Closed-loop Identification

KARIMI Alireza    BONVIN Dominique

The main objective of this project is the development of an algorithm to identify the parameters of a SISO plant in closed-loop operation by minimizing the infinity norm of the modeling error weighted by two closed-loop sensitivity functions. An upper bound for the weighted modeling error can also be obtained and will be used in the design of a robust controller. Two approaches can be considered: In the first one, the problem will be formulated as pseudo-linear matrix inequalities and will be solved iteratively using the LMI tool box. The Second approach uses the dual Youla parameterization to parameterize all the plants that stabilize the closed-loop system with a given controller. In this case, the closed-loop output error will be linear with respect to the parameters and, since the matrix inequalities become linear and convex, they can be solved using the LMI toolbox. The main disadvantage is the possible high order of the resulting model.

Landau I. D. and A. Karimi. A Unified Approach to Model Estimation and Controller Reduction (Duality and Coherence). European Journal of Control , November 2002, Vol. 8, No. 6, 561-572

Landau I. D. and A. Karimi. A Unified Approach to Closed-Loop Plant Identification and Direct Controller Reduction. European Control Conference 2001, Porto, Portugal (September 2001), 1780-1785