title: Design Methodology for Magnetic Field-Based Soft Tri-Axis Tactile Sensors.
abstract: Tactile sensors are essential if robots are to safely interact with the external world and to dexterously manipulate objects. Current tactile sensors have limitations restricting their use, notably being too fragile or having limited performance. Magnetic field-based soft tactile sensors offer a potential improvement, being durable, low cost, accurate and high bandwidth, but they are relatively undeveloped because of the complexities involved in design and calibration. This paper presents a general design methodology for magnetic field-based three-axis soft tactile sensors, enabling researchers to easily develop specific tactile sensors for a variety of applications. All aspects (design, fabrication, calibration and evaluation) of the development of tri-axis soft tactile sensors are presented and discussed. A moving least square approach is used to decouple and convert the magnetic field signal to force output to eliminate non-linearity and cross-talk effects. A case study of a tactile sensor prototype, MagOne, was developed. This achieved a resolution of 1.42 mN in normal force measurement (0.71 mN in shear force), good output repeatability and has a maximum hysteresis error of 3.4%. These results outperform comparable sensors reported previously, highlighting the efficacy of our methodology for sensor design.
authors: School of Mechanical Engineering, University of Leeds, Leeds LS2 9JT, UK. H.Wang1@leeds.ac.uk.
authors: Hongbo
authors: H
authors: Wang
authors: Department of Aeronautics, Imperial College London, London SW7 2AZ, UK. g.de-boer@imperial.ac.uk.
authors: Greg
authors: G
authors: de Boer
authors: School of Mechanical Engineering, University of Leeds, Leeds LS2 9JT, UK. el11jwk@leeds.ac.uk.
authors: Junwai
authors: J
authors: Kow
authors: School of Mechanical Engineering, University of Leeds, Leeds LS2 9JT, UK. A.Alazmani@leeds.ac.uk.
authors: Ali
authors: A
authors: Alazmani
authors: Dyson School of Design Engineering, Imperial College London, London SW7 2AZ, UK. m.ghajari@imperial.ac.uk.
authors: Mazdak
authors: M
authors: Ghajari
authors: Department of Aeronautics, Imperial College London, London SW7 2AZ, UK. r.hewson@imperial.ac.uk.
authors: Robert
authors: R
authors: Hewson
authors: School of Mechanical Engineering, University of Leeds, Leeds LS2 9JT, UK. P.R.Culmer@leeds.ac.uk.
authors: Peter
authors: P
authors: Culmer
keywords: Hall effect sensor; calibration; design methodology; force sensors; hyperelastic elastomer; magnetic field; moving least square; silicone rubber; soft sensing; tactile sensors