Multi-channel compensator design for feedback control systems by compensator improvement

In the past few years there has been an increasing interest in the use of the computer for designing compensators of control systems.1,2,3,4,5,6 The compensator design technique presented in [1] is basically a weighted least squares fit of the actual frequency response curve to some desired frequency response. Somewhat different, the method described in [2] and [3] designs compensators by embedding the frequency response design specifications in a cost function which is then minimized with respect to the compensator coefficients. These methods are definitely an asset when used to design practical compensators for control systems; however, in some cases a priori knowledge must be used for selecting certain weighting constants, or computer programs containing these algorithms must be run several times while transmuting these constants before an acceptable design can be achieved.