Method and apparatus for shape and end position determination using an optical fiber

US7813599B2 · kind B2 · utility

Assignee

• The United States of America as represented by the Administrator of the National Aeronautics and Space Administration · US

Inventor

• Jason P. Moore · Vancouver, US

Key dates

• Filing date: Feb 23, 2009
• Grant date: Oct 12, 2010
• Expiry date: Feb 23, 2029

Classification

• Technology area (CPC G): Physics
• CPC primary: G01B11/18
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A method of determining the shape of an unbound optical fiber includes collecting strain data along a length of the fiber, calculating curvature and bending direction data of the fiber using the strain data, curve-fitting the curvature and bending direction data to derive curvature and bending direction functions, calculating a torsion function using the bending direction function, and determining the 3D shape from the curvature, bending direction, and torsion functions. An apparatus for determining the 3D shape of the fiber includes a fiber optic cable unbound with respect to a protective sleeve, strain sensors positioned along the cable, and a controller in communication with the sensors. The controller has an algorithm for determining a 3D shape and end position of the fiber by calculating a set of curvature and bending direction data, deriving curvature, bending, and torsion functions, and solving Frenet-Serret equations using these functions.