新型5轴混联加工单元的后置处理算法

doi:10.3901/JME.2023.01.298

摘要/Abstract

摘要： 5轴混联加工单元因其高刚性、快速响应及灵活调姿等优点，已被视为复杂铝合金结构件高效加工的一种替代方案。后置处理是改善此类装备加工能力的重要环节。以一种新型5轴混联加工单元为研究对象，提出一种可提高其加工件表面质量的后置处理算法。首先，基于B样条曲线构造一种双参数曲线插补算法，进行刀尖和刀轴轨迹的光顺处理，并采用参数同步化保证刀尖点与刀轴点的同步插补。其次，通过推导混联加工单元的速度映射模型，构造驱动轴的速度分配算法以确保刀尖进给速度的稳定性；接着，运用混联加工单元的位置逆解与速度分配策略，将其末端的进给速度、光顺处理后的刀尖插补点及刀轴插补点转换成驱动轴的位置与速度运动控制点集，实现混联加工单元刀具轨迹的后置处理；最后，基于前期开发的实验样机开展一组S形试件的切削实验，验证所提后置处理算法的有效性。

关键词: 混联加工单元, 逆运动学, 光顺处理, 速度分配, S形试件

Abstract: Due to the merits of high stiffness, quick dynamic response and flexible posture adjustment, 5-axis hybrid machine units have been regarded as an alternative solution for high-efficiency machining of aluminum alloy structural components with complex geometries. Post-processing is of great importance to the improvement of machine capacity of hybrid machine units. A post-processing algorithm is proposed to improve the surface quality of the workpieces for a novel hybrid kinematic machining unit. Firstly, by adopting the B-spline curve, a double parameter curve interpolation algorithm is formulated to smooth the tool tip and tool axis trajectory. And then, the parameter synchronization is used to ensure the synchronous interpolation of tool tip and tool axis. Secondly, the velocity mapping model of the hybrid kinematic machining unit is formulated and a velocity allocation algorithm is proposed to ensure the stability of tool tip velocity. Thirdly, by using the inverse kinematics and the velocity allocation algorithm, the feedrate, the tool tips and the tool axis vectors are converted into a set of motion control points of the servo motors. Based on this, the post-processing of tool-path is realized for the hybrid kinematic machining unit. Finally, based on a laboratory prototype of the hybrid kinematic machining unit, a set of machining tests on S-shape workpiece is carried out to verify the effectiveness of the proposed post-processing algorithm.

Key words: hybrid kinematic machining unit, inverse kinematics, smoothing processing, velocity allocation, S-shape workpiece

中图分类号:

TH164

张俊, 鲍雨菲, 方汉良, 宋亚庆. 新型5轴混联加工单元的后置处理算法[J]. 机械工程学报, 2023, 59(1): 298-308.

ZHANG Jun, BAO Yufei, FANG Hanliang, SONG Yaqing. Post-processing Algorithm of a Novel Five-axis Hybrid Kinematic Machining Unit[J]. Journal of Mechanical Engineering, 2023, 59(1): 298-308.

