Surgical Instrument Articulation With Capstan-Driven Cable Control
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Solution Overview
Problem
Existing robotic surgical instruments face limitations in navigating within a surgical site via rotation and manipulation alone, restricting their ability to effectively maneuver within complex surgical environments.
Innovation Solution
The surgical instrument incorporates a housing, a shaft, an end effector assembly, and an articulation mechanism with first and second articulation cables, utilizing capstans or a swashplate assembly to articulate the end effector assembly in multiple directions through tensioning and slackening of the cables, allowing for enhanced maneuverability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If rotation and manipulation features are incorporated into robotic surgical instruments, then the ability to orient the end effector is improved, but the ability to navigate within complex surgical sites remains limited
Solution Approach 1:
The shaft is divided into a proximal section and an articulating section, allowing independent movement of the articulating section relative to the proximal section. This segmentation enables the end effector to navigate complex surgical sites by articulating at the joint between sections, while the proximal section remains stable for orientation control.
Solution Approach 2:
The articulating section is configured to articulate relative to the proximal section, creating a dynamic joint that enables multi-directional navigation. This dynamic articulation capability allows the instrument to adapt to complex surgical geometries while maintaining controlled orientation of the end effector.
2Adaptability or versatility
If articulation mechanisms with multiple cables and capstans are added to enable multi-directional movement, then navigation capability is improved, but device complexity increases
Solution Approach 1:
Multiple articulation cables are routed through the proximal section and connected to capstans that are integrated into the housing. The capstans combine cable tensioning and directional control functions, reducing the number of separate components needed while achieving multi-directional articulation capability.
Solution Approach 2:
Capstans serve as intermediary mechanisms that convert rotational motion into cable tensioning forces. By using capstans as mediators between the control system and the articulation cables, the system achieves complex multi-directional articulation through a manageable set of mechanical components.
3Measurement precision
If articulation cables are routed through the proximal section to the articulating section, then precise control of end effector position is improved, but the structural complexity of the shaft increases
Solution Approach 1:
Articulation cables are used as flexible elements routed through the proximal section of the shaft to control the articulating section. These flexible cables transmit control forces precisely while allowing the shaft structure to remain relatively simple, avoiding the need for rigid mechanical linkages.
Solution Approach 2:
The patent replaces complex rigid mechanical linkages with flexible articulation cables that are tensioned and slackened to control articulation. This substitution of cable-driven mechanics for rigid mechanical connections simplifies the shaft structure while maintaining precise position control capability.
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 articulation mechanism enables precise and versatile movement of the end effector, facilitating improved navigation and operation within surgical sites, enhancing the instrument's ability to perform tasks such as grasping and cutting with reduced input requirements.
Implementation Method 1
a first capstan including a proximal end portion of the first articulation cable at least partially wound thereabout. The first capstan is configured to rotate in a first direction to wind up the proximal end portion of the first articulation cable to tension the first articulation cable and in a second direction to unwind the proximal end portion of the first articulation cable to slacken the first articulation cable.
Data Source
AI summary
A surgical instrument includes a housing, an articulating shaft, and an end effector assembly extending from the articulating shaft. Tensioning a first articulation cable and slackening a second articulation cable articulates the end effector assembly in a first direction and the opposite articulates the end effector assembly in a second, opposite direction. An articulation mechanism includes first and second capstans including proximal end portions of the first and second articulation cables at least partially wound thereabout. The first capstan is configured to rotate in a first direction to wind up the proximal end portion of the first articulation cable to tension the first articulation cable and in a second direction to unwind the proximal end portion of the first articulation cable to slacken the first articulation cable. The second capstan acts in an opposite manner to tension and slacken the second articulation cable.