An Eddy current-Based Angle Sensor with a Minimally Modified Shaft as a Sensing Element

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Name of the Speaker: A. S. Anil Kumar (EE19D012)
Guide: Dr. Boby George
Co-Guide : Dr. Subhas Mukhopadhyay
Venue/Online meeting link:
Date/Time: 3rd February 2023 (Friday), 3:00 PM

Thin noncontact angle sensors that provide reliable, high-resolution output even in a dusty and humid environment are very valuable in industrial applications. In this talk, a novel design to realize a thin eddy-current-based angle sensor will be presented. The proposed sensor is realized by converting the shaft, whose angle of rotation is to be measured, into the sensing element. The modification to the shaft is minimal; a small surface groove is introduced without affecting the mechanical strength. The stationary part of the sensor consists of two layers of flexible square-planar coils. Depending on the angular position of the shaft, the inductances of the planar coils get modified. These are measured using a specially designed circuitry, optimized for this sensor. The output for the entire circle range (360o) is derived from the inductance values of each coil using a successive approximation algorithm developed for this purpose. Finite-element analysis was used to design the sensor and analyze the axial/radial misalignment of the rotor. A sensor prototype was built and tested. The output showed a resolution of 0.1o and a worst-case linearity error of 0.9%. The prototype sensor dimensions are selected such that it fits a standard steering column. The proposed sensor is thin, easy to manufacture at low cost, tolerant to axial vibration by design, and has a 360o sensing range. The details will be presented in the talk.