Flexible multibody system modelling of an aerial rescue ladder using Lagrange’s equations

ABSTRACT Due to limited weight and stiffness, large-scale robots are susceptible to structural oscillations during operation. In this publication, a model for the vertical dynamics of an aerial rescue ladder as an application example for large scale flexible robots is derived based on the Lagrange formalism. The model consists of five flexible segments, each using an arbitrary number of flexible modes. Kinematic loops occurring due to the type of interconnection between the telescopic elements are implicitly solved by the chosen assumed modes. Linearized system matrices are extracted from the model directly and very efficiently. In the resulting modelling process, the manipulator is solely described by its position and orientation kinematics and thus an adaption to different kinds of manipulators is straightforward. A validation against real world measurement data confirms the high accuracy of the derived model.