Robust, fragile, or optimal?
- 1 August 1997
- journal article
- Published by Institute of Electrical and Electronics Engineers (IEEE) in IEEE Transactions on Automatic Control
- Vol. 42 (8) , 1098-1105
- https://doi.org/10.1109/9.618239
Abstract
We show by examples that optimum and robust controllers, designed by using the H/sub 2/, H/sub /spl infin//, l/sup 1/, and /spl mu/ formulations, can produce extremely fragile controllers, in the sense that vanishingly small perturbations of the coefficients of the designed controller destabilize the closed-loop control system. The examples show that this fragility usually manifests itself as extremely poor gain and phase margins of the closed-loop system. The calculations given here should raise a cautionary note and draw attention to the larger issue of controller sensitivity which may be important in other nonoptimal design techniques as well.Keywords
This publication has 6 references indexed in Scilit:
- μ -synthesis of an electromagnetic suspension systemIEEE Transactions on Automatic Control, 1995
- Robustness of Dynamic Systems with Parameter UncertaintiesPublished by Springer Nature ,1992
- On the structure of H/sup infinity / control systems and related extensionsIEEE Transactions on Automatic Control, 1991
- Control of Uncertain SystemsPublished by Springer Nature ,1990
- State-space solutions to standard H/sub 2/ and H/sub infinity / control problemsIEEE Transactions on Automatic Control, 1989
- A system-theoretic approach to stability of sets of polynomialsContemporary Mathematics, 1985