Computer-aided Design Database Research Articles

CAD와 BOM 통합 데이터베이스 기반 로봇 조립 계획 시스템 아키텍처 개발

This study proposes a system architecture based on integrated Computer-Aided Design (CAD) and Bill of Material (BOM) databases for a robot assembly planning system. The architecture consists of CAD, Product Data Management (PDM) and robot assembly planning applications based on CAD, BOM and robot databases. It manages shape and product structure data from 3D CAD files as data objects in CAD and BOM databases, and stores general robot assembly planning data from robot teaching results as robot path objects in the robot database. Robot engineers create robot assembly plans using a process BOM that incorporates data from the CAD, BOM and robot databases. Throughout the generation of robot assembly plans, the architecture uses the shape data of participating parts in CAD database to automatically calculate the positions of robot end-effectors. This paper describes the implementation of applications and databases in the architecture using FreeCAD, MariaDB and Apache Tomcat Web application server. It also outlines cases of experimental robot assembly planning using the implemented planning systems and robot arms at laboratory level.

From Automated Design to Digital Double of APCS for a TPP

The concept of a digital twin of an automated process control system (APCS) of a thermal power plants (TPPs) is considered. The principles of its formation and use are proposed on the basis of a design database developed within the framework of a computer-aided design (CAD) system for thermal automation and measurements. Examples of design automation systems aimed at solving similar problems are given and the features of the proposed CAD system are indicated. The typical structure of the APCS and the relationship of its main components—sensors, cables, executive and switchboard devices, signal connection tables, as well as the software and hardware complex (composition and distribution of modules of communication devices with an object)—are described. A description of the project database’s structure is given, which provides comprehensive work with both project documentation and information about the main components of the APCS. The sequence in execution of design procedures and links between the design database and the CAD database during their implementation are shown. Methods for increasing the productivity of designers are considered, such as the use of standard solutions in the organization of measurements and control schemes for actuators of thermal power plants, multiple use of information with a single input, and synthesis of text and graphic design documentation based on the project database. It is proposed to use a digital twin at all stages of the object’s life cycle: during design, installation, commissioning, and operation. The effectiveness of working with information thanks to an intuitive interface for navigating through the project was demonstrated. Examples of objects, in the implementation of which the considered CAD system was used, are given.

Broad spectrum assessment of the epitope fluctuation—Immunogenicity hypothesis

Prediction of immunogenicity is a substantial barrier in vaccine design. Here, a molecular dynamics approach to assessing the immunogenicity of nanoparticles based on structure is presented. Molecular properties of epitopes on nonenveloped viral particles are quantified via a set of metrics. One such metric, epitope fluctuation (and implied flexibility), is shown to be inversely correlated with immunogenicity for each of a broad spectrum of nonenveloped viruses. The molecular metrics and experimentally determined immunogenicities for these viruses are archived in the open-source vaccine computer-aided design database. Results indicate the promise of computer-aided vaccine design to bring greater efficiency to traditional lab-based vaccine discovery approaches.

3D reconstruction of as-built industrial instrumentation models from laser-scan data and a 3D CAD database based on prior knowledge

In the operation and maintenance phase of industrial plants, it is important to ensure that the as-built condition of every piece of installed instrumentation, and any changes that may subsequently occur, are properly recorded and adjusted in interpretive documents. However, the manual creation of industrial instrumentation models from an acquired set of three-dimensional (3D) point clouds is difficult. This paper proposes an approach for the reconstruction of 3D models of as-built industrial instrumentation from terrestrial laser-scan data and a 3D computer-aided design (CAD) database based on prior knowledge. An experimental evaluation of an actual industrial plant demonstrates that incorporating prior knowledge into the reconstruction process greatly reduces the manual interaction required, facilitating the process of reconstructing 3D models of as-built industrial instrumentation from unstructured (raw) laser-scan data. The proposed approach could be successfully utilized to assist in the reconstruction of 3D models of as-built industrial instrumentation during the operation and maintenance phase of an industrial plant.

