产品装配顺序规划方法的研究

计算机辅助装配顺序规划是有关产品装配研究的重要内容。在提高装配顺序规划质量的条件下，综合拆分法与优先约束法的优点，提出了一种装配顺序规划的新方法。在子装配、组件预识别的基础上，采用割集法将产品进行拆分。基于装配城信息建立零件几何优先关系，基于产品共性特征及个性特征建立工艺优先关系，最终生成合理可行的装配顺序，并对实例进行分析。     

装配规划中基于割集的装配顺序生成方法

针对装配规划提出一种新的装配零件关系的描述方法，该方法应用改进的关联图－优先约束关联图，描述装配零件间的连接关系、优先关系及约束关系。在生成产品装配顺序时，充分地把装配优先关系与割集法副合到装配顺序搜索中，有效地生成产品所有满足装配条件的装配顺序，为装配规划提供参考的装配工艺路径。     

集成环境下基于割集的装配顺序生成算法研究

在分析总结以往学者对装配顺序规划研究的基础上，综合拆卸法和优先约束法的特点，探讨了一种新的装配顺序分析方法，该方法利用产品的装配域信息，根据图论的割集法对产品进行拆分，建立几何优先约束关系，然后通过人机交互的方式建立工艺优先约束关系，最终得到可行的产品装配顺序。实现了集成环境下基于割集的装配顺序规划。给出了割集的生成算法框图以及装配顺序规划的算法框图，最后通过实例验证。     

集成环境下基于CAD产品装配顺序规划

在分析总结以往学者对装配顺序规划的研究基础上，综合拆卸法和优先约束法的特点，探讨了一种新的装配顺序分析方法，该方法利用产品的装配域信息，根据图论的割集法对产品进行拆分，建立几何优先约束关系，然后通过人机交互的方式建立工艺优先约束关系，最终得到可行的产品装配顺序。实现了集成环境下基于CAD产品装配顺序规划。本文给出了割集的生成算法框图以及装配顺序规划的算法框图，最后通过实例验证。     

面向序列规划的装配工艺APS树模型生成的研究

分析了现有装配序列规划方法和装配序列表达模型的缺陷，提出了一种合理的装配工艺APS树模型，并用这种模型表达非线性的装配序列。利用产品功能结构树和零部件的信息，采用基于装配关系图分割的几何推理和基于规则的知识推理的方法来简化工艺子装配体的识别，以此生成装配结构树。然后，利用装配知识判定子装配体的装配优先约束关系，提高由装配结构树生成装配工艺APS树的效率。最后，基于装配结构树，通过不断添加数据节点和关系节点，自上而下分层规划，从而生成产品的装配工艺APS树。     

计算机辅助几何可行装配顺序推理及基优化分析

针对装配优先关系分析,几何可行装配顺序推理以及最优几何可行装配顺序选择3个层次的问题,提出了一种系统化的分析方法-几何约束分析方法,该方法从装配体中各个零件之间的约束方向分析出发,可以自动求解出正确和完备的装配优先关系;在装配优先关系的约束政下,可以计算出所有的几何可行装配顺序规划;并从操作空间大、装配方便角度出发,设计出几何可行装配顺序优选算法;可以从大量的几何可行装配顺序中求解出几何性能最佳的装配顺序规划,应用具体实例分析演示了几何约束方法在计算机中的实现过程,并证实了该方法的实用性有效性。     

计算机辅助几何可行装配顺序推理及其优化分析

针对装配优先关系分析、几何可行装配顺序推理以及最优几何可行装配顺序选择3个层次的问题,提出了一种系统化的分析方法——几何约束分析方法。该方法从装配体中各个零件之间的约束方向分析出发,可以自动求解出正确和完备的装配优先关系在装配优先关系的约束下,可以计算出所有的几何可行装配顺序规划;并从操作空间大、装配方便角度出发,设计出几何可行装配顺序优选算法,可以从大量的几何可行装配顺序中求解出几何性能最佳的装配顺序规划。应用具体实例分析演示了几何约束分析方法在计算机中的实现过程,并证实了该方法的实用性和有效性。     

