Controlling aliased dynamics in motion systems? An identification for sampled-data control approach

Abstract

Sampled-data control systems occasionally exhibit aliased resonance phenomena within the control bandwidth. The aim of this paper is to investigate the aspect of these aliased dynamics with application to a high performance industrial nano-positioning machine. This necessitates a full sampled-data control design approach, since these aliased dynamics endanger both the at-sample performance and the intersample behaviour. The proposed framework comprises both system identification and sampled-data control. In particular, the sampled-data control objective necessitates models that encompass the intersample behaviour, i.e., ideally continuous time models. Application of the proposed approach on an industrial wafer stage system provides a thorough insight and new control design guidelines for controlling aliased dynamics.

Keywords:

• aliased dynamics
• continuous time system identification
• sampled-data control
• intersample behaviour
• motion systems
• mechatronics

Acknowledgements

The author would like to thank Marc van de Wal, Robbert van Herpen, and Maarten Steinbuch are for their contribution to this research, and the late Okko Bosgra is gratefully acknowledged for fruitful discussions in an early stage of this research. Finally, the author would like to thank the reviewers and guest editors for their constructive comments that have improved this paper. Philips Innovation Services is gratefully acknowledged for access to the experimental set-up and their support for this research. This work is partially supported by the Innovational Research Incentives Scheme under the VENI grant Precision Motion: Beyond the Nanometer (no. 13073) awarded by NWO (The Netherlands Organisation for Scientific Research) and STW (Dutch Science Foundation).

Notes

1. The notation ω is used to represent both radial sampling frequencies and exogenous inputs, it follows from the context which one is referred to.