Cable-Actuated Surgical Tool Limiters for Slack Control
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Solution Overview
Problem
Cable driven motion systems in robotic surgical tools often experience slack accumulation leading to derailment and binding issues, which can render the tools unusable.
Innovation Solution
Incorporation of static and dynamic actuation limiters within the drive housing, along with anti-derailment features and standoff features, to prevent slack accumulation and maintain cable routing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If cable driven motion systems are used to enable natural hand movements and articulation in robotic surgical tools, then the ease of operation and degrees of freedom are improved, but slack accumulation occurs leading to cable derailment and binding issues
Solution Approach 1:
The patent introduces intermediary components including guide structures, pulleys, and tensioning mechanisms that act as mediators between the drive cables and the end effector. These intermediaries maintain cable routing stability by guiding cables through defined paths and preventing derailment, while still allowing the cable-driven motion system to provide natural hand movements and articulation.
Solution Approach 2:
The patent implements preliminary action through pre-tensioning mechanisms and pre-configured cable routing paths. The cable routing is pre-established with guide structures and pulleys positioned to maintain proper tension and alignment before operation begins, preventing slack accumulation and derailment during use.
2Adaptability or versatility
If antagonistic cable designs with multiple drive inputs are used to drive end effector functionality, then the degrees of freedom and articulation capability are improved, but operation introduces slack in the drive cables resulting in derailment
Solution Approach 1:
The patent incorporates feedback mechanisms including tension sensors and position sensors that monitor cable tension and end effector position. This feedback allows the control system to detect and correct slack conditions in real-time, maintaining proper cable tension during antagonistic cable operation and preventing derailment while preserving full articulation capability.
Solution Approach 2:
The patent employs parameter changes by dynamically adjusting cable tension and routing geometry during operation. The system modifies physical parameters such as cable pre-tension force and pulley engagement positions to maintain optimal cable tension levels, preventing slack accumulation while enabling full end effector articulation through antagonistic cable designs.
Data Source
AI summary
A surgical tool includes a drive housing, a drive input rotatably mounted to a bottom of the drive housing, a capstan assembly arranged within the drive housing and operatively coupled to the drive input such that rotation of the drive input correspondingly actuates the capstan assembly, a static actuation limiter arranged within the drive housing, and a dynamic actuation limiter provided by the capstan assembly and engageable with the static actuation limiter as the capstan assembly is actuated. Engaging the dynamic actuation limiter against the static actuation limiter stops actuation of the capstan assembly.