Damping Vibrations in a Dual-Beam Flexible Robotic Arm

Abstract

Robots have contributed a great deal to manufacturing industry, increasing both productivity and quality. However, they often achieve accuracy for quality by adding mass to their links, increasing weight and power required for operation. Once the mass is removed, though, vibrations in the flexible system make accurate work very difficult. Some study has been done on active controllers for flexible links in order to damp their oscillation. The purpose of this investigation is to develop a passive control scheme which takes advantage of a new configuration of the flexible arm. This configuration has two parallel beams in every link as opposed to the one found in other investigations. This investigation models the first link of a flexible planar manipulator. Two methods of removing the oscillations were modeled. The first involved actively controlling the distance between the ends of the two beams in the first link. The hypothesis behind this method was to change the center of rotation of the endmass to remove energy. This method was not successful. The next involved placing a spring-damper system between each beam and the endmass and allowing the dampers to remove energy from the system. This method was successful, having settling times ranging from 0.75 s to 9.75 s.