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Thursday, April 28, 2011 9:15 a.m., ECSS 3.503
(Osborne Conference Room)







 me seminar

“Robust and Adaptive Control of Uncertain Nonlinear Systems”
Dr. Parag Patre, NASA Langley Research Center

This talk will focus on the control of nonlinear dynamical systems with the motivation that improved performance may be achieved by maintaining the complete nonlinear model of the systems in their control design. The control of systems with uncertain nonlinear dynamics has been a decades-long mainstream area of focus. The general trend for previous control strategies developed for uncertain nonlinear systems is that the more unstructured the system uncertainty, the more control effort (i.e., high gain or high frequency feedback) is required to reject the uncertainty, and the resulting stability and performance of the system is diminished (e.g., uniformly ultimately bounded stability). This presentation will describe the development of a new continuous robust integral of the sign of the error (RISE) feedback element that can be used to reject unstructured uncertainty and yield asymptotic stability results. As a means to improve the control performance, development will also be presented to illustrate how the amalgamation of the RISE terms with an adaptive model-based feed-forward term can be used to yield an asymptotic tracking result for systems that have mixed unstructured and structured uncertainty. Applications of the proposed robust and adaptive nonlinear control methods will be presented to provide insight into the pervasive applicability of this area of research, including muscle control, satellite attitude control, human-robot interaction and friction identification. Future applications in the area of aviation safety, energy efficiency, renewable energy and interconnected systems will be discussed.

Parag Patre received his BTech degree in mechanical engineering from the Indian Institute of Technology in 2004. He was then with Larsen & Toubro Limited of India until 2005. He received his PhD in mechanical engineering from the University of Florida in 2009 and is now a postdoctoral fellow at NASA’s Langley Research Center. His research interests include Lyapunov-based design and analysis of control methods for uncertain nonlinear systems, robust and adaptive control, aviation safety, control in the presence of actuator and sensor failures, decentralized adaptive control, energy engineering, and neural network-based control. He received the 2009 Best Dissertation Award from the University of Florida’s Department of Mechanical and Aerospace Engineering, and he is lead author of the upcoming book based on his dissertation, “RISE-based Robust and Adaptive Control of Nonlinear Systems.”