A novel method of suppressing machining vibr2ation in robotic milling using magneto-rheological foam damper

Owing to their remarkable flexibility and favorable cost-effectiveness, industrial robots have found extensive applications to cutting of materials across sophisticated manufacturing fields. However, the structurally low rigidity of these robots renders the tool tip prone to substantial oscillations during machining processes, significantly impacting product fabrication quality. The objective of this study is to present a novel methodology employing magnetorheological dampers for mitigating vibrations during robotic milling operations. Specifically, a new type of ring nested Magneto-Rheological Foam Damper (MRFD) working in the squeeze mode is developed. Firstly, the MRFD's structure is designed considering the vibrational characteristics of robotic milling. Subsequently, a damping force model of the MRFD is derived. The feasibility of the MRFD's structural design is validated by the finite element analyses, which is instrumental in comprehending the influence of structural parameters on the electromagnetic characteristics of the MRFD. Next, a prototype of the MRFD is fabricated selecting appropriate parameters. Finally, a series of excitation and milling experiments are conducted on a KUKA KR500 robot. The outcomes demonstrate a substantial reduction (37%-69%) in radial vibration amplitude at the tool tip during robotic milling, highlighting the effectiveness of the developed MRFD. This research endeavor has introduced a pioneering avenue and framework for vibration control in robotic milling, offering a novel paradigm for enhancing the precision of robotic machining.