In this paper, we present an experimental evaluation of several link position tracking control algorithms for rigid-link flexible-joint robot manipulators. To study the performance of the controllers, an IMI 2-link direct-drive planar robot manipulator was
modified to approximate linear torsional spring couplings from the actuators to the links. Preliminary experimental results seem to indicate that reduced-order, model-based controllers with an actuator feedback loop provide relatively good link position tracking while a full-order, model-based controller offers some further improvement in link position tracking at the expense of increased computation.