For suffi ciently small dimensions, the response of shape memory alloy (SMA) actuators is not independent of the sample size. The response of SMA single crystal micro/nanopillars is shown to depend on the size of the specimen. An increase in the critical stresses for the start and fi nish of austenite to martensite transformation is seen when reducing the diameter into the submicron region. In ...

In this paper we present a walking pattern filter for Shape Memory Alloy (SMA) actuated biped robots. SMAs are known for their slow response. The actuation speed limitation can potentially lead to stability problems for biped robots. This filter adapts the human motion for a SMA biped in order to have a stable walking pattern. The Zero Moment Point (ZMP) is used as a main criterion of the filte...

In this work, we model a thermoelectric shape memory alloy(SMA) actuator as part of a research effort to design high-force, high-frequency SMA actuators. Cyclic phase transformation in a SMA layer is achieved by alternately heatinglc6oling using the thermoelectric Peltier effect. The thermal and mechanical fields during phase transformation are, in general, highly coupled and the extent of this...

This paper describes a method for improving the speed of actuators based on shape memory alloys (SMA) by increasing the rate at which an SMA element can safely be heated. The method consists of measuring the electrical resistance of an SMA element, calculating a maximum safe heating current as a function of measured resistance, and ensuring that the actual heating current does not exceed this m...

Bio-inspiered actuators are one of the most interesting topics in robotics. In particular, shape memory alloy (SMA) based actuators are one of these emerging technologies inspired by animal muscles. The main advantages of this type of actuators are their high force-weight ratio and its noiseless operation. Nonetheless, other features regarding frequency response and power consumption make their...

The paper proposes an efficient methodology that allows to design smart deformable aeronautical configurations are able achieve pre-defined target shapes by adjusting the temperature of Shape Memory Alloy (SMA) actuators. SMA-based actuation finds extensive application in morphing concepts which adopted aeronautics enhance aerodynamic performance continuously varying geometry wing. A novel robu...

Shape Memory Alloys (SMA's) are generally considered to be a slow and imprecise means of actuation. With the SMA actuator designed at McGill University we wish to show the contrary. In this paper, several SMA actuators are used to actively damp an external impulse disturbance on a mass to be isolated from vibrations. The vibration isolation testbed consists of a `strong' actuator to low-pass th...

The effect of superposed transitions in actuators with layered shape memory alloy (SMA) films undergoing martensitic phase transformation is analyzed in terms of a model developed for two layers of different composition, deposited at the same temperature on a substrate. A significant difference is observed in the actuation versus temperature relationship, depending on the thermal and elastic pr...

This paper presents a micro-sized self-reconfigurable modular robotic system using shape memory alloy (SMA) actuators. Composed of identical robotic modules, the system can actively configure various structures. The motion of module is based on two-dimensional rotation by using an actuator mechanism with two SMA torsion coil springs. The micro-sized module measures 2cm cube and weighs 15g, half...

Actual endoscopes and boroscopes, widely used in industry and in minimal invasive surgery, have considerable limitations, mainly due to their low number of degrees of freedom and their manual operation. Two different solutions for the electrical actuation of articulated endoscopes are presented in this paper. The technical constraints for this kind of application are very limited space for the ...