Modeling of the dynamic behavior of machine tools: influences of damping, friction, control and motion

Abstract

In the process of designing a machine tool virtual models are required to predict the dynamic behavior and optimize the machine tool performance. For this purpose, the different influencing factors mass, stiffness and damping properties as well as friction forces, feed drive controls and movements have to be considered in the simulation. However, usually no suitable models and modeling approaches are available for all of these various influencing factors. In this paper, models are provided for the mentioned influencing factors. Subsequently, a modeling approach is proposed, which allows to predict the dynamic behavior with high accuracy. By using this modeling approach, the influencing factors are investigated and evaluated with regard to their effects on the vibration behavior of a machine tool. The nonlinear friction forces and the linear dissipation sources have the greatest impact on the damping behavior. In comparison, the impact of the feed drive control on the vibration behavior is low. Movements can greatly influence the vibration behavior. Their effects are mainly restricted to the axial modes of the feed drives. At these modes, the damping ratios can vary under motion by up to ±35% compared to a standstill. With these insights and the proposed models and modeling approaches new possibilities arise to predict and optimize the dynamic behavior of a machine tool and thus to enhance the machine tool performance.