This award is for support of a joint research project, in the area of dynamics and control of flexible multibody systems, by Dr. Ahmed Shabana, Department of Mechanical Engineering, University of Illinois, Chicago, Illinois and Dr. Said M. Megahed, Department of Mechanical Design and Production, Cairo University, Cairo, Egypt. The focus of the research will be on the non-linear coupling between the small and large deformation and the control forces in complex multibody systems by utilizing a full finite element representation instead of the usual modal description. The absolute coordinate formulation proposed by Shabana will be used for the motion control of flexible systems. A full finite element representation is obtained for the flexible body in terms of global displacement and slope coordinates. Using this representation, small and large deformation problems can be easily solved, and the phenomena of wave propagation of the control forces in very flexible multibody components can be efficiently captured. Because of the nature of the coordinates used in this new procedure, the development of a systematic methodology for the control of very flexible structures that undergo large rotations becomes feasible. The coupling between the control forces and the large deformation in high-speed very flexible systems will be examined analytically and numerically, and the potential of using piezo-electric actuators in the control of these structures where inertial effects are significant will be explored. Flexible robotic systems will be used as the primary application in this research.
Scope: This award will allow a US scientist and a US graduate student to collaborate with Egyptian scientists in a project that deals with an important problem. The US scientist, Dr. Shabana will carry out the modeling, while Dr. Megahed will conduct the experimental study at Cairo University. The PIs have an outstanding track record and their areas of expertise are well matched. Dr. Shabana has extensive expertise in the study of multi-body dynamical systems, and is an authority in the field of dynamics of coupled nonlinear structures. Dr. Magahed's expertise in robotic systems is a definite advantage to the specific system in the study. The impact of the study can be extremely significant from the fundamental and applied research points of view. The impact will be on the fundamental modeling issues, the design issues, and ranges of commercial applications and on the collaboration between the two countries. The proposed effort offers the possibility of significant improvement in the way flexible bodies are added to multi-body dynamics codes. This proposal meets the INT objective of supporting US-foreign scientific collaboration in areas of mutual benefit.
