Hysteretic dynamical systems are challenging to control due to their hard nonlinearity and difficulty in modeling. One type of systemwith hysteretic dynamics that is gaining use in aerospace systems is the shape-memory alloy-based actuator. These actuators provide aircraft and spacecraft systems with the ability to achieve component-level or vehicle-level geometry or shape changes. Characteriza...

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...

A novel Shape Memory Alloy (SMA) actuator consisting of several thin NiTi bers woven in a counter rotating helical pattern around supporting disks is rst described. This structure accomplishes a highly eecient transformation between force and displacement overcoming the main mechanical drawback of shape memory alloys, that being limited strain. Time domain open loop experiments were then conduc...

Components made of alloys with a magnetic shape memory (MSMA) are not commonly used in industrial systems or prototype solutions. The reasons behind this include the cost and implementation difficulties attached to MSMA alloys synthesis technology. The article presents the results of a prototype actuator in which the active element is a rod made of Ni-Mn-Ga alloy and with dimensions of 2x1x20 m...

The blood ducts must be occluded to avoid loss of blood from vessels in laparoscopic surgeries. This paper presents a locking mechanism to be used in a ligation laparoscopic procedure (LigLAP I), as an alternative solution for a stapling procedure. Currently, stapling devices are being used to occlude vessels. Using these devices may result in some problems, including injury of bile duct, takin...

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...