Computer aided recycling manufacturing system based on product model for reusable mechanical parts

当重新使用旧零件时，需要根据其使用历史数据来评估其质量，因为旧零件可能会因之前使用过程中的磨损和变形等劣化而改变其尺寸和精度。为了构建计算机辅助回收制造系统，这一评价过程应该得到产品信息处理的支持。作为研究的结果，提出了产品模型的结构和新的评价方法，并为每个几何元素定义了形状公差。为几何元素之间的几何关系定义了几何关系约束。将满足产品功能的功能约束定义为装配关系的几何精度、运动轨迹等，并从产品模型中生成与每个功能约束相对应的行为-机构关系表。在评估的准备阶段，通过行为模拟来尝试由行为-机制关系表给出的每一组劣化状态。在行为模拟中，可移动元件中的相应几何关系约束的值被解释为零件之间的间隙的尺寸。通过叠加行为模拟的结果，可以计算出该组劣化状态对行为的影响，作为相应的评估几何精度的值。对于评估，将使用阶段的产品行为与行为-机制关系表中的每个功能约束的阈值进行比较。如果发现要实现的功能约束被满足，则可以利用对应于功能要求的行为-机构关系表来预测相关可移动元件的劣化状态。使用该方法，估计每个可移动元件的劣化状态。

When re-using used parts, their quality needs to be evaluated based on their usage history data, since used parts may have changed their size and accuracy due to deterioration such as abrasion and deformation during their former use. In order to construct a computer aided recycling manufacturing system, this evaluation process should be supported from the product information processing. As results of this research, the structure of the product model and the new evaluation procedure were provided.Form tolerances are defined for each geometric element. A geometrical-relation constraint is defined for the geometrical relation between geometric elements. Functional constraints for satisfying the product function are defined as the geometrical accuracies of assembly relations, motion trajectory and so on. Corresponding to each functional constraint, a behavior-mechanism relation table is generated from the product model. In the preparation stage of the evaluation, each set of deteriorated status given by the behavior-mechanism relation table is tried with the behavior simulation. In the behavior simulation, the value of the corresponding geometrical-relation constraint in the movable element is interpreted as a dimension of the clearance between parts. By superimposing the result of behavior simulation, the effect of that set of deteriorated status on the behavior can be calculated as the value of the corresponding evaluated geometrical accuracy. For the evaluation, the product behavior at the usage stage is compared with the threshold value of each functional constraint in the behavior-mechanism relation table. If a functional constraint to be achieved is found to be satisfied, the behavior-mechanism relation table corresponding to the functional requirement can be utilized for predicting the deteriorated status of the related movable elements. Using this methodology, the deteriorated status for each movable element is estimated.