Shape memory actuator

Safety devices -standards and specifications [MATERIALS STANDARDS AND SPECIFICATIONS] (Vol 16) -shape-memory actuators for [SITAPE-MEMORYALLOYS] (Vol 21) -use of bismuth alloys [BISMUTH AND BISMUTH ALLOYS] (Vol 4)... 

The thermosetting polymer may also be the host of a variety of NPs such as POSS, CNTs, and nanoclays [21]. Self-healing thermosetting polymers with potential applications in paints and coatings have been developed [27, 28]. Thermosetting polymers also have a great potential as shape-memory actuators [29, 30]. 

Tellinin J, Suorsa I, Jaaskelainen A, Aaltio I, Ullakko K (2002) Basic properties Of magnetic shape memory actuators hi Proceedings of ACTUATOR 2002, 8th international conference on new actuators 2002, Bremen, Germany 566-569... 

Gunes, I.S., Jimenez, G.A., and Jana, S.C. (2009) Carbonaceous fillers for shape memory actuation of polyurethane composites by resistive heating. Carbon, 47, 981. 

In this study, adaptive control algorithms have been utilized for designing active controllers for smart structure test articles. Adaptive control schemes require only a limited a priori knowledge about the system in order to be controlled. The availability of limited control force and inherent deadband and saturation effects of shape memory actuators are incorporated in the selection of the reference model. The vibration suppression properties of smart structures were successfully demonstrated by implementing the conventional model reference adaptive controllers on the smart structure test articles. The controller parameters converged to steady state values within 8 s for both direct and indirect MRACs. 

Shape Memory Actuators 151 Table 6.3. Comparison of shape memory ahoy systems... 

Electrical Shape Memory Actuators Actuator Shape and Stroke... 

Based on this concept, the shape memory actuator system can be simulated by a nonlinear dynamical model. 

The properties of electrically activated shape memory actuators described so far have indicated that these actuators are well-suited to drive mechanical mechanisms. The advantages and disadvantages of this kind of new actuator principle are smnmarized in Table 6.6. 

Shape memory actuators offer a lot of advantages, but there are also some quite serious drawbacks. When comparing SM actuators with other actuator principles (such as piezoelectric stacks or solenoids), it should be taken into consideration that research for improved shape memory materials is relatively young. With shape memory alloys and actuators slowly gaining commercial importance it is expected that in the next few years new SM alloys will emerge that have higher transition temperatures and good effect stability [85,86]. 

The analysis of the advantages and disadvantages reveals good feasibility and opportunities for electrically heated shape memory actuators, especially in two fields of application ... 

The advantages of SM actuators listed in Table 6.6 gain importance where small mechanisms are concerned. The following properties recommend utilization of shape memory actuators in millimeter- or micrometer-sized mechanical mechanisms ... 

In this section some examples of precision engineering prototypes are presented that apply electrically heated shape memory actuators as driving elements. Further on flexure hinges of pseudo-elastic SM alloys will be presented. 

Use of solid state actuators. Small shape memory actuators can apply relatively high forces and strokes, can be well integrated into the grippers mechanical structure, and do not emit particles into the clean-room environment. 

The advantages offered by shape memory actuators become most obvious where small-sized devices are concerned. Due to the very high work-per-volume ratio, SM actuators of millimeter or micrometer dimensions have large actuator strokes and forces. The response time strongly decreases with shrinking actuator size. 

Hesselbach, J. Stork, H. Simulation and Control of Shape Memory Actuators. Proc. 5th Int. Conf. on New Actuators, June 26-28, Bremen, Germany (1996), pp. 396-399... 

Misra, M.S. Carpenter, B. and Maclean, B. Adaptive Structure design Employing Shape Memory Actuators. AGARD-CP 531, Paper 15 (1992)... 

Tseng, L.F., Mather, P.T., Henderson, J.H., 2013. Shape-memory-actuated change in scaffold fiber alignment directs stem ceU morphology. Acta Biomateriaha 9, 8790-8801. 

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