Multibody Dynamics Including Translation between the Bodies - with Application to Head-Neck Systems

Abstract

This report presents new and recently developed concepts which are useful for obtaining and solving equations of motion of multibody mechanical systems with translation between the respective bodies of the system. These concepts are then applied in the study of human/neck systems in high acceleration configurations. The developed concepts include the use of Euler parameters, Lagrange's form of d'Alembert's principle, quasi-coordinates, relative coordinates, and body connection arrays. This leads to the development of efficient computer algorithms for the coefficients of the equations of motion. The developed procedures are applicable to 'chain-link' systems such as finite-segment cable models, mechanisms, manipulators, robots, and human body models. The application with human head/neck models consists of a 54 degree of freedom, three-dimensional system representing the head, the vertebrae, and the connecting discs, muscles, and ligaments. The computer results for the system in a high acceleration configuration agree very closely with available experimental data.