Abstract: To accurately evaluate the health status of engine cylinder head assembly system,aiming at the problems of randomness and fuzziness in the process of system evaluation,a health status evaluation method based on brittleness and cloud model was proposed.According to the characteristics of engine cylinder head assembly system and the principle of index system construction,a three-level evaluation index system was established to comprehensively characterize the health status of the system.The health status of engine cylinder head assembly system was classified by brittleness,and the uncertain mapping between evaluation index value and evaluation set was realized with cloud model theory.Then the health status of the system was evaluated based on cloud barycenter evaluation method,which effectively solved the problem of uncertainty conversion between qualitative concept and quantitative value in the evaluation process.Combined with brittleness theory and polymorphism theory,the calculation model of system brittleness was constructed,and the results of system health assessment were verified and analyzed based on the real-time brittleness value of the system.An engine cylinder head assembly system was taken as an example to verify the correctness and effectiveness of the proposed method.

Key words: cloud model, brittleness, cloud barycenter evaluation method, health status, engine cylinder head assembly system

摘要： 为实现对发动机缸盖装配系统健康状态的准确评估,针对发动机缸盖装配系统评估过程中存在的随机性和模糊性问题,提出一种基于脆性度和云模型的健康状态评估方法。基于发动机缸盖装配系统自身特点及指标体系构建原则,建立了表征系统健康状态的三级评估指标体系;利用脆性度划分发动机缸盖装配系统健康状态等级,通过运用云模型理论实现评估指标值和评语集之间的不确定映射,基于云重心评判法完成对系统健康状态的评估,有效解决了评估过程中定性概念和定量数值间的不确定性转换问题;结合脆性理论和多态理论构建系统脆性度计算模型,基于系统实时脆性度值对上述系统健康状态评估结果进行验证分析;以某实际发动机缸盖装配系统为例,验证了所提方法的正确性和有效性。

关键词: 云模型, 脆性度, 云重心评判法, 健康状态, 发动机缸盖装配系统