Improvements on Flat Output Characterization for Fractional Systems

Abstract

Abstract In trajectory planning, flatness is used to compute inputs generating suitable trajectories, without using any integration. The flatness property of linear controllable time-invariant fractional systems is studied. The formalism of polynomial matrix of the fractional differential operator is used leading to the characterization of fractionally flat outputs. The so-called defining matrices, which are transformations that express all system variables in function of the fractionally flat outputs and a finite number of their time derivatives, are introduced and characterized in this fractional context. Flatness of fractional systems is then applied to the trajectory planning of a real thermal experiment.