Robust feedrate control for high-efficiency machining using quantitative feedback theory
Journal
Journal of the Chinese Institute of Engineers, Transactions of the Chinese Institute of Engineers,Series A/Chung-kuo Kung Ch'eng Hsuch K'an
Journal Volume
41
Journal Issue
7
Pages
566-578
Date Issued
2018
Author(s)
Huang H.-W.
Abstract
This study used quantitative feedback theory (QFT) to design a robust controller suitable for various cutting conditions. First, servo dynamics and milling process models were identified. The nominal plant was defined for milling process conditions of 20-mm cutting depth, 500-rpm spindle speed, and 1-mm cutting width, and the workpiece material was aluminum. Different milling conditions can result in different milling process models, which are regarded as perturbed plants. The differences between nominal and perturbed plants were treated as system uncertainties and were applied in designing the QFT controller to ensure that robust performance could be guaranteed under various milling conditions. Instead of using force measured by a dynamometer, the robust controller adjusted feedrate according to the spindle current, which was easy to measure online. The experimental results illustrated that the cutting force could be maintained at a constant level at different cutting depths, and machining time could be reduced by over 20% compared with uncontrolled cases. The proposed controller’s robustness was validated by testing different tools, workpiece materials, and cutting parameters in different experiments.
Publisher
Taylor and Francis Ltd.
Type
journal article