Several position identification methods have been used for mobile robots. We propose a new method called "cooperative positioning system (CPS)". For CPS, we divide the robots into two groups, A and B. The group A remains stationary and acts as a landmark while group B is moving. Group B then stops and acts as a landmark for group A. This "dance" is repeated until the target position is reached. By using the concept of "portable landmarks", CPS has a far lower accumulation of positioning error than dead reckoning, and can work in three-dimensions which is not possible with dead reckoning; it can therefore work in uncharted environments. In this paper we outline the second prototype CPS machine model (CPS-II) and report the results of position identification experiments. Experimental results using this model give a positioning accuracy of o.4% for position and 1.0 degree for attitude.

Investigates impact dynamics among free-floating multibody systems in space, by developing an extended inertial tensor concept, and establishes the theoretical basis for floating chain collisions. The authors have developed a concept named an 'extended inversed inertia tensor' (Ex-IIT), paying attention to free-floating behavior in the space environment. They apply Ex-IIT to impulse minimization arguments. To illustrate the magnitude of the impulses caused by link collisions in various conditions, the concepts of 'impulse index' and 'impulse ellipsoid' are introduced. By means of these concepts, the authors discuss the relationship of the impulse to collision directions and link postures, in order to determine the condition minimizing the impulse.

The authors present a basic formulation of motion dynamics of a free-floating rigid-link system to establish a basis of the collision dynamics. They propose a novel concept named extended generalized inertia tensor (Ex-GIT), which is an extended version of the GIT for ground-based arms, and discuss the virtual mass concept. By means of these 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.>