Department of Mechanical Engineering

ME Seminar Series: What Do UAVs in GPS-Denied Environments Have in Common with E. Coli Bacteria?

 

Department of Mechanical Engineering Seminar Series
11:00 AM– 12:00 PM
November 6, 2007
1227 Hoover Hall

What Do UAVs in GPS-Denied Environments Have in Common with E. Coli Bacteria?

Miroslav KrsticHarold W. Sorenson Professor, Department of Mechanical and Aerospace Engineering, UC–San Diego

Abstract

In the absence of GPS-based position awareness (such as underwater, in buildings and caves, etc.), vehicles have to rely on solving real-time optimization problems based on other signals that might be available for measurement, such as acoustic, electomagnetic, thermal, or concentration of chemical agents. I will discuss the use of extremum seeking as a tool for navigating UAVs in GPS-denied environments. The challenge in this problem is that it violates the standard assumptions of asymptotic stability of the plant in the classical theory of extremum seeking and introduces nonholonomic kinematic constraints. Using averaging we characterize the complex almost periodic attractors that our vehicles converge to. We illustrate the utility of the approach for several applications: tracking of a moving source of diffusive contaminant, source seeking extensions to 3D and to a model of fish locomotion, experimental results with mobile robots, and a stochastic extremum seeking algorithm that conjectures what strategy might be used by bacteria (such as the flagella-actuated E. Coli) to climb food gradients. The last in this list of applications reveals the close connection between extremum seeking and the methods of "stochastic approximation."

Biography

Dr. Krstic is the Director of the Center for Control Systems and Dynamics at UCSD. He obtained his PhD at UC Santa Barbara in 1994. Krstic is a coauthor of the books Nonlinear and Adaptive Control Design (1995), Stabilization of Nonlinear Uncertain Systems (1998), Flow Control by Feedback (2002), Real Time Optimization by Extremum Seeking Control (2003), and Control of Turbulent and Magnetohydrodynamic Channel Flows (2007). He received the NSF Career, ONR YI, PECASE, and the UCSD Research Award, the Axelby and Schuck paper prizes, and is a Fellow of IEEE and Distinguished Lecturer of the Control Systems Society.

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