Magnetic Position System Design Method Applied to Three-Axis Joystick Motion Tracking

Perla Malagò,Florian Slanovc,Stefano Lumetti,Andrea Pellegrinetti,Claas Abert,Stefan Herzog,Michael Ortner,Thomas Schaden,Mohssen Moridi,Dieter Suess

doi:10.3390/s20236873

Perla Malagò, Florian Slanovc + Show 8 more

Open Access

https://doi.org/10.3390/s20236873

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Abstract

This manuscript discusses the difficulties with magnetic position and orientation (MPO) system design and proposes a general method for finding optimal layouts. The formalism introduces a system quality measure through state separation and reduces the question “How to design an MPO system?” to a global optimization problem. The latter is then solved by combining differential evolution algorithms with magnet shape variation based on analytical computations of the field. The proposed formalism is then applied to study possible realizations of continuous three-axis joystick motion tracking, realized with just a single magnet and a single 3D magnetic field sensor. The computations show that this is possible when a specific design condition is fulfilled and that large state separations as high as can be achieved under realistic conditions. Finally, a comparison to state-of-the-art design methods is drawn, computation accuracy is reviewed critically, and an experimental validation is presented.

Highlights

Magnetic position and orientation (MPO) detection systems determine the relative motion between permanent magnets and magnetic field sensors by measuring the modulation of the magnetic field
This is expressed by Equation (2) for implementation of the three-axis joystick proposed in Section 2.3, where α and B are of similar dimensions
The difficulties related to magnet position and orientation (MPO) system design are discussed

Summary

Introduction

Magnetic position and orientation (MPO) detection systems determine the relative motion between permanent magnets and magnetic field sensors by measuring the modulation of the magnetic field. Such systems offer many advantages like robustness against dirt and temperature, long lifetimes ensured by contactless operation, as well as high resolutions at low cost and low power operation [1,2]. A position system of specific interest is the three-axis joystick, which combines regular 2D joystick motion with rotation of the lever about its own axis.

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