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

Abstract

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.

Design and Experimental Validation of an Active Catheter for Endovascular Navigation

“…3. Active catheter featured with three SMA actuators [21] SMA actuators having the shape of flat springs have been used regarding the possibility to produce very small actuators [22][23][24]. In [23] for example, a 0.9-mm-diameter catheter has been realized this way.…”

X-ray to MR: the progress of flexible instruments for endovascular navigation

“…To form a unitary body, an outer tubing was employed, and inner tubing was added to facilitate the insertion/removal of guidewires and intravascular devices. Namazu et al utilises similar fabrication and actuation techniques [181,182]. (c) SMA wires: In this design, a plurality of parallel SMA wires (three or four) are embedded into a flexible multi-lumen tube [183][184][185][186][187]192].…”

“…The two main sources of safety hazards are the steering mechanism or the catheter tracking method. Tendon-driven [178][179][180][181][182][183][184][185][186][187][188][189][190][191][192] SMA driven method takes advantage of the shape memory effect of SMA.…”

A survey on actuators-driven surgical robots

“…Mechanical structure of hand-held instrument (a) Systematic view of the hybrid tool with tendon-gear and tendon-sheath mechanism, (b) Detail presentation of end-effector 97 <Figure>Fig. 13 49,69,72,172,181,203 <Table>Table 8: Highlight the different approaches for the modelling and control of magnetic actuators with references from 15, 182 <Table>Table 9: Comparisons for all actuators in terms of size, power consumption, force/torque ranges, and scaling possibilities with references from 34,153,1,2,30,37,45,50,72,81,90,93,94,107,132,142,150,172,178,189,190,204 24,212 Entirely appropriate for discrete structures and good approximation for continuous structures 86 Easy to apply and compute 86 Require configuration information for the modelling 86 Represent continuum robot geometry with a finite number of mutually tangent curved segments 24,212 Most well-known kinematic framework for continuum robots 24,212 Complex identification 86  Configuration information is not required 86 High accuracy and noise reduction 86 Able deal with disturbances and uncertainties due to the use of adaptive control …”