Model order reduction of commensurate linear discrete-time fractional-order systems

This paper presents an approach to model order reduction of linear time-invariant discrete-time commensurate fractional-order state space systems by means of the Balanced Truncation Approximation and Singular Perturbation Approximation methods. Mathematical formulas for computation of controllability and observability Gramians for the fractional-order systems are derived. This enables an extension of classical SVD-originated model order reduction algorithms to model reduction of discrete-time fractional-order state space systems. Simulation experiment illustrates the efficiency of the introduced methodology.