Robust attenuation of direct-drive robot-tip vibrations

This paper suggests and employs a method for reducing vibrations at the tip of a robot. The vibrations, caused by structural flexibility, are detected using accelerometers. The robot control system consists of two complementary sub-systems: a nominal motion controller and a vibration compensator. The former one realizes joint motions in accordance with a prescribed tip trajectory. The latter one robustly attenuates oscillations at the tip that are due to structural flexibility. The benefits of this set-up are experimentally verified for a spatial directdrive robot with 3 revolute degrees of freedom.