机床多体系统空间刚度场约束下的加工误差预测  

Prediction of Machining Error for Machine Tool Multi-Body System Restrained by Stiffness Field

作　　者：高羡明[1] 洪军[1] 甄宜超 

机构地区：[1]西安交通大学机械制造系统工程国家重点实验室,西安710049 [2]西安精雕软件科技有限公司,西安710119

出　　处：《西安交通大学学报》2016年第6期90-96,158,共8页Journal of Xi'an Jiaotong University

基　　金：国家自然科学基金资助项目(51575428);国家"863计划"资助项目(2012AA040701);国家重大专项资助项目(2015ZX04014021)

摘　　要：针对机床加工误差预测结果不连续的问题,提出了一种基于多体系统理论的机床加工空间连续误差预测方法。该方法结合多体系统运动学求解特点,将机床部件视作弹性体,利用低序体阵列和传递矩阵来描述机床部件之间的运动关系;基于刚度缩聚理论与最小二乘法原理,提取体单元移动载荷约束下的刚度缩聚模型;基于雅克比传递矩阵建立整机空间加工误差模型。结合切削工艺模拟方法,以某镗铣复合加工中心加工发动机壳体为例,对发动机壳体的立面、底面以及孔特征进行立铣、端铣、镗孔加工误差预测。基于复合工艺约束下的加工误差预测模型,对多种装夹角度下的发动机壳体加工误差进行了对比分析,结果表明,利用多体系统进行低序体阵列描述,有利于实现组合式加工误差求解,可用于机床的组合优化分析;结合切削工艺模拟的复合加工误差分析,以发动机壳体装夹角度为优化目标进行加工工艺优化设计,当转角为90°时,加工精度可提高35%。该方法能够有效地预测加工误差,进而支持机床的工艺优化设计。A novel method for machine tool multi-body system restrained by stiffness field is proposed to solve the difficulty of discontinuous machining error prediction result.According to the characteristics of multi-body system kinematics solution,the machine tool component is considered as an elastic body,and the lower body array and transfer matrix are used to describe the motion relationship between the machine tool components.Following the condensation approach of stiffness matrix and the least square evaluation,the stiffness model under moving load of machine tool component can be obtained.Then Jacobian matrix is taken to construct the machining error prediction model.This method is verified in a boring milling machining error prediction for an engine cylinder head.The combined machining error prediction method enables to optimize the angle of clamping in engine shell machining process.Describing multi-body system by lower body array facilitates evaluating errors in united machining process.Accordingto the combined machining error prediction,the machining precision can be increased by 35% at working degree of 90°.

关 键 词：数控机床 多体系统理论 误差预测 加工空间 工艺优化 

分 类 号：TG502.1[金属学及工艺—金属切削加工及机床]