Pole-assignment robustness in a ring for structured perturbation systems

A simple approach is proposed to analyze the pole-assignment robustness in a ring between two circles for linear uncertain systems. The explicit element bounds on highly structured perturbations are obtained to retain the system's poles located within a predetermined ring. Under these allowable highly structured perturbations, both stability robustness and certain performance robustness will thus be ensured. The proposed method is computationally simple and can be easily calculated by a computer. Illustrative examples are included.<
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