Dual-Quaternion Tracking Loops for Spacecraft Screw Motion

This paper is concerned with pose and pose rate control of a rigid body. The proposed control approach contains an inner loop that tracks the desired pose rate command and an outer loop that tracks the desired pose command. The control algorithm uses the unit dual quaternion as a measure of pose errors to achieve tracking via instantaneous screw motion. The resulting tracking error equation is directly related to the screw motion parameters and can be used to determine the controller gains. The paper discusses the stability of the new algorithm and presents its performance via simulation.