Stabilizing region of PDμ controller for fractional order system with general interval uncertainties and an interval delay.

This paper concentrates on computing the stabilizing region of PD μ controller for fractional order system with general interval uncertainties and an interval delay . The stabilizing region means the complete/approximate set of PD μ controllers that stabilize the given closed-loop control system. General interval uncertainties refer to both coefficients and orders of the fractional system suffer from interval uncertainties. Interval delay indicates that the delay also vary in a specified interval. Firstly, a method is presented to calculate the stabilizing region for general interval fractional system with an interval time-constant delay . Based on a novel mapping function and the concept of critical controller parameters, the stabilizing region can be determined numerically. Secondly, the stabilizing region computation problem for general interval fractional system with an interval time-varyingdelay is considered. By applying a revised small-gain theorem, the stabilizing region can be calculated like the time-constant delay case. Thirdly, two alternative methods are proposed to improve the computational efficiency of stabilizing region calculation. Both methods can reduce the number of polynomials which are used to determine the stabilizing region. Examples are followed to illustrate the proposed results. [ABSTRACT FROM AUTHOR]