Modeling of a new SMA micro-actuator for active endoscopy applications

Abstract

Shape Memory Alloys (SMA) are good candidates to actuate endoscope heads but the cooling problem must be solved particularly in confined situations. For these reasons, a new SMA micro-actuator specially designed for active endoscopy applications has been developed in our laboratory. This work is a new step in the approach of using integrated thermoelectric cooling with SMA actuators. In fact, the Peltier effect is very attractive in such a case because this reversible phenomenon reduces the overheating of the external environment and provides forced cooling that decreases the response time. In this paper the actuator design and its working principle are presented. A fine modeling of the coupled mechanical and thermal behaviors gives a better understanding of the physical phenomenon involved in the actuator. Finally an experimental prototype has been developed and tested in order to verify the model predictions.

A novel low-profile shape memory alloy torsional actuator

“…For our application, photoetching processes [39,38,2] are not desirable due to large material thickness (150 μm). However, we have found no significant deterioration in SMA performance due to the laser heat affected zone [44,45,5,36,2]. A series of actuators are cut side-by-side, connected by small tabs.…”

Comparative Review of Endoscopic Devices Articulations Technologies Developed for Minimally Invasive Medical Procedures

“…Some of them have not been studied for a long time and present a great potential for improving their implementation in efficient systems, such as the ionic and electronic EAP actuators. Others, such as the SMA, have been extensively used for this kind of applications, but research groups could still bring improvements (such as in the device from Abadie et al [1]) in order to improve the dynamics of the actuation, one of the main drawbacks of these actuators.…”

“…Another ring-shaped modular based system has been developed by Abadie et al [1] that consists in antagonistic NiTi blades that bend in opposite direction when heated. Thermoelectric junctions P or N-doped are placed between the structural rings and the SMA blades, in order to generate a reversible Peltier thermoelectric effect for heat production or absorption.…”

Developing a novel SMA-actuated robotic module

“…Following that, Elahinia showed the shortcomings of the existing models for complex loadings [20] and introduced an enhanced SMA phenomenological model [21]. These basic models have let the researchers to develop actuators for new applications in the recent years [24][25][26].…”