Contactless and selective energy transfer to a bistable micro-actuator using laser heated shape memory alloy

Abstract

Contactless energy transfer (CET) methods offer great flexibility in the design of complex micro-systems. This paper reports a laser based contactless and selective energy transfer method. A compliant bistable micro-actuator (curved beam of size 25 mm × 1.5 mm × 0.508 mm) is actuated between its two stable positions using the laser heated shape memory alloy (SMA) active elements (size: 3 mm × 1 mm × 0.1 mm). The switching time of the actuator turns out to be 0.5 s for d 0 equal to 700 µm and a laser power of 90 mW (d 0 is half of the total stroke length). The paper also demonstrates the selective energy transfer technique to the SMA active elements by depositing silver based optical filters directly onto the SMA active elements. A successful demonstration is presented for four wavelengths, 532, 660, 785, and 980 nm, using different values of d 0 for the bistable micro-actuator. Finally, a long-term test is performed to highlight the thermo-mechanical effect on the selective addressing capability of the optical filters.

Shape Memory Alloy (SMA) Actuators: The Role of Material, Form, and Scaling Effects

“…The MIM structure tunes light absorption to wavelengths of 532, 660, 785, and 980 nm by changing the thickness of the insulator; different light sources allow for selective actuation. [ 72 ] Such treatments can be very useful; no‐contact methods (such as lasers) can then be applied for selective actuation of a SMA structure.…”

Nonlinear dynamics and snap-through regimes of a bistable buckled beam excited by an electromagnetic Laplace force

“…Other contactless actuation devices proposed in the literature exploit different kinds of actuating forces such as electrostatic forces which are effective only at microscopic scale [Chen and Meguid, 2015, Krylov et al, 2011, Park and Hah, 2008, Younis et al, 2010 with extension to dynamics of arch-shaped beams [Krylov and Dick, 2010, Ouakad, 2014, Ramini et al, 2016, Wu et al, 2014. Micro-beams actuated by electro-thermo-mechanical effect or by shape memory alloys heated by laser are reported in [Barth et al, 2010, Zaidi et al, 2012. Our method based on Laplace forces provides an excellent control of the beam dynamics for a beam of 20cm length.…”

Surface Nanopatterned Shape Memory Alloy (SMA)‐Based Photosensitive Artificial Muscle

“…As discussed earlier, plasmonic effects can be induced by making patterns on the surface, or by depositing thin films. Zaidi et al introduced a color filter fabricated by plasmaenhanced chemical vapor deposition (PE-CVD); [19] however, their approach provided only localized microscale absorptance changes. Further, the PE-CVD process is more involved, as pattern creation requires the use of a mask, which must be fabricated and precisely aligned.…”