Abstract
Performances of flexible link multibody systems, in terms of accuracy and repeatability, can be negatively affected by link flexibility that causes unwanted vibration. Therefore, advanced controllers are necessary for vibration suppression. The synthesis of such controllers typically relies on the knowledge of all the system state variables, whose direct measurement is complicated, or at least of a meaningful set of the most relevant ones. For such a reason, these state variables should be estimated through state observers. In particular, state observers based on reduced-order dynamic models should be employed, to reduce the computational effort. This paper shows some preliminary results on state estimation in flexible-link multibody systems based on nonlinear, reduced-order dynamic model formulated through independent coordinates. Reduction is performed through a modified Craig-Bampton strategy. Numerical simulations of a six-bar planar mechanism show that the proposed observer delivers accurate estimates of both the rigid and elastic variables.