COORDINATION OF MOTION IN A SPACECRAFT MANIPULATOR SYSTEM

A control scheme for the coordination of motion in a space-craft/manip ulator system is presented. It is shown how end-effector motion can be decoupled from satellite motion, satellite rotation, or total system momentum by selecting suitable generalized speeds for the satellite. T he schemes are based on recursive calculation of kinematics and dynami cs, and 12 degrees of freedom can be controlled without excessive comp utational effort. Feedback linearization and decoupling of end-effecto r motion and total system momentum are discussed in detail. The satell ite controller can then be developed independently of the manipulator controller and reaction jets and momentum wheels are used only to repo sition the satellite. The end effector can be controlled accurately wi th a high bandwidth, while a slow, gross positioning can be used for t he satellite. The resulting controller is very efficient in terms of f ueL The spacecraft/manipulator system is regarded as a redundant manip ulator of the macro-micro type with 12 degrees of freedom, and a redun dancy resolution scheme based on the augmented task space approach is used to generate the position and orientation reference for the spacec raft. The proposed controller was simulated with a 12-degrees-of-freed om model that was generated with a recursive formulation of the Jacobi ans. The results are presented in this article.