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IEEE Joint CS/RA/SMC Chapter, Technical Meeting “Nonlinear observers: Precursors for controlling noisy real-world systems”
August 14, 2017 @ 11:00 am - 12:00 pm
Speaker: Professor Krishna Vijayaraghavan, Simon Fraser University
Title: Nonlinear observers: Precursors for controlling noisy real-world systems
Abstract: Physical systems are subject to unknown disturbances and measurement noise. While there have been several advances in nonlinear control theory, these techniques often require the availability of the full state measurements. Nonlinear observers are thus crucial to obtaining accurate state estimation in the presence of sensor and actuator disturbances. This talk focuses on the design of a H∞ observer/filter for “generalized-sector bounded” nonlinear system, in the presence of both sensor and input disturbances. The generalized-sector bounded nonlinearity is a super-set of Lipschitz, bounded Jacobian, one-sided Lipschitz, monotonically increasing and dissipative nonlinearities which are the most common classes of nonlinearities. This talk examines the challenges with an observer design for this nonlinearity and then presents a linear matrix inequality for explicitly calculating the observer gain. The talk then compares the nonlinear H∞ observer to Extended Kalman Filter (EKF) by comparing the variation between the two Riccati equations. Results are presented that show that the H∞ filter offers faster convergence of the estimation covariance at large estimation errors during the transience of the filter.
Speaker’s bio: Dr. Vijayaraghavan received his Ph.D. and M.S in Mechanical Engineering, from the University of Minnesota (Twin cities), U.S.A, in 2010 and 2005 respectively, and his B.Tech. in Mechanical Engineering from the Indian Institute of Technology (I.I.T) Madras, Chennai, India, in 2003. He has been with the School of Mechatronic Systems Engineering at Surrey campus of Simon Fraser University. His research team has been developing new observer for a wider class of nonlinear systems as well as creating observers for fault detection and parameter estimation, with applications in alternate energy systems. His other research interests include modeling and control of fuel-cells, co-design based optimization of wind turbines and smart grids, and improving engineering pedagogy. Dr. Vijayaraghavan has active collaboration with industry and is the recipient of the Early Career Researcher suppliant from Natural Sciences and Engineering Research Council of Canada (NSERC) in 2013. He is a member of ASME and IEEE and has chaired several sessions IEEE, ASME conferences. Dr. Vijayaraghavan is also part of Sticks and Stars, an ongoing joint program between Surrey School District and SFU. The program aims to scientific curiosity in at risk kids through Lego building workshops.