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A multistage reduction technique for feedback stabilizing distributed time-lag systems. (English) Zbl 0629.93046
This paper presents a method which can be used to stabilize a system with state and control delays of the form: $$\dot x=\int\sp{0}\sb{-h}d\alpha (s)x(t+s)+\int\sp{0}\sb{-h}d\beta (s)u(t+s).$$ A preliminary requirement for this method is that the equation $A=\int\sp{0}\sb{-h}\exp (As)d\alpha (s)$ can be solved with respect to the unknown matrix A. Let $\Gamma$ be the set of the matrices A which solve this last equation. Then, it is proved that $\sigma$ (A) is contained in the spectrum of the delay system for each $A\in \Gamma$. Moreover, a special transformation can be applied to the pairs (x,u) (which solve the delay system) so that the transformed pair is solution of an ordinary differential equation. It is shown, under suitable assumptions, that a feedback which stabilizes this last equation can be used for the task of stabilizing the delay system.
Reviewer: L.Pandolfi

##### MSC:
 93D15 Stabilization of systems by feedback 34K35 Functional-differential equations connected with control problems 93C05 Linear control systems 93B17 System transformation 93B55 Pole and zero placement problems 93C25 Control systems in abstract spaces
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