Constrained Iterative Feedback Tuning for Robust Control of a Wafer Stage System

Abstract— Iterative feedback tuning (IFT) enables the datadriven tuning of controller parameters without the explicit need for a parametric model. It is known, however, that IFT can lead to non-robust solutions. The aim of this paper is to develop an iterative feedback tuning approach with robustness constraints. A constrained IFT problem is formulated that is solved by introducing a penalty function. Essentially, the gradient estimates decompose into (a) the well-known IFT gradients and (b) the gradients with respect to this penalty function. The latter are obtained through a non-parametric model of the controlled system. This guarantees robust stability while only requiring a non-parametric model. Experimental results obtained from the motion control systems of an industrial wafer scanner confirm enhanced performance with guaranteed robustness estimates.

• Type: Journal
• Year: 2016
• Where: TCST
• Authors: Marcel François Heertjes, Bart Van der Velden, Tom Oomen
• Keywords: TCST 2016