参考文献

[1] WANG Liping, WU Jun, WANG Jinsong. An experimental study of a redundantly actuated parallel manipulator for a 5-DOF hybrid machine tool[J]. IEEE-ASME Transactions on Mechatronics, 2009, 14(1):72-81.
[2] SON S, KIM T, SARMA S E, et al. A hybrid 5-axis CNC milling machine[J]. Precision Engineering, 2009, 33(4):430-446.
[3] 许允斗, 胡建华, 张东胜, 等. 一种所有转轴均连续的五自由度混联机器人机构[J]. 机械工程学报, 2018, 54(21):19-24. XU Yundou, HU Jianhua, ZHANG Dongsheng, et al. A kind of five degrees of freedom hybrid robot with all rotating shafts continuous[J]. Journal of Mechanical Engineering, 2018, 54(21):19-24.
[4] AMANULLAH A N M, SALEH T, KHAN R. Design and development of a hybrid machine combining rapid prototyping and CNC milling operation[J]. Procedia Engineering, 2017, 184:163-170.
[5] DONG Shengzhang, YUN Douxu, JIAN Taoyao, et al. Analysis and optimization of a spatial parallel mechanism for a new 5-DOF hybrid serial-parallel manipulator[J]. Chinese Journal of Mechanical Engineering, 2018, 31(3):60-68.
[6] LIU Qi, HUANG Tian. Inverse kinematics of a 5-axis hybrid robot with non-singular tool path generation[J]. Robotics and Computer Integrated Manufacturing, 2019, 56:140-148.
[7] CHEN H, RAKHA H A, LOULIZI A, et al. Development and preliminary field testing of an in-vehicle eco-speed control system in the vicinity of signalized intersections[J]. IFAC-Papers On Line, 2016, 49(3):249-254.
[8] FANG Hanliang, TANG Tengfei, ZHANG Jun. Kinematic analysis and comparison of a 2R1T redundantly actuated parallel manipulator and its non-redundantly actuated forms[J]. Mechanism and Machine Theory, 2019, 142:153087.
[9] 姚哲, 冯景春, 王宇晗. 面向五轴加工的双NURBS曲线插补算法[J]. 上海交通大学学报, 2008, 42(2):235-244 YAO Zhe, FENG Jingchun, WANG Yuhan. Dual NURBS curve interpolation algorithm for 5-axis machining[J]. Journal of Shanghai Jiao Tong University, 2008, 42(2):235-244.
[10] 王洋, 倪雁冰, 黄田, 等. 并联机床插扑算法与原理性插补误差预估[J].机械工程学报, 2001, 37(6):15-18. WANG Yang, NI Yanbing, HUANG Tian, et al. Interpolation algorithm and error prediction of principle interpolation for parallel machine tools[J]. Journal of Mechanical Engineering, 2001, 37(6):15-18.
[11] SHI Jing, BI Qingzhen, WANG Yuhan. Five-axis interpolation of continuous short linear trajectories for 3[PP] S-XY hybrid mechanism by dual Bézier blending[J]. Journal of Shanghai Jiao Tong University, 2016, 21(1):90-102.
[12] 赵欢, 张永红, 丁汉. 五轴线性刀路的转接光顺及轨迹生成算法[J]. 机械工程学报, 2018, 54(3):108-116. ZHAO Huan, ZHANG Yonghong, DING Han. A corner rounding and trajectory generation algorithm for five-axis linear toolpath[J]. Journal of Mechanical Engineering, 2018, 54(3):108-116.
[13] ZHANG Jun, ZHANG Liqiang, ZHANG Kai, et al. Double NURBS trajectory generation and synchronous interpolation for five-axis machining based on dual quaternion algorithm[J]. The International Journal of Advanced Manufacturing Technology, 2016, 83(9):2015-2025.
[14] LI Dongdong, ZHANG Weimin, ZHOU Wei, et al. Dual NURBS path smoothing for 5-axis linear path of flank milling[J]. International Journal of Precision Engineering and Manufacturing, 2018, 19(12):1811-1820.
[15] JAHANPOUR J, MOTALLEBI M, PORGHOVEH M. A novel trajectory planning scheme for parallel machining robots enhanced with NURBS curves[J]. Journal of Intelligent & Robotic Systems, 2016, 82(2):257-275.
[16] SHEN Xu, XIE Fugui, LIU Xinjun, et al. A smooth and undistorted toolpath interpolation method for 5-DoF parallel kinematic machines[J]. Robotics and Computer Integrated Manufacturing, 2019, 57:347-356.
[17] 周玉龙. 满足非线性误差要求的五轴进给速度控制方法[J]. 机械工程学报, 2014, 50(7):215-218. ZHOU Yulong. Research on feedrate control of five-axis based on non-linear error[J]. Journal of Mechanical Engineering, 2014, 50(7):215-218.
[18] MANSOUR S Z, SEETHALER R. Feedrate optimization for computer numerically controlled machine tools using modeled and measured process constraints[J]. Journal of Manufacturing Science and Engineering, Transactions of the ASME, 2017, 139(1):011012.
[19] WANG Dong, WU Jun, WANG Liping. A post-processing strategy of a 3-DOF parallel tool head based on velocity control and coarse interpolation[J]. IEEE Transactions on Industrial Electronics, 2017, 65(8):6333-6342.
[20] LIU Min, HUANG Yu, YIN Ling, et al. Development and implementation of a NURBS interpolator with smooth feedrate scheduling for CNC machine tools[J]. International Journal of Machine Tools and Manufacture, 2014, 87:1-15.
[21] 张俊, 蒋舒佳, 池长城. 2UPR&2RPS型冗余驱动并联机器人的运动学标定[J]. 机械工程学报, 2021, 57(15):62-70. ZHANG Jun, JIANG Shujia, CHI Changcheng. Kinematic calibration of a 2UPR&2RPS redundantly actuated parallel robot[J]. Journal of Mechanical Engineering, 2021, 57(15):62-70.
[22] HUANG Jie, DU Xu, ZHU LiMin. Real-time local smoothing for five-axis linear toolpath considering smoothing error constraints[J]. International Journal of Machine Tools and Manufacture, 2018, 124:67-79.
[23] 田梦婷. 2-UPS/2-UPR混联机床数控后置处理系统研究[D]. 秦皇岛:燕山大学, 2017. TIAN Mengting. Research of NC post processing system for 2-UPS/2-UPR hybrid machine tool[D]. Qinhuangdao:Yanshan University, 2017.
[24] 张俊, 鲍雨菲, 蒋舒佳, 等. 五自由度混联机床数控系统V1.0:中国, 2020SR0167905[P]. 2020-02-04. ZHANG Jun, BAO Yufei, JIANG Shujia, et al. A nuberical control system of five-axis hybrid machine tool:China, 2020SR0167905[P]. 2020-02-04.