Dynamic Cable Preload Tensioning for Surgical End Effector Control

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Solution Overview

Problem

Surgical instruments with slack or low tension in cables experience jumpy or unpredictable motion of the end effector, and high preload tension increases friction and operational forces, necessitating a solution to maintain consistent cable tension.

Innovation Solution

A surgical instrument with a dynamic preload tensioner that adjusts the path of flexible tensioning elements using drive components, allowing for controlled tension adjustment and reduced friction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high preload tension is applied to the cable, then cable tension consistency is improved, but friction and operational forces increase

Engineering Contradiction:

Improvecable tension consistencyVSAvoidoperational forces

Core Design Contradiction:

ReliabilityVSForce

Solution Approach 1:

The patent applies a dynamic tensioner that can adjust cable tension in real-time based on operational conditions. The tensioner modifies the path of the flexible tensioning element dynamically, allowing the system to maintain optimal tension without applying excessive static preload, thereby reducing friction and operational forces while ensuring cable tension consistency.

Inventive Principle:

Principle #15Dynamics

2Reliability

If high preload tension is applied to the cable, then cable tension consistency is improved, but friction at contact surfaces increases

Engineering Contradiction:

Improvecable tension consistencyVSAvoidfriction

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The dynamic tensioner adjusts the cable path dynamically to maintain appropriate tension levels without excessive preload. This reduces the friction at contact surfaces where the cable rides along surfaces and contacts curved surfaces of openings, while still ensuring sufficient tension to prevent jumpy or unpredictable motion.

Inventive Principle:

Principle #15Dynamics

3Force

If cable tension is reduced, then operational forces decrease, but cable motion becomes jumpy or unpredictable

Engineering Contradiction:

Improveoperational forcesVSAvoidcable motion stability

Core Design Contradiction:

ForceVSReliability

Solution Approach 1:

The dynamic tensioner continuously adjusts cable tension to maintain motion stability without requiring high static preload. By dynamically modifying the cable path and tension levels based on real-time conditions, the system ensures smooth cable motion while keeping operational forces at appropriate levels.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS20260033906A1Systems to apply preload tension for surgical instruments and related methods

Publication Date: 2026.02.05 INTUITIVE SURGICAL OPERATIONS INC

AI summary

A surgical system includes a dynamic preload tension feature for a tensioning element that actuates a distal end component of a surgical instrument. The surgical instrument includes a chassis at a proximal end of the surgical instrument, drive components mounted in the chassis, a distal end component at a distal end of the surgical instrument, a flexible tensioning element coupled between a first of the drive components and the distal end component, and a dynamic preload tensioner mounted in the chassis and coupled to a second of the drive components. The flexible tensioning element extends along a path. The dynamic preload tensioner is configured to be driven by the second of the drive components to be moved relative to the chassis and is positioned to change the path of the flexible tensioning element as the dynamic preload tensioner moves relative to the chassis.