Modal sensitivity analysis of planar robots, based on a simplified CMS approach

摘要

Abstract The modal properties of industrial robots have become a major issue following the increasing demand for faster, lighter manipulators. In this article, the basic in‐plane and out‐of‐plane modal analysis of a planar robot with revolute joints is conducted via component mode synthesis (CMS) using a limited number of low‐order monomials as mode shapes for the different links, and an automatic coordinate reduction procedure in the assembly phase which accounts for the physical characteristics of the joints. This model is then used to study the effect of variations in configuration, payload and various physical parameters on the natural frequencies of the robot. As regards the influence of physical parameter variations, frequency sensitivity coefficients are evaluated in a straightforward manner requiring only one eigenvalue analysis, and allow to determine the eigenvalue variations. It is observed that relatively large variations of parameters can be accommodated using these sensitivity coefficients.