**1. Introduction**

30 Will-be-set-by-IN-TECH

[83] Zhang, Y., He, J. & Yang, J. [2006]. Initial research on development of a flexible pectoral

[84] Zhong, Z. W. & Yeong, C. K. [2006]. Development of a gripper using SMA wire, *Sensors*

fin using Shape Memory Alloy, *Automation, Proceedings of* pp. 255–260.

URL: *http://ieeexplore.ieee.org/xpls/abs\_all.jsp?arnumber=4026090*

URL: *http://linkinghub.elsevier.com/retrieve/pii/S0924424705005935*

*and Actuators A: Physical* 126(2): 375–381.

Actuators based on shape memory alloys (SMA) proved to be particularly advantageous with respect to other actuation technologies when they are embedded in applications requiring strict compliance to a set of compatibility (e.g. mechanical, biological, weight, …) and environmental constraints. Most noteworthy are the uses in miniaturised components, lightweight systems, sensing-actuating systems (e.g. actuators interacting with changing environmental variables), low-noise or low-impact appliances (e.g. actuators with reduced interaction with the environment) and self-sensing controllable devices. With particular regard to these preferred applications, SMA can also play a role in solving specific actuation problems in the fields of Medical Rehabilitation and Neuroscience. The main characteristics expected of SMA actuators for these fields are light weight and portability; self-adjustment to evolving needs; applicability of actuation in shielded environments (with bioimaging and diagnostic devices: magnetic resonance imaging (MRI, fMRI), magnetoencephalography (MEG), and the like).

Taking the move from these key ideas, this Chapter will discuss some innovative uses and some implemented examples of biomedical devices based on the Shape Memory Effect (SME), explaining their advantages and limitations. In particular, it will address the following main topics: analysis of the relevant literature and background; the derivation of technical constraints and required material properties given the expected biomechanical and or clinical cases; the mathematical design of sample actuators and their implementations; ideas for their clinical application and control. It is important to notice that these same concepts can be easily transferred to other important industrial engineering fields.
