Evaluation of feedback-control systems subjected to large signals

IN THIS PAPER methods are presented for determining design modifications to improve the large-step response of a feedback-control system. This may be the response to a command or to a disturbance. The methods are applicable to systems of higher order as well as second order, and to systems with one or more important nonlinear effects. It is shown that the results obtained by application of the methods may be used to investigate questions not ordinarily answered by studies on a system subjected to small signal variations, such as: 1. Should a controller which has a dual mode of operation be instrumented for the system? 2. Should the saturation level for the cascaded components of the system be increased, thus usually mcreasing the linear range; or decreased, thus usually saving weight, bulk, and cost. 3. For an over-all required power gain in several cascaded components from the error to output, how should this power gain be distributed among the several cascaded components?