OPTIMAL MIX OF PASSIVE AND ACTIVE CONTROL IN STRUCTURES

This paper shows how to redesign a structure to make it easier to control. We begin with any active controller (say, designed to give the "ideal" performance). Next, we divide this controller into two parts-one that can be synthesized simply by structure redesign (this we call the passive control) and one that is to be synthesized as an active controller. Given that the total closed-loop response must not be changed from the "ideal," the passive part of the controller is designed to minimize the amount of control power needed for the active part. Necessary and sufficient conditions for a globally optimum structure is given, and gradient calculations are not required. Two simple algorithms which converge to the global optimum solution are provided.