Effect of Gravity on the Static and Dynamic Characteristics of a Single Link Component of Flexible Multibody Systems

As large space structures and the component links of robotic manipulators become increasingly more flexible, axial loadings are playing an increasingly more important role in the elastic characteristics of the systems. The research presented in this paper provides a relatively simple theoretical model based on the quasi-dynamics of a component link for flexible multibody systems. The theoretical model has shown that the axial component of gravity can play a major role in predicting accurate first and second natural frequencies and the static deflections of component links typical of flexible multibody systems. By definition, the axial loading contribution is a function of rigid body orientation, with the more significant influence occurring in the vertical positions. Furthermore, the degree of this effect is directional, depending on whether the axial loading is compressive or tensile. The results elude to a possible simple, approximation approach for modeling complex multilink systems subject to gravitational loading. In addition, the presented analysis approach has been experimentally validated where the theoretical results have been shown to agree very well with the experimental findings.