plane approach. Unfortunately however, analytical methods for the design of more general nonlinear servo systems are virtually nonexistent. An analytical method based on a rather restrictive approximation was proposed by Kochenburger1 for analyzing contactor servos. Extension of Kochenburger´s method to more general problems is discussed by Johnson.2