Feedback control systems subjected to large signals

IN FEEDBACK CONTROL SYSTEMS it is often found that a controller which has a dual mode of operation offers definite advantages. Such a controller has one mode of operation for small signals and a second mode for large signals. The first mode can usually be designed with linear studies using a periodic, aperiodic, or statistical test signal, depending on the application. A “large-step” test function is usually satisfactory, regardless of the application, for design of the second mode.