Modal Identification of a Robot Arm with an Open Cross Section

Abstract

Industrial robots are more and more used for highly dynamic operations. For the adequate design of control laws it is no longer sufficient to consider the robot arms as rigid. The arms flexibility and vibration characteristics have to be taken into account. Since analytical Finite Element models need to be verified and validated experimental investigations are usually performed. The report describes the modal identification tests on a robot arm with an open cross section. The robot arm was softly suspended by bungees and excited by impacts applied with a modal hammer and by a burst random applied with an aerodynamic shaker. Based on the measured Frequency Response Functions 9 modes are identified very clearly in the frequency range up to 1100 Hz. The identified modal parameters are presented and discussed.