功能分解有向网络图构造及计算机化实现

受运动复合机构构成原理知识欠缺的制约，基于功能综合方法的运动复合机构创新设计仍是挑战性课题。基于分层递阶理论，建立功能分解商空间模型，根据功能分解层粒度要求以及属性函数对目的功能层的贴近度，采用模糊等价映射和改进的宽度优先求解算法，给出手段功能层最佳分解方案，通过逐层分解细化，得到以基本操作为功能单元的功能分解与或树。遍历功能分解与或树分支及叶节点，确定功能有向网络图拓扑结构。在商空间模型下，功能分解是一个不依赖于知识与专家经验的粒度细化求解过程，能够解决运动复合机构功能分解问题，为后续获得由基本机构巧妙组合创成新颖组合机构方案提供功能分解模型支持。结合干粉压片机机构功能要求，给出了功能分解的算法及功能分解有向网络图构建的计算机化实现。

Construction of Functional Directed Network and Its Computerized Realization

Because of a lack of knowledge to support functional reasoning from functional requirements of kinematic compound mechanisms to their constituent basic mechanisms, the conceptual design of kinematic compound mechanisms based on functional synthesis approach is still a challenging task. With the aid of the stratified hierarchical theory, a functional decomposition model in quotient space is proposed. According to the requirements of granularity in the functional decomposition layer, and the close degrees to the purpose functional layer defined in the attribute function, based on fuzzy equivalence relation and the improved breadth-first algorithm, the optimum decomposition scheme of the purpose functional layer are configured. Through refining the decompose process step by step, the functional means tree corresponding to basic operation actions as the minimum functional units is obtained. Traversing all tree branches and leaf nodes in the functional means tree, the topology of the functional directed network is determined. In the quotient space model, the functional decomposition process does not rely on humans' experiments as well as knowledge in the database. Therefore it can be applied to solve the functional decomposition problem of conceptual design for kinematic compound mechanisms, and gives functional decomposition supports in exploring innovative compound mechanisms combined by a number of basic mechanisms ingeniously. Taking a powder tablet pressing mechanism as an example, the algorithm of the functional decomposition and the computerized realization to construct the functional directed network graph are given.