Event Location: NSH 1305
Bio: Todd Murphey received his undergraduate degree in mathematics from the University of Arizona and a Ph.D. in Control and Dynamical Systems from the California Institute of Technology. He was a postdoctoral scholar at Northwestern University for a year, after which he worked for the Aerospace Corporation in the Electro-Mechanical Control Department. He was an Assistant Professor of Electrical and Computer Engineering at the University of Colorado at Boulder from 2004 to 2008 and is now an Assistant Professor of Mechanical Engineering at Northwestern University. He is a recipient of a National Science Foundation CAREER award.

Abstract: Physical sensing and control often involves switching in the governing equations of motion. For instance, skid-steered vehicles must violate nonholonomic constraints in order to maneuver. This sliding of the wheel against the ground causes the vehicle to behave discontinuously during a maneuver as well as making the vehicle’s state difficult to estimate. Choreography for dancers can be viewed as a motion description language, where each element of the choreography corresponds to a different set of dynamics governing the system evolution. Both examples are naturally represented as hybrid systems, and control can be viewed in terms of hybrid optimal control over the space of all possible choreographic behaviors. I will show how both first-order and second-order optimization techniques can be employed, even in the presence of significant noise. Moreover, because of the quadratic convergence associated with second-order methods, one can implement these techniques in real-time settings. Lastly, I will discuss challenges in software implementation of these ideas and how these hybrid optimization techniques are being applied to robotic marionettes in a project with Disney Imagineering.