【作者】 王冬梅；

【导师】 殷国富；

【作者基本信息】 四川大学 ， 机械制造及其自动化， 2006， 博士

【摘要】 现代机构设计包括功能原理设计、方案设计、尺寸综合、运动、动力学分析及评价决策等阶段，具有复杂性、不确定性、创造性、高精度性、综合性、跨学科性等特点，这个过程是个基于经验的设计过程，现有的计算机辅助机构设计一般局限于机构的尺寸综合阶段，仅能满足机构的计算、绘图、三维建模等方面的工作，并且设计精度有待于提高，设计者还需要具备大量的、全面的经验和创新设计方法。如何运用现代设计方法，面向机构整个设计过程，将设计经验、知识形式化、数字化并以显示的方式保存下来并且采用符合设计思维的知识模型和知识处理技术以延伸、启发和提高设计者的设计能力，进行计算机辅助机构设计，是现代机构设计研究的重要内容。本文针对现代机构设计技术研究存在的问题，将现代设计方法融入机构设计过程进行计算机辅助机构设计技术研究，重点研究了机构知识资源的分类、描述、知识资源库的构建、层次结构、应用技术以及功能原理求解、方案设计求解及尺寸综合求解的关键技术，开发了基于知识的计算机辅助机构设计支持系统，本文的研究成果和特色如下：(1)分析了基于知识的计算机辅助机构设计支持系统的功能需求，提出了由知识资源应用分系统、知识管理分系统、机构设计过程分系统、设计过程管理分系统、信息交换分系统所组成的计算机辅助机构设计支持系统的软件功能模型，建立了面向机构设计过程的智能化设计平台。(2)对机构知识按照设计过程、精确性、表现形式、描述方式进行多维度的分类，提出了多维机构知识分类模型，并分析了机构设计知识的特点，提出了基于知识元的设计知识统一描述方法和面向机构设计过程的知识资源库的构成方案，并研究了基于MOP和TOPS方式的实例库组织方式及基于多层次的抽象实例库组织模型的实例聚类算法、规则库的组织形式和形式化描述、模型库组成和存储的层次结构，建立了知识资源库的管理模型，探讨了知识资源的应用技术。(3)提出了在功能原理设计阶段用自然语言描述法进行功能描述的方法，在知识推理阶段用基于功能基的功能信息模型精确描述功能的方法，并且建立了功能及行为信息模型，综合了几种功能原理设计方法，提出了以功能-行为-结构方式为主，功能-工艺动作过程-动作-执行机构为辅的功能原理求解方式。此外，建立了功能抽象和功能分解的求解过程模型，建立了功能分析工具库以支持功能原理设计，并对机构输入、输出运动约束、及运动特性进行了编码。(4)机构选型和构型是机构方案设计的两个阶段，机构选型设计大都依赖于设计实例和基本机构类型，因此本文研究了基于实例的推理技术原理，提出了三级检索选型流程的方法。研究了基本机构功能载体库的信息模型和实例的信息模型建立方法，探讨了实例的推理步骤、冲突消解策略及基于归纳法和最邻近法的实例检索机制，研究了基于选型方案设计的重用层次、设计需求语义元符号串表达、设计方案的树形结构及符号化表达、方案结构树重建等重构技术。(5)机构的参数化设计是方案设计确定了基本型式后，对于结构型式相对固定的机构进行精确、具体的参数设计，本文分析了传统的参数化设计的不足及知识融合的参数化设计技术的特点，研究了基于知识融合参数化技术进行机构参数设计的关键技术：知识约束模型的建立方法，并应用于滑动螺旋机构进行了软件的开发。(6)平面连杆机构的尺度综合问题可归结为满足给定轨迹要求与满足给定位置或运动规律的要求，目前计算机辅助连杆尺寸综合的关键问题是优化算法的确定，本文分析了平面连杆机构的特点和几种优化算法的特点，提出了运用遗传算法进行优化综合的求解策略，并以可调五杆机构轨迹综合问题为例，建立了优化模型，运用遗传算法进行尺寸优化综合，最后给出了优化综合实例。更多还原

