Design, identification and control of a fast nanopositioning device

Abstract

This paper presents t h e design, identification and control of a nanopositioning device. T h e device is actuated by a piezoelectric stack and its motion is sensed by a Linear Variable Differential Transformer (LVDT). A fourth order single input single output model has been identified to describe its dynamics. It is demonstrated t h a t PI control law does not meet the bandwidth requirements for positioning. This motivated the design and implementation of a n ' H , controller which demonstrates substantial improvements in t h e positioning speed and precision besides eliminating t h e undesirable nonlinear effects of t h e actuator. T h e characterization of the device in terms of bandwidth, resolution, and repeatability is also shown.

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Fractal compression and adaptive sampling: reducing the image acquisition time in scanning probe microscopy

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