基于概率方法的机器人铣削加工颤振稳定性研究
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摘要
将可靠性概率方法引入到机器人铣削模态耦合颤振预测中,首先建立可靠性模型,得到极限状态方程.其次,应用四阶矩法计算其可靠度和灵敏度以分析各参数对于铣削加工稳定性的影响.最后,基于机器人铣削加工骨头的工程背景给出了一个算例研究.结果表明:机器人两自由度方向的刚度、切削力系数和加工进给方向会影响铣削加工的稳定性;在一定范围内,增加X方向刚度,降低Y方向的刚度,减小切削力系数以及合理选择加工进给方向有利于避免模态耦合颤振的发生;系统对于切削力系数的变化相较于X,Y方向刚度更加敏感,对稳定性的影响更显著.
The reliability method was introduced into the prediction of modal coupling chatter in robotic milling. Firstly,the reliability model was established and the limit state equation was obtained. Secondly,the fourth-order moment method was used to calculate the reliability and sensitivity to analyze the influence of various parameters on the milling stability. Finally,an example was given based on the engineering background of robotic milling bone. The results showed that the two-degree-freedom stiffness,cutting force coefficient and feeding direction of the robot will affect the stability of the milling process. Within a certain range,increasing the stiffness in X divection, reducing the stiffness in Y direction,reducing the cutting force coefticient and choosing the feed divection resonably are helpful to avoiding modal coupling chatter. The system is more sensitive to the change of cutting force coefficients than to the stiffness in X and Y directions,and has more significant benefit influence on stability.
The reliability method was introduced into the prediction of modal coupling chatter in robotic milling. Firstly,the reliability model was established and the limit state equation was obtained. Secondly,the fourth-order moment method was used to calculate the reliability and sensitivity to analyze the influence of various parameters on the milling stability. Finally,an example was given based on the engineering background of robotic milling bone. The results showed that the two-degree-freedom stiffness,cutting force coefficient and feeding direction of the robot will affect the stability of the milling process. Within a certain range,increasing the stiffness in X divection, reducing the stiffness in Y direction,reducing the cutting force coefticient and choosing the feed divection resonably are helpful to avoiding modal coupling chatter. The system is more sensitive to the change of cutting force coefficients than to the stiffness in X and Y directions,and has more significant benefit influence on stability.
引文
[1]王战玺,张晓宇,李飞飞,等.机器人加工系统及其切削颤振问题研究进展[J].振动与冲击,2017,36(14):147-155.(Wang Zhan-xi,Zhang Xiao-yu,Li Fei-fei,et al. Review on the research developments of robot machining systems and cutting chatter behaviors[J]. Journal of Vibration and Shock,2017,36(14):147-155.)
[2] Tobias S A,Fishwick W. The chatter of lathe tools under orthogonal cutting conditions[J]. Transaction of the ASME,1958,80(2):1079-1088.
[3] Li J,Li B,Shen N,et al. Effect of the cutter path and the workpiece clamping position on the stability of the robotic milling system[J]. The International Journal of Advanced Manufacturing Technology,2017,89(9/10/11/12):2919-2933.
[4] Pan Z,Zhang H,Zhu Z,et al. Chatter analysis of robotic machining process[J]. Journal of Materials Processing Technology,2006,173(3):301-309.
[5] Tunc L T,Stoddart D. Tool path pattern and feed direction selection in robotic milling for increased chatter-free material removal rate[J]. The International Journal of Advanced Manufacturing Technology,2017,89(9/10/11/12):2907-2918.
[6] Cen L,Melkote S N. CCT-based mode coupling chatter avoidance in robotic milling[J]. Journal of Manufacturring Processes,2017,29:50-61.
[7] Duncan G S,Kurdi M,Schmitz T,et al. Uncertainty propagation for selected analytical milling stability limit analyses[J].Transactions of NAMRI/SME,2006,34:17-24.
[8] Liu Y,Li T,Liu K,et al. Chatter reliability prediction of turning process system with uncertainties[J]. Mechanical Systems and Signal Processing,2016,66:232-247.
[9] Liu Y,Meng L,Liu K,et al. Chatter reliability of milling system based on first-order second-moment method[J]. The International Journal of Advanced Manufacturing Technology,2016,87(1/2/3/4):801-809.
[2] Tobias S A,Fishwick W. The chatter of lathe tools under orthogonal cutting conditions[J]. Transaction of the ASME,1958,80(2):1079-1088.
[3] Li J,Li B,Shen N,et al. Effect of the cutter path and the workpiece clamping position on the stability of the robotic milling system[J]. The International Journal of Advanced Manufacturing Technology,2017,89(9/10/11/12):2919-2933.
[4] Pan Z,Zhang H,Zhu Z,et al. Chatter analysis of robotic machining process[J]. Journal of Materials Processing Technology,2006,173(3):301-309.
[5] Tunc L T,Stoddart D. Tool path pattern and feed direction selection in robotic milling for increased chatter-free material removal rate[J]. The International Journal of Advanced Manufacturing Technology,2017,89(9/10/11/12):2907-2918.
[6] Cen L,Melkote S N. CCT-based mode coupling chatter avoidance in robotic milling[J]. Journal of Manufacturring Processes,2017,29:50-61.
[7] Duncan G S,Kurdi M,Schmitz T,et al. Uncertainty propagation for selected analytical milling stability limit analyses[J].Transactions of NAMRI/SME,2006,34:17-24.
[8] Liu Y,Li T,Liu K,et al. Chatter reliability prediction of turning process system with uncertainties[J]. Mechanical Systems and Signal Processing,2016,66:232-247.
[9] Liu Y,Meng L,Liu K,et al. Chatter reliability of milling system based on first-order second-moment method[J]. The International Journal of Advanced Manufacturing Technology,2016,87(1/2/3/4):801-809.