Integration of Parameter and Tolerance Design with Off-Line Quality Control

9503935 Ting本项目通过在设计过程的早期阶段集成参数设计和公差分配，解决了机械系统设计的性能、质量和可制造性问题。该项目包括三个主要任务：(1)通过几何公差表示、带有运动链的机械组件的建模和形状公差的建模来表征公差；(2)开发机械系统的稳健设计方法，以确定性能特征和系统灵敏度指数的推导；(3)通过确定性能、可制造性和成本的公差分配来综合性能公差和可制造性公差，并实现性能、质量和可制造性的最优决策。该方法将在一个案例研究中进行演示。本研究结果为理解公差对成绩的影响提供了一种有效的方法。这种方法处理的是整个系统的容差敏感度，而不是单个环节。然而，它允许人们明确地确定每个个体公差对性能质量的相对影响，并选择对公差不那么敏感的系统。对于机构综合，它适用于任何类型的综合问题，包括函数、轨迹和运动生成或有限、无穷小和混合位置。其有效性保持不变，无论所需职位的数量或链接的数量。综上所述，本研究提出了一种方法，使设计人员能够在设计过程的早期阶段同时进行最优参数设计和公差分配。从而实现了制造成本的降低、产品设计和样机的快速制作以及离线质量控制。

9503935 Ting This project addresses the issue of mechanical system design for performance quality and manufacturability by integrating parameter design and tolerance allocation at an early stage in the design process. The project includes three main tasks: (1) characterizing tolerances by geometric tolerance representation, modeling of mechanical assemblies with kinematic chains, and modeling of form tolerances; (2) developing a robust design methodology for mechanical systems that identifies performance characteristics and derivation of system sensitivity indices; and (3) synthesizing tolerances for performance and manufacturability by determining tolerance allocation for performance, manufacturability and cost reduction, and achieving optimal decisions for performance, quality and manufacturability. The approach will be demonstrated in a case study. The results of this research offer an effective method to understand the effects of tolerances on performance. This method treats the tolerance sensitivity of the whole system rather than an individual link. Yet, it allows one to identify unambiguously the relative impact of each individual tolerance on the performance quality and to select a system less sensitive to the tolerances. For mechanism synthesis, it is applicable to any type of synthesis problems, including function, path, and motion generation or finite, infinitesimal and mixed positions. Its effectiveness remains unchanged regardless of the number of desired positions or the number of links. In summary, this research leads to a method which enables designers to vigorously pursue the optimal parameter design and tolerance allocation concurrently in the early stage of the design process. Thus, manufacturing cost reduction, fast product design and prototyping, and off-line quality control is achieved.