基于误差流理论的多工位装配过程质量稳定性

为适应质量控制对象由产品转向过程的趋势，对多工位装配过程中的质量稳定性问题进行研究。将多工位装配过程视为一维离散时变系统，采用状态空间方程对其进行建模，模型中的系统矩阵包含了装配过程中的物理结构信息。通过对比理想状态和实际情况下的模型，得到装配过程的误差流模型。在此基础上，根据有界输入有界输出(BIBO)稳定性的概念，通过分析过程误差流模型可得到判断过程是否质量稳定的判定条件，并进一步提出衡量质量稳定性优劣的指标—稳定度这一新概念。以汽车白车身装配过程中一个三工位薄壁件装配为例，对所提出的判据和稳定度概念进行仿真验证。

QUALITY STABILITY OF MULTI-STATIONS ASSEMBLY PROCESS BASED ON STREAM OF VARIATION

The quality stability of multi-stations assembly process is investigated for the transformation from production to process in quality control. The assembly process is regarded as one dimension discrete variant system and modeled by state space equation which contains the physical structure information of assembly process in its system matrix. By compared ideal state with actual condition, the model of stream of variation can be obtained. From the view of stream of variation, the conditions to judge if the process is stable and the index-“stability degree” to show the degree of stability are proposed under the concept of BIBO stability of system. A sheet metal assembly process with three stations, in the white body assembly of car, is given for illustration and verification.