A vertical/horizontal two-dimensional piezoelectric driven inertial slider micropositioner for cryogenic applications

Abstract

We have developed a simple, two-dimensional piezoelectric tube device which uses the inertial slider method to achieve remote micropositioning in the vertical and horizontal directions. The motion of the slider car occurs with respect to a quartz rod which is attached to, and accelerated by the piezo tube. The vertical motion, against or with gravity, is achieved by activating the longitudinal mode of the piezo tube. The horizontal motion is a rotation about the quartz rod, achieved by activating the bending mode of the piezo tube. The device is very compact, works at cryogenic temperatures and is ultrahigh vacuum compatible. Step sizes from 10 to 3000 nm and speeds up to 0.2 mm/s are possible. A computer simulation model of the inertial slider process has been developed also, to investigate the effectiveness of various activating waveforms. It confirms the advantage of a cycloidal-like waveform recently reported in the literature. Also, the model predictions are consistent with the results obtained in the laboratory. A diagram of the analog circuit developed to produce a cycloidal-like waveform to drive the piezoelectric is included. We briefly describe an alternative design where the activating piezoelectric is attached to the slider car which moves vertically on a fixed quartz rod.

Piezoelectric Inertia Motors—A Critical Review of History, Concepts, Design, Applications, and Perspectives

“…Many developments were not intended for industrial production, but for use in the developers' own laboratories. Reported improvements of motor designs mostly concerned the maximum slope a motor could handle-using mechanisms to generate a gravity-independent normal force, vertical motion was soon achieved [44,[48][49][50]-and the integration of multiple degrees of freedom into one device [30,42,[49][50][51][52]. Since 1990, the number of publications regarding inertia motors has continuously increased.…”

“…Many authors thus describe these motors as "inertial slider", "inertial sliding drive", "inertia slip drive", "friction-inertia actuator", or similar [32,[42][43][44]47,49,[122][123][124][125][126][127][128], also as a comprehensive term when differentiating between "stick-slip drive" and "inertial drive" [65,111,121]. Zhang et al [32] (p. 674) criticise short terms like "inertia motor" as misleading, because they omit the friction necessary for the motor to function.…”

“…Aluminum oxide (Al 2 O 3 , sometimes as a ceramic, in most cases in crystalline form as corundum and its varieties sapphire and ruby) predominates [104,105,126,[153][154][155][156][157], but quartz (SiO 2 ) [49,104,154], different glasses [105,158,159], or other ceramics [158] are also used. Combinations of one of these hard materials and metals are also common, mostly with steel [30,44,51,52,78,96,139,160,161] or bronze [49,162,163], sometimes also with other metals [49,[164][165][166]. A steel-steel couple is also used sometimes [34,47,50,62,84,157], while couples of steel with other metals [167], of two relatively soft partners like bronze [168], or with a very soft partner like polytetrafluorethylene (PTFE) [169,170] or other plastics [84,118,138,…”

“…Subsequently, this type of signal has frequently been applied-sometimes with variations to be able to generate the signal using analog circuits, as then digital-to-analog converters did not have the necessary dynamics [49]. For similar technical reasons, some authors have used simple driving circuits in which the slow edge of the signal is determined by the discharge curve of a capacitor [164,167,244].…”

A simple, ultrahigh vacuum compatible scanning tunneling microscope for use at variable temperatures

“…We use an ordinary 4 He glass cryostat which is surrounded by a liquid N 2 Dewar. When the STM is operated only down to the temperature range of liquid N 2 , the inner Dewar is filled with He gas.…”