RESEARCH Professor Paden's research is directed at understanding the dynamics and control of electromechanical systems. Applications of interest are biomedical systems, precision machine control, control of flexible robots, MEMS, and magnetic bearings. A substantial fraction of his research deals with theoretical developments in nonlinear tracking control. Nonlinear control of periodic motions by methods known as repetitive controllers and learning controllers is one current topic. Applied research is focused on robust design and control of MEMS oscillators, and the control of artificial hearts, and biomedical systems, is an emerging research activity in Professor Paden's group. Research Projects: 1) Dynamic Models for Electrodynamic Suspended Magnetic Levitation (NSF CMS-0220386). This project applies mathematical analysis to investigate the dynamic propoerties of electrodynamic suspension (EDS) mag-lev systems. The ojectives are to develop, validate, and analyze dynamical models for EDS on perforated track; investigate fundamental limitations of the proposed technology, and facility cost-effective engineering designs. 2) Theory of Nonlinear Repetitive and Learning Control Algorithms (NSF). This is a theoretical project dealing with the control of nonlinear periodic systems. Stability and performance of control algorithms are under study using dynamical system concepts, and infinite-dimensional Newton-type algorithms. Applications included micro-positioning systems, noncircular machining, and cardiovascular control. 3) Design and control of artificial heart-assist devices. In contrast to total artificial hearts, heart-assist devices are becoming viable therapies. Dr. Paden participates in a number of design teams in the design of magnetically-suspended left-ventricular assist devices (LVAD's) intended for use as long-term medical implants. These LVAD's are sophisticated electromechanical devices and pose many challenging research problems in mechatronics, control system design, magnetic levitation, and physiologic control.