ALPHA-STABILITY ANALYSIS OF PERTURBED SYSTEMS WITH MULTIPLE NONCOMMENSURATE TIME DELAYS

In terms of the fundamental matrix and the Jordan canonical form of th e system matrix A(o), a new and simple a-stability criterion for multi ple noncommensurate time-delay systems is proposed. The criterion is s ufficient to ensure that all roots of the system's characteristic equa tion Lie to the left of Re(s) = -alpha, alpha, greater than or equal t o 0 and is also extended to the delay systems with parametric perturba tions. It wilt be seen that if alpha is not equal to zero, the corresp onding stability criteria depend on the delay time.