Current modelling techniques only allow realtime simulation of strongly simplified models of flexible mechanisms. Both the number of degrees of freedom needed to accurately describe flexibility as the DAE-character of the system equations limit the computational efficiency. Bodylevel model reduction such modal synthesis is typically used to decrease the computational load of a simulation, but this cannot fully meet the demands for real-time simulation of flexible mechanisms. In this research, Global Modal Parametrization, a model reduction technique initially proposed for controller design for flexible mechanisms, is further developed to speed up simulation of multibody systems. The reduction is achieved by a system-level modal description, as opposed to the classic body-level modal description. As the dynamics is configuration-dependent, the systemlevel modal description is chosen configuration-dependent in such a way that the system dynamics is optimally described with a minimal number of degrees of freedom. Another novelty is GMP-based simulation. In a numerical experiment, simulation results for the original model equations are compared with simulation results for the model equations obtained after model reduction, showing a good match. The approximation errors resulting from the model reduction techniques are investigated by comparing results for different mode sets. The mode set affects the approximation error similarly as it does in linear modal synthesis.

sponsorship: Institute for the Promotion of Innovation through Science and Technology in Flanders (IWT-Vlaanderen)