Title: Non-diagonal multivariable fractional prefilter in motion control

Authors: Najah Yousfi-Allagui; Nabil Derbel; Pierre Melchior

Addresses: Control and Energy Management Laboratory (CEM), Engineering School, University of Sfax, BP W, 3038 Sfax, Tunisia ' Control and Energy Management Laboratory (CEM), Engineering School, University of Sfax, BP W, 3038 Sfax, Tunisia ' UMR 5218 CNRS, Bordeaux Institute of Technology, University of Bordeaux, 351 cours de la libération, 33405 Talence Cedex, France

Abstract: A novel approach for robust Commande Robuste d'Ordre Non Entier (CRONE) control of multi input multi output (MIMO) systems using quantitative feedback theory (QFT) design is discussed through fractional prefilters with off-diagonal elements. More design flexibility is guaranteed when using the non-diagonal prefilter. For a given system, the CRONE control approach is combined with QFT design to get the controller matrix. After that, the classic diagonal fractional prefilter expression is extended to a fully populated prefilter matrix. The Davidson-Cole fractional prefilter optimisation is used to determine the diagonal terms of prefilter. The role of the off-diagonal elements of prefilter is to eliminate loop interactions in the case of reference tracking. So a sequential design procedure is proposed in order to get the fully populated prefilter matrix elements. The performance of the novel methodology is finally verified by adopting the designed prefilter and controller to govern the MIMO SCARA robot model.

Keywords: CRONE control; coupling matrix; fractional prefilter; Davidson-Cole prefilter; multivariable control; MIMO systems; robust control; path tracking; quantitative feedback theory; QFT.

DOI: 10.1504/IJMIC.2017.086569

International Journal of Modelling, Identification and Control, 2017 Vol.28 No.3, pp.271 - 283

Received: 03 Jun 2016
Accepted: 21 Sep 2016
Published online: 12 Sep 2017 *

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