Variable-Rigidity Insertion Tool for Adaptive Friction Control
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Solution Overview
Problem
Existing variable-rigidity devices for insertion tools, such as endoscopes, face challenges in dynamically adjusting rigidity to navigate through varying frictional forces and deformations within insertion targets, particularly in medical and industrial applications, where consistent and stable operation is required.
Innovation Solution
A variable-rigidity device comprising a tubular member with alternating high-rigidity and low-rigidity portions and a core member with corresponding sections, controlled by an actuator that generates fluctuating forces to adjust the relative positions of these components along the longitudinal axis, allowing for adaptive rigidity changes in response to load conditions and frictional forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the insertion tool uses a uniform rigid structure, then it maintains high rigidity for stability, but it cannot adapt to varying frictional forces and may get stuck or cause damage during insertion
Solution Approach 1:
The insertion tool is divided into multiple sections along its longitudinal axis, with each section capable of independent rigidity adjustment. The tubular member includes alternating high-rigidity and low-rigidity portions, allowing different segments to have different mechanical properties. This segmentation enables the tool to adapt to varying frictional forces at different insertion depths without requiring a completely complex reconfigurable structure.
Solution Approach 2:
The rigidity of the insertion tool is made dynamic through the actuator system that can change the relative positions of the core member and tubular member. This allows the tool to transition between rigid and flexible states as needed during insertion, rather than being fixed in one state. The dynamic adjustment capability resolves the contradiction by providing adaptability without requiring permanent structural complexity.
2Reliability
If the insertion tool increases rigidity to maintain stability during operation, then operational stability improves, but frictional resistance increases making insertion more difficult
Solution Approach 1:
Different portions of the insertion tool have different rigidity characteristics - high-rigidity portions provide stability where needed, while low-rigidity portions reduce frictional resistance during insertion. The tubular member specifically includes alternating high-rigidity and low-rigidity portions along its length, allowing local adaptation to mechanical requirements. This local quality differentiation resolves the contradiction by providing stability only where necessary rather than uniformly throughout the entire tool.
Solution Approach 2:
The rigidity parameter of the insertion tool is changed dynamically during operation through actuator-driven relative movement between the core member and tubular member. By adjusting the overlap position between these members, the tool can transition between rigid and flexible states, changing the rigidity parameter to match the immediate operational requirements rather than maintaining a fixed high rigidity that would increase frictional resistance.
3Adaptability or versatility
If the actuator moves the core member at constant speed, then operation is simple, but it cannot respond to varying load conditions and frictional forces
Solution Approach 1:
The control system monitors load conditions and frictional resistance during insertion, then adjusts the actuator speed and force accordingly. When high frictional resistance is detected, the system increases actuator force or adjusts the relative movement between core and tubular members to maintain optimal rigidity. This feedback mechanism enables the tool to respond to varying load conditions automatically without requiring complex manual control, resolving the contradiction between adaptability and ease of operation.
Data Source
AI summary
A variable-rigidity device includes a tubular member including a plurality of high-rigidity portions and low-rigidity portions arranged along a longitudinal axis, a core member arranged on an inner side of the tubular member and including a plurality of high-rigidity core portions and low-rigidity core portions; and an actuator configured to relatively move the core member with respect to the tubular member, in which the actuator is configured to cause a first force to repeatedly fluctuate with a passage of time, the first force causing the core member to relatively move with respect to the tubular member in an axial direction along the longitudinal axis.