US-Egypt Cooperative Research: Large Deformation Dynamics and Controls

9820069Shabana描述：该奖项是为了表彰由伊利诺伊大学芝加哥分校机械工程系Ahmed Shabana博士和埃及开罗大学机械设计与生产系Said M.Megahed博士在柔性多体系统动力学和控制领域联合开展的研究项目。研究的重点将是复杂多体系统的大、小变形与控制力之间的非线性耦合，用完整的有限元表示代替通常的模态描述。将Shabana提出的绝对坐标公式用于柔性系统的运动控制。得到了柔性体在整体位移和斜率坐标下的完整有限元表示。利用这种表示法，可以很容易地解决大变形和小变形问题，并可以有效地捕捉控制力在非常灵活的多体部件中的波动传播现象。由于这一新程序中使用的坐标的性质，开发一种系统的方法来控制经历大旋转的非常灵活的结构变得可行。对高速超柔性系统中控制力和大变形之间的耦合进行了解析和数值分析，并探讨了在惯性效应较大的结构中使用压电式执行器进行控制的可能性。柔性机器人系统将作为本研究的主要应用。范围：该奖项将允许一名美国科学家和一名美国研究生与埃及科学家在一个处理一个重要问题的项目中进行合作。美国科学家沙巴纳博士将进行建模，而梅加德博士将在开罗大学进行实验研究。私人投资总监有着出色的记录，他们的专业领域也很匹配。沙巴纳博士在多体动力学系统研究方面拥有丰富的专业知识，是耦合非线性结构动力学领域的权威。马加德博士在机器人系统方面的专业知识对这项研究中的特定系统来说是一个明确的优势。从基础研究和应用研究的角度来看，这项研究的影响可能是极其重大的。这将对基本的建模问题、设计问题、商业应用的范围以及两国之间的合作产生影响。拟议的工作提供了在将柔体添加到多体动力学代码中的方式方面进行重大改进的可能性。这项建议符合INT的目标，即支持美国和外国在互利领域的科学合作。

9820069ShabanaDescription: 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.