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	 High Performance Motion Control of Rotary Table for 5-Axis Machining Centers
    Ryuta Sato and Masaomi Tsutsumi
 Institute of Symbiotic Science and Technology, Tokyo University of Agriculture and Technology
 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan
    
    
Received:August 28, 2007Accepted:September 1, 2007Published:November 5, 2007    
	
    
    
Keywords:5-axis machining center, rotary table, motion control, worm gear, synchronous accuracy	
	Abstract	
    We discuss motion control techniques of rotary tables for 5-axis machining  centers. Three translational axes and two rotary ones are controlled  simultaneously in the machining of complex shapes such as impellers. A  tilting rotary table powered by a worm gear is generally used as the rotary  axes for 5-axis machining centers, and various causes of inaccuracy exist in  the rotary axes.    In this study, we clarified three causes of inaccuracy exists in the rotary  axis: rotational fluctuation in the worm gear, backlash, and measurement  delay of rotary encoder for feedback. Motor torque saturation of the rotary  axis also causes a problem when rotational velocity is changed rapidly.    Based upon investigated results, we propose compensators for improving  synchronous accuracy. We avoid torque saturation in the rotary axis through  acceleration-deceleration design. To verify the effectiveness of the  proposed compensators, we applied them to an experimental set-up including a  rotary axis. As the results of experiments, it is clarified that the  proposed compensators improve the synchronous accuracy of translational and  rotary axes.		
	
	
    
    Cite this article as:R.  Sato and M.  Tsutsumi, “High Performance Motion Control of Rotary Table for 5-Axis Machining Centers,” Int. J. Automation Technol., Vol.1 No.2, pp. 113-119, 2007.Data files: