Suboptimum H2 pseudo-rational approximations to fractional-order linear time invariant systems

Abstract

In this paper, we propose a procedure to achieve pseudo-rational approximation to arbitrary fractional-order linear time invariant (FO-LTI) systems with suboptimum H2-norm. The proposed pseudo-rational approximation is actually a rational model with a time delay. Through illustrations, we show that the pseudo-rational approximation is simple and effective. It is also demonstrated that this suboptimum approximation method is effective in designing integer-order controllers for FO-LTI systems in general non-commensurate form. Useful MATLAB codes are also included in the appendix. © 2007 Springer.