Shape Sensor with Pre-Set Perturbations for Surgical Kinematic Chain
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Solution Overview
Problem
Existing minimally-invasive surgical instruments face challenges in accurately determining the relative pose information of links in a kinematic chain, which is crucial for precise surgical maneuvers, as current shape-sensing technologies often rely on complex bend sensing methods that are prone to errors and require guesswork about the shape and orientation of the kinematic chain.
Innovation Solution
Incorporating a shape-sensing segment with pre-set perturbations within the kinematic chain, such as optical fiber with Fiber Bragg Gratings, that provide shape information to determine relative partial-pose information, including displacement, angle, and three-dimensional position and orientation of links, without needing to sense bends directly, using interrogators and processors to analyze the shape data and generate accurate pose information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex bend sensing methods are used to determine joint angles and link positions, then measurement capability is provided, but measurement precision deteriorates due to errors and guesswork about shape and orientation
Solution Approach 1:
The patent applies preliminary action by pre-setting known perturbations (bends, curves, or shape changes) at specific locations along the optical fiber before insertion into the kinematic chain. These predetermined geometric features serve as reference markers that simplify the sensing process. When the fiber moves with the kinematic chain, the interrogator detects changes in the positions and orientations of these pre-set perturbations, enabling direct calculation of joint angles and link positions without complex bend sensing algorithms or guesswork about the overall fiber shape.
2Measurement precision
If pre-set perturbations are incorporated in the shape-sensing segment, then measurement precision improves for relative pose information, but device complexity increases due to additional components and setup
Solution Approach 1:
The patent applies copying by creating simplified reference copies of geometric features (perturbations) along the optical fiber. Instead of measuring the complete complex three-dimensional shape of the fiber, the system uses these copied geometric markers as proxies for position and orientation measurement. The interrogator only needs to detect the positions and orientations of these simplified perturbation features rather than reconstructing the entire fiber geometry, thereby improving measurement precision while managing device complexity.
3Loss of information
If direct bend sensing is used without pre-set perturbations, then device complexity is reduced, but loss of information occurs regarding accurate shape and orientation data
Solution Approach 1:
The patent applies preliminary action by pre-setting known perturbations (bends, curves, or shape changes) at specific locations along the optical fiber before insertion into the kinematic chain. These predetermined geometric features serve as reference markers that simplify the sensing process. When the fiber moves with the kinematic chain, the interrogator detects changes in the positions and orientations of these pre-set perturbations, enabling direct calculation of joint angles and link positions without complex bend sensing algorithms or guesswork about the overall fiber shape.
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 allows for precise determination of joint angles and link positions within the kinematic chain, providing accurate feedback to surgeons without relying on assumptions about the shape and orientation, enhancing the precision and reliability of minimally-invasive surgical systems.
Implementation Method 1
optical fiber shape sensors operate via optical time domain reflectometry (OTDR) or via optical frequency domain reflectometry (OFDR)
Implementation Method 2
optical fiber shape sensors operate via optical time domain reflectometry (OTDR) or via optical frequency domain reflectometry (OFDR)
Implementation Method 3
Scattering mechanisms that have been used include Rayleigh scattering, Raman scattering, Brillouin scattering, and Fluorescence scattering
Implementation Method 4
Scattering mechanisms that have been used include Rayleigh scattering, Raman scattering, Brillouin scattering, and Fluorescence scattering
Implementation Method 5
Scattering mechanisms that have been used include Rayleigh scattering, Raman scattering, Brillouin scattering, and Fluorescence scattering
Implementation Method 6
Scattering mechanisms that have been used include Rayleigh scattering, Raman scattering, Brillouin scattering, and Fluorescence scattering
Implementation Method 7
Fiber Bragg Gratings and the Kerr effect have also been used in shape-sensing sensors
Implementation Method 8
Fiber Bragg Gratings and the Kerr effect have also been used in shape-sensing sensors
Implementation Method 9
electromagnetic fields have been used in combination with sensors mounted on an endoscope to determine a position of an endoscope
Implementation Method 10
the changes in resistance of a piezoresistive flexible shape sensor have been used to measure shape changes
Data Source
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.