ABSTRACT
After retirement from the aerospace industry I began a project to revisit the subject of rigid body dynamics. My objective and purpose was to arrange the ideas of the subject into what I considered to be a rational, operational framework consistent with my experience and with my own thought processes. This effort focused mainly on the fundamental problem of generating differential equations of motion.
The differential equations of motion for a single body are of course developed from Euler's two laws of motion for bodies of extension. As the work evolved it became clear to me that understanding how to describe body displacement was invaluable in describing kinematics not only for a single body but also for a system of bodies. That is, the displacement function provides a consistent, rational means for incorporating desired constraints. This is done in a way that eliminates workless constraint forces and moments from the system differential equations of motion. This is of particular concern in multibody systems.
The work is not complete but rather suggests an approach that I believe is rational and practical; it is documented and is available through the link below.
The paper has not been peer reviewed. Any comments will be appreciated.