A remote position sensing method based on passive high magnetic permeability thin films

Heng Wang, Rajesh Rajamani

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


This article develops a fundamental new sensing principle for measuring the position of a moving object. The moving object is equipped with a thin film of high magnetic permeability. A stationary electromagnet and a magnetic sensor are located nearby. As the moving object's position changes, the coupling between the electromagnet and the magnetic sensor changes, allowing highly accurate measurement of position of the moving object. This new sensing principle will allow remote non-contacting position measurement of moving objects without requiring any electronics or battery on the object. The feasibility of the new measurement system is verified using an experimental piston-cylinder system in which the position of the piston is accurately estimated with an accuracy of approximately 1% of the range of motion. The thin film is inexpensive and lightweight and could enable a new generation of position sensors superior to currently available position measurement technologies.

Original languageEnglish (US)
Pages (from-to)217-223
Number of pages7
JournalSensors and Actuators, A: Physical
StatePublished - Aug 15 2019

Bibliographical note

Funding Information:
Rajesh Rajamani obtained his M.S. and Ph.D. degrees from the University of California at Berkeley in 1991 and 1993 respectively and his B.Tech degree from the Indian Institute of Technology at Madras in 1989. Dr. Rajamani is currently Professor of Mechanical Engineering at the University of Minnesota. His active research interests include sensing and estimation for smart mechanical systems. Dr. Rajamani has co-authored over 140 journal papers and is a co-inventor on 13 patent applications. He is the author of the popular book “Vehicle Dynamics and Control” published by Springer Verlag. Dr. Rajamani has served as Chair of the IEEE Technical Committee on Automotive Control and on the editorial boards of the IEEE Transactions on Control Systems Technology, the IEEE/ASME Transactions on Mechatronics, and the IEEE Control Systems Magazine. Dr. Rajamani is a Fellow of ASME and has been a recipient of the CAREER award from the National Science Foundation, the 2001 Outstanding Paper award from the journal IEEE Transactions on Control Systems Technolog y, the Ralph Teetor Award from SAE, and the 2007 O. Hugo Schuck Award from the American Automatic Control Council. Several inventions from his laboratory have been commercialized through start-up ventures co-founded by industry executives. One of these companies, Innotronics, was recently recognized among the 35 Best University Start-Ups of 2016 in a competition conducted by the US National Council of Entrepreneurial Tech Transfer.

Funding Information:
This research was supported in part by funding from the National Science Foundation under Grant CMMI 1562006 .

Publisher Copyright:
© 2019

Copyright 2019 Elsevier B.V., All rights reserved.


  • Magnetic sensors
  • Mechanical actuators
  • Mechanical motion measurement
  • Position sensors

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