Magnetic Joystick Angular Detection with Dual-Source Field Decomposition

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Solution Overview

Problem

Current joystick controllers require multiple sensors to achieve full three-axis control, which complicates design and increases manufacturing costs, while non-contact magnetic field sensing technologies face challenges in accurately detecting rotation and 3D position with mechanical wear and limited robustness.

Innovation Solution

A sensor system utilizing a single magnetic field sensor with two magnetic sources, a rotatable quadrupolar magnet and a pivotable dipole magnet, to detect rotation and 3D angular directions by analyzing the superimposition magnetic field at multiple measurement locations, allowing for compact and robust angular detection and 3D joystick functionality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple sensors are used to achieve full three-axis control, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improvethree-axis control accuracyVSAvoidsensor system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines multiple sensing functions (rotation detection and 3D position sensing) into a single magnetic field sensor. The sensor simultaneously detects the rotation angle of the first magnetic source and the two angular directions of the second magnetic source, eliminating the need for multiple separate sensors while maintaining full three-axis control capability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single magnetic field sensor performs multiple functions: it detects rotation around the first axis, pivot movements around two other axes, and provides full three-axis control information. This multi-functional approach replaces what would traditionally require multiple specialized sensors.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Measurement precision

If multiple sensors are used for three-axis control, then measurement precision is improved, but manufacturing cost increases

Engineering Contradiction:
Improvethree-axis control accuracyVSAvoidmanufacturing cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

By merging multiple sensing functions into a single magnetic field sensor, the patent reduces the total number of components that need to be manufactured, assembled, and calibrated. This significantly lowers manufacturing costs while maintaining full three-axis control precision through the use of two magnetic sources.

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If mechanical contact sensing is used, then measurement precision is achieved, but reliability decreases due to mechanical wear

Engineering Contradiction:
Improverotation detection accuracyVSAvoidsensor durability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent replaces mechanical contact sensing with non-contact magnetic field sensing. The magnetic field sensor detects the magnetic fields generated by the two magnetic sources without any physical contact, eliminating mechanical wear and significantly improving reliability while maintaining measurement precision for rotation and 3D position detection.

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

4Device complexity

If a single sensor is used for both rotation and 3D detection, then device complexity is reduced, but measurement precision may worsen

Engineering Contradiction:
Improvesensor system simplicityVSAvoidangular detection accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent segments the magnetic field sensing into two distinct magnetic sources: a first magnetic source for rotation detection around the first axis, and a second magnetic source for 3D position sensing with two angular directions. This segmentation within a single sensor allows independent optimization of each sensing function while maintaining overall system simplicity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Each magnetic source generates a magnetic field with specific characteristics suited for its detection function. The first magnetic source is optimized for rotation detection, while the second magnetic source is optimized for 3D angular detection. The single sensor is configured to detect the distinct magnetic field contributions from each source, achieving high precision for both functions simultaneously.

Inventive Principle:
Principle #3Local quality

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 accurate and robust angular rotation detection and 3D joystick functionality with reduced sensor complexity, minimizing mechanical wear and manufacturing costs, and enhancing the system's reliability and accuracy by decomposing the sensed magnetic field into distinct contributions.

Implementation Method 1

a first magnetic source... is generating a first magnetic field contribution of at least quadrupolar order at the sensitive surface... a second magnetic source... is generating a second magnetic field contribution at the sensitive surface... detecting at least an in-plane component of a superimposition field of the generated first and second magnetic field contributions

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Data Source

PatentEP3702736B1Sensor system for rotation angular detection and 3D joystick function
Publication Date: 2023.08.02 MELEXIS TECHNOLOGIES SA
  • EP3702736B1 patent drawingFigure 1~2
  • EP3702736B1 patent drawingFigure 3
  • EP3702736B1 patent drawingFigure 4~6

AI summary

A sensor system and a joystick comprising the sensor system, wherein the sensor system comprises a magnetic field sensor (1), a first and a second magnetic source (2, 3). The first magnetic source is rotatable relative to a sensitive surface (10) of the sensor and generates a first magnetic field contribution (B; Bm1) of at least quadrupolar order. The second magnetic source is pivotable with respect to the sensitive surface and generates a second magnetic field contribution (Berr; Bm2). The sensor is configured for detecting at least an in-plane component of a superimposition field (Bsup) of the first and second magnetic contributions at each of a plurality of lateral measurement locations (A-H) on the sensitive surface, obtaining measurements indicative of a field gradient for at least two in-plane components (Bx, Bx-y) of the first magnetic contribution, obtaining measurements indicative of a field mean for at least two in-plane components (Berr,x, Berr,y) of the second magnetic contribution, and determining a rotation angle (α) for the first source (2) from the field gradient measurements and two angular directions (θ, (ϕ) for the second source (3) from the field mean measurements. Lateral measurement locations are arranged into at least two pairs of diametrically opposite measurement locations with respect to a center location (P) on the sensitive surface.