Minimal-Coordinate Kinematical Formulations in Multibody Systems and Their Application to Engineering and Biomechanics Problems
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Minimal-Coordinate Kinematical Formulations in Multibody Systems and Their Application to Engineering and Biomechanics Problems
Fri, 11/09/2015 - 16:30 to 17:15
Location:
Speaker:
Prof Andrés Kecskeméthy
Affiliation:
University of Duisburg-Essen, Germany
Synopsis:
The efficient analysis and processing of kinematics is an important tool for many applications, ranging from engineering problems to new challenges in biomechanics. Examples are the structural and dimensional synthesis of mechanisms, the generation of real-time dynamics codes, up to the efficient modeling of biomechanical interactions in human gait motion. In this talk, two examples of minimal-coordinate kinematical approaches in multibody analysis and biomechanics are discussed, showing their potentials to tackle non-trivial research problems.
As a first example, a particular interpretation of multiloop mechanisms as systems of coupled kinematical loops – termed the kinematical network – is presented. By this concept, closed-form solutions can be generated for many practical cases, which allow one (a) to produce highly efficient codes for the dynamical equations, including mixed subsystems of differing subgroup dimensionality in SE(3), such as planar, cylindrical and spherical motions, and (b) to resolve open challenges in structural rigidity detection, such as the double banana or the 7-roof problem of nucleationfree mechanisms. By embedding the ensuing relative kinematics in an abstract differential-geometric setting, the main operations of reduction to minimal coordinates for the dynamical equations are shown to be representable by generic mappings between manifolds and their tangent and cotangent spaces as well as their metrics, yielding the different methodologies for generation of the dynamical equations as ``flavors’’ of the generic mappings in an object-oriented framework. This is also shown to be useful for the problem of interpolation and optimization of motion in 3D space under dynamical effects, as applicable for example to roller-coaster layout, time-optimal path planning, optimal skiing motion, and reconstruction of the human spine motion from camera-tracked skin markers.
As a second example, some novel minimal-coordinate approaches for the efficient biomechanical modeling of the human musculoskeletal system will be presented. These include a novel approach for the real-time computation of musculotendon paths using geodesic variations as well as a holonomic foot-ground contact model for forward dynamic simulations. With these, direct feedback of musculoskeletal motion in clinical settings becomes more reachable, as will be shown with our object-oriented biomechanics simulation environment.
Biography:
Professor Andrés Kecskeméthy is the Chair for Mechanics and Robotics at the Institute of Mechatronics and System Dynamics in the University of Duisburg-Essen, Germany. He is currently Editor-In-Chief of the Journal Mechanism and Machine Theory and Associate Editor of the Journal Multibody System Dynamics.
Dr Kecskeméthy graduated from the University of Stuttgart in Mechanical Engineering in 1984 and received his Ph.D. in Mechanical Engineering from the University of Duisburg in 1993, both with distinction. From 1994 to 1995, he stayed as a senior guest researcher at the Centre for Intelligent Machines at McGill University with a fellowship from the German Research Foundation (DFG). In 1996, Dr. Kecskemethy was appointed Professor at the Technical University of Graz, where he held the Chair for Mechanics until 2002. In 2002, Professor Kecskeméthy moved to the University of Duisburg-Essen as the Chair for Mechanics and Robotics. Dr Kecskemethy served as Dean of the Faculty of Engineering and as Chairman of the Senate of the University Duisburg-Essen. His memberships include the German Engineering Association VDI and the International Federation for the Promotion of Mechanism and Machine Science, where he is since 2013 Chairperson of the IFToMM Germany Member Organization. Dr Kecskemethy has organized the 5th International Workshop on Computational Kinematics (CK 2009) in Duisburg, Germany and the 1st and 2nd International Conferences on Interdisciplinary Applications in Kinematics (IAK 2008 and IAK 2013) in Lima, Peru.
Dr Kecskeméthy has worked in the areas of kinematics and dynamics of multibody systems, covering topics such as modelling and control of mechatronic systems, vehicle dynamics, design of legged machines, biomechanics of human motion, virtual reality design environments and heavy-weight robotics. In these areas, he has authored or co-authored more than 200 proceedings and journal papers, and has secured over the past years several research funds for engineering and biomechanics projects. Dr Kecskemethy and his co-workers have designed the C++ object-oriented multibody library “Mobile” for industrial applications and its specialisation “MobileBody” for biomechanics of musculoskeletal motion, as well as the symbolic closed-form multibody mechanisms code generator SymKin.