Mechanical model and contouring analysis of high-speed ball-screw drive systems with compliance effect

Abstract

The compliance effect of a high-speed ballscrew feed-drive system is modelled in this work. A mechanical model of a ball-screw feed drive system including the motor, ball-screw, coupling, supporting bearing, linear guide and machine structure was developed. It was found that at high acceleration, the mechanical compliance caused a significant contouring error. Smoothing the acceleration and deceleration control input command did improve the transient deviation in the contouring error. However, the steady state error caused by the elastic elongation in the mechanical elements was not improved. It was also shown that the inertia force of the slide and saddle comprised the dominant loading on a high speed machine tool drive mechanism. A topology structure optimisation method is proposed to reduce the moving weight. This method can help the designer efficiently reduce the moving weight of a machine tool axis in a systematic way. More than a 30% weight reduction was demonstrated in a spindle carrier structural design.

Investigating the factors affecting human's weight perception in lifting objects with a power assist robot

“…It is assumed that increase in mechanical time constant increased the inertia of the rotor of the servomotor and hence reduced the load inertia to rotor inertia ratio. Reduction in the load inertia to rotor inertia ratio resulted in a lower relative contribution of the load inertia to the total inertia of the system and the reduced inertia contribution of the load under dynamic touch might cause the perceptual attenuation i.e., the feeling of reduced heaviness [20]- [21], [23]. This result indicates the validity of our findings of experiment 1.…”

Study on dynamics of large machine tool feed system based on distributed-lumped parameter model

“…(7) where parameters value were given in Table(1) and (4). e J was the equivalent rotary inertia, e B was the equivalent damping coefficient.…”

“…In fact in order to improve the driving stiffness, a larger diameter ball screw would be selected, but the system inertia would increase at the meantime. The increased inertia impaired the system response, so the longer lead was needed, but consequently the effect of torsion on driving precision would be enhanced [4]. To overcome these difficulties, modeling a feed system suitable for large machines is essential.…”

A synthetical modelling for machine tool feed drives

“…Erkorkmaz and Altintas (2001) presented a method for identifying the dynamic parameters, as well as the friction characteristics of machine tool drives, the inertia and viscous friction were estimated through an unbiased least squares scheme. The compliance effect of a high-speed ball-screw feed-drive system was modelled by Chen et al (2004). Varanasi and Nayfeh (2004) developed a model of lead-screw system dynamics that accounted for the distributed inertia of the screw and the compliance and damping of the thrust bearings, nut and coupling.…”