A CAD-Based Tool for Calculating Power Deposition on Tokamak Plasma-Facing Components

The SMARDDA software library is used to model plasma interaction with complex engineered surfaces. A simple flux-tube model of power deposition necessitates the following of magnetic fieldlines until they meet geometry taken from a CAD (Computer Aided Design) database. Application is made to 1) models of ITER tokamak limiter geometry and 2) MASTU tokamak divertor designs, illustrating the accuracy and effectiveness of SMARDDA, even in the presence of significant nonaxisymmetric ripple field. SMARDDA's ability to exchange data with CAD databases and its speed of execution also give it the potential for use directly in the design of tokamak plasma facing components.

Content-based text mining technique for retrieval of CAD documents

The computer aided design (CAD) document provides an effective communication medium, a legal contract document, and a reusable design case for a construction project. Due to technological advancements in CAD industry, the volume of CAD documents has been increased dramatically in the database of construction organizations. Traditional retrieval methods relied on textual naming and indexing schemes that require the designers (engineers and architects) to memorize in details the meta-information used to characterize the drawings. Such approaches easily overwhelmed the users' memory capability and thus caused low reusability of CAD documents. In this paper, a content-based text mining technique is adopted to extract the textual content of a CAD document into a characteristic document (CD), which can be retrieved with similarity matching using a Vector Space Model (VSM), so that the automated and expedited retrievals of CAD documents from vast CAD databases become possible. A prototype system, namely Content-based CAD document Retrieval System (CCRS), is developed to implement the proposed method. After preliminary testing with a CAD database with 2094 Chinese annotated CAD drawings collected from two real-world construction projects and a public engineering drawing database, the proposed CCRS is proven to retrieve all relevant CAD documents with relatively high precision when appropriate query is specified. Finally, three search strategies are recommended for the users to narrow down search scope while a target CAD document is desired. It is concluded that the proposed content-based text mining approach provides a promising solution to improve the current difficulty encountered in retrieval and reusability of vast CAD documents for the construction industry.

A CAD system for extraction of mating features in an assembly

PurposeThe information and knowledge about a product and its assembly are necessary to generate all feasible assembly sequences of that product. Assemblies contain a very large amount of information and complex relationships. Identifying assembled parts as well as their contact surfaces is very important in design and manufacturing since this information is essential. The problem is to not only make the information available but also use the relevant information for making decisions, especially determination of the optimum assembly sequence. This paper aims to address these issues.Design/methodology/approachThis paper describes a system for processing assembly models and extracting assembly related data using application programming interface (API) of the computer‐aided design (CAD) software. These data are used to identify the relationships between different components of an assembly thus encouraging generation of feasible assembly sequences.FindingsInstead of total human interpretation of the assembly design, a direct CAD database interface approach has been proposed to extract the relation with minimal manual involvement. The information extracted is used to generate a list describing the links between the assembled parts, the involved features and the type of link explicitly to facilitate assembly analysis and planning.Originality/valueThe methodology of using the API of the CAD modeling package SolidWorks, is a novel approach in which the assembly mate information is captured. Instead of total human interpretation of the assembly design, a direct CAD database interface approach has been proposed to extract the relation with minimal manual involvement.

