Workspace and Manipulability Analysis of Space Manipulator

Abstract

This paper investigates operational performance of space manipulators installed on a free-flying robot satellite, by difining and analyzing its workspace and manipulability measure. The one-to-one correspondence is not found between joint space and inertial task space in space free-flying manipulators, therefore, their workspaces should be defined with some additional restrictions on a base satellite motion or an operation path of manipulator hand. According to these conditions, the authors classify and define five types of workspaces, which are new and important concept for operating space manipulators. A manipulability measure is defined by the generalized Jacobian matrix, which describes kinematic and dynamic property of a space free-flying manipulator. The manipulability of space manipulators is evaluated lower than that of ground-fixed manipulators, because it is reduced by dynamical coupling between the manipulator motion and the base satellite. Operation posture and configuration design problems for a two dimensional robot satellite model are discussed with respect to wide workspace and high manipulability.