Model order identification for fractional models

This paper deals with continuous-time system identification using fractional differentiation models. So far, no algorithm exists concerning model order identification of fractional models. The “simplified” refined instrumental variable method is proposed to estimate parameters of fractional differential equation models when all the fractional orders are assumed known. Then an optimization approach based on this instrumental variable estimator is presented. This two-stage algorithm, called oosrivcf is then used for model order identification by using simultaneously two criteria: the Young Information Criterion (YIC) and the R_T² criterion.