Analysis of effective vibration frequency of cable-driven parallel robot using mode tracking and quasi-static method

Abstract

Recently, cable-driven parallel robots (CDPRs) have been used in many industry applications because of many advantages such as large workspace, high moving sensitivity and so on. In this paper, finite element model (FEM) including cables and end-effector was constructed and the pre-stressed modal analysis was carried out to obtain the natural frequencies. It was verified based on experimental results in order to investigate the effective frequency that most affects the dynamics of the end-effector. Two frequency response function (FRF) test results showed the vibration of end-effector was affected by the transversal vibration of cable. The effective frequency was extracted and investigated under asymmetric tension conditions using mode tracking and quasi-static method while the end-effector moves according to pre-programmed route. As a result, the minimum effective frequency occurred at the limit of the CDPR's motion, and was shown to be approximately a third of the maximum effective frequency. Total vibration amplitude of the minimum effective frequency was about three or four times larger than that of the maximum frequency.