Path tracking design by frequency band limited fractional differentiator prefilter: Square MIMO systems

An approach to path tracking design based on fractional differentiation has been proposed with its application on a multivaribale systems. In previous works, a first approach using Davidson-Cole prefilter has been developed and applied to MIMO (Multi Inputs Multi Outputs) systems. The goal of this paper is the extension of this work using a Frequency Band Limited Fractional Differentiator (FBLFD) prefilter. The global transfer function is assimilated to a FBLFD prefilter, whose main properties are to have no overshoot on the plant and to have maximum control value for starting time. The MIMO-QFT (Multi Input Multi output-Quantitative Feedback Theory) robust synthesis design combined with CRONE control procedure and taking into account plant uncertainties is used in this paper to extract the CRONE controller expression. After that, the prefilter parameters are optimized taking into account tracking performance specifications and actuators physical constraints. The proposed design is applied to an example taken from the literature.