Multiple-Pull-Wire Robotic Articulation for Neutral-Axis Stability
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Solution Overview
Problem
Existing endoscopes and catheters face challenges in maintaining a constant neutral axis during bending operations, leading to undesirable properties such as curve alignment and muscling, which complicates navigation and control in anatomical structures.
Innovation Solution
The use of a hypotube backbone with a spiraled lumen and a jacket, formed from materials like nitinol, provides axial stiffness and allows for controlled bending of the distal end, while a sheath and flexible endoscope are mounted to robotic arms to maintain a virtual rail configuration, enabling precise navigation through anatomical lumens.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If traditional pull wires are used for catheter articulation, then the catheter can bend at the distal end, but the neutral axis shifts during bending causing muscling and curve alignment issues
Solution Approach 1:
The catheter shaft is divided into multiple discrete articulation segments along its length. Each segment can be independently controlled by separate pull wires, allowing localized bending without affecting the entire shaft. This segmentation maintains the neutral axis position stable while enabling precise articulation control at specific locations.
Solution Approach 2:
The invention transitions from traditional single-plane pull wire articulation to multi-dimensional control by arranging pull wires in a helical pattern around the catheter shaft. This three-dimensional wire arrangement enables articulation in multiple directions while maintaining neutral axis stability through symmetric force distribution.
2Adaptability or versatility
If early endoscope designs with numerous levers and buttons were used, then various functionalities could be performed, but the device became difficult to steer and navigate
Solution Approach 1:
The invention extracts the complex manual control interface (levers and buttons) from the endoscope itself and replaces it with a simplified robotic control system. The endoscope retains only the essential functional elements while steering and navigation are managed externally through robotic manipulation, reducing the operational burden on the user.
Solution Approach 2:
The manual mechanical control system (levers and buttons) is replaced with an automated robotic system that uses motorized actuators and sensors to control endoscope navigation. This substitution maintains full functional capabilities while dramatically improving ease of operation through automated positioning and reduced manual manipulation.
3Adaptability or versatility
If catheters are made flexible to navigate non-linear lumens, then navigation capability improves, but control precision and stability decrease
Solution Approach 1:
The flexible catheter is divided into multiple rigid or semi-rigid segments that can articulate relative to each other. This segmentation allows the catheter to navigate non-linear lumens through controlled inter-segment bending while each segment maintains sufficient stiffness for precise control and stable positioning.
Solution Approach 2:
The catheter employs composite construction combining flexible materials for navigation with stiffer reinforcement elements for control precision. The composite structure enables the catheter to bend and adapt to non-linear pathways while maintaining adequate rigidity for accurate positioning and stable operation at the distal end.
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 configuration maintains a constant neutral axis during bending, reducing unwanted bending and torque along the shaft, enhancing control and navigation efficiency in non-linear pathways.
Implementation Method 1
the backbone may be formed from a nitinol alloy
Implementation Method 2
the backbone may be formed from a nitinol alloy
Implementation Method 3
a spiral lumen spiraled around the backbone along the length of the backbone
Data Source
AI summary
An instrument includes an elongate shaft, a set of pull wire lumens disposed within the elongate shaft, the set of pull wire lumens comprising first, second, third, and fourth pull wire lumens, and a set of pull wire segments comprising first, second, third, and fourth pull wire segments disposed within the first, second, third, and fourth pull wire lumens, respectively, each of the set of pull wire segments having a proximal portion that is configured to be manipulated by a robotic input.