Trajectory Planning and Servo Control Strategy of EDM Milling Based ona 6-DOF Serial Robot

doi:10.3901/JME.2023.09.020

Abstract

Abstract: Aiming at the problems of insufficient flexibility and limited size of workpiece in traditional EDM milling, an EDM milling method based on a 6-DOF serial robot is proposed. Based on quaternion theory, the complex trajectory planning method of tool electrode is established to achieve the variable attitude milling of tool electrode. To solve the problem that the serial robot cannot meet the rapid response requirements of EDM for real-time adjustment of discharge gap, a servo control strategy of tool electrode vertical trajectory fallback is proposed to realize the rapid adjustment of machining gap. Using three and six degrees of freedom of the robot, the EDM milling experiments under fixed attitude and variable attitude of tool electrode are carried out, respectively. The experimental results show that the discharges occur between the end of tool electrode and the surface of workpiece with variable attitude milling of tool electrode, and the groove width of milling track is slightly larger than the diameter of tool electrode, Therefore, the precision and efficiency of EDM milling curved workpiece with the variable attitude of tool electrode are higher. Finally, three complex tracks are machined by EDM milling on the hemispherical workpiece, which verifies the feasibility and effectiveness of EDM milling based on a 6-DOF serial robot, and this method has a great market application potential.

Key words: EDM milling, 6-DOF serial robot, trajectory planning, servo control strategy, 3D curved surface machining

CLC Number:

TG156

YUE Xiaoming, ZANG Shuo, XU Zuoke, ZHANG Qinhe, ZHANG Jianhua, HUO Mengyou. Trajectory Planning and Servo Control Strategy of EDM Milling Based ona 6-DOF Serial Robot[J]. Journal of Mechanical Engineering, 2023, 59(9): 20-27.

References

[1] MULLYA S A,KARTHIKEYAN G,GANACHARI V S. Electric discharge milling:A state-of-the-art review[J]. Journal of the Brazilian Society of Mechanical Sciences and Engineering,2021,43(9):1-22.
[2] MASUZAWA T,FUJINO M,KOBAYASHI K,et al. Wire electro-discharge grinding for micro-machining[J]. CIRP Annals-Manufacturing Technology,1985,34(1):431-434.
[3] YU Z Y,MASUZAWA T,FUJINO M. Micro-EDM for three-dimensional cavities-development of uniform wear method[J]. CIRP Annals-Manufacturing Technology,1998,47(1):169-172.
[4] 李刚. 基于直线电机的微细电火花加工系统及其关键技术研究[D]. 哈尔滨:哈尔滨工业大学,2007. LI Gang. Research on micro EDM system based on linear motor and its key technologies[D]. Harbin:Harbin Institute of technology,2007.
[5] 董颖怀,王振龙,彭子龙,等. 微型涡轮发动机中压气机部件设计仿真及加工实验[J]. 上海交通大学学报,2009,43(9):1517-1520. DONG Yinghuai,Wang Zhenlong,Peng Zilong,et al. Design simulation and machining experiment of compressor components in micro turbine engine[J]. Journal of Shanghai Jiaotong University,2009,43(9):1517-1520
[6] KUNIEDA M,MIYOSHI Y,TAKAYA T,et al. High speed 3D milling by dry EDM[J]. CIRP Annals-Manufacturing Technology,2003,52(1):147-150.
[7] 武鑫磊,刘永红,纪仁杰. 电弧铣削技术现状与展望[J]. 电加工与模具,2021(6):1-10. WU Xinlei,Liu Yonghong,Ji Renjie. Current situation and Prospect of arc milling technology[J]. Electric Machining and Mould,2021(6):1-10.
[8] 赵万生,顾琳,徐辉,等. 基于流体动力断弧的高速电弧放电加工[J]. 电加工与模具,2012(5):50-54. ZHAO Wansheng,GU Lin,XU Hui,et al. High speed arc discharge machining based on hydrodynamic arc breaking[J]. Electric Machining and Mould,2012(5):50-54.
[9] GU Lin,ZHANG Fawang,ZHAO Wansheng,et al. Investigation of hydrodynamic arc breaking mechanism in blasting erosion arc machining[J]. CIRP Annals,2016,65(1):233-236.
[10] WANG F,LIU Y,SHEN Y,et al. Machining performance of inconel 718 using high current density electrical discharge milling[J]. Advanced Manufacturing Processes,2013,28(10):1147-1152.
[11] WANG F,LIU Y,ZHANG Y,et al. Compound machining of titanium alloy by super high speed EDM milling and arc machining[J]. Journal of Materials Processing Technology,2014,214(3):531-538.
[12] ZHU G,ZHANG M,ZHANG Q,et al. High-speed vibration-assisted electro-arc machining[J]. The International Journal of Advanced Manufacturing Technology,2019,101:3121-3129.
[13] HAN F,WANG Y,MING Z. High-speed EDM milling with moving electric arcs[J]. International Journal of Machine Tools & Manufacture,2009,49(1):20-24.
[14] 王翔,周建平,许燕,等. 基于直流电源的短电弧铣削加工性能研究[J]. 机床与液压,2021,49(9):71-76. WANG Xiang,ZHOU Jianping,XU Yan,et al. Research on machining performance of short arc milling based on DC power supply[J]. Machine Tools and Hydraulics,2021,49(9):71-76.
[15] 吕志鹏,伍吉仓,公羽. 利用四元数改进大旋转角坐标变换模型[J]. 武汉大学学报:信息科学版,2016,41(4):547-553. LÜ Zhipeng,WU Jicang,GONG Yu. Using quaternion to improve the coordinate transformation model of large rotation angle[J]. Journal of Wuhan University:Information Science Edition,2016,41(4):547-553.