Compact Robotic Wrist With Independent Cable Actuation
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Solution Overview
Problem
Current robotic end effectors, particularly in surgical settings, face limitations such as occlusion of the worksite, insufficient access in confined spaces, and inability to perform complex operations due to their rigid or flexible designs, which are not well-suited for single port surgeries or areas with anatomical obstructions.
Innovation Solution
A robotic tool with a wrist mechanism featuring four independent cable ends, pulleys, and motors that allow for independent control of tension, enabling multi-axial motion and improved maneuverability, including the use of twisted strings and locking mechanisms to enhance rigidity and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If straight rigid tools are used, then structural strength and simplicity are improved, but access to confined spaces and maneuverability around anatomical structures deteriorates
Solution Approach 1:
The tool is divided into multiple segments or sections that can articulate relative to each other, allowing the tool to bend and reach around anatomical structures while maintaining structural integrity through controlled segmentation
Solution Approach 2:
The tool transitions from a static rigid structure to a dynamic articulated structure with multiple degrees of freedom, enabling real-time adjustment of the tool's configuration to navigate complex surgical pathways and access confined spaces
2Adaptability or versatility
If flexible curved tools are used, then access to confined spaces and maneuverability are improved, but rigidity to resist bending loads deteriorates
Solution Approach 1:
Different sections of the tool have different mechanical properties - distal sections are more flexible for navigation while proximal sections maintain higher rigidity for load-bearing operations, creating a gradient of stiffness along the tool's length
Solution Approach 2:
The tool employs composite construction combining materials with different mechanical properties to achieve both flexibility for maneuverability and sufficient rigidity for resistting bending loads during surgical operations
3Object-affected harmful factors
If multiple tools are introduced through single port surgery, then trauma to patient is reduced, but cooperative interaction and convergence on operative space become difficult
Solution Approach 1:
The articulated tool design provides universal adaptability allowing multiple tools to converge at different angles on the same operative space while maintaining cooperative interaction through their ability to articulate and position themselves optimally for suturing tasks
4Strength
If pre-formed curved profile tools are used, then rigidity is improved, but ability to bend within body to accommodate operative geometry in situ deteriorates
Solution Approach 1:
The tool employs dynamic articulation mechanisms that allow the tool to change its configuration in real-time within the patient's body, transitioning from a pre-formed curve to an adaptable structure that can assume different geometries based on operative requirements
Data Source
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Figure 2
AI summary
A surgical tool includes a tool shaft, and end effector and a wrist that couples the end effector to the tool shaft. The tool includes a drive mechanism configured to effect movement of one or both of the wrist and the end effector in yaw and pitch via independent actuation of four independent cable ends of two or more independent cables that extend between the drive mechanism and the wrist.