Kinematics and control of a space manipulator using the macro-micro manipulator concept

A control scheme for the coordination of motion in a spacecraft/manipulator system is presented. The augmented task-space approach is used for feedback linearization and decoupling of the system, and it is shown how end-effector motion can be decoupled from satellite motion, satellite rotation, or total system momentum by selecting suitable coordinates to represent the motion of the satellite. The schemes are based on recursive calculation of kinematics and dynamics, and 12 degrees-of-freedom can be controlled without excessive computational effort. Feedback linearization and decoupling of end-effector motion and total system momentum are discussed in detail. The satellite controller can then be developed independently of the manipulator controller, and reaction jets and momentum wheels are used only to reposition the satellite. The spacecraft-manipulator system is regarded as a redundant manipulator of the macro-micro type, and a redundancy resolution scheme is used to generate the position reference for the spacecraft. The proposed controller was simulated with a 12-degrees-of-freedom model which was generated with a recursive formulation of Jacobians and the dynamics, and the results are presented