STABILITY AND ROBUST STABILITY OF UNIFORM SYSTEMS

The characteristic function of a uniform system, i.e., a system consis ting of identical components and amplifiers, is of the form D(f(s)), w here D(p) is a polynomial and f(s) is the transfer function of the com ponents. The stability condition is expressed as p(i) is an element of H, i = 1,...,n, where p(i) are the zeros of the polynomial D(p) and t he domain H depends on the function f(s). A general robust stability c ondition is stated for the case in which the polynomial D(p) and the f unction f(s) contain uncertainty (''zero exclusion principle''). On th e basis of this generalized criterion, the Kharitonov and the edge the orems are generalized and robust stability criteria under H-infinity u ncertainty and arbitrary delays are derived.