Parasitic torque pulsation suppression in drive train of flexible joint industrial robot

摘要

Lightweight flexible joint robot features complicated eigenfrenquency matrix within control bandwidth, and potential consequence is that resonance vibration can be easily triggered, if not properly handled, so as to degrade the desired path performance. Control techniques based on accurate dynamic model can be adopted to avoid stepping into the minefield based on the assumption that drive train is ideally working with no parasitic disturbance present. But realistic imperfection of motor and gear does exist and the inherent periodical torque pulsation might lead to uncontrollable vibration when its frequency happens to coincide with one of the vibration modes. Such resonance will introduce undesirable path ripple and seriously deteriorate the path accuracy, which is totally unacceptable in continuous path process, especially for some demanding applications. To suppress the occurrence of such situation and further improve the path performance, such kind of vibration has to be settled down from the origin of vibration. In this paper, identification and compensation of torque ripples in drive train are discussed after in-depth analysis on the root causes. A typical case is then presented as a practical example and feasibility of the proposed scheme is verified in simulation environment.