Day 1 :
Georgia Institute of Technology, USA
Daniel P Schrage had a distinguished career in three different fields. 1) As a military officer and commander in nuclear weapons in Europe and in combat aviation
systems operations in Southeast Asia; 2) As an Engineer, Manager and Senior Executive in the Science & Technology development, design and production of all
of today’s complex Army aviation systems, e.g. UH-60 Black Hawk, AH-64 Apache and CH-47 Chinook; and 3) As a Professor, Director and advisor/ consultant
to government & industry from academia. He has obtained BS Engineering degree from USMA in 1967; MS in AE from Georgia Tech in 1974; MA in Bus Admin,
from Webster U in 1975 and a DSc in Mechanical and Aerospace Engineering from Washington U in 1978. He has over 100 publications, including many refereed
papers and book chapters.
Functional Safety Methods (FSM) have been developed and implemented for different domains of complex systems over
the past 30 years. However, as mech-aero systems have become more complex with the integration of cyber and physical
systems, there is a need to revisit and evolve these FSM methods for the successful co-design of Cyber Physical Vehicle Systems
(CPVS). This presentation will describe how this evolution of FSM for civil aircraft and systems development has taken place
over the past decade by using a Development Assurance (DA), rather than a Qualification Assurance (QA) approach. It
will then describe how the DA approach can be and should be applied for certification of military complex CPVS and for
Unmanned Aerial Systems (UAS), both with civil and military application.
Columbia University, USA
Time : 10:00-10:30
Richard W. Longman is professor of mechanical and of civil engineering, Columbia University, and was Distinguished Romberg Guest Professor, University of Heidelberg, Germany. He received a 50,000 Euro Award for lifetime achievement in research from the Alexander von Humboldt Foundation, and the Dirk Brouwer Award from the American Astronautical Society (AAS) for contributions to spaceflight mechanics. He is Fellow of AAS and AIAA. He served the AAS as Vice President - Publications, VP Technical, First Vice President, and Member Board of Directors. His PhD is from the University of California, San Diego. Professor Longman has coauthored approximately 450 publications.
The actuators for spacecraft attitude control systems usually use reaction wheels or control moment gyros (CMG’s). Slight imbalance in the wheels produces spacecraft jitter that adversely affects pointing accuracy. The new field of satellite laser communication between spacecraft and between spacecraft and ground, pushes the importance of effective methods for addressing the resulting jitter. NASA JPL has developed a high-precision laser system that can span interplanetary distances with millimeter accuracy that can help send messages at high data rates at large interplanetary distances. The LADEE spacecraft recently accomplished at “record shattering” data download rate of 622 megabits per second from the moon. The field of repetitive control is specifically designed to learn to cancel periodic disturbances to control systems. It can be applied to the mirror of the outgoing laser to learning to adjust pan and tilt to cancel the influence of jitter on laser pointing. This presentation examines the issues and methods involved in adjusting the parameters of repetitive control systems to eliminate the maximum amount of jitter from the beam.
Air Force Institute of Technology, USA
Time : 10:30-11:00
Two objectives dominate consideration of control moment gyroscopes (CMGs) for spacecraft maneuvers: High torque (or equivalently momentum) and singularity-free operations. Utilizing a 3/4 CMG skewed-pyramid the optimal singularity-free configuration is revealed. Next, this presentation develops a decoupled control strategy to reduce the remaining singular conditions. Analysis and simulation is provided to justify the argument with experimental verification performed on a free-floating satellite simulator. Furthermore, a singularity penetration algorithm is developed, simulated, and experimentally proven to fly through singularities even without singularity reduction.
Timothy Sands completed his PhD at the Naval Postgraduate School and postdoctoral studies at Stanford University and Columbia University. He is Dean and Senior Military Professor at the Air Force Institute of Technology. He has published research in archival journals, conference proceedings, a book chapter, in addition to keynote and invitational presentations.
University of California, San Diego, USA
Time : 11:50-12:20
Robert Skelton is Professor emeritus at UCSD and a TIAS Faculty Fellow at Texas A&M. He is a member of the National Academy of engineering, a member of the Thomas Green Clemson Academy of Science, a Fellow of AIAA and IEEE, and a joint recipient of the Norman Medal from ASCE. He has awards from the Japanese society from the Promotion of Science, the Alexander von Humboldt Foundation. He held the Russell Severance Springer Chair at UCB. Of his 5 books, the most recent are Tensegrity Systems (with de Oliveira) and A Unified Algebraic Approach to Linear Control Design (with Iwasaki and Grigoriadis).
Form-finding is a nonconvex problem, where a specified variety of structural members may fill a space, but the connections and the nodes are free to be optimized to achieve a specified shape or mechanical property. Tensegrity structures are prime examples of these types of topology optimization problems. From the static equations characterizing all equilibria, it is common to try to solve the nonlinear problem of finding the forces in the members and finding the node locations that globally minimizes mass, subject to yield or buckling constraints. There is helpful information missing in this formulation of the problem. The kinematics and dynamics show how the natural motion must move from one configuration to another, and control theory allows one to use that information to solve a form-finding problem by dynamic relaxation.