面向数控机床装配精度预测的元动作误差建模技术

摘要

装配是保证产品质量的重要环节,而装配精度是装配过程的重要度量指标.为预测数控机床最终装配精度,利用”功能-运动-动作(Function-Movement-Action,FMA)”的功能分解原则对机床的装配过程进行结构化分析,将机床分解至基本动作单元-元动作;构建基于元动作的装配误差传递层次架构图,清晰地表达了各装配单元间的装配关系及几何特征之间的逻辑关系;以几何特征误差在装配过程中的传递与积累为基础,构建多层次状态空间模型预测数控机床最终装配精度;以某数控加工中心的Z轴进给功能装配单元为例,验证了该方法在机床装配误差预测中的可行性.%Assembly is a key of product quality assurance,and assembly precision is an important measurement index in assembling process.There were four steps to predict assembly precision of NC machine.Firstly,the functional decomposition approach "function-motion-action" was used to analyze its assembly process structurally,then it was decomposed down into basic action,i.e.meta-action.Secondly,in order to express the assembly relationship between the assembly units and the logical relationship between the geometry features,the frame chart of assembly errors propagation via meta-action was constructed.Thirdly,the multi-level model for state space was built to predict final assembly precision of NC machine on the basis of the propagation and accumulation of geometry errors.Finally,the effectiveness of multi-level model for state space was demonstrated by an example of Z axis feed function assembly unit from a certain machining center.