Low-cost magnetic torque sensor principle

Ruser, H.; Tröltzsch, Uwe; Horn, M.

doi:10.1109/icsens.2002.1037228

Cited by 4 publications

(2 citation statements)

References 8 publications

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“…Contactless technique sensors can be used with fewer shaft design changes. The elastomagnetic effect of ferromagnetic materials exhibits the phenomenon that strain or stress induced by the torque on the shaft can change the magnetic properties of a magnetostrictive material and cause hysteresis deformation and permeability [5]. A frequency modulation-(FM-) type wireless CMOS IC magnetoimpedance (MI) sensor is constructed using flashannealed amorphous wire [6].…”

Section: Introductionmentioning

confidence: 99%

A Feasibility Study of a Noncontact Torque Sensor with Multiple Hall Sensors

Lee

Cho

2015

Journal of Sensors

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The feasibility of a noncontact sensor is investigated. This type of sensor can potentially be used for torque measurement in a speed-variable power transmission system. Torque can be read by examining the phase difference between two induction signals from respective magnetic sensors that detect the magnetic field intensity of permanent magnets mounted on the surface of a shaft in rotation. A real-time measuring algorithm that includes filtering and calibration is adopted to measure the torque magnitude. It is shown that this new torque sensor can perform well under rotation speeds ranging from 300 rpm to 500 rpm. As an interim report rather than a complete development, this work demonstrates the feasibility of noncontact torque measurement by monitoring a magnetic field. The result shows an error of less than 2% within the full test range, which is a sufficient competitive performance for commercial sensors. The price is very low compared to competitors in the marketplace, and the device does not require special handling of the shaft of the surface.

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Section: Introductionmentioning

confidence: 99%

A Feasibility Study of a Noncontact Torque Sensor with Multiple Hall Sensors

Lee

Cho

2015

Journal of Sensors

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“…Furthermore, the axle or hollow shaft requires a special surface lamination with a highly permeable magnetic material. Other suggestions for contact-less torsional sensors without special preparations of the axle or hollow shaft are described, for example, in [8]. Necessarily, the measurement object has to be ferromagnetic in order to provoke any magneto-elastic effect by the application of an external magnetic field.…”

Section: Introductionmentioning

confidence: 99%

Contact-less magneto-elastic torsional sensor based on phase-shift measurements

Buchenau¹,

Schmidt²,

Eckert³

2014

Meas. Sci. Technol.

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We report on the development of a contact-less measurement technique for torsional shear stress τ in ferromagnetic axles or hollow shafts, based on the magneto-elastic effect. In general, two different measuring principles for ferromagnetic materials can be realized, based on: the evaluation of the change of magnetic polarization influenced by shear stress ΔJ(τ) or the change of the magnetic susceptibility ΔχA(τ). The comprehension of the magnetic polarization or the magnetic susceptibility in a sensor concept requires an external magnetic field. Alternating magnetic fields were used as shear stress can disturb not only the amplitude but also the phase distribution of the applied magnetic field. As a result of a torsional moment acting on an axle or hollow shaft, an angle of twist η appears, which is constant over the length of the twisted object. This angle of twist can be understood as a shift of infinitesimal thin cross-sections in which the whole length of the axle is separated. Besides the macroscopic deformation effect, shear forces also affect the Weiss-domains in the micro-scale of the ferromagnetic material. The effects in the micro-scale are the base of the magneto-elastic effect. The combination of the deformation effect in the macro-scale and the deformation of the Weiss-domains in the micro-scale leads to a sophisticated measurement principle for torsional stress in axles or hollow shafts. Magneto-sensitive detectors along or around the measurement object open up the possibility for a contact-less detection of torsional stress in ferromagnetic materials. Besides a strong measuring signal, free from electromagnetic interference, the introduced contact-less measurement principle offers different advantages, like independence from compression strength, nominal tensile stress, impact load, ferromagnetic hysteresis effects and independence of the temperature-dependent electrical conductivity of the axle or hollow shaft. The characteristics of such a type of sensor are considered by a model based on Maxwell’s equations. Besides the chosen design of a contact-less torsion sensor and an experimental set-up, the obtained test results are illustrated and reported in this paper.

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