Steven Devos

A Nanometre-precision, Ultra-stiff Plezostepper Stage for ELID-grinding

Abstract The extremely high machine stiffnesses required for a successful Implementation of ELectrolytic in-process Dressing (ELID) grinding cannot be obtained win conventional technologies. In this paper, an Innovative drive concept is presented, where the actuation and guiding functions in three degrees of freedom are combined in one functional unit, using an original plezo-stepping technology. The stage is actively positioned by a set of six ‘feet’ giving it an infinite static stiffness in all six degrees of freedom. The drive motions in x-, y- and C-directions are obtained by rolling the feet over the base surface in a three-by-three feet gait pattern. The stepping resolution can be as low as 2.5 nm. Hammering is avoided by force-controlled stepping. The x and y stage positions are interferometrically measured. Thermal errors are minimised by a symmetrical design.

Energy-autonomous wireless vibration sensor for condition-based maintenance of machinery

This paper addresses the development of an energy-autonomous wireless vibration sensor for condition-based monitoring of machinery. Such technology plays an increasingly important role in modern manufacturing industry. In this work, energy harvesting is realized by resorting to a custom designed thermoelectric generator. The developed wireless vibration sensor has a remotely tunable sampling rate, which caters to the different needs of various operating conditions. The two key features, energy autonomy and wireless measurement, are demonstrated successfully by the experimental results obtained on the thermoelectric generator and the wireless sensor.

A fast, high-stiffness and high-resolution piezoelectric motor with integrated bearing and driving functionality

Abstract With growing requirements on the precision of production machines, as expressed by the Taniguchi curves, the need arises for novel actuators that are able to combine high stiffness and high position resolution with high drive speeds. In this paper two novel integrated linear actuation systems with high active stiffness and with the unique ability to provide simultaneously high-resolution slow motion and lower-resolution high-speed motion, based on piezotechnology, are presented. Potential applications are stages for novel high-precision abrasive machining (e.g. ultraprecision grinding), lithography (e.g. extreme-UV wafer steppers), positioning devices working in vacuum (e.g. scanning electron microscopy).