  This paper investigates adaptive zero reaction motion control for
free-floating space manipulators with uncertain kinematics and dynamics. The
challenge in deriving the adaptive reaction null-space (RNS) based control
scheme is that it is difficult to obtain a linear expression, which is the
basis of the adaptive control. The main contribution of this paper is that we
skillfully obtain such a linear expression, based on which, an adaptive version
of the RNS-based controller (referred to as the adaptive zero reaction motion
controller in the sequel) is developed at the velocity level, taking into
account both the kinematic and dynamic uncertainties. It is shown that the
proposed controller achieves both the spacecraft attitude regulation and
end-effector trajectory tracking. The performance of the proposed adaptive
controller is shown by numerical simulations with a planar 3-DOF
(degree-of-freedom) space manipulator.
