Magnetic Trocar Pose Estimation for Sterile Robotic Docking

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Solution Overview

Problem

Existing trocar docking techniques for surgical robotic arms face challenges such as optical tracking interference from sterile barriers and the degradation of electrically powered components, which reduces the lifespan and versatility of trocars.

Innovation Solution

The use of permanent magnets in the trocar to generate magnetic fields for detection by the surgical robotic arm, allowing for magnetic sensing that does not require line-of-sight alignment and eliminates the need for electrically powered components, enabling robust and versatile trocar docking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If optical tracking through visual imaging sensors is used to guide the surgical robotic arm to the trocar, then the docking process can be automated, but the sterile barriers or drapes that cover the surgical robotic arm block the visual sensors and interfere with tracking

Engineering Contradiction:

Improveautomatic dockingVSAvoidblockage by sterile barriers

Core Design Contradiction:

Extent of automationVSObject-affected harmful factors

Solution Approach 1:

The patent replaces optical tracking with magnetic field sensing. Magnetic field sensors on the robotic arm detect the magnetic field generated by magnets in the trocar, enabling automatic docking without line-of-sight requirements. This substitution eliminates interference from sterile barriers while maintaining automation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces magnetic fields as an intermediary for communication and positioning between the robotic arm and trocar. The magnets in the trocar generate magnetic fields that serve as a medium for the sensors to detect position and orientation, bypassing the need for direct visual contact through sterile barriers.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Extent of automation

If electrically powered components are used in the trocar to generate signals for guiding the robotic arm, then automatic alignment can be achieved, but the components degrade due to repeated use and sterilization procedures, reducing trocar lifespan

Engineering Contradiction:

Improveautomatic alignmentVSAvoidtrocab lifespan

Core Design Contradiction:

Extent of automationVSDuration of action of stationary object

Solution Approach 1:

The patent uses permanent magnets in the trocar instead of electrically powered components. Magnets are passive, have no moving parts, and do not degrade through sterilization or repeated use, making the trocar more durable and suitable for multiple uses while maintaining automatic alignment capability.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent replaces electrically powered signal generation components with passive permanent magnets. This substitution eliminates the need for power sources, circuitry, and electronic components in the trocar, thereby eliminating degradation issues associated with electrical components while preserving the ability to guide the robotic arm.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Device complexity

If manual maneuvering of the robotic arm is used to align with the trocar, then no complex sensing systems are required, but the docking process is time-consuming and labor-intensive

Engineering Contradiction:

Improvesensing system complexityVSAvoiddocking time

Core Design Contradiction:

Device complexityVSLoss of time

Solution Approach 1:

The patent uses magnetic field sensing to automatically determine the position and orientation of the trocar relative to the robotic arm. This automated sensing and alignment process replaces manual maneuvering, significantly reducing docking time while maintaining relatively simple system architecture using permanent magnets and magnetic sensors.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 enables precise and reliable automatic alignment and mechanical coupling of the surgical robotic arm with the trocar, even under sterile conditions, while extending the trocar's lifespan by avoiding the degradation associated with electrically powered components.

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 detection by a sensor system in a surgical robotic arm

Methodology Applied

Scientific EffectMagnetic field: Magnetic Field

Data Source

PatentUS11819288B2Trocar pose estimation using machine learning for docking surgical robotic arm to trocar

Publication Date: 2023.11.21 AURIS HEALTH INC

AI summary

A surgical robotic system senses position or orientation of an object, which may be a trocar that has a magnetic field. Magnetic field sensors are coupled to a surgical robotic arm. A machine learning model coupled to the magnetic field sensors is trained to output three-dimensional position and/or three-dimensional orientation of the trocar or other object. Other aspects are also described.