Soft Core Electromagnets Linear Control for Magnetic Navigation

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Solution Overview

Problem

Existing magnetic manipulation and navigation systems face challenges in precise control and space constraints, particularly when using electromagnets, which can hinder imaging systems and require complex modeling due to their large size and interaction with superconducting coils.

Innovation Solution

A magnetic manipulation and navigation system utilizing at least six electromagnets with soft magnetic cores, fixed in relation to the body, and a control unit that adapts current supply to operate the coils within their linear regions, allowing for precise control of magnetic elements by exploiting linear superposition of magnetic fields for force and torque application.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If electromagnets are used for magnetic manipulation, then control flexibility is improved, but space requirements increase and imaging compatibility deteriorates

Engineering Contradiction:
Improvecontrol flexibilityVSAvoidspace requirements
Core Design Contradiction:
Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

The patent changes the magnetic property parameter of the electromagnet cores from hard magnetic material to soft magnetic material. This parameter change allows the cores to be magnetized and demagnetized easily by external currents, enabling flexible control while maintaining compact size. The soft magnetic cores can rapidly respond to current changes, providing the needed adaptability without requiring large magnet volumes.

Inventive Principle:
Principle #35Parameter changes

2Force

If electromagnets operate in saturation regime, then magnetic field strength increases, but control precision deteriorates due to non-linear behavior

Engineering Contradiction:
Improvemagnetic field strengthVSAvoidcontrol precision
Core Design Contradiction:
ForceVSMeasurement precision

Solution Approach 1:

The patent implements dynamic control by operating the electromagnets in the linear region of their B-H curves rather than in saturation. This dynamic operating point selection allows the magnetic field strength to be precisely controlled through current adjustment while maintaining a linear relationship between current and field output. The system dynamically adjusts current levels to achieve desired field strengths without entering the non-linear saturation regime, thereby preserving control precision.

Inventive Principle:
Principle #15Dynamics

3Device complexity

If fixed electromagnets are used, then system complexity is reduced, but control precision deteriorates due to inability to adjust field distribution

Engineering Contradiction:
Improvesystem complexityVSAvoidcontrol precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent employs periodic or time-varying currents applied to the fixed electromagnets to achieve dynamic field distribution control. By modulating the current in a periodic manner or varying it over time, the system can create moving magnetic field patterns, focus fields at different locations, and adjust field gradients without physically moving the magnets. This temporal modulation of fixed electromagnets provides the precision of adjustable field distribution while maintaining the simplicity of fixed magnet mounting.

Inventive Principle:
Principle #19Periodic 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 approach enables precise control of magnetic elements with up to five degrees of freedom, overcoming space constraints and improving imaging compatibility by maintaining electromagnets in non-saturation regimes, resulting in enhanced precision and flexibility for medical and industrial applications.

Implementation Method 1

at least six electromagnets having soft magnetic cores, said magnets being fixed in relation to said body, and a control unit supplying the current for the electromagnets

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

allowing for precise control of magnetic elements by exploiting linear superposition of magnetic fields for force and torque application

Methodology Applied
Scientific EffectLorentz force: Lorentz Force

Data Source

PatentEP2475322B1Magnetic manipulation and navigation system for a magnetic element
Publication Date: 2016.03.16 ETH ZURICH
  • EP2475322B1 patent drawingFigure 1
  • EP2475322B1 patent drawingFigure 2
  • EP2475322B1 patent drawingFigure 3

AI summary

A magnetic manipulation and navigation system for moving a magnetic element through a body (3) comprising at least six electromagnets (1) fixed in relation to said body (3) and a control unit supplying the current for the electromagnets (1). The electromagnets (1) have soft magnetic cores and the current supplied by the control unit to each of the electromagnets (1) is adapted to operate the electromagnetic coils of each of the electromagnets (1) in their core's linear regions being delimited by the value of the flux density of each electromagnet being in an interval between the negative and positive saturation value of each electromagnet., the lower representation (5) showing the deviation due to the use of soft magnetic cores in all electromagnets.