Shape Sensor Segments for Surgical Instrument Pose Tracking

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Solution Overview

Problem

Existing minimally-invasive surgical instruments lack accurate methods to determine the relative pose information of links in a kinematic chain, which is crucial for precise surgical maneuvers, as current shape-sensing technologies face challenges in accurately measuring joint angles and link positions without relying on guesswork or complex shape and orientation assumptions.

Innovation Solution

Incorporating a shape-sensing segment with pre-set perturbations within the kinematic chain of a minimally-invasive surgical instrument, where the shape-sensing segment, often an optic fiber with Fiber Bragg Gratings, provides shape information used to determine relative partial-pose information of links through interrogators and processors, allowing for precise measurement of link positions and angles without requiring assumptions about the shape or orientation of the kinematic chain.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional shape-sensing technologies are used to measure joint angles and link positions, then the system can obtain some pose information, but the measurement precision is insufficient due to reliance on guesswork and complex shape and orientation assumptions

Engineering Contradiction:

Improvejoint angle and link position measurement accuracyVSAvoidcomplexity of shape and orientation assumptions

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The optical fiber is divided into multiple discrete shape-sensing segments, each containing specific perturbations. This segmentation allows independent measurement of each segment's shape changes, eliminating the need for complex global shape and orientation assumptions while improving measurement precision of joint angles and link positions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Known perturbations (such as bends or shape features) are pre-introduced into the optical fiber segments during manufacturing. These preliminary shape features serve as reference points that simplify the measurement process, allowing direct calculation of pose information without requiring complex real-time shape reconstruction assumptions.

Inventive Principle:

Principle #10Preliminary action

2Measurement precision

If shape-sensing segments with pre-set perturbations are introduced to improve measurement accuracy, then the measurement precision improves, but the device complexity increases due to additional components and processing requirements

Engineering Contradiction:

Improverelative pose information accuracyVSAvoidcomplexity of shape-sensing segment integration

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The shape-sensing segments with pre-set perturbations are integrated directly into the existing kinematic chain structure of the surgical instrument. This merging approach combines the sensing functionality with the mechanical structure, improving measurement precision without proportionally increasing overall device complexity.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The optical fiber segments serve multiple functions: they act as both structural elements within the kinematic chain and as shape-sensing elements. This multi-functionality allows the same component to contribute to both mechanical operation and measurement, improving pose information accuracy while minimizing additional device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach enables accurate determination of joint angles and link positions, providing reliable feedback to surgeons without relying on shape or orientation assumptions, enhancing the precision and reliability of minimally-invasive surgical systems.

Implementation Method 1

Most approaches use a backscatter method that measures changes in backscattered light caused by a change in the shape of the optical fiber

Methodology Applied

Scientific EffectOptical backscatter: Scattering

Implementation Method 2

Fiber Bragg Gratings and the Kerr effect have also been used in shape-sensing sensors

Methodology Applied

Scientific EffectFiber Bragg Gratings: Bragg Diffraction

Implementation Method 3

Fiber Bragg Gratings and the Kerr effect have also been used in shape-sensing sensors

Methodology Applied

Scientific EffectKerr effect: Kerr Effect

Data Source

PatentUS8896847B2Method and system to sense relative partial-pose information using a shape sensor

Publication Date: 2014.11.25 INTUITIVE SURGICAL OPERATIONS INC

AI summary

A shape-sensing segment traverses through at least a portion of a kinematic chain of a tele-operated slave surgical instrument in a tele-operated minimally-invasive surgical system. The shape-sensing segment includes a pre-set perturbation. Shape information from the pre-set perturbation allows determination of relative partial-pose information for at least one link in the kinematic chain.