Table of Contents
Journal of Metallurgy
Volume 2011, Article ID 685429, 9 pages
Research Article

Titanium-Nickel Shape Memory Alloy Spring Actuator for Forward-Looking Active Catheter

1Division of Mechanical Systems, Department of Mechanical and Systems Engineering, University of Hyogo, 2167 Shosha, Himeji, Hyogo 671-2201, Japan
2New Business Department, Kobe Material Testing Laboratory, 47-13 Niijima, Harima, Kako, Hyogo 675-0155, Japan

Received 1 April 2010; Revised 7 December 2010; Accepted 9 January 2011

Academic Editor: Brij Kumar Dhindaw

Copyright © 2011 Takahiro Namazu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The fabrication and characterization of forward-looking active catheter actuated by titanium-nickel (Ti-Ni) shape memory alloy (SMA) springs are described. The catheter has been designed for wide-range observation of an affected area inside a blood vessel when the blood vessel is occluded. The developed active catheter consists of eight Ti-Ni SMA spring actuators for actuation of catheter tip, an ultrasonic transducer for forward-looking, a guide wire, a polyurethane tube for coating, and spiral wirings for realization of various flexure motions of catheter tip using Ti-Ni SMA actuators. The size of the catheter is 3.5 mm in diameter and 60 mm in length of the sum of transducer and actuator sections. Ti-Ni SMA springs were fabricated from a Ti-50.9at.%Ni sheet by electrochemical etching with a mixed solution of ethanol and lithium chloride. The catheter was assembled by hand under a stereomicroscope. The tip of the produced catheter was able to move in parallel toward at least eight directions by controlling an applied current to Ti-Ni SMA springs. We have confirmed that the active catheter was able to observe an object settled in the front.