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Design of a controllable shape-memory-actuator with mechanical lock function

 
: Neugebauer, Reimund; Drossel, W.-G.; Pagel, K.; Bucht, A.; Zernecke, A.

:
Postprint urn:nbn:de:0011-n-1568741 (823 KByte PDF)
MD5 Fingerprint: 8e3ef18321ab417d848965482b87ee12
Copyright 2011 Society of Photo-Optical Instrumentation Engineers. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited.
Created on: 29.3.2011


Ghasemi-Nejhad, M.N. ; Society of Photo-Optical Instrumentation Engineers -SPIE-, Bellingham/Wash.; American Society of Mechanical Engineers -ASME-:
Active and Passive Smart Structures and Integrated Systems 2011 : 7 - 10 March 2011, San Diego, California, United States
Bellingham, WA: SPIE, 2011 (Proceedings of SPIE 7977)
ISBN: 978-0-8194-8539-7
Paper 797719 (Vol.1)
Conference "Active and Passive Smart Structures and Integrated Systems" <2011, San Diego/Calif.>
English
Conference Paper, Electronic Publication
Fraunhofer IWU ()

Abstract
Machine tools for small work pieces are characterized by an extensive disproportion between workspace and cross section. This is mainly caused by limitations in the miniaturization of drives and guidance elements. Due to their high specific workloads and relatively small spatial requirements, Shape-Memory-Alloys (SMA) possess an outstanding potential to serve as miniaturized positioning devices in small machines. However, a disadvantage of known actuator configurations, such as an SMA wire working against a mechanical spring, is that energy is steadily consumed to hold defined positions. In this paper we present a novel SMA actuator design, which, due to an antagonistic arrangement of two SMA elements does not require energy whilst holding position. The two SMA actuators are applied in a differential setup and were designed regarding material, geometrical parameters, applied load, and control aspects. Furthermore, closed loop control concepts for positioning applications are implemented. These not only cover approaches using sensors, but also sensor-Iess concepts which utilize the distinctive length - resistance - correlation of SMAs for position controlling. Furthermore, a model/sam pie actuator has been used to demonstrate the designs capabilities to serve as miniaturized positioning device in small machines.

: http://publica.fraunhofer.de/documents/N-156874.html