摘要
多轴联动机床刀尖点在空间运动过程中由于机床结构构形改变和轴间耦合作用,会造成动结合部刚度的非线性变化,进而改变系统惯性矩阵、刚度矩阵元素的量值,从而导致系统动态特性的改变。以一台典型的三轴联动龙门机床为研究对象,采用集中参数法建立轴间耦合下三轴联动机床系统的动力学模型,并推导系统的动力学方程,其系数矩阵是系统运动状态的函数。利用所建模型,对系统频率和频率响应函数相对于位置参数的变化进行分析。仿真和试验结果表明:轴间耦合作用对多轴联动机床的动态特性影响较大,系统的固有频率及对应幅值与刀尖点在x轴、y轴、z轴运动位置的变化有很大关系,极端位置的固有频率相差10%左右,响应的幅值变化量可达2倍左右。
Because of the changing of the machine tool configuration and the axis coupling forces in multi-axis machine tools motion, the stiffness of the kinematic joints will change nonlinearly, therefore the amount of the inertia matrix, stiffness matrix of the system will vary, resulting in the variation of the dynamic characteristics of the system. A typical three axis gantry-type machine tool is taken as an object of investigation, using the lumped-parameter method to set up the dynamic model of machine tool and derive the dynamic equation. The system matrices with respect to position are established. Based on the dynamic model, the variations of the frequencies and frequency response functions with respect to position parameters are calculated. Modal testing is carded out to validate the accuracy of the model. The simulation and experimental results show that： the dynamic characteristics of the machine tool are greatly affected by axial coupling, the natural frequencies and the reacceptance of the tool cutting point （TCP） are greatly changed when the TCP is moving along x-axis, y-axis or z-axis. Comparing two extreme positions, the maximum changing of natural frequencies is up to 10% and response magnitude up to 2 times.
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2014年第15期89-96,共8页
Journal of Mechanical Engineering
基金
国家重点基础研究发展计划(973计划
2009CB724407)
国家科技重大专项(2011ZX04016-031)
国家自然科学基金(51235009)资助项目
关键词
轴间耦合
多轴联动机床
变动态特性
位置维
axis coupling effects； multi-axis machine tool； variation of the dynamic characteristics； position-dependent
