Design and implementation of a portable amagnetic shape memory rotary actuator

Abstract

Actuators based on standard technologies often do not comply with environmental constraints on electromagnetic noise. Even though shape memory actuators are not ferromagnetic, activation by Joule’s effect poses a question about magnetic compatibility. This article presents a new concept design of a rotary actuator based on a double coil of NiTi wire, which permits to abate dramatically the electromagnetic fields generated. A particular implementation of the idea was devised as a case study to investigate feasibility. The desired torque and stroke were 83 N cm and 40°, respectively, and mechanical tests confirmed that a maximal stroke of 38° can be achieved for resisting torques ranging from 33 to 122 N cm. The built prototype proved appropriate to respond to the needs of a neuroscience study requiring mobilization of the ankle. So, this device was tested during measurement of brain activity in healthy subjects with both magnetoencephalography and functional magnetic resonance imaging, that is, diagnostic equipment with very demanding constraints on electromagnetic noise. Neither magnetoencephalography signals nor the functional magnetic resonance imaging images were affected by any electromagnetic noise or artifacts, allowing for further analysis and extraction of neurological features. Besides the discussed uses, this type of actuator could find an application in several fields, such as biomedical, robotic, aerospace, or automotive.

Can passive mobilization provide clinically-relevant brain stimulation? A pilot eeg and nirs study on healthy subjects

“…The SMA actuator itself did not contribute significantly to that noise. This is in line with previous results on the compatibility of SMA actuation and neuroscience instrumentation [6]. No influence on the required quality of EMG signals from the leg muscles was evidenced, although the calf was contacting the leg rest of the mobilizer.…”

Passive ankle dorsiflexion by an automated device and the reactivity of the motor cortical network

“…the heating of resistive conductors by an electric current. Our group has already published some work on applications of SMA actuation for the rehabilitation field [2,8,9]. For more details on SMA, the reader is referred to specialized literature [10].…”

“…1) utilizes a shape memory alloy (SMA) actuator [2] (for a brief description of SMA, see the Appendix, below). The present actuator is based on the Ni-Ti alloy and is specifically designed in order to produce very limited electromagnetic noise.…”

Mechanically Stimulated Osteoblast Cells Growth

“…In the bones of the young and most of the adult, all these functionalities appear, so that when an accident requires a human operation it is good to resort to mild and specialized interventions so that the bone in question can quickly recover all features. Otherwise, the body of that person has a major future health and integrity problem, as is the case with older people or those with serious bone diseases (Roger, 2015;Benchea et al, 1976;McCracken et al, 2000;Pittaccio et al, 2015;Viscuso and Pittaccio, 2012;Priadko et al, 2017;Nikolaev et al, 2008;Yang et al, 2013;Van Humbeeck, 2010;Otsuka and Ren, 1999;Otsuka et al, 1971;Velázquez and Pissaloux, 2012;Melton and Mercier, 1980;Knowles and Smith, 1981;Miyazaki et al, 1984;Lahoz and Puértolas, 2004;Matsumoto et al, 1987;Šittner et al, 2014;Duerig, 1990;Naresh et al 2016;Ziólkowski, 2012;Shaw et al, 2008;Aversa et al, 2018;a-c, 2016Mirsayar et al, 2017;Petrescu et al, 2015, 2016 a-c; Petrescu and Calautit, 2016 a-b; Kus and Breczko, 2010;Otsuka et al, 1976, Yang andb 1992;Harrison and Hodgson, 1975;Hanlon et al, 1967;Huang et al, 2003;Sofla et al, 2008;Tamburrino, 2016;Apicella et al, -20112015;Gramanzini et al, 2016;Kummer, 1986;…”