Magnetic Trocar Docking for Precise Robotic Arm Alignment

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Solution Overview

Problem

Existing trocar docking systems for robotic surgery face challenges such as precise alignment difficulties, interference from sterile barriers, and reduced trocar lifespan due to electrically-powered components, which hinder accurate and reliable robotic arm attachment.

Innovation Solution

The use of permanent magnets in the trocar to generate magnetic fields, sensed by a sensor system, allows for precise robotic arm alignment and docking without line-of-sight requirements, ensuring robustness and longevity of the trocar.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If visual sensors are used for optical tracking to guide the robotic arm to the trocar, then alignment precision is improved, but the system becomes vulnerable to interference from sterile barriers and drapes that block the line of sight

Engineering Contradiction:
Improvealignment precisionVSAvoidinterference from sterile barriers
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces optical tracking systems with magnetic field-based sensing. Magnets embedded in the trocar generate magnetic fields that are detected by sensors on the robotic arm, eliminating the need for line-of-sight optical tracking and removing the vulnerability to sterile barrier interference.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces magnetic fields as an intermediary between the trocar and the robotic arm sensing system. The magnetic fields serve as a non-line-of-sight communication medium that penetrates sterile barriers, enabling alignment guidance without direct visual contact.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If electrically-powered components are added to the trocar to enable ultrasonic triangulation or electromagnetic field detection, then docking accuracy is improved, but the trocar lifespan is reduced due to degradation from repeated use and sterilization

Engineering Contradiction:
Improvedocking accuracyVSAvoidtrocar lifespan
Core Design Contradiction:
Measurement precisionVSDuration of action of stationary object

Solution Approach 1:

The patent uses permanent magnets instead of electrically-powered components. The magnets are embedded directly in the trocar structure, require no power source, and cannot degrade from electrical use or sterilization, thereby extending the trocar's operational lifespan while maintaining docking accuracy.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent substitutes electrically-powered electromagnetic field generation with passive permanent magnets. This eliminates the need for batteries, motors, or electronic circuits in the trocar, removing the sources of degradation and extending the device's service life.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Device complexity

If manual docking of the robotic arm to the trocar is performed, then device complexity is reduced, but alignment precision deteriorates due to the difficulty of achieving precise alignment

Engineering Contradiction:
Improvedocking system complexityVSAvoidalignment precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent implements self-aligning capabilities through magnetic field sensing. The robotic arm's sensors automatically detect the magnetic field signature of the trocar and guide the arm into the correct alignment, eliminating the need for complex manual alignment procedures while maintaining precision.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent introduces real-time feedback through magnetic field sensing. Sensors on the robotic arm continuously monitor the magnetic field strength and orientation, providing feedback to the control system to automatically adjust the arm's position and orientation for precise docking alignment.

Inventive Principle:
Principle #23Feedback

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

Enables accurate and precise robotic arm docking with trocars, maintaining trocar durability and versatility by eliminating the need for electrically-powered components and overcoming alignment obstacles.

Implementation Method 1

The use of magnets, for example, non-electrically powered magnets such as permanent magnets, in the trocar can provide magnetic fields for sensing by a sensor system

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Data Source

PatentEP3930613B1Systems and methods for magnetic sensing and docking with a trocar
Publication Date: 2025.12.24 VERB SURGICAL INC
  • EP3930613B1 patent drawingFigure 1
  • EP3930613B1 patent drawingFigure 2
  • EP3930613B1 patent drawingFigure 3

AI summary

A surgical robotic system has a tool drive coupled to a distal end of a robotic arm that has a plurality of actuators. The tool drive has a docking interface to receive a trocar. One or more sensors in the docking interface sense a magnetic field generated by the trocar. One or more processors are configured to determine a position and orientation of the trocar based on the sensed magnetic field, and then drive the actuators to orient the docking interface to the determined orientation of the trocar, or otherwise guide the robotic arm toward the determined position of the trocar. Other aspects are also described and claimed.