State estimator synthesis for position dependent flexible systems with position independent error convergence

In this paper a state estimator for high tech flexible systems with an inherent nonlinearity in the output dynamics is proposed. We consider an application in which sensor measurements of the flexible system become parameter (position) dependent. An LPV setting is proposed for the design of estimators that estimate flexible modes of the system. The possibility of pole placement for the error dynamics is investigated and characterized. In particular, necessary and sufficient conditions are derived for the estimator convergence to be parameter independent. In addition, an eigenvalue-shifting technique that improves the convergence of the estimated flexible modes is presented. Simulation results on a basic example and a full flexible system model are used to demonstrate the merits of the proposed estimation algorithms.