Robust Stability of Linear Time-Delay Systems with Unknown Parameters and Delays
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Abstract
This paper investigates the robust stability of a class of linear time-delay systems subject to unknown parameters and delays. Since the exact values of these quantities are often unavailable in practice, an analytical framework based on the distribution of characteristic roots is developed. Through theoretical derivation of the characteristic equation for the perturbed system, an upper bound on its unstable eigenvalues is established. Subsequently, by employing the argument principle, sufficient conditions for robust stability are derived for both first-order and high-order time-delay systems. These conditions are easy to verify with low computational cost and are convenient for direct engineering application.
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