共查询到20条相似文献,搜索用时 15 毫秒
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为了实现以自顶向下为主、自底向上为辅的双向产品设计方法,本文提出了一种面向产品族的混合装配模型。该模型由装配骨架模型、层次模型、约束关系模型、零件属性模型及参数化设计模型组成。通过引入高层次的装配骨架模型反映设计者的设计意图并自动向下游传播装配约束,实现自顶向下面向过程的设计方法;通过引入低层次的约束关系模型记录零件之间的各种约束关系,检验、改进和完成最终装配模型的重建,实现自底向上的面向结果的设计方法;通过引入参数化设计模型完成装配体的变形设计,实现以往知识的重用。最后用实例说明该混合装配建模方法的有效性。 相似文献
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Christophe Perrard Eric Bonjour 《The International Journal of Advanced Manufacturing Technology》2013,69(1-4):669-685
Sequence planning generation is an important problem in assembly line design. A good assembly sequence can help to reduce the cost and time of the manufacturing process. This paper focuses on assembly sequence planning (ASP) known as a hard combinatorial optimization problem. Although the ASP problem has been tackled via even more sophisticated optimization techniques, these techniques are often inefficient for proposing feasible assembly sequences that satisfy the assembly planners’ preferences. This paper presents an approach that makes easier to check the validity of operations in assembly process. It is based on a model of the assembly planners’ preferences by means of strategic constraints. It helps to check a priori the consistency of the assembly constraints (strategic and operative constraints) given by the assembly system designers before and while running an assembly plan generation algorithm. This approach reduces the solution space significantly. A case study is presented to demonstrate the relevance of the proposed approach. 相似文献
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Hsin-Yi Lai Chin-Tzwu Huang 《The International Journal of Advanced Manufacturing Technology》2004,24(9-10):752-763
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 . 相似文献
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基于配合约束的装配序列规划的遗传算法研究 总被引:5,自引:1,他引:4
为提高装配序列规划问题的寻优效率,提出了一种将装配约束条件和遗传算法相结合的求解方法.对配合约束进行了分类并给出每种类型特征尺寸的定义.在此基础上,引入特征标签的概念,用于描述零件的装配特征信息和配合约束关系.根据零件间特征标签的相似程度设计了可装配度函数,以度量装配的可行程度,并以该函数为基础构建了遗传算法的适应度函数.另外,为减少无用个体的数目,提出了基于配合约束的子代个体的保留策略,并以此为指导进行子代的有效性检验.最后,通过实例说明了该算法的有效性. 相似文献
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An Intelligent Computer-Aided Assembly Process Planning System 总被引:5,自引:1,他引:4
This paper presents an intelligent computer-aided assembly process planning system (ICAAPP) developed for generating an optimal
assembly sequence for mechanical parts. The system employs a graph set technique for creating an assembly model. The set includes
an attributed topological graph, an attachment constraint graph, a tolerance graph and a special process constraint graph.
In the generation of assembly sequences for any product, the critical problems to be addressed include determining the base
part, selection of subassemblies, defining all necessary constraints, and quantifying and solving these constraints. In the
ICAAPP system, algorithms have been developed for the selection of the base part, defining of the subassemblies, and determination
of the constraint values. A simple mechanical assembly is used to illustrate the feasibility of the proposed algorithms. 相似文献
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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。 相似文献
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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。 相似文献
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Efficient method of assembly sequence planning based on GAAA and optimizing by assembly path feedback for complex product 总被引:5,自引:5,他引:0
Cheng Hui Li Yuan Zhang Kai-fu 《The International Journal of Advanced Manufacturing Technology》2009,42(11-12):1187-1204
In the process of complex product assembly, assembly resources (fixtures, tools, operations, and so on) must enter assembly environment with parts together to rapidly finish product assembly. Assembly planning must take assembly resources into account fully. But, designer cannot plan every assembly procedure because of the lack of assembly resources during assembly design. Then, it will cause assembly failures and redesign for assembly easily. This paper investigates an efficient method of assembly sequence planning based on genetic algorithm and ants algorithm (GAAA) and optimizing by assembly path feedback to assembly process planning including assembly resources for complex products. Firstly, a new GAAA is investigated to rapidly plan assembly sequence in order to solve the nondeterministic polynomial-bounded problem in high searching and solving efficiency. Secondly, on the basis of the assembly sequence, a B-Rep filling algorithm