Shape Memory Alloy (SMA)‐Based Microscale Actuators with 60% Deformation Rate and 1.6 kHz Actuation Speed

Abstract

Shape memory alloys (SMAs) are widely utilized as an actuation source in microscale devices, since they have a simple actuation mechanism and high-power density. However, they have limitations in terms of strain range and actuation speed. High-speed microscale SMA actuators are developed having diamond-shaped frame structures with a diameter of 25 µm. These structures allow for a large elongation range compared with bulk SMA materials, with the aid of spring-like behavior under tensile deformation. These actuators are validated in terms of their applicability as an artificial muscle in microscale by investigating their behavior under mechanical deformation and changes in thermal conditions. The shape memory effect is triggered by delivering thermal energy with a laser. The fast heating and cooling phenomenon caused by the scale effect allows high-speed actuation up to 1600 Hz. It is expected that the proposed actuators will contribute to the development of soft robots and biomedical devices.

New frontiers for the materials genome initiative

“…a, b A shape memory alloy with the shape depicted in (a) that after stretched to the shape depicted in (b) returns to its original shape (Reprinted with permission from ref. 215 , Copyright John Wiley & Sons, Inc. 2018), c gamma TiAl turbine blade used in various Boeing models, developed using recently assembled materials databases (Adapted with permission from ref. 133 , Copyright Springer Nature 2016), and (d) nickel-based materials currently in development for use in future energyefficient, highly reliable aircraft engines: microscale view (left) and simulation (right) (Adapted with permission from ref.…”

Review of Soft Linear Actuator and the Design of a Dielectric Elastomer Linear Actuator

“…However, due to the sliding between the two rolled DE membranes, the deformation is not inhomogeneous. The inhomogeneous deformation is [59]; c bundle of SMA wires [32]; d SMA spring robot [31]; e robotic hand driven by SMA wires [34]; f high-speed microscale SMA actuators [35]; g Nitinol hydraulic bellow actuator [36]; h biocompatible shape memory polymer actuators [53]; i arm-like electrothermal actuator [55] one of the main causes of actuating instability. Teh et al [9] developed a cylindrical actuator, which significantly enlarged the electrically induced linear strains to 200%.…”

“…Andrianesis et al [34] made a robot hand system with the SMA wires. Some recent studies focused on increasing the actuation frequency by using a diamond structure [35] and the application in minimally invasive surgeries (MIS) [36].…”

Fabrication and Characterization of Nanoscale Shape Memory Alloy MEMS Actuators

“…Specifically, by 3D printing polymeric materials mated with NiTi films, the following metrics were achieved: >5000 reversible actuation cycles with very limited degradation, low voltage actuation of 3.7 V (which is compatible with common Li-ion batteries), large strokes (85 μm for 415 μm length cantilever), and large force-displacement product of 1.2 × 10 −7 N-m, with an impressively small volume and weight (1.04 × 10 −5 cm 3 and 1.27 × 10 −5 g, respectively). By comparison in [38], 1.6 kHz actuation frequency was achieved using a pulsed laser to actuate a FIB cut NiTi SMA microactuator spring of 25 μm thickness. Most recently NiTi SMA has even recently been integrated with Si photonics to form a physically actuated optical coupler/de-coupler type device with excellent nano-positioning accuracy to within 4 nm and on/off ratio of 9 dB [7,39].…”