Computer-Aided Design Data Extraction Approach to Identify Product Information

Many approaches have been proposed in previous such as AUTOFEAT algorithm, feature recognition, Intelligent Feature Recognition Methodology (IFRM), a part recognition algorithm and graph theory-based approach in order to solve the integration issue between CAD and CAM. However, there is no direct connection from CAD database and machine database. Therefore, comparison among the approaches has been conducted because to recognize the suitable approach is the importance tasks before this research can be proceed for the next stage. This study focused on CAD data extraction approach to identify product information. CAD data referred as Computer-Aided Design (CAD) data extracted from the CAD drawing which contained the drawing of product that be produce by manufacturing. CAD data consisted of geometric and non-geometric data. Geometric data contained lines, curves and vertex. While non-geometric data include texts, colors and layers. The extracted CAD data were needed to generate the product information which is useful information for the machine in production field to produce the product for the manufacturing same as depicted in the CAD drawing. Basically, the product information consisted of product details such as length, thickness, wideness and radius of the product, processes information for the machine to process the product such as taper, cutting, drilling and punching. In addition, product information also contained type of materials for the product. As a result, feature recognition is the most suitable approach can be applied for this research. Thus, the approach was selected to precede the next stage. Conclusion from the comparison among the approaches is in term of accuracy of extracted data is not accurate when the drawing is incomplete drawing or contains the noise such as unwanted lines or any shapes cross the object in the drawing.

Large-Scale Dynamic Terrain in Three-Dimensional Construction Process Visualizations

Visualization can be of significant value in improving the verification, validation, and communication of discrete-event simulation models of construction operations, which in turn can make the models more credible and thus useful in operations planning. The presented work extends the state-of-the-art of visualizing simulation models of construction operations in three-dimensions. The writers present efficient methods and a tool, ViTerra, that can be used to automatically generate photorealistic, digital, three-dimensional (3D) terrain computer-aided design databases to represent construction job sites in animations of simulated construction processes. The work capitalizes on the availability of detailed topographical and aerial imagery data that are readily available in digital format from several government and private organizations. In addition to automated terrain generation techniques, the presented work implements animation methods to describe the evolution of virtual jobsites by depicting deformations to the visualized terrains in response to common construction operations such as earthmoving and trenching. The writers' first contribution alleviates the need to manually create 3D terrain models for use in animations as has been the case hitherto. The writers' second contribution (1) enhances realism in animations of several common construction operations; and (2) allows the visualization of several other construction processes that were hitherto impossible to animate accurately in 3D.

Automatic extraction of machining primitives with respect to preformed stock for process planning

There is a need for the integration of computer-aided design (CAD) information with manufacturing models, such as machining process simulation models, upstream with concurrent engineering activities. Because it is often difficult to interface various CAD formats with such applications, there is a need to standardize input file formats, which then can be used by any module that has the appropriate interface. The STEP standard is a very useful standard for the neutral file format specification. The present work describes in detail the building of a STEP parser for the Application Protocol for Configuration Controlled Design of 3-D mechanical parts (AP203). Such a STEP parser is complemented with a visualization front end in the form of a Java applet, which is used to display the STEP entities in 3-D within a web browser over the Internet. The current work outlines a generic framework for a STEP parser module. Its use in the design and development of CAD-based process engineering applications is illustrated by example of a CAD interface to a machining process simulation program, which requires the workpiece CAD information, namely the surface geometry, to be machined to determine chip loads and hence cutting forces. The applicability of the STEP parser in the building of a CAD database cataloging system is also discussed.

Subresolution placement using infrared image alignment to the computer-aided design database for backside probing and editing

As more integrated circuits are packaged in controlled collapse chip connection format, internal debug tools need to image devices through their silicon packaging. Infrared (IR) optical systems make through-silicon imaging possible, but navigation becomes challenging because IR resolution is often lower than positioning accuracy required for design debug. We perform subresolution image alignment between computer-aided design (CAD) and IR images to obtain the required placement accuracy. Our goal is to automate and improve CAD-based IR navigation for silicon-side probing and editing. Using our alignment algorithm, which combines equalization, oversampling, and cross correlation, we demonstrate the ability to achieve 0.1 μm placement accuracy with a 1 μm resolution optical system.

