Surgical Adapter Torque Transducer for Precise Force Limiting

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Solution Overview

Problem

Existing robotic surgical systems face challenges in precisely controlling and measuring the forces applied by drive motors, leading to issues with the life expectancy and performance of drive mechanisms and end effectors.

Innovation Solution

The integration of torque transducers that can measure torque when the drive motors are active or inactive, allowing for precise control and feedback in surgical devices, including staplers, wristed or cable-controlled devices, and endoscope manipulation, while maintaining a sterile interface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If torque transducers are integrated to measure torque when drive motors are active and inactive, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improvetorque measurement precisionVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The torque transducer is integrated into the sterile interface module, merging the measurement function with the existing drive mechanism structure. This allows torque measurement during both active and inactive motor states without adding separate, standalone measurement systems, thereby improving measurement precision while limiting the increase in device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The sterile interface module acts as an intermediary between the drive motor and the surgical instrument, incorporating the torque transducer within this interface. This mediator approach enables precise torque measurement while maintaining the sterile barrier and existing mechanical pathways, resolving the contradiction between measurement precision and device complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If torque transducers are used to limit forces experienced by drive cables, then reliability is improved, but device complexity increases

Engineering Contradiction:
Improvedrive mechanism reliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The torque transducer provides real-time feedback on the forces experienced by drive cables, enabling the control system to monitor and limit cable tension. This feedback mechanism prevents over-tensioning and damage to drive cables, improving reliability while incorporating the measurement capability within the existing sterile interface module structure to minimize complexity increases.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The torque transducer is positioned to detect forces before they reach damaging levels, allowing preliminary action to be taken by the control system to prevent cable damage. This proactive force limiting approach improves drive mechanism reliability while using the integrated transducer design to avoid excessive complexity.

Inventive Principle:
Principle #10Preliminary action

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

This solution provides increased fidelity and precision in controlling surgical devices, extending their life and reliability by accurately measuring and limiting forces, preventing damage, and enhancing operational feedback.

Implementation Method 1

The body of the torque transducer is configured to deflect or flex in response to torque applied about the transducer axis

Methodology Applied
Scientific EffectDeformation: Deformation

Data Source

PatentEP4005521B1Robotic surgical assemblies and adapter assemblies thereof
Publication Date: 2026.01.07 COVIDIEN LP
  • EP4005521B1 patent drawingFigure 1
  • EP4005521B1 patent drawingFigure 2A
  • EP4005521B1 patent drawingFigure 2B

AI summary

An instrument drive unit comprising a mounting plate, a first motor having a drive shaft extending towards the mounting plate and a first torque transducer securing the first motor to the mounting plate, the first torque transducer including a motor flange secured to the first motor and a mounting flange secured to the mounting plate, the mounting flange formed of a ring of radial protrusions and defining recesses between each of the radial protrusions.