制造可靠性约束下的车身装配偏差动态建模与诊断研究

Fault diagnosis and quality control in the auto body assembly deviations is one of the most important ways to improve the dimensional quality. However, the characteristics, such as multi-station, complicated relationships between root causes and measurement features and small sample, become important obstacles for common use of the diagnostic techniques. Fault diagnosis in the assembly shop always depends on engineering experience. Therefore, based on the reliability analysis of the manufacturing process, the approaches on predictive control for assembly features and fault diagnosis in multi-station assembly process are proposed in this proposal. The specific content is as follows: reliability modeling for manufacturing process for describing relationship between reliability index and main manufacturing parameters; Constructing a dynamic model among main manufacturing parameters, reliability of manufacturing process and quality of the auto body. This model will bridge the process design and process control in the manufacturing process; Sensitivity analysis between main manufacturing parameters and auto body product quality. Based on that, the predictive control method will be proposed; based on posterior probability inference, a diagnosis method for multi-station assembly process can be constructed. At last, the proposed methods will be used and tested, which will provide a useful approach and technique basis for continuous improvement of domestic assembly dimensional quality.

车身装配偏差诊断是提升产品质量的重要途径之一。然而，车身装配工位多、偏差关系复杂以及检测样本小等因素已成为制约传统诊断控制技术推广应用的主要瓶颈。装配车间偏差诊断长期依赖经验、缺乏可靠的理论支持。本项目以制造可靠性的评价和控制为出发点，通过装配可靠性关系的融合建模实现多工位偏差的诊断与制造系统优化设计，保证车身产品尺寸质量。具体内容包括：探索制造过程可靠性评估方法，建立可靠性指标与制造影响因素之间的关系模型；研究制造影响因素—制造可靠性—车身产品可靠性之间的动态关联模型，搭建制造系统工艺设计到装配质量控制之间的桥梁；结合制造影响因素对车身产品可靠性的敏感度分析，研究制造工艺的设计评估与预测控制方法；结合偏差源节点的概率推理实现多工位偏差源诊断。最后通过工程应用验证方法的有效性，为我国车身装配精度持续提升奠定理论与技术基础。

汽车制造是数百个零部件经过冲压、焊装、总装等工序的复杂工艺流程，具有多级、多层面的复杂制造系统特征，质量特征众多、尺寸偏差源复杂。车身制造过程监控与偏差诊断是实现装配质量提升的重要途径。现有基于数据驱动的偏差源诊断方法，如模式匹配法和基于估计的偏差源诊断方法，缺乏对产品和工艺知识的深度应用，导致诊断结论解释困难，导致车身多工位制造质量诊断长期依赖经验、缺乏可靠理论支持。.本项目以车身装配过程的偏差源要素与产品尺寸质量特征间的偏差流影响关系为研究对象，提出车身制造可靠性约束下的装配偏差动态建模方法，通过分析车身制造过程中钣金件材料、模具、夹具磨损以及工艺参数等因素在制造过程中的动态变化特性，研究了车身制造工艺以及产品的系统可靠性综合评价方法，获得了车身装配系统渐进退化规律与可靠度评价模型，在此基础上，构建了多工位装配过程偏差传递的动态模型，提出了多源装配偏差源诊断推理、夹具系统维护策略以及车身产品检测系统优化方法，为制造过程车身装配质量的诊断控制与质量提升提供一定的理论基础和参考。本项目的研究内容主要包括：（1）车身制造过程动态因素分析；（2）车身多工位装配系统可靠性评价方法；（3）车身装配工艺优化设计；（4）装配偏差动态贝叶斯网建模与偏差诊断；（5）面向动态过程的夹具系统维护策略优化。经过三年时间已完成项目研究目标，发表与项目紧密相关且标注本项目资助的SCI期刊论文4篇、EI期刊论文1篇、国际会议论文2篇、中文核心期刊4篇，申请国家发明专利3项（授权1项）。