Design and Implementation of Desired Interaction Yielding Fractional-Order Controller With Application to Wheeled Mobile Robot

A new method for the design of a fractional-order controller (FOC), with the objective of making responses of designed multiple-input-multiple-output (MIMO) closed-loop system transfer function matrix (DCL-TFM) as close as possible to that of a MIMO model CL-TFM (MCL-TFM), is proposed. In the present work, it is not necessary that the order of the MCL-TFM to be equal to that of the DCL-TFM. The proposed method can be used for FO/integer-order (IO) controller design for FO/ IO MIMO systems with or without time-delay without any modification. The proposed method gives flexibility to a designer in incorporating a desired degree of coupling along with desired time-domain specification in the DCL-TFM. The developed controller design procedure is illustrated for the design of the FOC for the velocity control of the wheeled mobile robot (WMR), which has been modelled as time-delay linear time-invariant MIMO IO system. The developed algorithm is also illustrated for FOC design for an FO MIMO plant with time-delays. Using the proposed method, an IO controller (IOC) with the same objective is also designed. A comparative analysis of results validates the superiority of the FOC over its IO counterpart.