Coordinated Control of a Free-floating Space Robot for Capturing a Target

Aiming at the target capturing task, in order to improve the control efficiency and save the fuel, some methods are proposed to realize the coordinated motion between the manipulator and its base under the free-floating mode, only using the control of the manipulator itself. Firstly, typical control tasks of autonomous target capturing are analyzed. Correspondingly, the control purpose and its requirement for the degrees of freedom of the manipulator are determined. Then, differential kinematics equations for target capturing, visual monitoring and position tracking missions are established under the free motion and attitude stabilization/adjustment of the base. These kinematics equations are expressed in a unified form, based on which resolved motion rate control methods are used to attain the control objectives. Finally, a simulation system is developed to verify the proposed methods. The simulation results demonstrate the effectiveness of the proposed methods.