Aiming at the problem that the contact points on ruby ball will lead to different pre-travel errors under different stylus orientations, leading to low calibration accuracy and efficiency, a feasible graph construction method for optimizing stylus orientation is proposed. Firstly, the interference-free stylus orientations at each to-be-measured point are calculated according to the bounding box algorithm. Then, the relationship between the touch positions on the ruby ball and the rotating axis of machine tool is established by using the kinematics chain of machine tool, and then the feasible graph of the rotary angle of the machine tool turntable is constructed. In order to improve the detection accuracy, the stylus orientation is optimized based on the principle of reducing the changes of the ruby ball contact positions and the direction of the machine tool rotary axis, so as to meet the conditions of interference-free and minimum ruby ball contact positions. Finally, the centrifugal impeller exemplifies that this method can not only ensure the least number of the touch positions and greatly shorten the calibration time but also reduce the introduced error of the machine tool and improve the measurement accuracy. The experimental results show that the method has good repeatability and feasibility.
[1] LI W L, WANG G, ZHANG G, et al. Interference-free inspection path generation for impeller blades using an on-machine probe[J]. Transactions on Mechatronics, 2017, 22:1218-1226.
[2] 蔺小军, 陈悦, 王志伟, 等. 面向自适应加工的精锻叶片前后缘模型重构[J]. 航空学报, 2015, 36(5):1695-1703. LIN X J, CHEN Y, WANG Z W, et al. Model restructuring about leading edge and tailing edge of precision forging blade for adaptive machining[J]. Acta Aeronautics et Astronautica Sinica, 2015, 36(5):1695-1703(in Chinese).
[3] CAI Y L, CUI N N, MO X, et al. The pre-travel error study of electrical trigger probe in on-machine measurement[J]. Key Engineering Materials, 2016, 693:1466-1473.
[4] 王立成, 黄信达, 丁汉. 原位检测系统中触发式测头的误差分析与补偿[J]. 中国机械工程, 2012, 23(15):1774-1778. WANG L C, HUANG X D, DING H. Error analysis and compensation for touch trigger probe of on-machine measurement system[J]. China Mechanical Engineering, 2012, 23(15):1774-1778(in Chinese).
[5] LI H, ZHAO H, DING H. A novel on-machine measurement method based on the force controlled touch probe[C]//International Conference on Intelligent Robotics and Applications, 2018:486-497.
[6] WOZNIAK A, DOBOSZ M. Metrological feasibilities of CMM touch trigger probes. Part I:3D theoretical model of probe pre-travel[J]. Measurement, 2003, 34(4):273-286.
[7] RENEMAYER J R, GHAZZAR A, ROSSY O. 3D characterization, modelling and compensation of the pre-travel of a kinematic touch trigger probe[J]. Measurement, 1996, 19(2):83-94.
[8] 田文杰, 牛文铁, 常文芬, 等. 数控机床几何精度溯源方法研究[J]. 机械工程学报, 2014, 50(7):128-135. TIAN W J, NIU W T, CHANG W F, et al. Research on geometric error tracing of NC machine tools[J]. Journal of Mechanical Engineering, 2014, 50(7):128-135(in Chinese).
[9] 叶建华, 高诚辉, 江吉彬. 旋转台几何误差的在机测量与辨识[J]. 仪器仪表学报, 2015, 36(12):2804-2810. YE J H, GAO C H, JIANG J B. On-machine measurement and identification for the geometric errors of rotary table[J]. Chinese Journal of Scientific Instrument,2015,36(12):2804-2810(in Chinese).
[10] LEE K, LEE D, YANG S. Parametric modeling and estimation of geometric errors for a rotary axis using double ball bar[J]. The International Journal of Advanced Manufacturing Technology, 2012, 62(5-8):741-750.
[11] ZHANG Y, YANG J, ZHANG K. Geometric error measurement and compensation for the rotary table of five-axis machine tool with double ball bar[J]. The International Journal of Advanced Manufacturing Technology, 2013, 65(1-4):275-281.
[12] JIANG Z X, SONG B, ZHOU X D, et al. On-machine measurement of location errors on five-axis machine tools by machining tests and a laser displacement sensor[J]. International Journal of Machine Tools & Manufacture, 2015(95):1-12.
[13] 李祥宇, 任军学, 梁永收, 等. 复杂通道零件五轴加工刀轴规划[J]. 航空学报, 2014, 35(9):2641-2651. LI X Y, REN J X, LIANG Y S, et al. Five-axis machining tool shaft planning for complex channel parts[J]. Acta Aeronautics et Astronautica Sinica, 2014, 35(9):2641-2651(in Chinese).
[14] BALASUBRAMANIAM M, LAXMIPRASAD P, SARMA S, et al. Generating 5-axis NC roughing paths directly from a tessellated representation[J]. Computer-Aided Design, 2000, 32(4):261-277.
[15] 史中权. 基于数控系统的机床振动在线控制技术研究[D]. 南京:南京航空航天大学, 2017:1-10. SHI Z Q. Research on online vibration control of machine tools based on CNC system[J]. Nanjing:Nanjing University of Aeronautics & Astronautics, 2017:1-10(in Chinese).
[16] 唐晓, 江磊, 李乐, 等. 一种采用综合比较方式的后置处理转角优化算法[J]. 机床与液压, 2019, 47(4):99-102. TANG X, JIANG L, LI L, et al. A post processing corner optimization algorithm using comprehensive comparison[J]. Machine Tool and Hydraulics, 2019, 47(4):99-102(in Chinese).
[17] WAN N, JIANG R Z, ZHAO H, et al.An inspection path optimization of impeller for balancing efficiency and accuracy[J]. Measurement, 2019(141):472-485.
[18] MAHBUBUR R M, HEIKKALA J, LAPPALAINEN K, et al. Positioning accuracy improvement in five-axis milling by post processing[J]. International Journal of Machine Tools & Manufacture, 1997, 37(2):223-236.
[19] KHAN A W, CHEN W Y. Systematic geometric error modeling for workspace volumetric calibration of a 5-axis turbine blade grinding machine[J]. Chinese Journal of Aeronautics, 2010, 23(5):604-615.
[20] 莫蓉, 常智勇, 刘红军, 等. 图表详解UG NX二次开发[M]. 北京:电子工业出版社, 2008. MO R, CHANG Z Y, LIU H J, et al. Charts detailing UG NX secondary development[M]. Beijing:Publishing House of Electronics Industry, 2008(in Chinese).
[21] 鞠萍华, 黄洛. 在线测量系统测头误差补偿技术研究[J]. 机械科学与技术, 2018, 37(7):81-88. JU P H, HUANG L. Research on the probe error compensation technology of online measurement system[J]. Mechanical Science and Technology for Aerospace Engineering, 2018, 37(7):81-88(in Chinese).
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