Nonlinear dynamics investigation of a multi-axis drive system due to the kinematic joints

Machining performance is greatly affected by vibration characteristics of machining tool systems. However, the nonlinear vibrations of kinematic joints were rarely considered in the dynamic models of multi-axis feed drive systems. In this paper, the relationships between contact loads and deformations of kinematic joints are analyzed in relative coordinate system. The interface forces between each axis feed drive system are assembled considering the relative displacements and interaction force of worktables, and the dynamic differential equations with 21 degrees-of-freedom are derived via the lump mass method. The dynamic model of machine tool feed drive system is verified by vibration test. The main parameters which affect the dynamic performance and stability are analyzed. Results indicate that the variations of excitation frequency, worktable position and mass lead to complex nonlinear behaviors, including hardening type nonlinearity, jump discontinuous phenomenon, and chaotic motion. The study may contribute to a further understanding of the dynamic characteristics and provide some guidelines to vibration control for multi-axis machine tool systems.

Automated summary

This paper analyzes the impact of nonlinear vibrations of kinematic joints on machining performance and verifies the dynamic model through experiments. The study shows that changes in excitation frequency, worktable position, and mass can result in various complex nonlinear behaviors.