Validation of a dynamics simulation for a structurally flexible manipulator

Abstract

This paper first outlines the generally accepted procedures for model validation. Four dynamics models are then described which represent the full range of nonlinear complexity for modeling structural flexibility in robotic manipulators. Test manoeuvres are performed on a 2-DOF flexible-link direct-drive manipulator. The natural frequencies and mode shapes are captured very well by the finite element model when damping is incorporated. The performance of the four dynamics models with and without damping is also compared to one another and to the experiment. High order nonlinearities and model damping are shown to be less important for slow manoeuvres by close agreement between the simple and complex models. The importance of the high order terms is also shown to decrease for fast manoeuvres in the presence of damping. Results for the exact nonlinear model are inconclusive because of its poor convergence characteristics.