Representing Relationships in Hierarchical Assemblies

Author(s):  
Jeff Heisserman ◽  
Raju Mattikalli

Abstract Computer aided design tools are gaining popularity in industry due to their ability to model the geometric aspects of products. This has shown substantial benefit for reducing the need and expense of building physical prototypes and allowing parts and tooling to be manufactured directly from these models. However, the current capabilities in existing CAD tools for modeling assemblies are quite limited. In this paper we introduce a representation for describing interfaces between parts within hierarchical assemblies for capturing functional and physical mating relations. This representation is designed to support automated reasoning and automated generation and modification of assemblies. It is also designed for use with very large assemblies, compactly representing the interfaces of parts and assemblies that are reused within larger assemblies. We describe how this representation is used in our prototype design system, Genesis, for designing aircraft systems.

2018 ◽  
pp. 145-153 ◽  
Author(s):  
V. L. Olenev ◽  
I. Ya. Lavrovskaya ◽  
L. I. Kurbanov ◽  
I. L. Korobkov ◽  
Yu. E. Sheynin

Modern spacecraft onboard networks consist of a large number of nodes which interact with each other via a communication network. SpaceWire is a new generation technology which is being integrated into new spacecraft systems. In order to check network operation on the early stages of network design it is reasonable to perform its software simulation. The paper provides an analysis of existing simulation tools for the on-board and local area networks. We overview the main abilities of the existing software and then propose the computer-aided design (CAD) system for SpaceWire onboard networks design and simulation - SANDS. This software will solve important tasks, which spacecraft developers face with during implementation of satellites and other space vehicles. SANDS system will support the full on-board network design and simulation flow, which begins from the network topology automated generation and finishes with getting the network structure, configuration and parameters setting, simulation results and statistics.


Author(s):  
A. N. Bozhko

Computer-aided design of assembly processes (Computer aided assembly planning, CAAP) of complex products is an important and urgent problem of state-of-the-art information technologies. Intensive research on CAAP has been underway since the 1980s. Meanwhile, specialized design systems were created to provide synthesis of assembly plans and product decompositions into assembly units. Such systems as ASPE, RAPID, XAP / 1, FLAPS, Archimedes, PRELEIDES, HAP, etc. can be given, as an example. These experimental developments did not get widespread use in industry, since they are based on the models of products with limited adequacy and require an expert’s active involvement in preparing initial information. The design tools for the state-of-the-art full-featured CAD/CAM systems (Siemens NX, Dassault CATIA and PTC Creo Elements / Pro), which are designed to provide CAAP, mainly take into account the geometric constraints that the design imposes on design solutions. These systems often synthesize technologically incorrect assembly sequences in which known technological heuristics are violated, for example orderliness in accuracy, consistency with the system of dimension chains, etc.An AssemBL software application package has been developed for a structured analysis of products and a synthesis of assembly plans and decompositions. The AssemBL uses a hyper-graph model of a product that correctly describes coherent and sequential assembly operations and processes. In terms of the hyper-graph model, an assembly operation is described as shrinkage of edge, an assembly plan is a sequence of shrinkages that converts a hyper-graph into the point, and a decomposition of product into assembly units is a hyper-graph partition into sub-graphs.The AssemBL solves the problem of minimizing the number of direct checks for geometric solvability when assembling complex products. This task is posed as a plus-sum two-person game of bicoloured brushing of an ordered set. In the paradigm of this model, the brushing operation is to check a certain structured fragment for solvability by collision detection methods. A rational brushing strategy minimizes the number of such checks.The package is integrated into the Siemens NX 10.0 computer-aided design system. This solution allowed us to combine specialized AssemBL tools with a developed toolkit of one of the most powerful and popular integrated CAD/CAM /CAE systems.


Author(s):  
А.И. Гайкович ◽  
С.И. Лукин ◽  
О.Я. Тимофеев

Процесс создания проекта судна или корабля рассматривается как преобразование информации, содержащейся в техническом задании на проектирование, нормативных документах и знаниях проектанта, в информацию, объем которой позволяет реализовать проект. Проектирование может быть представлено как поиск решения в пространстве задач. Построение цепочки последовательно решаемых задач составляет методику проектирования. Проектные задачи могут быть разбиты на две группы. Первая группа ‒ это полностью формализуемые задачи, для решения которых есть известные алгоритмы. Например, построение теоретического чертежа по известным главным размерениям и коэффициентам формы. Ко второй группе задач можно отнести трудно формализуемые или неформализуемые задачи. Например, к задачам этого типа можно отнести разработку общего расположения корабля. Важнейшим инструментом проектирования современного корабля или судна является система ав­томатизированного проектирования (САПР). Решение САПР задач первой группы не представляет проблемы. Введение в состав САПР задач второй группы подразумевает разработку специального ма­тематического аппарата, базой для которого, которым является искусственный интеллект, использующий теорию нечетких множеств. Однако, настройка искусственных нейронных сетей, создание шкал для функций принадлежности элементов нечетких множеств и функций предпочтений лица принимающего решения, требует участие человека. Таким образом, указанные элементы искусственного интеллекта фиксируют качества проек­танта как специалиста и создают его виртуальный портрет. The process of design a project of a ship is considered as the transformation of information contained in the design specification, regulatory documents and the designer's knowledge into information, the volume of which allows the project to be implemented. Designing can be represented as a search for a solution in the space of problems. The construction of a chain of sequentially solved tasks constitutes the design methodology. Design problems can be divided into two groups. The first group is completely formalizable tasks, for the solution of which there are known algorithms. For example, the construction of ship's surface by known main dimensions and shape coefficients. Tasks of the second group may in­clude those which are difficult to formalize or non-formalizable. For example, tasks of this type can include develop­ment of general arrangement of a ship. The most important design tool of a modern ship or vessel is a computer-aided design system (CAD). The solu­tion of CAD problems of the first group is not a problem. Introduction of tasks of the second group into CAD implies development of a special mathematical apparatus, the basis for which is artificial intelligence, which uses the theory of fuzzy sets. However, the adjustment of artificial neural networks, the creation of scales for membership functions of fuzzy sets elements and functions of preferences of decision maker, requires human participation. Thus, the above elements of artificial intelligence fix the qualities of the designer as a specialist and create his virtual portrait.


