FORMULATION AND EFFICIENT COMPUTATION OF INVERSE DYNAMICS OF SPACE ROBOTS

A free-flying space robot is expected to perform various tasks for the construction and maintenance of space structures. Such a robotic system has kinematic and dynamic features that differ from those fixed on the earth mainly because of the momentum constraints that govern its motion. This paper presents the solution to the inverse dynamics problem of a space robotic system, in the presence of external generalized forces. While solving for the inverse dynamics, the computations for the inverse kinematics are considered simultaneously, and both computations are developed on the basis of momentum constraints. An efficient computational scheme for the inverse dynamics problem is then established. We also discuss an intrinsic feature of space robotic systems that can be utilized to reduce the computational time by parallel recursion. We conclude the paper with a discussion on the importance of the role of momentum constraints in the solution of inverse dynamics.