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We propose a nonlinear hybrid dual quaternion feedback control law for multibody spacecraft-mounted robotic systems (SMRSs) pose control. Indeed, screw theory expressed via a unit dual quaternion representation and its associated algebra can be used to compactly formulate both the forward (position and velocity) kinematics and pose control of [Formula: see text]-degree-of-freedom robot manipulators. Recent works have also established the necessary theory for expressing the rigid multibody dynamics of an SMRS in dual quaternion algebra. Given the established framework for expressing both kinematics and dynamics of general [Formula: see text]-body SMRSs via dual quaternions, this paper proposes a dual quaternion control law that achieves simultaneous global asymptotically stable pose tracking for the end effector and the spacecraft base of an SMRS. The proposed hybrid control law is robust to chattering caused by noisy feedback and avoids the unwinding phenomenon innate to continuous-based (dual) quaternion controllers. Additionally, an actuator allocation technique is proposed in the neighborhood of system singularities to ensure bounded control inputs, with minimum deviation from the specified spacecraft base and end-effector trajectories during controller execution. 

Space-mounted robotics is becoming increasingly mainstream for many space missions. The aim of this article is threefold: first, to give a broad and quick overview of the importance of spacecraft-mounted robotics for future in-orbit servicing missions; second, to review the basic current approaches for modeling and control of spacecraft-mounted robotic systems; and third, to introduce some new developments in terms of modeling and control of spacecraft-mounted robotic manipulators using the language of hypercomplex numbers (dual quaternions). Some outstanding research questions and potential future directions in the field are also discussed.