Nested Elastic Tube Manipulator for Orthopedic Stability
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Solution Overview
Problem
Current snake-like dexterous manipulators used in minimally-invasive surgical procedures lack structural stability to withstand high external end-effector forces, limiting their application in procedures such as orthopaedics.
Innovation Solution
A manipulator device composed of elastic materials with shape memory, such as nitinol, and control wires that allow for bending and flexing through a system of notches and termination devices, enabling precise control and insertion of instruments into the body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If snake-like dexterous manipulators are used for minimally-invasive surgery, then dexterity and ability to navigate constrained environments is improved, but structural stability to withstand high external forces deteriorates
Solution Approach 1:
The patent implements a nested tube structure where multiple elastic tubes are positioned concentrically within each other. The first elastic tube is surrounded by a second elastic tube, which is in turn surrounded by a third elastic tube, creating a nested configuration that provides both flexibility for navigation and structural stability through the layered construction
Solution Approach 2:
The patent employs composite construction by combining multiple elastic tubes with different material properties and structural characteristics. Each tube can be made from materials with varying elastic moduli and mechanical properties, creating a composite structure that balances dexterity and structural stability
2Strength
If multiple elastic tubes are nested to improve structural stability, then strength to withstand forces is improved, but device complexity increases
Solution Approach 1:
The manipulator is segmented into multiple functional sections along its length, with each section containing the nested tube structure. This segmentation allows the complex stable structure to be divided into manageable modules that can be independently controlled and positioned, reducing overall system complexity
Solution Approach 2:
The nested tube structure serves multiple functions simultaneously: it provides structural stability, enables dexterous movement, and acts as a conduit for control wires and instruments. This multi-functionality reduces the need for separate components, thereby managing device complexity
3Ease of operation
If control wires are constrained to elastic sheets with notches to enable bending, then ease of operation is improved, but manufacturing precision requirements increase
Solution Approach 1:
The notches are pre-formed into the elastic tubes during manufacturing at predetermined locations and orientations. This preliminary action of creating the notches before final assembly ensures that the control wires will engage at the correct positions to produce the desired bending moments, simplifying the overall manufacturing process while maintaining precision requirements
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
The device provides enhanced structural stability and flexibility, allowing for precise manipulation and insertion of instruments in constrained environments, improving the capability to perform minimally-invasive surgical procedures, including those in orthopaedics.
Implementation Method 1
A manipulator device composed of elastic materials with shape memory, such as nitinol
Implementation Method 2
a first sheet of a first material having elasticity, a second sheet of a second material having elasticity
Data Source
AI summary
A device includes first and second sheets of first and second elastic materials, respectively, and a control wire. The first sheet has a first thickness and a first length and is shaped to have a first cross-section having a first inner periphery and a first outer periphery. The second sheet has a second thickness and a second length and is shaped to have a second cross-section having a second inner periphery and a second outer periphery. One of the first sheet and the second sheet has a spacing disposed in along one of the first length and the second length, respectively. The first outer periphery is less than or equal to the second inner periphery. The second sheet surrounds the first sheet. The control wire has an end constrained to one of the first sheet the first material and the second sheet. The control wire is disposed within the spacing.