Implementation of the Low-frequency Compensators on CNC Servo Control Systems through EtherCAT

• Main Authors: Hong, Huai-En, 洪懷恩
• Other Authors: Hsu, Pau-Lo
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/33418777277850908258

碩士 === 國立交通大學 === 電控工程研究所 === 104 === In CNC controllers, in addition to the basic P controller, other controllers mainly in the high-frequency range mainly are as (1) proportional-derivative (PD) control to stabilize its performance and (2) the feedforward control greatly improving the tracking performance in the position loop. Furthermore, two more advanced compensators are proposed in this paper as: (3) the digital disturbance observer (DDOB) based on a linear model obtained from the presently proposed pseudo chirp sine CNC G code and (4) the 1st-order low-frequency F filter for friction compensation. With the real-time INtime operating system based on EtherCAT and the ITRI CNC control interface, experimental results indicate that the sampling time can be operated at 0.25ms without data dropout. All above four controllers/compensators can be flexibly integrated and efficiently implemented on the CNC controller through the EtherCAT interface. Experimental results on the Tongtai TC-2000 CNC Lathe indicate that the roundness measured from the encoder is improved form 23.1 to 8.6 . Roundness measured from the double ball bar is also significantly reduced from 27.4 to 11.1 , and is reduced to 6.6 by tuning its servo control gain and step type backlash compensation to further decrease the lost motion effect on the CNC machine tool.