Six-Degree-of-Freedom Input Device Using Orthogonal Magnetic Sensors

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Solution Overview

Problem

Existing 3D input devices can only determine relative displacements and rotations, lack precision due to limited movement range and accuracy, and are unable to replicate natural movements like guiding a pen or tool, as they cannot provide absolute position and orientation in three-dimensional space.

Innovation Solution

A device with two non-collinearly oriented permanent magnets, arranged in orthogonal planes with multiple sensors, allowing for the determination of absolute position and orientation, enabling six degrees of freedom movement, including three translations and three rotations, by measuring magnetic flux density.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single permanent magnet is used for position detection, then the device structure is simple, but only five degrees of freedom can be determined and absolute position cannot be measured

Engineering Contradiction:
Improvemagnet arrangementVSAvoidposition and orientation detection
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The single magnet is divided into two separate permanent magnets with non-collinear dipole moments. This segmentation allows the system to determine all six degrees of freedom (three translations and three rotations) by measuring the magnetic field vectors from both magnets, enabling absolute position and orientation detection that was not possible with a single magnet.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The dipole moments of the two permanent magnets are arranged in a non-collinear configuration (e.g., orthogonal arrangement). This dimensional arrangement creates a three-dimensional magnetic field signature that allows sensors to uniquely determine the absolute position and orientation of the input element in 3D space, breaking the axial symmetry limitation of single-magnet systems.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Stability of the object's composition

If the ball is rigidly connected to the input device, then the structure is stable, but the movement range and accuracy are limited

Engineering Contradiction:
Improveball connectionVSAvoidspatial freedom of movement
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The rigid mechanical connection between the ball and input device is replaced with a magnetic field-based detection system. Two permanent magnets embedded in the ball generate a magnetic field signature that sensors can detect without physical contact. This substitution allows the ball to move freely in three-dimensional space while maintaining stable magnetic field generation for accurate position and orientation tracking.

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

3Volume of moving object

If the movement range is limited, then the device structure is compact, but the accuracy and value range of displacement determination are reduced

Engineering Contradiction:
Improvedevice sizeVSAvoiddisplacement accuracy
Core Design Contradiction:
Volume of moving objectVSMeasurement precision

Solution Approach 1:

The system transitions from measuring only one-dimensional displacement to detecting six-degree-of-freedom movement (three translations and three rotations) in three-dimensional space. The non-collinear magnet arrangement creates a unique magnetic field signature at each position and orientation, enabling accurate determination of absolute position and orientation over an extended spatial range while maintaining a compact device structure.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 precise and natural movement input with increased spatial freedom, providing accurate absolute position and orientation data, significantly improving the accuracy and range of displacement and rotation calculations compared to conventional 3D mice.

Implementation Method 1

sensors for measuring the magnetic flux density of the field generated by the two permanent magnets

Methodology Applied
Scientific EffectMagnetic flux density measurement: Magnetic Field

Data Source

PatentEP3433582B1Apparatus for inputting absolute position and orientation of an input element
Publication Date: 2020.09.16 VER ZUR FORDERUNG VON INNOVATIONEN DURCH FORSCHUNG ENTWICKLUNG & TECHTRANSFER E V VER INNOVENT
  • EP3433582B1 patent drawingFigure 1
  • EP3433582B1 patent drawingFigure 2~4

AI summary

The invention addresses the problem of providing an apparatus for inputting absolute position and orientation of an input element and six degrees of freedom of the movement, namely three translations and three rotations of the input element, to a computer, in which the translations and rotations of the input element in a large spatial area are directly converted into translations and rotations of an element in computer software. According to the invention, the problem is solved with an apparatus for inputting absolute position and orientation of an input element (1), containing two permanent magnets, wherein the input element (1) is arranged in a freely movable manner in the effective range of sensors (4), by virtue of the fact that the dipole moments of the two permanent magnets of the input element (1) are not arranged with a collinear orientation with respect to one another and the sensors (4) for measuring the magnetic flux density of the field generated by the two permanent magnets are arranged in two planes (5, 6) which are orthogonal with respect to one another, wherein at least three sensors (4) are arranged in each plane (5 and 6). In this case, conventional NdFeB magnets are used as permanent magnets.