Author(s):  
Gary A. Gabriele ◽  
Agustî Maria I. Serrano

Abstract The need for superior design tools has lead to the development of better and more complex computer aided design programs. Two of the more important new developments in application tools being investigation are Object Oriented Languages, and HyperMedia. Object Oriented Languages allow the development of CAD tools where the parts being designed and the design procedures specified are conceptualized as objects. This allows for the development of design aids that are non-procedural and more readily manipulated by the user trying to accomplish a design task. HyperMedia allows for the easy inclusion of many different types of data, such as design charts and graphs, into the tool that are normally difficult to include in design tools programmed with more conventional programming languages. This paper explores the development of a computer aided design tool for the design of a single stage gear box using the development HyperCard® environment and the HyperTalk® programming language. The resulting program provides a user friendly interface, the ability to handle several kinds of design information including graphic and textual, and a non-procedural design tool to help the user design simple, one stage gear boxes. Help facilities in the program make it suitable for undergraduate instruction in a machine elements design course.


Author(s):  
Т. В. Самодурова ◽  
Н. Ю. Алимова ◽  
О. А. Волокитина ◽  
О. В. Гладышева

Постановка задачи. Для получения оптимальных проектных решений, удовлетворяющих условиям безопасности движения в сложных погодных условиях, необходимо сравнение вариантов автомобильных дорог по условиям снегонезаносимости. Такие расчеты должны стать составной частью системы автоматизированного проектирования САПР-АД. Результаты. Предложен системный поход к решению задачи, определен перечень информации, необходимой для проведения расчетов. Выполнен анализ результатов исследований по снегозаносимости дорог, проводимых в России и за рубежом. Предложены расчетные схемы и модели для оценки вариантов продольного профиля и земляного полотна автомобильной дороги по снегозаносимости. Предложены решения для оценки вариантов плана трассы с использованием карт с расчетными параметрами метелей. Выводы. Реализация предложенной методики проведения расчетов позволит на стадии проектирования оценить варианты автомобильной дороги по условиям снегозаносимости. Statement of the problem. In order to obtain optimal design solutions that meet the conditions of safety traffic in difficult weather conditions, it is necessary to compare the options of highways according to the snow tolerance conditions. Such calculations should become an integral part of the CAD-AD computer-aided design system. Results. A systematic approach to solving the problem is set forth, a list of information necessary for calculations is identified. The results analysis of studies on the snow-bearing capacity of roads conducted in Russia and abroad is carried out. Calculation schemes and models are suggested to evaluate options for the longitudinal profile and the roadbed for the snow-bearing capacity. Solutions for evaluating variants of the route plan using maps with calculated parameters of snowstorms are proposed. Conclusions. The implementation of the proposed calculation methodology will make it possible at the design stage to evaluate the options of the highway according to the conditions of the snow-bearing capacity.


2017 ◽  
Vol 9 (7) ◽  
pp. 168781401771038 ◽  
Author(s):  
Isad Saric ◽  
Adil Muminovic ◽  
Mirsad Colic ◽  
Senad Rahimic

This article presents architecture of integrated intelligent computer-aided design system for designing mechanical power-transmitting mechanisms (IICADkmps). The system has been developed in C# program environment with the aim of automatising the design process. This article presents a modern, automated approach to design. Developed kmps modules for calculation of geometrical and design characteristics of mechanical power-transmitting mechanisms are described. Three-dimensional geometrical parameter modelling of mechanical power-transmitting mechanisms was performed in the computer-aided design/computer-aided manufacturing/computer-aided engineering system CATIA V5. The connection between kmps calculation modules and CATIA V5 modelling system was established through initial three-dimensional models – templates. The outputs from the developed IICADkmps system generated final three-dimensional virtual models of mechanical power-transmitting mechanisms. Testing of the developed IICADkmps system was performed on friction, belt, cogged (spur and bevel gears) and chain transmitting mechanisms. Also, connection of the developed IICADkmps system with a device for rapid prototyping and computer numerical control machines was made for the purpose of additional testing and verification of practical use. Physical prototypes of designed characteristic elements of mechanical power-transmitting mechanisms were manufactured. The selected test three-dimensional virtual prototypes, obtained as an output from the developed IICADkmps system, were manufactured on the device for rapid prototyping (three-dimensional colour printer Spectrum Z510) and computer numerical control machines. Finally, at the end of the article, conclusions and suggested possible directions of further research, based on theoretical and practical research results, are presented.


2019 ◽  
Vol 1333 ◽  
pp. 082005
Author(s):  
S V Bibikov ◽  
V O Bolshakov ◽  
M E Kalinkina ◽  
A G Korobeynikov ◽  
O I Pirozhnikova ◽  
...  

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