分析热动态伪滞后效应对直接进给轴驱动精度的影响，对进给轴具有的热伪动态特性进行建模和误差补偿研究。依据一维热传导和一维热膨胀理论，推导直线电机驱动进给轴热动态过程的温度分布模型和热变形误差动态模型，通过有限元分析方法和试验相结合，构建基于关键温度点的直接进给轴热伪滞后变形动态识别模型。应用激光干涉仪测量直接进给轴的热变形量，采用温度传感器和红外测温仪测量直接进给轴关键点的温度，构建进给轴动态热变形补偿系统，依据实时温度对应的热变形数据，发送热变形预测值给运动控制卡，进而向伺服控制器发送控制补偿指令，通过对直接进给轴的运动叠加控制，实现对直接进给轴的热变形补偿。在自构建的直接进给轴试验台上进行试验研究，结果表明：动态识别模型能有效的预测动态热行为，通过构建热变形补偿系统，可使直接进给轴进给精度提高75%。
The influence of thermal dynamic hysteresis effect on the direct feed axis is analyzed. The modeling and error compensation method of the thermal dynamic characteristic are proposed. First one-dimensional heat conduction and one-dimensional thermal expansion theory are applied to establish the temperature distribution model and thermal deformation dynamic model. A dynamic identification model of thermal hysteresis deformation, which is based on critical temperature points, is built for the direct feed axis with combination of finite element method and experiment test. The deformation of direct feed axis is measured by laser interferometer. The temperature of critical points on direct feed axis is measured by temperature sensors and infrared thermometers. A dynamic thermal deformation compensation system for the mechanism is constructed with a motion control system. The compensation control instruction is feed back to the servo controller according to the real-time temperature corresponding to the thermal deformation. To demonstrate the procedure of the proposed approach, an experiment was conducted on the self-construction test rig. The results show that the modeling method for the hysteresis behavior is practical and effective in the thermal deformation compensation for the feed mechanism. The driving precision of the feed axis increased 75% with the thermal deformation compensation system.
[1] CHEN S L,HSIEH T H. Repetitive control design and implementation for linear motor machine tool[J]. International Journal of Machine Tools and Manufacture,2007,47(12-13):1807-1816.
[2] HSIEH M F,TUNG C J,YAO W S. Servo design of a vertical axis drive using dual linear motors for high speed electric discharge machining[J]. International Journal of Machine Tools & Manufacture,2007,47:546-554.
[3] 代晓明,杨庆东. 高架桥式龙门高速加工中心直线进给系统的设计[J]. 机械制造,2005,43(485):12-14. DAI Xiaoming,YANG Qingdong. The design of the linear feed system of an overhead gantry high speed machining center[J]. Machine Manufacturing,2005,43(485):12-14.
[4] 齐陆燕,王禹林,冯虎田. 直线电机驱动型工作台热态特性分析[J]. 机床与液压,2013(17):16-20. QI Luyan,WANG Yulin,FENG Hutian. Thermal characteristics analysis for worktable driven by linear motor[J]. Machine Tool & Hydraulics,2013(17):16-20.
[5] 邓小雷,蒋丰骏,周兆忠. 数控机床三明治复合结构进给系统设计[J]. 机床与液压,2013(23):108-111. DENG Xiaolei,JIANG Fengjun,ZHOU Zhaozhong. Design of sandwich composite structure feed system for CNC machine tool[J]. Machine Tool & Hydraulics,2013(23):108-111.
[6] HARPER K,DAMAZO B,DONMEZ A. Development of a linear motor drive test bed and initial thermal behavior results[J]. American Society for Precision Engineer,2010,34(3):76-82.
[7] KIM J J,JEONG Y H,CHO D W. Thermal behavior of a machine tool equipped with linear motors[J]. International Journal of Machine Tools and Manufacture,2004,44(7-8):749-758.
[8] UHLMANN E,HU J. Thermal modelling of an HSC machining centre to predict thermal error of the feed system[J]. Production Engineering,2012,6(6):603-610.
[9] EUN I U. Effects of insulation layer upon the thermal behavior of linear motors[J]. Journal of Mechanical Science & Technology,2003,17(6):896-905.
[10] VENUGOPAL R,BARASH M,SHAW M C. Thermal effects on the accuracy of numerically controlled machine tools[J]. CIRP Annals-Manufacturing Technology,1986,35(1):255-258.
[11] 唐治,闫开印,田怀文. 基于动态反馈神经网络模型的数控机床热误差实时预报补偿[J].机械设计与制造,2007(8):119-121. TANG Zhi,YAN Kaiyin,TIAN Huaiwen. Real-Time predictive compensation for thermal error of NC machine tool based on dynamic feed back neural network model[J]. Machinery Design & Manufacture,2007(8):119-121.
[12] GUO Z,LIU S,WANG H. Dynamic modeling and experimental verification for the feeding system of a gantry machine tool based on thermal-mechanical coupling[J]. International Journal of Advanced Manufacturing Technology,2016,85(1):227-236.
[13] 夏军勇,吴波,胡友民,等. 多变化热源下的滚珠丝杠热动态特性[J]. 中国机械工程,2008,19(8):955-958. XIA Junyong,WU Bo,HU Youmin,et al. The thermal dynamic characteristic of ball-screw under the variational multi-thermal source[J]. China Mechanical Engineering,2008,19(8):955-958.
[14] 王维,杨建国,姚晓栋,等. 数控机床几何误差与热误差综合建模及其实时补偿[J]. 机械工程学报,2012,48(7):165-170. WANG Wei,YANG Jianguo,YAO Xiaodong,et al. Synthesis modeling and real-time compensation of geometric error and thermal error for CNC machine tools[J]. Journal of Mechanical Engineering,2012,48(7):165-170.
[15] KIM B S,SONG Y C,PARK C H. Robust thermal error modeling and compensation for a nano level thermal drift in a high precision lathe[J]. International Journal of Precision Engineering & Manufacturing,2011,12(4):657-661.
[16] 林献坤,王益涵,朱琳. 应用潜变量回归在线补偿直接进给轴热误差[J]. 光学精密工程,2015,23(2):430-437. LIN Xiankun,WANG Yihan,ZHU Lin. Online compensation of thermal error for dual direct feed drive system with latent variable model[J]. Optics and Precision Engineering,2015,23(2):430-437.
[17] HONG Y,JUN N. Dynamic modeling for machine tool thermal error compensation[J]. Transactions of the ASME,2003,125(5):245-254.
[18] TAN B,MAO X,LIU H,et al. A thermal error model for large machine tools that considers environmental thermal hysteresis effects[J]. International Journal of Machine Tools & Manufacture,2014,82-83(7):11-20.