CAD data visualization for machining simulation using the STEP standard

There is a need for the integration of computer-aided design (CAD) information with manufacturing models, such as machining process simulation models, upstream with concurrent engineering activities. Because it is often difficult to interface various CAD formats with such applications, there is a need to standardize input file formats, which then can be used by any module that has the appropriate interface. The STEP standard is a very useful standard for the neutral file format specification. The present work describes in detail the building of a STEP parser for the Application Protocol for Configuration Controlled Design of 3-D mechanical parts (AP203). Such a STEP parser is complemented with a visualization front end in the form of a Java applet, which is used to display the STEP entities in 3-D within a web browser over the Internet. The current work outlines a generic framework for a STEP parser module. Its use in the design and development of CAD-based process engineering applications is illustrated by example of a CAD interface to a machining process simulation program, which requires the workpiece CAD information, namely the surface geometry, to be machined to determine chip loads and hence cutting forces. The applicability of the STEP parser in the building of a CAD database cataloging system is also discussed.

Integration of heterogeneous CAD databases using STEP and the Internet

In a large-scale design process, designers cooperate in a complex situation where a variety of software tools run on different hardware platforms. This paper presents a data enhancement approach to integrate heterogeneous Computer-Aided Design (CAD) databases through the Internet. The data enhancement means topological changes in a geometric model and additional information in design semantics. The geometric data is enhanced using a non-manifold modeler to produce data sets valuable in downstream applications such as a Finite Element Method (FEM) solver or a detail design system. As a practical example, a shipbuilding product model database has been implemented based on the Standard for the Exchange of Product (STEP) model data methodology and shipbuilding features. The system has been implemented on a network environment that consists of a Web browser, Common Object Request Broker Architecture (CORBA) objects, a relational database management system, a data enhancement module, and various computer-aided applications.

An Integrated Approach for Computer Aided Design in Multibody System Dynamics

In this paper the integration of Solid Modeling CAD (Computer Aided Design) systems within a dynamic simulation environment is described. According to the different multibody formalisms and the computer codes, a general description and an organization of multibody system data are introduced to fulfill the needs of a modular simulation system based upon numerical and symbolical formalisms. With respect to different solid model construction methods, the multibody system components are generated by the extraction of an extended CAD database. A system-independent modeling kernel library is developed from the object-oriented construction of abstract data types and operations. The basic steps and the advantages in this new automated mechanical design chain are demonstrated by examples.

Streamlining Fluid Dynamics

More-intuitive pre-processors and advanced solvers are making computational fluid dynamics (CFD) software easier to use, more accurate, and faster. CFD techniques involve the solution of the Navier-Stokes equations that describe fluid-flow processes. Using MSC/ PATRAN as a starting point, AEA Technology plc, Harwell, Oxfordshire, England, has developed a pre-processor for its software that is fully computer-aided design (CAD)-compatible and works with native CAD databases such as CADDS 5, CATIA, Euclid3, Pro /ENG INEER, and Unigraphics. The simplicity of modeling complex geometries in CFX allows more details to be included in models, such as gangways between coaches, bogies, and even some parts of the pantograph. CFX 5's coupled solver offers a radically different approach that solves all the hydrodynamic equations as a single system. CFX 5 has demonstrated its ability to deliver much faster pre-processing and shorter run times, thus increasing productivity for its users. CFX 5.2 should be a further step forward in commercial CFD, with its mixed element types combining the accuracy of prismatic meshes adjacent to surfaces with the speed and geometric flexibility of tetrahedral elements in the remainder of the grid.

Boundary Representation-Based Feature Recognition

This paper introduces an ongoing research which is aimed at the development of an intelligent form feature extraction system from Computer Aided Design (CAD) database, a high level data structure form useful for Computer Aided Manufacturing (CAM) such as Automated Process Planning System (APPS). Part description in CAD models is the form of basic geometry and topology that is unsuitable for direct application in APPS. Furthermore, CAD software does not incorporate sufficient manufacturing specific data to be used in APPS. Therefore, feature recognition systems will provide the capabilities for bridging the gap between the CAD database and the CAM database. A solid boundary representation (B-rep) model of the part is used to describe the part. This paper concentrates on the recognition of machinable features of either depression or protrusion types to be used in Automated Process Planning System. Logical procedures were developed to recognise these features which consists of both simple and intersecting features.