【Abstract】 Modern Mechanism design involves the stages of function and principle design, scheme design, dimension synthesis, kinematics, dynamic analysis and evaluation decision-making and so on, with the characteristics of complexity, uncertainty, creativity, high precision, synthetically, cross-subject and etc. This is a design process based on experience. The current CAD on mechanism is limited to the phase of dimension synthesis, which only meets the requirements of calculation , drawing and 3D modeling, and the design precision needs to be further improved. Furthermore, the current CAD mechanism requests designer to own abundant experiences and creative design technique and methodology, Therefore, how to use modern design methodology during the whole process of mechanism design to formalize and digitize mechanism design knowledge so as to preserve them in explicit forms and to use knowledge model accordingly with design idea and technique to dispose knowledge and extend, enlighten and improve design ability of designer in the process of CAD is a key issue in modern mechanism design.Based on problems in technique research of modern mechanism design, this paper aims at research techniques on CAD of mechanism which joins modern design methodology into the process of mechanism design. This research focuses upon the classification, description of knowledge resource on mechanism, construction, hierarchy and application technology of knowledge resource base and key techniques of function and principles solution, scheme design solution and dimension synthesis solution and develops computer aided mechanism design support system based on knowledge. The achievements of this research are highlighted as follows:(1) The software functional model in support of computer aided mechanism design system which is composed of knowledge resource subsystem, knowledge management subsystem, mechanism design process subsystem, design process management subsystem and information exchange subsystem is presented on analysis of function requirements of the supporting system of computer aided mechanism design based on knowledge, and the intelligent design platform oriented to the mechanism design process is built up.(2) Multi-dimension classification model of mechanism design knowledge is put forward, which classify according to design process, accuracy, represent formation, description method as well as the characters of mechanism design knowledge is analysised. A unified design knowledge description method based on knowledge element and composing scheme of knowledge resource base oriented to the process of mechanism design is proposed. The organization method of case base based on the way of MOP and TOPS and a clustering analysis arithmetic of case based on multi-level abstract case base organization model、organization method and formalization description , the composing of model base and storage hierarchy are studied as well as the management model of knowledge resource is set up, application technology of knowledge resource is explored.(3) The method of function description by nature language description at the stage on function and principle design and by precision description of function information model based on function basis at the stage on knowledge reasoning are proposed and the information model of function and behavior are set up. By analyzing the method of function and principle design regarding the solution method of function-behavior-structure as main method and function-process-behavior-structure as supplement one is put forward; furthermore, the solution model of process of function abstraction and function disassembling is set up. and the tool base of function analysis in support of function and principle design is set up, and the movement restrictions of input and output and movement characteristic is coded.(4) Model synthesis and model construction of mechanism are two stages in the process of mechanism scheme design, the model synthesis of mechanism mostly rely on design case and basic mechanism model, so this paper studied the technique principle based on case-reasoning, put forward a kind of method of three layer search to model synthesis and the foundation method of information model of basic mechanism function carrier base and case. This paper also probed into the reasoning step on case, the way of conflict clearing up and case search in nearest neighbor method. Furthermore, the paper research the arrangement of scheme reuse, the expression of symbol cluster of semantics element of design request, the tree-like structure of design scheme and its symbol and reconstruction technique of scheme structure tree.(5) The mechanism parametric design is a precise and idiographic parametric design oriented to mechanism of structure invariability relatively. The paper analysised the limitation of traditional parametric design and studied the characteristics of the parametric design based on knowledge fusion and the key parametric techniques based knowledge fusion in the process of mechanism design: the method of establishing knowledge constraint model and developed software of slippage helix transmission. (6) Dimension synthesis of planar linkages may come down to the request which is to fulfil given track and/or given location. At present, the key of CAD of dimension synthesis of planar linkages is to ascertain the optimized algorithmic. This paper analysised the characteristics of planar linkages and several optimized algorithmic, probed into methods to use genetic algorithmic to optimize synthesis. Furthermore, based on the example of path synthesis solution for adjustable five-bar mechanism, this paper set up an optimized model to use genetic algorithmic to optimize synthesis, and at last an example of optimized synthesis was given.更多还原