Simplification of inverse kinematics routine of robot manipulators using disturbance observer in task space

The authors propose a simple high-performance control strategy based on disturbance compensation by the disturbance observer in task space. The disturbance observer makes robot manipulators linear in task space and realizes acceleration control. The inverse kinematics routine can be simplified, because the disturbance observer compensates not only the disturbance but also the error due to the simplification of the inverse kinematics routine. The strategy was applied to a three-degree-of-freedom direct drive robot to show its effectiveness experimentally