Reverse Engineering Physical Models Employing Wrap-Around B-Spline Surfaces and Quadrics

Reverse engineering involves digitizing a three-dimensional model or part, by means of a tactile or non-contact optical sensor, converting the data to a CAD (computer aided design) database description and manufacturing by CNC (computer numerical controlled) machines. This paper demonstrates an effective approach to the reverse engineering of physical models by employing a three-dimensional laser scanning system in conjunction with surface-fitting software developed by the authors. Accurate surface data are collected by the laser scanner and then input to the surface-fitting software. Surface entities such as B-spline and quadric functions are employed to build the CAD model. The CAD model is compatible with popular design and manufacturing software packages. A telephone receiver is used to illustrate the efficiency of the process.

Computer-aided torch trajectory generation for automated coating of parts with complex surfaces

The work presented in this paper is concerned with the design and development of an efficient computer software package for off- line programming of robots for spray coating. The developed package (called CA- COATS) allows the spray torch to track a path, maintaining the specified spraying distance and proper orientation relative to the part surface at all points, and thus ensuring uniform coating thickness. This software package is done off- line and is complete in itself, eliminating the need for another computer-aided design database of the base surface (although the package can be made to interface with such a database if so desired). Because the algorithm has no iteration, it is computationally efficient. With minor modifications, this package can also be extended to waterjet coating- removal systems.

Nanophase materials in solid freeform fabrication

Solid freeform fabrication (SFF) is a manufacturing technology that produces parts directly from computer-aided design databases. Examples of the SFF approach are selective laser sintering (SLS) and selective laser reactive sintering (SLRS), both of which have the potential to directly produce structurally sound metallic or ceramic parts. The development of suitable materials systems that can optimize the SLS or SLRS processes are critical to this technology. For instance, nanocomposites, in which the constituents are mixed on a nanometer scale, have the potential to provide important advantages in the SLS and SLRS processes. One strategy is to design and develop nanocomposites in which one nanosize component has a lower melting point than the other nanosize component, either of which can serve as the matrix phase. The nanoscale dispersion of the low-melting component can aid the sintering process during SLS or SLRS. In this article, the philosophical basis for SLS and SLRS of nanocomposites is discussed. Conceptual design of nanocomposite systems and the SLS/SLRS results of a few exploratory systems are presented.

Representation of process system knowledge through component constraint descriptions

Automated development of models for use in computer simulations of engineered systems (e.g. electronic, power, thermal, process systems, etc.) can represent a significant advantage to system designers and troubleshooters. The fact that most modern systems have been designed in Computer-Aided Design (CAD) environments represents a unique opportunity for automatically generating a model from the electronic representation of a system. Models generally require definition of the system structure (i.e. component connectivity) and of the behavioral description of its components. With some exceptions, determination of the system connectivity from a CAD representation is a relatively uncomplicated procedure. However, the assignment of a functional behavior to each component of the system depicted in the CAD representation is a significant problem. This is because behavioral information is usually not included in the CAD representation of the system, as it is not required by the typical users of the CAD graphic output. The overall issue addressed in this paper, therefore, is the determination of the correct behavioral attributes for the components making up the modeled system. This will be addressed through the identifcation and matching of system components to elements of an external base of generic component knowledge. The components' behavioral representation (i.e. transfer function) will be set equal to that of its matching element in this external database. The compatibility of a hard-to-identify system component with its (known) neighboring components can be used to shed some light on its identity. Component compatibility can also be used to determine correct connectivity when that defined by the CAD database is incorrect. This compatibility can be determined through the use of domain (system) knowledge, in the form of system theory and/or practice. The representation of this knowledge as a series of constraints is the focus of this paper. Verification of this technique using a testbed system is also reported here.