标题: 以EtherCAT实现CNC伺服控制低频补偿器
Implementation of the Low-frequency Compensators on CNC Servo Control Systems through EtherCAT
作者: 洪怀恩
徐保罗
Hong, Huai-En
Hsu, Pau-Lo
电控工程研究所
关键字: 运动控制;循圆运动;扰动观测器;系统鉴别;CNC;motion control;circular motion;disturbance observer;system ID;CNC
公开日期: 2016
摘要: 在CNC工具机的控制器上,除了原有的P控制以外,本研究整合了分别属于高频域及低频域的控制补偿器,提升CNC的运动精密度,除了原有属于改善高频域控制范围的控制器,包含 (1)提升稳定性的PD(比例-微分)控制器,及 (2)改善追迹误差的位置回路前馈控制器外,本研究并提出在CNC工具机控制器上可具体实现的低频补偿器,包含(3) 利用CNC的G指令达成pseudo chirp sine鉴别方式,设计数位式扰动观测器DDOB,以及 (4) 提出具判断功能之一阶低频F filter 摩擦力补偿器。本研究在东台TC-2000的CNC机台上,透过工研院所开发的以INtime即时环境之EtherCAT网路化CNC控制介面,实现整合式精密运动控制器,经由实验证实,取样时间可快速至0.25ms。本研究证明整合了(1)至(4)之伺服控制架构后,可以确实提升整体运动精密度,其真圆度和原始P控制比较,由23.1 改善至8.6 ,改善率达62.77%。本研究并以循圆测试仪量测机械端精密度,由27.4 改善至11.1 ,最后透过调整驱动器刚性及工研院控制器step背隙补偿,改善背隙误差带来的失运动(lost motion)现象,机械端真圆度可再改善至6.6 ,前述实验结果说明本研究成果可凸显EtherCAT于实现弹性的CNC控制架构与运动精密补偿器之应用。
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.
URI: http://etd.lib.nctu.edu.tw/cdrfb3/record/nctu/#GT070360006
http://hdl.handle.net/11536/138998
显示于类别:Thesis