DocumentCode :
2191359
Title :
Uncertain LTI-models for linear control design of non-linear systems
Author :
Glad, S.T. ; Helmersson, A. ; Ljung, L.
Author_Institution :
Dept. of Electr. Eng., Linkoping Univ., Sweden
Volume :
3
fYear :
2001
fDate :
2001
Firstpage :
2692
Abstract :
Much attention in robust identification and control has been focused on linear low order models approximating high order linear systems. We consider the more realistic situation with a linear model approximating a non-linear system. We describe how a linear time invariant (LTI) model with unstructured uncertainty, i.e. a "band" of Nyquist curves, can be developed using a non-linear model error model. Applying standard linear robust control design to this uncertain LTI model will lead to a (non-linear) closed loop system with performance robustness guarantees (in terms of gain from disturbance to output) well in line with the objectives of the linear design. Clearly the design can be successful only if the linear model is a reasonably good approximation of the system. A particular aspect of the design process is to define a workable definition of "practical stability" for robust control design, with possibly non-linear model errors. We use affine power norms for that purpose
Keywords :
control system synthesis; feedback; identification; linear systems; nonlinear control systems; robust control; uncertain systems; Nyquist curves; closed loop system; high order linear systems; linear control design; linear design; linear low order models; linear time invariant model; nonlinear model error model; nonlinear systems; performance robustness guarantees; practical stability; robust identification; uncertain LTI-models; unstructured uncertainty; Closed loop systems; Control design; Linear approximation; Linear systems; Performance gain; Power system modeling; Process design; Robust control; Robust stability; Uncertainty;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Decision and Control, 2001. Proceedings of the 40th IEEE Conference on
Conference_Location :
Orlando, FL
Print_ISBN :
0-7803-7061-9
Type :
conf
DOI :
10.1109/.2001.980677
Filename :
980677
Link To Document :
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