Decoupling and effects of the mechanical vibration on the dynamic precision for the direct-driven machine tool

The linear motor feed system realizes direct drive, and all the intermediate transmission components are canceled. The thrust harmonics and other disturbances act on the mechanical system directly because the mover is connected with the driven parts, leading to obvious mechanical vibrations. The mechanical dynamic characteristics have important effects on the thrust characteristics and dynamic precision of linear motor feed system. In this paper, the decoupling and effects of the mechanical vibration on the dynamic precision for the direct driven are researched. Firstly, the mechanical kinetic model is established considering the characteristics of the joint between the guide rail and block and servo stiffness. Then the model realizes decoupling through the modal analysis, and the vibration responses in different directions are analytically calculated. What is more, a modeling method for the linear motor feed system considering the mechanical characteristic is put forward based on the modal separation method (MSM). The effects of the mechanical vibration on the dynamic precision of feed system are discussed. At last, the experiments are carried out and the influences of the structure parameters on the mechanical characteristics and displacement fluctuations are analyzed through sensitivity analysis, which provides a theoretical basis for the mechanical active design and improvement.