Day: October 28, 2013

MEEM Graduate Seminar: Guaranteeing Accurate Decoupled Approximations Via Structural Design

The Department of Mechanical Engineering – Engineering Mechanics Graduate Seminar; Thursday, Oct. 31, 2013 4:00 – 5:00 p.m. Room 112, ME-EM Bldg.;
Professor Cornel Sultan, Aerospace and Ocean Engineering Department, Virginia Tech

Title: Guaranteeing Accurate Decoupled Approximations Via Structural Design

Coordinate coupling raises serious modeling, numerical, analysis, control
design problems that grow with the size of the system. Decoupled dynamic equations
facilitate all of the above processes since each equation can be treated independently.
Unfortunately, due to the inherent heterogeneity typical of most practical, complex
systems, these are not naturally decoupled so developing sufficiently accurate
decoupled approximations is of major interest.
In this talk the issue of building such accurate decoupled approximations is
addressed by leveraging concepts from control theory. Specifically, system gains (e.g.
energy gain, peak to peak gain) are used to characterize the approximation error. Then
some system parameters are selected to minimize this approximation error. The
advantage of using system gains is that the decoupling approximation is guaranteed to
be accurate over an entire class of signals (e.g. finite energy/finite peak signals).
These ideas are illustrated on tensegrity structures which are designed to yield
accurate decoupled linear models with respect to all signals of finite energy and finite
peak. Further analysis corrects several misconceptions regarding decoupling, system
properties, and control design.

Cornel Sultan holds M.S. in Mathematics, Ph.D. in
Aerospace Engr. from Purdue University (1999) and
has been affiliated, among others, with Harvard
Medical School and United Technologies Research
Center. Currently he is an Assistant Prof. in the
Aerospace and Ocean Engineering Department at
Virginia Tech where his principal research activities
are in tensegrity, membranes, rotorcraft, energy
harvesting, and coordinated control. He received a
NSF CAREER Award in 2010.