Rolling Contact Arm Unit for Adjustable Stiffness in Surgical Robots
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Solution Overview
Problem
Current minimally invasive surgical manipulators face challenges in controlling flexibility and stiffness, particularly when navigating curved internal organs and applying loads during single port surgery or Natural Orifice Translumenal Endoscopic Surgery (NOTES), as they lack adjustable stiffness and are prone to slippage during movement.
Innovation Solution
A robot arm unit with a series of links that come into rolling contact via specific surface features and wires, allowing adjustable stiffness through tension adjustment, and an anti-slip mechanism to prevent slippage, enabling flexible movement and load endurance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the surgical manipulator is designed for movement through ports, then it can perform minimally invasive surgery, but it becomes difficult to control and lacks flexibility for curved internal organs
Solution Approach 1:
The arm unit employs a dynamic structure where links can transition between rolling contact and sliding contact modes. The rolling contact portions enable flexible navigation through curved internal organs, while the controlled transition to sliding contact provides stability and ease of control during surgical operations. This dynamic adaptation resolves the contradiction between flexibility and controllability.
Solution Approach 2:
The arm unit is divided into multiple links connected by joints, allowing independent control of each segment. This segmentation enables the manipulator to navigate curved paths while maintaining overall controllability through coordinated movement of individual links, addressing both flexibility and ease of operation requirements.
2Adaptability or versatility
If the arm requires flexibility to pass along curved internal organs, then it can navigate complex anatomy, but it lacks stiffness to endure loads applied to surgical parts
Solution Approach 1:
The arm unit dynamically adjusts its mechanical properties through rolling contact between links. During navigation through curved internal organs, the rolling contact provides flexibility and adaptability. When load bearing is required during surgical operations, the same rolling contact mechanism provides increased stiffness and load endurance, eliminating the need to compromise between flexibility and strength.
Solution Approach 2:
The arm unit changes its physical parameters (stiffness, flexibility) through the rolling contact mechanism between links. By adjusting the contact conditions and tension in connecting wires, the arm can transition between flexible states for navigation and stiff states for load bearing, resolving the contradiction between adaptability and strength.
3Adaptability or versatility
If the arm unit uses rolling contact between links, then it achieves flexibility and adjustable stiffness, but it may experience slippage during movement
Solution Approach 1:
The arm unit employs a dynamic contact mechanism that transitions between rolling and sliding modes. The rolling contact provides flexibility and stiffness adjustment, while the controlled transition to sliding contact prevents slippage. This dynamic adaptation ensures both the desired flexibility and reliable slip resistance during surgical operations.
Solution Approach 2:
The rolling contact portions act as intermediaries between links, providing a controlled interface that enables flexibility while preventing slippage. The geometric design of these contact surfaces ensures proper rolling motion and prevents unintended sliding, resolving the contradiction between adaptability and reliability.
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 solution provides an arm unit with adjustable stiffness, enhancing flexibility for navigating curved organs and increasing stiffness for load endurance, thereby improving the efficiency and precision of minimally invasive surgical procedures.
Implementation Method 1
a plurality of wires penetrating the plurality of links to connect the links to one another
Implementation Method 2
a plurality of links to come into rolling contact with one another via at least two regions thereof
Data Source
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AI summary
An arm unit having an improved configuration to simply change stiffness according to varying situations and a robot having the same are provided. The robot includes an arm unit, and a drive unit to drive the arm unit. The arm unit includes a plurality of links to come into rolling contact with one another via at least two regions thereof, and a plurality of wires penetrating the plurality of links to connect the links to one another.