Real Time Integration Methods For Mechanical System Simulation

This book contains the edited versions of lectures and selected contributed papers presented at the NATO Advanced Research Workshop on Real-Time Integration Methods For Mechanical System Simulation, held in Snowbird, Utah, August 7-11, 1989. The Institute was attended by 42 participants from 9 countries, including leading mathematicians and engineers from universities, research institutions, and industry. The majority of participants presented either invited or contributed papers during the Institute, and everyone participated in lively discussions on scientific aspects of the program. The Workshop provided a forum for investigation of promising new directions for solution of differential-algebraic equations (DAE) of mechanical system dynamics by mathematicians and engineers from numerous schools of thought. The Workshop addressed needs and opportunities for new methods of solving of DAE of mechanical system dynamics, from the perspective of a broad range of engineering and scientific applications. Among the most exciting new applications addressed was real time computer simulation of mechanical systems that, for the first time in human history, permits operator-in-the-Ioop simulation of equipment that is controlled by the human; e.g., driving a vehicle, operating a space telerobot, operating a remote manipulator, and operating construction equipment. The enormous potential value of this new application and the fact that real-time numerical integration methods for DAE of mechanical system dynamics is the pacing problem to be solved in realizing this potential served to focus much of the discussion at the Workshop.

Multibody systems are used extensively in the investigation of mechanical systems including structural and non-structural applications. It can be argued that among all the areas in solid mechanics the methodologies and applications associated to multibody dynamics are those that provide an ideal framework to aggregate d- ferent disciplines. This idea is clearly reflected, e. g. , in the multidisciplinary applications in biomechanics that use multibody dynamics to describe the motion of the biological entities, in finite elements where multibody dynamics provides - werful tools to describe large motion and kinematic restrictions between system components, in system control where the methodologies used in multibody dynamics are the prime form of describing the systems under analysis, or even in many - plications that involve fluid-structure interaction or aero elasticity. The development of industrial products or the development of analysis tools, using multibody dynamics methodologies, requires that the final result of the devel- ments are the best possible within some limitations, i. e. , they must be optimal. Furthermore, the performance of the developed systems must either be relatively insensitive to some of their design parameters or be sensitive in a controlled manner to other variables. Therefore, the sensitivity analysis of such systems is fundamental to support the decision making process. This book presents a broad range of tools for designing mechanical systems ranging from the kinematic and dynamic analysis of rigid and flexible multibody systems to their advanced optimization.

This book contains the edited version of the lectures presented at the NATO ADVANCED STUDY INSTITUTE on "COMPUTER AIDED ANALYSIS OF RIGID AND FLEXIBLE MECHANICAL SYSTEMS". held in Troia. Portugal. from the 27 June to 9 July. 1993. and organized by the Instituto de Engenharia Mecanica. Instituto Superior Tecnico. This ASI addressed the state-of-art in the field of multibody dynamics. which is now a well developed subject with a great variety of formalisms. methods and principles. Ninety five participants. from twenty countries. representing academia. industry. government and research institutions attended this Institute. This contributed greatly to the success of the Institute since it encouraged the interchange of experiences between leading scientists and young scholars and promoted discussions that helped to generate new ideas and to defme directions of research and future developments. The full program of the Institute included also contributed presentations made by participants where different topics have been explored. Such topics include: formulations and numerical aspects in rigid and flexible mechanical systems; object-oriented paradigms; optimal design and synthesis; robotics; kinematics; path planning; control; impact dynamics; and several application oriented developments in weapon systems. vehicles and crash worthiness. These papers have been revised and will be published by Kluwer in a special issue of the Journal of Nonlinear Dynamics and in a forthcoming companion book. This book brings together. in a tutorial and review manner. a comprehensive summary of current work and is therefore suitable for a wide range of interests.

Mechanical engineering, an engineering discipline born of the needs of the industrial revolution, is once again asked to do its substantial share in the call for industrial renewal. The general call is urgent as we face profound issues of productivity and competitiveness that require engineering solu tions, among others. The Mechanical Engineering Series features graduate texts and research monographs intended to address the need for informa tion in contemporary areas of mechanical engineering. The series is conceived as a comprehensive one that will cover a broad range of concentrations important to mechanical engineering graduate edu cation and research. We are fortunate to have a distinguished roster of consulting editors, each an expert in one of the areas of concentration. The names of the consulting editors are listed on the front page of the volume. The areas of concentration are applied mechanics, biomechanics, computa tional mechanics, dynamic systems and control, energetics, mechanics of material, processing, thermal science, and tribology. Professor Leckie, the consulting editor for applied mechanics, and I are pleased to present this volume of the series: Kinematic and Dynamic Simulation of Multibody Systems: The Real-Time Challenge by Professors Garcia de Jal6n and Bayo. The selection of this volume underscores again the interest of the Mechanical Engineering Series to provide our readers with topical monographs as well as graduate texts. Austin Texas Frederick F. Ling v The first author dedicates this book to the memory of Prof F. Tegerizo (t 1988), who introduced him to kinematics.

