Kinematics, dynamics and design of a spherical positioning robot for satellite tracking and other applications.

Abstract

In order to avoid the keyhole problems associated with the current antenna mounting systems and to meet the requirements of target acquisition and tracking for high gain narrow beamwidth antennas, a novel antenna mounting system has been developed. The antenna is mounted on a parallel robot based on the Phillips-Sherwood mechanism that has either two or three degrees of freedom. Unlike conventional mounts this parallel robotic mounting system is able to point an antenna anywhere in the upper hemisphere without encountering singularities. Three other parallel mechanisms that are derivatives of the Phillips-Sherwood mechanism are analysed, and conclusions are drawn about the feasibility of such mechanisms for beam aiming applications. One mechanism in particular appears to offer many advantages, and a robot based on this mechanism may in fact prove to be superior to the first robotic aiming mechanism developed at the University of Canterbury.