装配顺序规划中的几何约束分析方法

针对目前计算机辅助装配顺序规划中存在的问题，提出了一种几何约束分析方法。该方法根据装配结构设计ＣＡＤ信息，利用ＧＣＡ最小约束装配状态算法，能够计算出正确、完备的装配优先关系，为进一步提高装配顺序规划的自动化水平和分析效率提供了一种有效途径。     

定位关系在装配序列规划中的应用研究

为提高产品仿真装配效率和满足装配工艺要求,提出一种基于定位关系分析的分类装配序列规划方法.首先对零件的装配特征属性进行预定义和分类,然后根据装配零件的联接关系,在可行拆装方向上建立所有邻接零件的定位关系链有向图;按照定位链顺序依次对零件进行干涉检测并更新其定位关系,最终获得可行装配序列.实例表明,该方法简化了模型的装配关系并有效缩小其装配序列解空间,在一定程度上提高了装配规划效率,并通过虚拟拆装仿真过程验证其生成序列的正确性和可行性.     

几何可行装配顺序推理方法及实现技术

在系统分析相关文献的基础上，重点针对装配优先关系推理和几何可行装配顺序计算，提出了一种系统化的分析方法－“几何约束分析”方法。该方法从装配体中各个零件之间的约束方向计算出发，可以自动求解出装配结构本身所固有的、隐含的装配优先关系，而且能够保证推理结果的正确性和完备性。在此基础上，设计出几何可行装配顺序的反向推理算法，并结合实例分析了基于几何约束分析方法的装配优先关系推理，及几何可行装配顺序推理的计     

Computer aided geometric feasible assembly sequence planning and optimizing

Assembly sequence planning (ASP) is the foundation of the assembly process planning and design for assembly (DFA). In ASP, geometric feasibility is the prerequisite in the valid assembly sequences searching. The assembly precedence relations’ (APRs) deriving and fulfilling are the essential tasks in the geometric feasible assembly sequence planning. In this paper, a systematical approach called geometric constraint analysis (GCA) is proposed and the corresponding software system is developed and integrated with CAD system. Using this system, only with a few mouse clicks on CAD draft, assembly precedence relations (APRs) can be derived correctly and completely. Then, all the geometric feasible assembly sequences can be inferred out automatically. Moreover, an optimal algorithm is designed and realized in the GCA method, by which, the most optimal assembly sequence in terms of the operation convenience can be found out from the immense geometric feasible sequences. An erratum to this article can be found at     

改进的装配序列规划方法研究

分析了传统零件序列表达方法的不足，提出以装配体联系图的各边为序列的表示方法，进而展开对边序列几何可行性分析、边序列还原、零件可行直线装配方向推理及边序列精简的研究；从便于高效自动筛选的角度研究了影响边序列质量的工艺因素（发生冲突的边的个数，稳定性和聚合性的影响，直线装配方向的改变次数），在此基础上建立了边序列的优化目标函数。基于遗传模拟退火算法的实例验证表明，该方法是一种有效的产品装配序列规划方法．     

基于复合装配图进行装配序列规划的研究

为了构建一个有效且便于使用的装配序列规划系统,给出了一个开放式装配模型———复合装配图,以有向装配连接图表述零件之间的优先关系,利用检查有向圈、删除冗余有向边确保该图正确、简洁。在此基础上,用无向边连接没有优先关系的零件,并根据装配代价和装配可行性对有向边、无向边赋权值,得到复合装配图。将装配序列规划描述为在复合装配图中求解特殊的最优H回路,并且基于分支定界法给出了满足优先关系、装配可行性、装配代价优化的装配顺序规划算法。最后通过实例验证了算法的有效性。     

考虑工具操作空间的装配序列生成方法

介绍了基于有向图的装配模型,该模型记录了零件间的优先关系,并对普通零件、紧固件进行不同的描述。在UG环境中对装配工具进行建模,在完整装配体中对工具的安装动作进行仿真和干涉检查,记录下工具同周围零件的潜在干涉信息,利用该信息快速检查装配序列是否满足工具的操作空间要求。然后应用改进的蚁群算法,在优先关系的指导下求解装配序列。针对妨碍工具操作等不可行的序列,提出信息素的惩罚蒸发策略,帮助蚁群避开不可行解。最后通过实例验证了算法的实用性。     

基于优先约束关系的装配序列规划研究

利用联结图方法建立设备的装配关系模型,生成联结矩阵,并利用子装配体的概念对模型进行简化.利用联结图模型分析零件间的优先约束关系生成优先关系矩阵,利用优先约束矩阵生成设备的可行装配序列,为设备装配序列选优提供基础.     

