VELOCITY-LEVEL KINEMATICS OF THE ATLAS SPHERICAL ORIENTING DEVICE USING OMNI-WHEELS

Abstract

Using a novel actuation concept employing omni-directional wheels (or simply omni-wheels), the Atlas simulator motion platform provides unlimited angular displacement about any axis. The Atlas concept completely decouples the orienting and positioning degrees-of-freedom and further decouples each of the positioning degrees-of-freedom. It consists of an omni-wheel driven sphere for orientation that has its geometric centre positioned by an $XYZ$-table. The Jacobian of the orienting device is independent of time and dependent only on the mechanism architecture, meaning that it is always invertible for any configuration provided that the initial design parameters do not result in architecture singularities. An examination of the Atlas Jacobian and its determinant identifies architecture singular design conditions. It is found that these are not design limiting. Discussion highlights the uniqueness of the Atlas concept and its associated kinematic advantages.