Rolling Joint Component for Snake-Like Surgical Motion Control
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Solution Overview
Problem
Existing snake-like surgical robots face challenges in simultaneously achieving strength, flexibility, and accuracy due to issues with rolling joints, such as asynchronous and sideways slippage, dislocation, and complex control algorithms.
Innovation Solution
The design incorporates a series of joint components with first and second rolling surfaces and spur gears to form synchronous bi-stable rolling joints, reducing friction and slippage, and allowing controlled motion, while also featuring a hollow interior for cable and instrument passage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If rolling joints are used in snake-like surgical robots, then flexibility and navigation capability are improved, but slippage and asynchronous motion occur resulting in uncontrolled movement
Solution Approach 1:
A spur gear is introduced as an intermediary element between the two rolling surfaces. The gear teeth engage with corresponding teeth on adjacent joint components, providing a positive mechanical constraint that prevents slippage and asynchronous motion while allowing the rolling surfaces to maintain their flexible, curved geometry for smooth navigation.
Solution Approach 2:
The rolling surfaces are designed as curved surfaces that roll against each other, replacing traditional rigid pivot joints. This curvature allows the joint to follow natural anatomical pathways and provides smooth, continuous motion while the spur gear ensures synchronized rotation of adjacent segments.
2Ease of operation
If rolling surfaces are used without additional constraints, then friction is reduced and motion is smooth, but sideways slippage occurs causing joint dislocation
Solution Approach 1:
The spur gear acts as a mediating constraint between the rolling surfaces. Its teeth engage with corresponding gear teeth on adjacent components, providing a positive mechanical stop that prevents sideways displacement and maintains joint alignment while allowing the rolling surfaces to continue their smooth rolling motion.
Solution Approach 2:
The joint component combines two different mechanical mechanisms: rolling contact for smooth motion and gear engagement for constraint. This composite approach integrates the advantages of both friction-based rolling and tooth-based positive drive, achieving both smooth operation and stable alignment.
3Device complexity
If traditional pivot point joints are used, then control algorithms are simpler, but force transmission capability and friction performance are inferior
Solution Approach 1:
The spur gear serves as an intermediary that bridges the gap between simple pivot joints and complex rolling mechanisms. By engaging gear teeth, it provides a well-defined mechanical relationship between adjacent joints that is easier to model than pure rolling contact, while still delivering superior force transmission and friction performance.
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 enhances force transmission capabilities, reduces the risk of joint dislocation and asynchronous movement, and simplifies control algorithms, enabling smooth and controlled motion within the human anatomy.
Implementation Method 1
A rolling joint is a mechanical structure where two curved surfaces roll against each other. A rolling joint offers advantages such as limited friction, since the surfaces roll against each other, leading to large force transmission capabilities.
Implementation Method 2
When adjacent joint components come together to form a joint, the two spur gears will engage with one another in a normal manner, thus limiting movement between adjacent joint components.
Data Source
Figure 1A~2C
Figure 1B
Figure 3A~3C
AI summary
A surgical instrument having a proximal end, a distal end and a shaft, the shaft comprising a plurality of joint components connected in series, each joint component comprising first and second connectors, which connectors are axially spaced apart from one another at first and second ends of a respective joint component, characterised in that the first connector comprises a first rolling surface, and the second connector comprise a second rolling surface, and wherein each joint component comprises a first spur gear extending from the first rolling surface, and a second spur gear extending from the second rolling surface, wherein the first rolling surface of a first joint component is engageable with the second rolling surface of a second joint component to form a rolling joint, and the second rolling surface of the first joint component is engageable with a first rolling surface of a third rolling joint.