PERIODIC OUTPUT-FEEDBACK STABILIZATION OF NEUTRAL SYSTEMS

In this paper, a new feedback control technique called periodic output feedback is investigated in the context of infinite-dimensional linea r systems modeled by neutral functional differential equations, In thi s method, discrete output samples are multiplied by a periodic gain fu nction to generate a continuous feedback control. This work focuses on stabilization of neutral systems with delayed control modeled in the state space W-2((1))([ - tau,0];R(n))xL(2)([ - tau,0],R(R)), where W-2 ((1))([ - tau,0];R(n)) denotes the Sobolev space of R(n)-valued, absol utely continuous functions with square integrable derivatives on [- ta u, 0]. We show that a class of these systems can be stabilized by peri odic output feedback, even though their input operators are unbounded, We overcome this difficulty by representing the system state using an abstract integral ''variation of constants'' formula. An algorithm is presented at the end of this paper to construct a periodic output fee dback gain function. An example is provided to illustrate the construc tion of the gain function.