Tendon-Driven Endoscopic Surgical End-Effector for Distal Dexterity
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Solution Overview
Problem
Existing endoscopic surgical instruments face challenges with limited distal-end dexterity, grasping force, and force-sensing capability, particularly in neurosurgery, where more robust and dexterous manipulation is required.
Innovation Solution
An end-effector for an endoscopic surgical instrument utilizing a tendon-driven mechanism with a ball joint and a bearing stud, allowing for two degrees of freedom of movement and enhanced force application, while maintaining a smaller size and reducing the risk of breakage and fatigue.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a tendon-driven mechanism with ball joint and bearing stud is used, then distal-tip dexterity and force application capability are improved, but device complexity increases
Solution Approach 1:
The end-effector is divided into distinct functional segments: a ball joint component for rotational movement, a bearing stud for support, and tendon attachment points for actuation. This segmentation allows each component to be optimized for its specific function while maintaining overall system dexterity.
Solution Approach 2:
The mechanism employs dynamic tendon actuation to control the ball joint, allowing the end-effector to achieve multiple degrees of freedom through flexible cable-driven motion rather than rigid mechanical linkages, thereby improving dexterity without proportionally increasing complexity.
2Force
If the end-effector is designed for greater force application, then grasping force and manipulation capability are improved, but the risk of breakage and fatigue increases
Solution Approach 1:
The design modifies material parameters and structural geometry to optimize the strength-to-weight ratio. The bearing stud and ball joint are engineered with specific dimensional parameters that distribute stress evenly, allowing high force application while minimizing stress concentration points that would lead to fatigue and breakage.
3Volume of moving object
If the end-effector size is reduced for endonasal procedures, then adaptability to delicate surgical sites is improved, but manufacturing precision requirements increase
Solution Approach 1:
The end-effector components are designed with nested geometries where the bearing stud fits within the ball joint housing, and tendon channels are integrated into the component structures. This nesting approach minimizes the overall envelope size while maintaining functional clearances and strength requirements.
Solution Approach 2:
Different regions of the end-effector components are manufactured with different precision levels tailored to their functional requirements. Critical interfaces such as the ball joint contact surfaces and tendon attachment points receive higher precision manufacturing, while non-critical surfaces use standard tolerances, optimizing the balance between size and manufacturability.
Data Source
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AI summary
An end-effector for an endoscopic surgical instrument, the end-effector comprising: a tool configured to interact with tissue; a main body comprising a bearing stud, the tool being connected to the bearing stud; a base comprising a surface facing the bearing stud, the bearing stud and the surface forming a ball joint; and a plurality of tendons connected to the main body so as to control movement of the tool in two degrees of freedom.