The design of optimal linear control systems with output feedback (Q1595548)

The paper deals with a stationary, completely controllable, and observable linear closed system which consist of a plant and a controller that processes the output of the plant. The performance of this system is characterized by a quadratic functional with respect to the states of the plant and of the controller. A necessary and sufficient minimum condition for a functional on the motions of the system is obtained in the complex (frequency) domain. This relation implies that the sensitivity function of an optimal system satisfies the Bode condition. A second form of the optimality relation is derived in order to find the coefficients of the controller.