Optimal non-fragile controller realization algorithm and application to control problems

WANG Dao-bo¹, WANG Hong-qiang¹

1.College of Automation Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China;2.Dept. of Electrical and Electronic Engineering, Imperial College London, England



Abstract:

To reduce the fragility encountered in controller implementation, which is a measure of extent to describe small perturbations in controller parameters caused by rounding-off errors or component tolerances, and keep the system stability and performance, approaches of weighted eigenvalue sensitivity and stability radii comparison were used for computation and reduction of controller fragility. An algorithm has been derived for the efficient reduction of controller fragility, which used eigenstructure decomposition to obtain the suboptimal solution. The algorithm was tested for different control problems through reducing their fragility by a large margin. Different canonical forms were analyzed for fragility, including controllable canonical form, observable canonical form, modal canonical form, balanced realization and optimal (non-fragile) form. Different realizations were implemented through C language Matlab EXecutable (CMEX) S-function discrete state space block. Double precision calculations were performed. Open and closed loop controller realizations were compared with simulink state space (optimal) block. Results of comparison indicate that the optimal non-fragile controller realization shows better results both in open loop and closed loop realization.

Key words:  controller fragility  eigenstructure decomposition  controller realizations

DOI：10.11916/j.issn.1005-9113.2010.01.017

Clc Number:TP273

Fund: