Mode shape compensator for improving robustness of manipulator mounted on flexible base

In this paper, the concept of the 'robust arm configuration' (RAC) is expanded using a mode shape compensator. This compensator improves the robustness of the arm configuration which is far out of the RAC. The compensator consists of a constant gain matrix and acceleration of each joint. The design method for this mode shaping matrix is presented based on the mode shaping algorithm. Effect upon the manipulability is also examined. It suggests that inclining of DME's principal axes, resulting in changing the rigid body dynamics, by the compensator leads to the improvement of the robustness. The validity is confirmed by a numerical example performed with a 2 DOF planar manipulator mounted on a 1 DOF flexible base. A high bandwidth settling is realized with obtained compensator.