Inversion-based feedforward design for constrained fractional control systems

In this paper we propose an input-output inversion-based methodology for the synthesis of the feedforward action for a fractional control system in order to achieve a predefined process variable transition from a steady-state value to another. In particular, the feedforward action is implemented either as a signal to be added to the feedback control variable or as a command signal to be applied (instead of the typical step signal) to the closed-loop system. The method allows the minimization of the transition time by taking explicitly into account constraints on the process input an output and their derivatives. Simulation results show the effectiveness of the technique.