Abstract: A composite attitude controller for the base and the manipulator is designed for a free-flying space robot via the backstepping method. The controller ,which feeds back the position and orientation of the manipulator tip in workspace, joint angle and speed in joint space, attitude and velocity of the base, can fulfill the task in workspace directly, avoiding the motion planning from workspace to joint space and complicated differentiating of Jacobian matrix. Meanwhile, attitude control of the base can extend the capacity of space robot and improved the character of dynamical singularity. Finally, the numerical simulation of a free-flying space robot validates the controller.

Key words: free-flying space robot, modeling, backstepping control