MULTIMODEL DISCRETE CONTROL WITH ONLINE UPDATING OF THE FRACTIONAL ORDER HOLD GAINS

Abstract

A multiestimation scheme for adaptive discrete-time control is presented. The different models of the scheme to be estimated are obtained from a set of different discretizations of a continuous-time unknown transfer function under a fractional order hold of correcting gain (β-FROH) which leads to distinct associate discrete-time models for the given continuous-time plant. The objective is to design a scheme being able to find the most appropriate value for the gain β to enhance the identification and tracking performances. The scheme chooses online the value of β with the best reference tracking performance by implementing eventually switches through time among a prefixed set of values characterizing the discrete models of the plant in a parallel multiestimation scheme. The switching rule is subjected to a minimum residence time in order to guarantee the closed loop stability. Simulations for two different practical cases, a controlled DC motor and a resonant circuit, are presented.

Additional information

Notes on contributors

A. Bilbao-Guillerna

The authors are very grateful to MEC and UPV by partial supports through Research Grants DPI 2003–00164 and Scholarship of A. Bilbao BES-2004-4261, and 9/UPV 00I06.I06-15263/2003.