Gimbal-Based Multi-Cluster Joints for Smooth Surgical Articulation
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Solution Overview
Problem
Existing articulating end-effector joints for minimally invasive surgical tools face challenges such as large angular range requirements, cable slack, backlash, and joint distortion due to buckling, which complicate miniaturization and increase complexity, cost, and jerkiness during rotations.
Innovation Solution
The use of multi-cluster articulation joints with a compact design, featuring a stack of gimbal guides and gimbals, provides orthogonal rotational freedom, a tight bend radius, and a central cable management guide to prevent lateral movement, ensuring smooth articulation and reduced sensitivity to compressive forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional articulating end-effector joints are used with large angular range requirements and cable control, then the device can achieve basic articulation functionality, but the device experiences cable slack, backlash, joint distortion due to buckling, and increased complexity
Solution Approach 1:
The joint is divided into multiple clusters, each containing a specific number of links (e.g., three links per cluster). This segmentation allows the complex articulation function to be distributed across multiple simpler units, reducing individual link complexity while maintaining overall articulation capability and eliminating cable slack through the multi-cluster architecture.
Solution Approach 2:
The patent implements a nested structure where multiple links are arranged in clusters, with each cluster containing nested links that articulate relative to each other. The cable management guide is nested within the joint structure, routing cables through the cluster arrangement. This nesting consolidates the articulation mechanism, reducing overall complexity while maintaining articulation smoothness.
2Adaptability or versatility
If the number of links in the articulating joint is increased to achieve larger angular range, then the articulation capability is improved, but the device size increases and miniaturization becomes more difficult
Solution Approach 1:
The joint clusters are segmented into discrete units with a specific number of links (e.g., three links per cluster). This segmentation allows the angular range to be achieved through the coordinated articulation of multiple compact clusters rather than requiring a single large mechanism, enabling miniaturization while maintaining versatility.
Solution Approach 2:
The patent utilizes multi-dimensional articulation through the cluster arrangement, where links articulate in multiple directions and planes. This dimensional approach allows the joint to achieve a large effective angular range within a compact volume by exploiting spatial arrangements rather than simply increasing the number of links in a single plane.
3Ease of operation
If tension members (cables) are used to control the articulating joint, then the joint can be articulated via proximal input, but cable slack and backlash occur during articulation
Solution Approach 1:
The cable management guide pre-routes the tension members through the joint clusters in a predetermined path that maintains cable tension during articulation. This preliminary routing arrangement prevents cable slack and backlash by ensuring cables remain taut throughout the range of motion, while still allowing easy articulation control via proximal input.
Solution Approach 2:
The cable management guide acts as an intermediary component that mediates between the tension members and the articulating links. It ensures proper cable routing and tension distribution through the multi-cluster joint, eliminating slack and backlash while maintaining ease of operation through the proximal articulation input.
4Power
If compressive forces are applied to the articulating joint during end-effector actuation, then the end-effector can be actuated, but joint distortion and buckling occur
Solution Approach 1:
The joint is segmented into multiple clusters that distribute the compressive loads across multiple links and articulation points. This segmentation prevents buckling by ensuring no single link bears excessive compressive force, while still allowing sufficient actuation power to be transmitted to the end-effector through the coordinated cluster arrangement.
Solution Approach 2:
The patent combines multiple links into clusters that work together to resist compressive forces. The clustered arrangement merges the structural support function across multiple elements, enhancing joint structural stability while maintaining the power transmission capability needed for end-effector actuation.
Data Source
AI summary
An articulating joint comprising a multi-cluster joint where every consecutive pair of links is interfaced by a gimbal, which offers rotation about two orthogonal axes within the same plane. Thus, the articulating joint comprises an alternating sequence of links and gimbals. Furthermore, there may be multiple cables attached to one or more of the links. As these cables are selectively pulled and released, one can achieve any desired articulation of the articulating joint. There may be a transmission member extending through the links and gimbals, parallel to the central longitudinal axis of the joint in its nominal non-articulated condition. This transmission member may be either a tension member that is pulled on (e.g. a cable or flexible pull rod) and that loads the articulating joint in compression, or the transmission member may be a flexible push rod that loads the articulating joint in tension.