Patent ID: 8961433
Filing Date: 2015-02-24
Classification: A61B,A61L,A61M

Abstract:
1. A system for controlling a thin flexible thermoplastic catheter comprising: a plurality of shape memory alloy filaments attached to the distal end of the catheter, each filament having a solid-state phase and a temperature, wherein the catheter is of a size configured for insertion into the blood vessel; a means for receiving a strain value for at least one of the filaments; a means for determining a solid-state phase change that will result in the strain value, whereby the solid-state phase change is dependent on the temperature and the temperature is dependent on a voltage; and a means for setting the voltage in each filament thereby resulting in bending of the catheter in three dimensional space, wherein the temperature is determined using a formula given by where m is the mass per unit length, c p is the specific heat capacity, V is the voltage applied across the shape memory alloy filament, R is the resistance per unit length, h is the coefficient of convection, A=πd is the circumferential area of cooling, d is the diameter of the filament, T is the temperature and T a is the ambient temperature.