Microelectromechanical digital-to-analog converters of displacement for step motion actuators

Citation
H. Toshiyoshi et al., Microelectromechanical digital-to-analog converters of displacement for step motion actuators, J MICROEL S, 9(2), 2000, pp. 218-225
Citations number
14
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Eletrical & Eletronics Engineeing
Journal title
JOURNAL OF MICROELECTROMECHANICAL SYSTEMS
ISSN journal
1057-7157 → ACNP
Volume
9
Issue
2
Year of publication
2000
Pages
218 - 225
Database
ISI
SICI code
1057-7157(200006)9:2<218:MDCODF>2.0.ZU;2-Q
Abstract
This paper presents a novel micromechanism for precise positioning by using an N-bit digital code. The mechanism is an N-stage network of connected su spensions, in which an electrostatic actuator is attached to the longer sus pensions of compliance 2C, and N of such unit structures are connected side by side with the shorter suspensions of compliance C. Each actuator is an electrostatic shuttle moving back and forth between the driving electrodes, and is operated by the corresponding digit of the input code. The N-bits o f Local displacement accumulate in the suspension network to synthesize an analog output, which is proportional to the analog value coded with the N-b it input. The output displacement is independent of the fluctuation of the driving voltage since the traveling distance of the shuttle is clipped by m echanical stoppers. We call the mechanism a microelectromechanical digital- to-analog converter (MEMDAC) since the function is equivalent to the electr ical digital-to-analog converter known as the R-2R resistor network. Three different types of MEMDAC's are compared, Preliminary results of a silicon micromachined 4-bit MEMDAC successfully showed a total stroke of 5.8 mu m w ith a step of 0.38 mu m. The positioning resolution can be made finer by si mply increasing the number of chained units.