GA Based Feature Recognition of Step File for CAD/CAM Integration

Feature-based method has been successfully applied in several fields of manufacturing. However, most of the applications use the solid modeling method that cannot meet the requirements of a product design that needs a free-form surface or a complicated surface. This research utilizes the Genetic Algorithm (GA) technique for feature recognition of STEP file. A GA model is proposed for optimizing the coordinates which is used for feature recognition. It is proposed as an input for automatic feature recognition in Computer Aided Design and Manufacturing (CAD/CAM) application. These methods accomplish their task based on recognition of features as GA made up. This technique used standard for exchange of product information (STEP) formats for geometrical data extraction representation to matching the coordinate from STEP file to decide the correct or optimize solution. Genetic operator such as selection, crossover and mutation are performed repeatedly to acquire the optimal sequences of coordinates. Even though the result of this processes are optimal, some coordinates are not placed in the correct position

Feature Extraction and Classification from Boundary Representation

In the paper, an algorithm for explicit feature extraction and classification from boundary representation is presented. It operates in two phases: the topological and the geometrical. While the topological part is just an adaptation of an already known algorithm, the geometrical part represents an original and new solution. In this part, the algorithm manipulates with features filled by material and the empty ones. The algorithm classifies extracted features into eight classes. It successfully and efficiently handles voids, nested features and many cases of mutual feature intersections. The time complexity depends on input data, and never exceeds O(n^2)

From computer-aided to intelligent machining: Recent advances in computer numerical control machining research

The aim of this paper is to provide an introduction and overview of recent advances in the key technologies and the supporting computerized systems, and to indicate the trend of research and development in the area of computational numerical control machining. Three main themes of recent research in CNC machining are simulation, optimization and automation, which form the key aspects of intelligent manufacturing in the digital and knowledge based manufacturing era. As the information and knowledge carrier, feature is the efficacious way to achieve intelligent manufacturing. From the regular shaped feature to freeform surface feature, the feature technology has been used in manufacturing of complex parts, such as aircraft structural parts. The authors’ latest research in intelligent machining is presented through a new concept of multi-perspective dynamic feature (MpDF), for future discussion and communication with readers of this special issue. The MpDF concept has been implemented and tested in real examples from the aerospace industry, and has the potential to make promising impact on the future research in the new paradigm of intelligent machining. The authors of this paper are the guest editors of this special issue on computational numerical control machining. The guest editors have extensive and complementary experiences in both academia and industry, gained in China, USA and UK

Optimal choice of machine tool for a machining job in a CAE environment

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.Developments in cutting tools, coolants, drives, controls, tool changers, pallet changers and the philosophy of machine tool design have made ground breaking changes in machine tools and machining processes. Modern Machining Centres have been developed to perform several operations on several faces of a workpiece in a single setup. On the other hand industry requires high value added components, which have many quality critical features to be manufactured in an outsourcing environment as opposed to the traditional in-house manufacture. The success of this manufacture critically depends on matching the advanced features of the machine tools to the complexity of the component. This project has developed a methodology to represent the features of a machine tool in the form of an alphanumeric string and the features of the component in another string. The strings are then matched to choose the most suitable and economical Machine Tool for the component’s manufacture. Literature identified that block structure is the way to answer the question ‘how to systematically describe the layout of such a machining centre’. Incomplete attempts to describe a block structure as alphanumeric strings were also presented in the literature. Survey on sales literature from several machine tool suppliers was investigated to systematically identify the features need by the user for the choice of a machine tool. Combining these, a new alphanumeric string was developed to represent machine tools. Using these strings as one of the ‘key’s for sorting a database of machine tools was developed. A supporting database of machine tools was also developed. Survey on machining on the other hand identified, that machining features can be used as a basis for planning the machining of a component. It analysed various features and feature sets proposed and provided and their recognition in CAD models. Though a vast number of features were described only two sets were complete sets. The project was started with one of them, (the other was carrying too many unwanted details for the task of this project) machining features supported by ‘Expert Machinist’ software. But when it became unavailable a ‘Feature set’ along those lines were defined and used in the generation of an alphanumeric string to represent the work. Comparing the two strings led the choice of suitable machines from the database. The methodology is implemented as a bolt on software incorporated within Pro/Engineer software where one can model any given component using cut features (mimicking machining operation) and produce a list of machine tools having features for the machining of that component. This will enable outsourcing companies to identify those Precision Engineers who have the machine tools with the matching apabilities. Supporting software and databases were developed using Access Database, Visual Basic and C with Pro/TOOLKIT functions. The resulting software suite was tested on several case studies and found to be effective

Automated feature recognition system for supporting engineering activities downstream of conceptual design.