The author developed this text over many years, teaching graduate courses in advanced dynamics and flexible multibody dynamics at the Daniel Guggenheim School of Aerospace Engineering of the Georgia Institute of Technology. The book presents a unified treatment of rigid body dynamics, analytical dynamics, constrained dynamics, and flexible multibody dynamics. A comprehensive review of numerical tools used to enforce both holonomic and nonholonomic constraints is presented. Advanced topics such as Maggi’s, index-1, null space, and Udwadia and Kalaba’s formulations are presented because of their fundamental importance in multibody dynamics. Methodologies for the parameterization of rotation and motion are discussed and contrasted. Geometrically exact beams and shells formulations, which have become the standard in flexible multibody dynamics, are presented and numerical aspects of their finite element implementation detailed. Methodologies for the direct solution of the index-3 differential-algebraic equations characteristic of constrained multibody systems are presented. It is shown that with the help of proper scaling procedures, such equations are not more difficult to integrate than ordinary differential equations. This book is illustrated with numerous examples and should prove valuable to both students and researchers in the fields of rigid and flexible multibody dynamics.

The book presents a new scientific approach to the problem of biomechanical systems description. This approach is based on development of a universal anthropomorphic model and employment of methodology of imitational dynamic modeling (IDM). The novelty of this approach is that there appears a possibility to operate with a whole class of models, derived from the universal model on the basis of motion separation principle. This is followed by utilization of iterational procedures realizing the method of successive approximations and resulting in description of the real motion with the pre-set accuracy level. By use of the IDM there has been for the first time ascertained certain laws governing human locomotions: presence of so-called controlling and stabilizing interlink moments, wavelike speeding of forces extremums along the kinematic chain, adaptation of control functions for astronauts motion coordination preservation. The book includes new theoretical conceptions explaining the deterioration of functional state of skeletal-muscular apparatus of astronauts due to zero-gravity influence. Contents:Human Motion ModellingMathematical Anthropomorphic ModelsThe Imitational Modelling AttributesAnalysisSynthesis Readership: Researchers, graduate and postgraduate students in biomechanics, applied mathematics and medical sciences. keywords:Human Motion Modelling;Anthropomorphic Mechanism;Biomechanics;Simulation;Mixed Dynamics;Forward Dynamics;Multibody System;Numerical Optimization

The chapters of this book summarize the lectures delivered du ring the NATO Advanced Study Institute (ASI) on Computational Methods in Mechanisms, that took place in the Sts. Constantin and Elena Resort, near Varna, on the Bulgarian Coast of the Black Sea, June 16-28, 1997. The purpose of the ASI was to bring together leading researchers in the area of mechanical systems at large, with special emphasis in the computational issues around their analysis, synthesis, and optimization, during two weeks of lectures and discussion. A total of 89 participants from 23 count ries played an active role during the lectures and sessions of contributed papers. Many of the latter are being currently reviewed for publication in specialized journals. The subject of the book is mechanical systems, Le. , systems composed of rigid and flexible bodies, coupled by mechanical means so as to constrain their various bodies in a goal-oriented manner, usually driven under computer con trol. Applications of the discipline are thus of the most varied nature, ranging from transportation systems to biomedical devices. U nder normal operation conditions, the constitutive bodies of a mechanical system can be consid ered to be rigid, the rigidity property then easing dramatically the analysis of the kinematics and dynamics of the system at hand. Examples of these systems are the suspension of a terrestrial vehicle negotiating a curve at speeds within the allowed or recommended limits and the links of multiaxis industrial robots performing conventional pick-and-place operations.

These proceedings contain lectures presented at the NATO Advanced Study Institute on Concurrent Engineering Tools and Technologies for Mechanical System Design held in Iowa City, Iowa, 25 May -5 June, 1992. Lectures were presented by leaders from Europe and North America in disciplines contributing to the emerging international focus on Concurrent Engineering of mechanical systems. Participants in the Institute were specialists from throughout NATO in disciplines constituting Concurrent Engineering, many of whom presented contributed papers during the Institute and all of whom participated actively in discussions on technical aspects of the subject. The proceedings are organized into the following five parts: Part 1 Basic Concepts and Methods Part 2 Application Sectors Part 3 Manufacturing Part 4 Design Sensitivity Analysis and Optimization Part 5 Virtual Prototyping and Human Factors Each of the parts is comprised of papers that present state-of-the-art concepts and methods in fields contributing to Concurrent Engineering of mechanical systems. The lead-off papers in each part are based on invited lectures, followed by papers based on contributed presentations made by participants in the Institute.