Wavelength Dependent Remote Power Supply for Shape Memory Alloy

Abstract

The use of shape memory alloy (SMA) actuators in smart structures is increasing significantly especially in the field of Micro-Electro-Mechanical Systems (MEMS) due to their unique properties. In this work wavelength dependent remote power supply for SMA is presented to avoid electrical cables from the working area of the structure and to demonstrate the selective addressing of a high number of micro-actuators placed in a small space. Low power (∼100 mW) continuous mode laser diodes are used as remote power supply sources. A thermal numerical model is presented to visualize the temperature evolution in a Nitinol sample (3 mm × 1 mm × 100 μm) irradiated by 785 nm laser source. A series of experiments are performed to validate the modelling results, to estimate the response time under different loadings (15 g and 20 g) and to demonstrate the wavelength dependent deformation in SMA samples for selective addressing which is realized by depositing thin layers having specific optical filtering properties directly over the SMA sample and using laser diode sources with different wavelengths (785 nm and 658 nm).

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

“…In our previous work [23,39], the feasibility of selective addressing using two different wavelengths, 660 nm and 785 nm, was proved. In that work, a Bragg structure made of alternate layers of amorphous hydrogenated silicon (a-Si:H) and amorphous polymethacrylic acid (a-pMA) was deposited onto the SMA active elements of thickness 100 µm.…”

Thermo-mechanical characterization of optical thin films filters deposited onto shape memory alloy micro-actuators

“…In our previous work [20], we realized selective addressing by using plasma techniques to deposit an optical thin films filter directly onto the SMA-based micro-actuator. This wireless actuation principle was then applied successfully to the micro-actuation of a bistable curved beam with two different laser sources [21].…”

Wireless microfluidic control with integrated shape-memory-alloy actuators operated by field frequency modulation

“…Passive actuation mechanisms eliminate the need for active circuitry and batteries and are thus potentially advantageous in terms of size, longevity, cost and robustness of the devices. Passively operated wireless microactuators have been reported to use several mechanisms, including electrostatic actuations induced by surface acoustic waves [12] and magnetic fields [13], magnetic actuations [14][15][16][17], energy-beam-assisted heating (for shape-memory alloys (SMA) [18][19][20][21] and bimorph [22][23][24]). However, they pose various practical issues such as small actuation force and stroke, use of high voltages, micromachining and integration of ferromagnetic materials, and actuator/system packaging.…”

“…To the best of the authors' knowledge, only a few of the techniques that use energy-beam-assisted heating for thermal actuations reported the control of multiple microactuators [20,21,24]. In these types of wireless actuation techniques, however, the overall systems with beam sources and optics for beam conditioning tend to be complicated and large.…”