Transfer of information between CAD models and downstream manufacturing process planning software typically involves redundant user interaction. Many existing tools are process-centric and unsuited for selection of a "best process" in the context of existing concurrent engineering design tools. A computer based Feature-Recognition (FR) process is developed to extract critical manufacturing features from engineering product CAD models. FR technology is used for automating the extraction of data from CAD product models and uses wire-frame geometry extracted from an IGES neutral file format. Existing hint-based feature recognition techniques have been extended to encompass a broader range of manufacturing domains than typical in the literature, by utilizing a combination of algorithms, each successful at a limited range of features. Use of wire-frame models simplifies product geometry and has the potential to support rapid manufacturing shape evaluation at the conceptual design stage. Native CAD files are converted to IGES neutral files to provide geometry data marshalling to remove variations in user modelling practice, and to provide a consistent starting point for FR operations. Wire-frame models are investigated to reduce computer resources compared to surface and solid models, and provide a means to recover intellectual property in terms of manufacturing design intent from legacy and contemporary product models. Geometric ambiguity in regard to what is ?solid? and what is not has plagued wire-frame FR development in the past. A new application of crossing number theory (CNT) has been developed to solve the wire-frame ambiguity problem for a range of test parts. The CNT approach works satisfactorily for products where all faces of the product can be recovered and is tested using a variety of mechanical engineering parts. Platform independent tools like Extensible Mark-up Language are used to capture data from the FR application and provide a means to separate FR and decision support applications. Separate applications are composed of reusable software modules that may be combined as required. Combining rule-based and case-based reasoning provides decision support to the manufacturing application as a means of rejecting unsuitable processes on functional and economic grounds while retaining verifiable decision pathways to satisfy industry regulators

Curve-Based Shape Matching Methods and Applications

One of the main cues we use in our everyday life when interacting with the environment is shape. For example, we use shape information to recognise a chair, grasp a cup, perceive traffic signs and solve jigsaw puzzles. We also use shape when dealing with more sophisticated tasks, such as the medical diagnosis of radiographs or the restoration of archaeological artifacts. While the perception of shape and its use is a natural ability of human beings, endowing machines with such skills is not straightforward. However, the exploitation of shape cues is important for the development of competent computer methods that will automatically perform tasks such as those just mentioned. With this aim, the present work proposes computer methods which use shape to tackle two important tasks, namely packing and object recognition. The packing problem arises in a variety of applications in industry, where the placement of a set of two-dimensional shapes on a surface such that no shapes overlap and the uncovered surface area is minimised is important. Given that this problem is NP-complete, we propose a heuristic method which searches for a solution of good quality, though not necessarily the optimal one, within a reasonable computation time. The proposed method adopts a pictorial representation and employs a greedy algorithm which uses a shape matching module in order to dynamically select the order and the pose of the parts to be placed based on the “gaps” appearing in the layout during the execution. This thesis further investigates shape matching in the context of object recognition and first considers the case where the target object and the input scene are represented by their silhouettes. Two distinct methods are proposed; the first method follows a local string matching approach, while the second one adopts a global optimisation approach using dynamic programming. Their use of silhouettes, however, rules out the consideration of any internal contours that might appear in the input scene, and in order to address this limitation, we later propose a graph-based scheme that performs shape matching incorporating information from both internal and external contours. Finally, we lift the assumption made that input data are available in the form of closed curves, and present a method which can robustly perform object recognition using curve fragments (edges) as input evidence. Experiments conducted with synthetic and real images, involving rigid and deformable objects, show the robustness of the proposed methods with respect to geometrical transformations, heavy clutter and substantial occlusion

Simple identification tools in FishBase

Simple identification tools for fish species were included in the FishBase information system from its inception. Early tools made use of the relational model and characters like fin ray meristics. Soon pictures and drawings were added as a further help, similar to a field guide. Later came the computerization of existing dichotomous keys, again in combination with pictures and other information, and the ability to restrict possible species by country, area, or taxonomic group. Today, www.FishBase.org offers four different ways to identify species. This paper describes these tools with their advantages and disadvantages, and suggests various options for further development. It explores the possibility of a holistic and integrated computeraided strategy

