Abstract
This paper presents a basic formulation of motion dynamics of free-floating link systems, to establish a basis of the collision dynamics. The authors propose a new concept named “Extended Inversed Inertia Tensor (Ex-IIT) ”, which is an extended version of the IIT for ground-based arms, and discuss the virtual mass concept. By means of the concepts, they formulate the collision problem focusing on a velocity relationship just before and after the collision without sensing the impact force, but considering the momentum conservation law. The validity of the formulation is confirmed by a simple free-floating experiment.