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1、* 五轴数控系统旋转轴快速平滑插补控制策略1,2 2 2 1,2 1,2 郑飂默林浒盖荣丽王峰张晓辉(1.中国科学院研究生院北京110039;2.中国科学院沈阳计算技术研究所高档数控国家工程研究中心,沈阳110171)摘要:在五轴联动加工中,刀轴矢量与旋转轴运动坐标之间存在非线性关系,刀轴矢量的平滑过渡不能保证旋转轴的平滑运动,尤其是当刀轴矢量接近机构奇异点时会引起旋转轴的剧烈震动,导致伺服报警,甚至损伤机床部件。通过分析旋转轴线性插补和矢量插补过程中刀具姿态的变化情况,抽象出刀具姿态误差模型。根据
2、加工允许的刀具姿态误差,在矢量插值段中插入线性插值段,防止靠近奇异点处产生的旋转轴急速转动。结合指令行程和旋转轴性能进行旋转轴插补速度钳制,使用三次样条曲线对矢量插值段和线性插值段进行平滑连接,保证整个插补过程中速度的连续平滑。试验结果表明,本策略可以在满足刀姿误差要求的同时,实现旋转轴的快速平滑插补,并且已经应用于某航空结构件的批量加工生产中。关键词:五轴数控系统运动控制刀姿误差奇异点中图分类号:TG156Fast Smooth InterpolationControl Strategy of R
3、otaryAxesforFiveaxisCNC Systems1,2 221,2 1,2 ZHENG Liaomo LIN Hu GAIRongli WANG Feng ZHANG Xiaohui (1. GraduateUniversity of ChineseAcademy of Sciences, Beijing 100039; 2. National Engineering ResearchCenter for HighEnd CNC, ShenyangInstituteof Computi
4、ngTechnology, ChineseAcademy ofSciences, Shenyang 110171 )Abstract:In the fiveaxismachining,duetothenonlinearrelationshipbetweenthetoolorientationvectorandtherotaryaxis coordinates,smooth interpolation movementofrotaryaxesisnotcapableofbeingguaranteedb
5、y smooth transition ofthetoolaxis vector.Especiallywhenthe vectorspass through thesingularpointoritsneighborhood,the strenuous mechanicalvibration ofthe rotaryaxis causes the servoalarm,even damagesthemachine parts.The toolposture errormodelis construc
6、tedbyanalyzingthe changingsituationofthetoolposture intheprocessoftherotaryaxislinearinterpolation andvectorinterpolation.Accordingto the acceptable valueofthepostureerrorinfiveaxismachining process, thelinearinterpolation range isinsertedintothevector
7、interpolation processingtoavoid the rapid rotation movementofthe rotaryaxesin the singularzone.Thenthe limitingvelocityis determinedaccordingtothe linearinterpolationrange andthe performance ofrotaryaxes. Finally,acubicspline curve isusedto eliminateth
8、e discontinuityofspeedproducedon the boundaryofthe range which performslinearinterpolationandthe range which interpolatesbythevectorinterpolation,andsmoothoperationisrealized.Experimentalresultsshowthatthefastsmooth interpolation ofrota