[127] Time-varying coupled vibration analysis of a ball-screw feed system

Q Wu1,2, F Gu2 and A D Ball2
1School of Mechanical and Electrical Engineering, Lanzhou University of Technology, China

2Centre for Efficiency and Performance Engineering, University of Huddersfield, UK

Email: q.wu@hud.ac.uk / f.gu@hud.ac.uk / andrew.ball@hud.ac.uk 

According to the vibration characteristics of the ball screw feed system, a hybrid modelling method is proposed to study its dynamic performance. The ball screw is modelled partially as a continuous body and the remaining components are considered as lumped mass bodies. The axial, torsional, lateral and bending vibration models of the ball-screw carriage system were established via the Rayleigh-Ritz series method based on the Timoshenko beam assumption and the energy variation principle. The established models present several coupling factors between the various vibrations of the ball screw.
Numerical simulations were conducted to analyse the natural frequency of the ball-screw system and the time-varying dynamic characteristics of the ball-screw system.
In addition, the vibration responses and modes at different carriage positions are obtained. It is shown that the change in the carriage position has a significant influence on the axial vibration, whereas it has less effect on the torsional modes, which indicates that the proposed hybrid model has the capability to predict the vibration characteristics of the feed system accurately. The results also provide an important basis for the further study of in-machining monitoring and quality control.
Keywords: hybrid modelling, ball screw, feed system, time-varying, coupled vibration.