LPV identification of high performance positioning devices

High performance positioning devices exhibit position dependent dynamics in the form of varying flexible modes, which are expected to dominate the dynamic behavior in the new generation of lightweight positioning structures. To handle such position-dependent behavior, the framework of Linear Parameter-Varying (LPV) systems offers powerful tools in terms of control synthesis with many successful practical applications. However, to achieve the desired performance, a low complexity but accurate LPV model of the underlying plant is of crucial importance. Obtaining LPV models for positioning devices based on first principle laws is a rigorous and costly process often resulting in models with inadequate accuracy. Therefore a data driven-modeling approach using Orthonormal Basis Functions (OBF's) is studied for the control oriented modeling of xy-positioning table dynamics. Through a simulation study it is demonstrated that the proposed modeling procedure, using only measurement data, can provide models whose accuracy is very close to the analytic models derived with the full knowledge of the system.