Cross-coupling Adaptive Control for CNC Machine Tools
| Autor: | Hsiung-Hai Hsiang, 向雄海 |
|---|---|
| Rok vydání: | 2009 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 97 When a CNC machine tool is machining, there are some uncertainties of parameters and disturbances in system’s model due to the weight and material of workpiece and cutting rate are usually variant. Therefore the controller must be robust for such varying conditions. Adaptive control is suitable for that. Besides, to improve the machining precision, it’s essential to improve the contour errors, which is the main goal of the cross-coupling control (CCC). This research proposes a simple and effective contour-error algorithm to reduce the amount of computation to about 1/13 and 1/5 compare with Koren’s and Yeh’s work respectively. In addition to robustness, this research proposes cross-coupling adaptive control (CCAC) by combining above two controllers that could bring a significant improvement of tracking and contour errors. Compare with the PI controller under disturbance, the experimental results show that the CCAC can reduce the maximum and RMS of tracking errors to 41.44 % and 37.94 % respectively, while CCC can only reduce to 98.8 % and 98.89 % in linear contouring. For the maximum and RMS of contour errors, CCAC can reduce to 42.73 % and 32.67 % respectively, while CCC can only reduce to 70 % and 59.69 % in linear contouring. In circle contouring, CCAC can reduce the maximum and RMS of tracking errors to 41.42 % and 37.25 % respectively, while CCC can only reduce to 98.32 % and 97.6 %. For the maximum and RMS of contour errors, CCAC can reduce to about 37.56 % and 27.42 % respectively, while CCC can only reduce to 71.04 % and 57.79 %. The results show the superiority of CCAC. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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