A systematic approach for automatic assembly sequence plan generation

This paper presents a systematic approach for automatic assembly sequence plan generation (ASPG) by using an integrated framework of the part liaison matrix and precedence Boolean relations. The objective of this study is to propose a unified and integrated mathematical representation, manageable by computer programs, that allows an optimal assembly sequence be generated for various different production conditions and environment. To meet the aforementioned objective, a five-step modelling procedure is presented. In the first step, the product design and production information associated with part allocations and assembling sequences are logically arranged, simplified and systematically coded into the liaison matrix and precedence Boolean algebraic expression. In the second step, the position and assembly sequence relations of the original product are simplified into the so-called sub-assembly by using a group-like technology method. By doing so, the liaison matrix and precedence Boolean relation of the grouped sub-assemblies can then be easily obtained in the third modelling step. In the fourth modelling step, the constrained precedence Boolean relations of the grouped sub-assemblies are characterised and generalised for use in the proposed model. By simultaneously solving the aforementioned general and constrained position and precedence Boolean relations, the optimised assembly sequence of the underlying product can be quickly obtained in the fifth modelling step. A product assembly example is presented to illustrate the effectiveness of the proposed modelling approach. The enhancement of assembly efficiency and quality are also carefully evaluated .     

Optimization of operation sequencing in CAPP using simulated annealing technique (SAT)

Computer-aided process planning (CAPP) is an important interface between computer-aided design (CAD) and computer-aided manufacturing (CAM) in computer-integrated manufacturing environment. A problem in traditional CAPP system is that the multiple planning tasks are treated in a linear approach. This leads to an over constrained overall solution space and the final solution is normally far from optimal or even non-feasible. The operation-sequencing problem in process planning is considered to produce a part with the objective of minimizing the sum of machine, setup and tool change costs. In general, the problem has combinatorial characteristics and complex precedence relations, which makes the problem more difficult to solve. In this paper, the feasible sequences of operations are generated based on the precedence cost matrix and reward–penalty matrix using simulated annealing technique (SAT), a meta-heuristic. A number of benchmark case studies are carried out to demonstrate the feasibility and robustness of the proposed algorithm. This algorithm performs well on all the test problems, exceeding or matching the solution quality of the results reported in the literature for most problems. The main contribution of this work focuses on reducing the optimal cost with a lesser computational time along with generation of more alternate optimal feasible sequences. The proposed SAT integrates robustness, convergence and trapping out of local minima.     

Assembly sequences merging based on assembly unit partitioning

Assembly sequence planning is a typical of combinatorial optimization problem which is difficult to be tackled when the number of parts of assembly becomes large. To reduce the searching space of assembly sequence planning of complex products, assembly sequences merging based on assembly unit partitioning is suggested. Assembly unit partitioning is presented to decompose the complex products into a group of assembly units containing a reduced number of parts or components, and the assembly design constraints and the assembly process constraints are comprehensively taken into account. The global optimal assembly sequences can be acquired through three steps. Firstly, the assembly units and decision graph of assembly unit are generated utilizing fuzzy analytical hierarchy process approach. Secondly, the optimal or near-optimal subsequences of assembly units can be obtained with current efficient methods of assembly sequence planning. Thirdly, under the assembly interference of assembly relations (geometrical constraints) of the whole products and the assembly precedence concluded by subsequences of assembly units, the assembly sequence merging is implemented to generate the global assembly sequences, and the optimal sequence is obtained through assembly sequences evaluation. The assembly constraints considered at the two previous steps is represented by the evaluation function. The effectiveness of the method is verified by an illustrative example and the results show that the searching space of assembly sequence merging of complex products is reduced remarkably and the optimal assembly sequence of the whole produces is obtained.