Anamersion: Toward a postcinematic poetics of immersion

The contribution of my practice-led research is the development of anamersion, a postcinematic poetics of immersion, which attends to the immersive conditions of contemporary life forms. Notions of mutational convergences of bodies, environments, and technologies and their differential mapping and navigation are developed in dialogue with Unica Zürn’s figuration of (her) (female) body and its institutionalisation as one formation in her illustrated text The House of Illnesses, Kathy Acker’s conception of the labyrinth as the site where codes are made flesh, and Porpentine Charity Heartscape’s explorations of trauma in their computer games set in horror mansions, with special attention to the way writing, drawing, and algorithmic operations often co-constitute each other in their works and in my own practice. Bringing these predominantly pre-computational engagements to bear on technology-dependent forms of immersion in gaming and virtual reality (VR), my practice-led research provides an analysis of immersive, navigational, and environmental figurations through modes of drawing, moving image, and multimedia installation that respond to Wynter’s call for a New Studia, and Zürn, Acker, and Heartscape’s disruptions of anatomical, architectural, and textual figurations on its own terms. Developing anamersion primarily with reference to Sylvia Wynter’s thought and, by extension, that of Zakiyyah Iman Jackson, Louis Chude-Sokei, Denise Ferreira da Silva, and others, emphasis is laid on the ways in which the over-represented genre of the human, Man, continues to manifest in and as bodies, environments, and technologies today. Understanding anamersion as a form of what Wynter calls figuration Work, anamersive approaches map, navigate, and traverse such generic structurations from the implicated and immersed positions, which have the potential to be in solidarity with the Wynterian unsettling of the genre Man by challenging conceptions of technology which carry over post-Enlightenment monohumanism into derivative posthumanisms, which continue to reproduce colonial logics with deadly consequences. Anamersion, as analytic and poetics, thus presents a significant and original contribution to the fields of artists’ moving-image and postcinematic studies, which focus on the environmental and navigational trajectories of moving-image and immersive technologies today and elaborates how these can be refigured to produce generative detachments and exits from the linear developmental narratives that underwrite a violent world order. KEYWORDS: anamersion, immersion, post-cinema, postcinematic, moving image, gaming, virtual reality, navigation, mapping, drawing, figuration, humanism, genre, environment, body, hybridity, technology, Sylvia Wynter, Kathy Acker, Unica Zürn, Porpentine Charity Heartscape

The practice of interdisciplinary design in Building Information Modelling (BIM)-enabled projects: A workplace study

Building Information Modelling (BIM) is believed to enable significant efficiency improvements in interdisciplinary design in construction. This is mainly based on the rhetoric of BIM dominated by promoting its capabilities for data transactions. However, literature shows that there are problems in applying BIM technologies in practice, because their use causes unanticipated shifts in the focus and organisation of design projects. Furthermore, changes wrought by applied BIM technologies transcend the boundaries of the organisation of individual projects, and displace the previous ethos of ‘professionalism’ in design in construction. Consequently, there is unresolved confusion and evaluation about BIM technologies in terms of the nature and extent of the change they create. The present research aims to develop a better-informed understanding of BIM-driven change in design in construction through an empirical study of ‘organising’ and ‘order’ in BIM-enabled interdisciplinary design projects. Using a practice-based methodology, this research focused on the interdisciplinary interactions during three projects. A practice-based methodology sees ‘organising ‘and ‘order ‘as continuously accomplished through the ongoing activities that are performed in practices. Therefore, the research scrutinised the interdisciplinary activities and processes which look mundane but enable ‘organising’, and ‘order ‘in the studied projects. Three explanatory organisational concepts are developed through the analyses of the empirical data: ‘organisational premises’, ‘purposeful artefact’, and ‘technological premises’. These concepts provide three different explanations about how ‘organising ‘interdisciplinary design in BIM-enabled projects is accomplished through the ongoing interdisciplinary activities performed in practices. Thus, they produce rich understanding of the complex organisational phenomena. Interdisciplinary design development is then seen as a ‘continuous process of (re-)establishing a shared sense of purposefulness ‘among the members of a design team, which largely depends on previous shared experiences. This continuous requirement for mutual dependency does not align well with the operational characteristics of BIM technologies, which are fundamentally planned and rigid. Therefore, practitioners experience divergent views of ‘organising’ (i.e. and ‘work’) in BIM-enabled projects. The ‘ordering ‘induced by BIM technologies appears in the interface of these different views of ‘organising’(and ‘work'), as it is here that practices unfold, and become directed towards one or other view. In such cases, the extent to which information modelling and design development can be prioritised is determined by the level of reliance on technology, and the level of authority of those individuals who are in control of the BIM technologies. The practice-based understandings of ‘organising ‘and ‘order ‘that emerge from the analyses are used herein to refine the notions of ‘design’, ‘design collaboration’, ‘use of information and communication technologies (ICT) in construction design’, and ‘CT-driven change in construction design’. Thus, the practice-based methodology reveals that some of the main arguments upon which the promotional rhetoric of BIM is founded are incomplete or flawed. Through its methodological and theoretical contributions, the present research evaluated BIM-driven change in design in construction, and created an agenda for further critical and practically-relevant studies into interdisciplinary design in construction. This shows the need for further research which should re-establish the use and development of BIM by aligning it with the realities of actual practice