Design and analysis of a high speed smart materials based nano-positioner.

Nanometre accuracy is required by many modern microactuators to provide the accuracy and small motions necessary for micro-assembly and nano-lithography. Piezoelectric actuators are designed to do just that, and are now possible to get displacements in the order of picometre range. Combined with high stiffness, fast frequency response and high bandwidth, they are ideal for precision positioning applications. The present work is based on work of Goldfarb and Celanovic [3]. A single layer and a multilayer piezoelectric actuator model are developed, with PID closed-loop feedback control to control each layer in piezoelectric stack separately, to achieve the commanded displacement profiles. The models are simulated in MATLAB. In each case, the results show fast response times of 0.3 milliseconds or less. Multilayer model is able to control individual layers separately or all simultaneously, with similar or better response times. In each case, the model showed the ability to track displacements ranging from 1 nm to several μm