Stability study of a third-order servomechanism with multiplicative feedback control

IN HIS PREVIOUS PAPERS1¿3 the first author has given a general analysis of nonlinear coupled circuits and applied the method to the analysis of servomechanisms with nonlinear feedback control. This paper reports the results of a stability study of a third-order servomechanism with multiplicative feedback control. The nonlinearities in the control system, and hence the differential equations representing the system, are introduced by the multiplication of certain quantities, or variables, of the system. For example, if the actuating signal e is multiplied by itself, one obtains e2, which in turn introduces a nonlinear term in the final differential equation representing the feedback control system.