Quaternion based computed-torque and feed-forward tracking controllers for a space robot

This paper presents both a quaternion based computed-torque trajectory tracking controller and a feed-forward trajectory tracking controller for a two-link space robot. First, the general form of the dynamical equations for a space robot modeled with quaternions is presented. The computed-torque controller is then presented and the stability of the resulting closed-loop system is analyzed via the second method of Lyapunov. This is followed by a discussion of the feed-forward controller. Tracking simulations are then presented and analyzed.