Principle of Dynamical Balance for Multibody Systems

A new formulation for multibody system dynamics is developed based on the concept of dynamical balance. In particular, we address the problem how to compose two known subsystem dynamics to generate the equations of motion for a composite system. The principle states that dynamical balance should hold between two subsystems, or the so-called d'Alembertian wrenches and torques of two subsystems should balance each other, for composite systems. The notion of body twists and wrenches is utilized to describe the principle. According to the principle, the dynamical balance condition is obtained just by taking the dual expression of the kinematical constraint in terms of the d'Alembertian wrenches and torques of subsystem dynamics. This work was supported by the Korea Research Foundation Grant (KRF-2003-003-D00015).