γ-δ Routh approximation for interval systems

The paper presents the /spl gamma/-/spl delta/ Routh approximation for interval systems. The interval /spl gamma/s and /spl delta/s are evaluated for the higher order interval systems, and then an rth-order approximant is obtained by retaining the first r, interval /spl delta/s, and /spl gamma/s. A numerical example illustrates the procedure.