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Design and modeling of a self-sufficient shape-memory-actuator

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

:
Preprint urn:nbn:de:0011-n-1654483 (2.8 MByte PDF)
MD5 Fingerprint: 8fafa2d103d56cdb140a6ff15259f5f0
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: 23.6.2011


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 79772H (Vol.2)
Conference "Active and Passive Smart Structures and Integrated Systems" <2011, San Diego/Calif.>
English
Conference Paper, Electronic Publication
Fraunhofer IWU ()
shape memory alloy; actuator; self sufficient; structure integrated; adaptive; ball screw drive

Abstract
In machine tools several time and position varying heat sources causes complex temperature distributions. The resulting problems are varying thermal deformations which cause a loss of accuracy as well as non optimal drive conditions. An option to deal with that issue is to use structure integrated SM-actuators which use the thermal energy accumulated by machining processes to yield an actuator displacement. That creates a structure inherent control loop. There the shape-memory-elements work as sensing element as well as actuation element. The plant is defined by the thermal and mechanical behaviour of the surrounding structure. Because of the closed loop operation mode, the mechanical design has to deal with questions of stability and parameter adjustment in a control sense. In contrast to common control arrangements this issues can only be influenced by designing the actuator and the structure. To investigate this approach a test bench has been designed. The heat is yielded by a clutch and directed through the structure to the shape memory element. The force and displacement of the actuator are therefore driven directly by process heat. This paper presents a broad mechanical design approach of the test bench as well as the design of the SMactuator. To investigate the thermo-mechanical behaviour of the structure-integrated actuator, a model of the test bench has been developed. The model covers the thermal behaviour of the test bench as well as the thermo-mechanical couplings of the shape memory actuator. The model has been validated by comprehensive measurements.

: http://publica.fraunhofer.de/documents/N-165448.html