机床工艺系统建模及精度保证技术.pdf

机床工艺系统建模及精度保证技术.pdf机床工艺系统建模及精度保证技术研究生:刘术林指导导师:王兴松教授东南大学机械工程学院摘要随着现代科技的飞速发展,人们对机械加工的精度不断提出更高的要求,精密和超精密加工技术始终是人们研究的重点。本文针对车削工艺系统中存在的加工误差进行分析,建立了车削工艺系统的静态误差模型和振动模型。设计了基于稀土超磁致伸缩材料的二维误差补偿机构,对工艺系统的误差进行补偿补偿试验。车削工艺系统主要由主轴、工件、刀央系统以尾架等组成。由于切削力的存在,在车削工件,特别是细长杆时,工艺系统将会发生变形,从而引起工件的加工误差。本文对车削变截面细长杆时工艺系统各组成部分的受力变形进行了分析,给出了工件误差的计算结果。运用动力学相关原理,建立了卡盘一顶尖装夹下欧拉一伯努利型细长阶梯梁的自由振动模型,求取了该工件自由振动时的固有频率和模态函数。在ANSYS中建立的工件模型进行分析。在此基础上,对工件在切削力作用下的受迫振动进行分析,给出了工件的受迫振动响应。针对切削加工中的颤振现象,在传统单自由度颤振模型的基础h,综合考虑了工件的振动响应以及重合度系数的影响,建立了两自由度的切削系统模型。利用该模型对切削系统的振动响应及切削稳定性进行仿真,分析了不同参数下系统发生颤振的临界切削宽度。设计了基于柔性铰链的二维微位移平台,解决了两个方向位移输出的耦合问题,并与稀土超磁致伸缩驱动器一起组成了二维误差补偿机构。建立了该驱动器的Duhem迟滞模型和系统的传递函数,在MATLAB中进行了仿真。使用基于Duhem逆模自订馈的 PID方法对误差补偿机构进行控制,仿真和实验表明该控制方法消除了系统的迟滞非线性。最后,利用设计的二维误差补偿机构对车削工艺系统的切削变形误差与行程误差进行补偿,成功降低了工件的加工误差,证明了本文方案的正确性。关键词:工艺系统,静态误差,颤振,动力学建模,重叠系数,二维误差补偿机构 Modeling and Precision Guaranteeing Technique ofMachine Tool Process System By LIU Shulin Supervised by Professor WANG Xingsong School ofMechanical Engineering,Southeast University Abstract With thefastdevelopment ofmodem technology,higher and higher accuracy ofmachinery required. Precisionandultra-precisionmanufacturing technology isalways thefocusofresearchers. The machining error due toprocess system oflathewas analyzed;Models of thestatic error and vibration of theprocess system were 2-DOFs pensation mechanism Was designed pensate theerrorofprocess system. The process system oflathe consists ofspindle,workpiece,tool system workpiecesespecially slim-longbeams,process system willdeformed as aresultof thecutting deformation willfinally cause machining thispaper'deformation ofthe process system when turningtrapezoidtapered slim-long beam was analyzed and relevant calculation resultoftheworkpiece error wasgiven. Freevibrationmodel oftheslim—long beam held between achuck and atailstock was put forward using dynamics itsnatural frequency and mode function were analysis made in ANSYS softwaregave resul