which can form a swept volume between the part and its kinetic orientation is developed to plan assembly path interactively. Thirdly, the performance of the assembly path according to the assembly sequence is analyzed and sent back to avoid the most of assembly collisions and interventions during product assembly design. Lastly, we develop a simulating system to simulate assembly sequence and path based on component application architecture for CATIA V5. The simulating result proved that the proposed method of assembly sequence planning based on GAAA and optimizing by assembly path feedback for complex products is efficient. Assembly optimal design including assembly resources can work well. 相似文献
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基于约束解除的装配序列并行化优化 总被引:1,自引:0,他引:1
为了提高产品装配的效率,提高装配序列的并行性,提出了基于约束解除和简化配合关联图的装配序列并行优化方法。给出了装配效率的评价指标一并行性评价因子的数学模型。将模糊逻辑用于装配约束的量化过程,通过约束归约方法将无约束条件下可自由运动零件的自身约束与零件间通过点、线、面之间几何约束关系所表达的装配约束进行求交,建立零件间的等价约束评价值即联接度,联接度概念的提出清晰地表达了配合关联图中的薄弱环节;在此基础上,建立装配体的赋权配合关联图,并根据联接度值的大小对零件间的虚联接进行简化,给出了一个基于阈值的追求装配最高并发度的配合关联图分解与重组策略,实现了装配序列并行优化,并通过实例说明了该算法的有效性。 相似文献
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针对跨区互联电网,提出了计及现货市场出清的大电网安全校核策略;分析了跨区互联电力市场出清以及安全校核的主要流程以及出清模式;分析了安全校核与潮流断面之间的关系。提出了以新能源机组外送交易电力最大、总成本最低和外送电力成本最低为目标的电力调度多目标优化模型,同时考虑安全校核约束。分析了考虑新能源的大电网多级安全校核流程,主要针对断面安全约束以及出清调度计划约束和新能源交易约束。仿真结果表明,安全校核作为电力调度和现货市场交易的约束,能够有效提升联络线功率平衡以及稳定性。 相似文献
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Integrated knowledge-based assembly sequence planning 总被引:14,自引:4,他引:10
Dr X. F. Zha Samuel Y. E. Lim S. C. Fok 《The International Journal of Advanced Manufacturing Technology》1998,14(1):50-64
This paper presents a novel approach and system for the automatic generation, selection and evaluation, optimisation, and simulation of assembly plans. The information and knowledge about a product and its assembly (e.g. assembly constraints, solid model and CAD database, heuristic rules) are described using a hybrid approach and model with numeric and symbolic representation. A new methodology is presented to generate all feasible assembly sequences of the product by reasoning and decomposing the feasible subassemblies, and representing them by the assembly Petri net modelling. Qualitative strategic constraints are then used to evaluate the feasible assembly sequences. In order to obtain a good assembly sequence, some quantitative criteria such as assembly time and cost, workstation number, operator number, and part priority index are applied to select the optimal assembly sequence. Based on DFA analysis, MTM time analysis, and assemblability analysis, estimates are made of the assembly time and cost of the product when each of these sequences is used. A knowledge-based system KAPSS has been developed to achieve the integration of generation, selection evaluation, and visualisation of the assembly sequences. 相似文献
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三维装配尺寸链的自动生成 总被引:17,自引:2,他引:15
提出了一种基于CAD模型的三维装配尺寸链自动生成方法。该方法从定义装配性能特征入手,首先对CAD装配模型进行深层次的解析及预处理,以获取隐含在模型内部的公差分析所需信息。然后利用图论理论,通过构建特征-尺寸邻接矩阵、特征-装配约束关系邻接矩阵、装配关系传递图等,将装配体中参与装配的零件和特征以及其之间的装配约束关系、尺寸及形状等信息的传递过程以图的形式进行表达。最后将三维尺寸链分为显式和隐式两类,对于显式尺寸链,由装配关系传递图搜索连通通路可直接获取尺寸链图和方程:对于隐式尺寸链,提出了尺寸方向差异度的概念、封闭环方向优先的搜索策略以及构建过渡尺寸链的方法,最终可获取尺寸链图和方程。该方法已在自主开发的三维装配尺寸链自动生成系统中得到了验证。 相似文献
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Formalized reasoning method for assembly sequences based on Polychromatic Sets theory 总被引:2,自引:2,他引:0
Shanshan Zhao Zongbin Li 《The International Journal of Advanced Manufacturing Technology》2009,42(9-10):993-1004
This paper presents a new formalized reasoning method for assembly sequences generation which reduces the solution space dramatically. Firstly, a polychromatic sets (PS) matrix is introduced to describe the relations between the part-match and freedom; Secondly, the polychromatic sets matrix of entirety and element are used to describe the relations between the parts and assembly constraints; assembly constraint models and connector assembly models are constructed in this phase; then, the solution method for constraint equations is given; and the reasoning algorithm of feasible sequence is presented. Finally, an application case is studied to demonstrate the effectiveness of the method. 相似文献
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针对活动线缆在安装和服役过程中受到单面约束时的运动过程仿真问题,提出一种基于弹性细杆静力学理论的光滑平面约束下的活动线缆物性建模与仿真方法。该方法通过分析活动线缆在光滑平面约束下的受力情况,将活动线缆所受到的约束力用拉格朗日乘子表达,将节点与平面的相对空间位置关系作为限制活动线缆运动的约束方程,得到分布力作用下的活动线缆Kirchhoff平衡方程,并建立活动线缆的物理模型。进而采用非线性约束优化方法求解模型。最后根据不同假设条件进行算例测试,通过比较活动线缆的仿真形态和实际形态,验证模型和数值解法的正确性。结果表明,该模型和解法能充分真实地表达活动线缆的基本物理特性和活动线缆受到光滑平面约束时的形变特点。 相似文献