Input Shaping to Reduce Vibration in Human-Operated Very-Flexible-Link Robot Manipulator

Abstract

Human-operated manipulators, such as construction crane, gantry crane, and tele-operatedrobot manipulator, are refrained from fast slewing because of the vibrations of its link and payload. To be long,light, fast, and to carry large payload, the manipulatorIs natural frequencies fall within the controller bandwidthresulting in resonance. In this paper, we apply the input shaping technique, in which the reference positionsignal is convolved with a properly designed impulse sequence to avoid exciting the natural frequencies, to avery-flexible-link robot manipulator to significantly reduce vibration. The technique is in real-time; therefore, thegiven reference position can be arbitrary and need not be known a priori, which suits the human-operatedsetting. Experimenting with a scale-down robot confirms the effectiveness of the technique in reducing slewingvibration. The result can be readily extended to a much-larger human-operated manipulator that vibrates.