Shape memory alloy (SMA) based actuators have a number of attributes which make them useful for robotic applications. Unfortunately their response is relatively slow, being limited by the speed with which the SMA can be heated and cooled. This paper describes two novel developments of the basic SMA actuator which improve dynamic performance. To allow rapid heating of the shape memory alloy wire...

T his is the third paper in our series to identify unusual phenomena and to provide recommendations for the thermo-mechanical characterization of shape memory alloy (SMA) wire. Part 1 provided some basic background of the martensitic transformations responsible for the shape memory effect and superelasticity1. The characterization of two typical NiTi SMA alloys began with differential scanning ...

Antagonistic shape memory actuated structures exploit opposing pairs of one-way shape memory alloy (SMA) linear actuators to create devices capable of a fully reversible response. Unlike many conventional reversible SMA devices they do not require bias force components (springs) to return them to their pre-actuated configuration. However, the repeated use of SMA antagonistic devices results in ...

In this paper the active control of beam deflection through heating and cooling of Shape Memory Alloy (SMA) wires is examined. A phenomenological constitutive law for SMA wires is coupled with beam theory to provide predictions of beam shape upon temperature change in the SMA actuator. Both the linear and nonlinear beam theory are presented, enabling calculation of large deflections. Examples f...

Shape memory alloy (SMA) thin films, especially those based on Ni-Ti, have received considerable attention since it was demonstrated that they can undergo a nearly perfect shape memory effect [1-7]. When SMA films are used as actuators in MEMS devices, biasing springs are generally needed to restore the initial state in order to achieve a twoway shape memory effect. As a result, use of SMA actu...

In this paper the design of a biped robot actuated with Shape Memory Alloy (SMA) springs with minimum degrees of freedom is presented. SMA springs are a class of smart materials that are known for their high power to mass and volume ratios. It was shown that utilizing spring type of SMAs have many advantages as large deformation, smooth motion, silent and clean movement compared to ordinary typ...

A new prosthetic hand with a fixed thumb and four fingers actuated by Shape Memory Alloy (SMA) type artificial muscle has been developed in this paper. Different from typical geared motor, SMA actuator is lightweight and silent, however shows a little short stroke and small attracting force per each unit. In order to achieve enough output force and motion range of each finger, multiple SMA type...

This study comprises finite element simulations and experimental studies of the shape memory effect due to the presence of SMA (shape memory alloy) wires in composite materials. FEA was performed using ANSYS, where the prestrain was modelled by equivalent changes in the expansion coefficient of the SMA. Three case-studies were simulated and their predictions were compared with experimental data...