基于元动作单元的数控机床故障分级决策方法

Fault classification decision method of CNC machine tool based on meta-action unit

为快速、准确地判断数控机床故障等级,避免出现花大代价处理次要故障,而关键故障却被忽略的情况,提出了一种以元动作单元为分析主体的数控机床故障分级决策方法。首先,为细化数控机床故障分析的粒度,使得分析过程更加简便,从系统功能分解的角度将数控机床按照"功能(function)-运动(motion)-动作(action)"逐层分解直至元动作层。其次,通过对分解过程进行分析,给出了元动作单元概念模型,明确了一个标准元动作单元需要包含的3类要素。然后,从动作的层面全面分析并总结元动作单元的故障模式类型。接着,定义了元动作单元故障模式的3个等级,按照评价指标对数控机床故障模式进行评价,再通过灰色聚类理论分析故障模式量化评价值,利用所得出的聚类结果建立了故障模式分级的原始决策表,随后通过粗糙集理论对原始决策表进行知识约简以使决策规则进一步简化,最终形成了一种能够快速、准确确定故障模式等级的决策方法。最后,通过对某数控机床齿条移动元动作单元的分析,验证了所提方法的合理性与有效性。实例分析结果表明使用该方法能够快速、准确地确定数控机床的故障模式等级,提高了决策效率,所得结论更加明确且具有针对性,可为后续的维修过程控制提供依据。研究结果能给相关企业确定数控机床故障等级提供有效指导,一定程度上优化企业维修资源的配置。

In order to quickly and accurately determine the fault classification of CNC(computerized numerical control)machine tools,a fault classification decision method based on the metaaction unit was proposed,which could avoid costly handing of minor faults while key faults were ignored.Firstly,to refine the granularity of fault analysis of CNC machine tools,which made analysis process more convenient,according to"function-motion-action",the CNC machine tool was decomposed to the meta-action layer by layer from the point of view of system functional decomposition.Secondly,the concept model of the meta-action unit was elaborated by analyzing the decomposition process and three elements of a standard meta-action unit were defined.Thirdly,fault modes of the meta-action unit were analyzed and summarized comprehensively.Fourthly,three levels of fault modes of meta-action unit were defined.According to the evaluation index,the fault modes of CNC machine tools were evaluated,and then the grey clustering theory was applied to analyze the quantified evaluation value of the fault modes,and the original decision ta ble of fault mode classification was established based on the clustering results obtained.After that the knowledge reduction of the original decision table made the decision rules further simplified through the rough set theory,ultimately a fast and accurate fault classification decision method was formed.Finally,the rationality and effectiveness of the proposed method was demonstrated by an example analysis of the rack movement meta-action unit in a certain CNC machine tool.The example analysis result indicated that the fault mode levels of CNC machine tools could be determined quickly and accurately so as to improve decision efficiency by this method,the obtained conclusion was more clear and pertinent,which could provide the basis for the subsequent maintenance process control.The research results can provide useful guidance for relevant enterprises to determine the fault levels of CNC machine tools,and to optimjze the allocation of enterprise maintenance resources to some extent.