Robust stability analysis of commensurate fractional order interval polynomials

This paper deals with robust stability of commensurate fractional order interval polynomials. Tan et al. obtain the robust stability result of fractional order interval polynomials. The result is that the fractional order interval polynomial is robustly stable if and only if all the exposed edge polynomials are robustly stable. In this paper, some simplification is presented for robust stability of the commensurate fractional order interval polynomials. That is, the commensurate fractional order interval polynomial is robustly stable if and only if all the outer edge polynomials are robustly stable. The problem of robust stability of commensurate fractional order interval polynomials can be changed to the problem about the zero exclusion principle for its value set.