Linear position estimation on smart actuators using a nonlinear observer

Hamidreza Movahedi, Ali Zemouche, Rajesh Rajamani

Research output: Chapter in Book/Report/Conference proceedingConference contribution

3 Scopus citations


This paper focuses on observer design for a dynamic system with non-monotonic nonlinear measurement equations. A Lyapunov-analysis-based observer design method for exponentially stable state estimation and a corresponding LMI for computing the observer design gains are developed. This observer design method is applied to linear position estimation using magnetic fields for smart industrial actuators. The output equations for magnetic field as a function of position are nonlinear and non-monotonic. A single constant gain that can satisfy the observer stability condition over the entire range of operating conditions does not exist, but a constant stabilizing gain does exist in each piecewise monotonic region. A methodology for discretizing the operating range into piecewise regions and using a finite state machine for switching between piecewise regions with stabilizing observer gains is developed. Experimental results are presented on the performance of the observer in accurately estimating linear position.

Original languageEnglish (US)
Title of host publication2019 American Control Conference, ACC 2019
PublisherInstitute of Electrical and Electronics Engineers Inc.
Number of pages6
ISBN (Electronic)9781538679265
StatePublished - Jul 2019
Event2019 American Control Conference, ACC 2019 - Philadelphia, United States
Duration: Jul 10 2019Jul 12 2019

Publication series

NameProceedings of the American Control Conference
ISSN (Print)0743-1619


Conference2019 American Control Conference, ACC 2019
Country/TerritoryUnited States

Bibliographical note

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


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