Computer-aided design system for site layout

A computer-aided design system is presented which allows a site layout to be developed, containing three-dimensional design features. The most important features of this class are roads and buildings. Interaction with a three-dimensional model is achieved by means of a two-dimensional graphics system and its associated devices. The analyses which may be carried out on the computer model of the site are outlined.     

Multiple-attribute decision making methods for plant layout design problem

The layout design problem is a strategic issue and has a significant impact on the efficiency of a manufacturing system. Much of the existing layout design literature that uses a surrogate function for flow distance or for simplified objectives may be entrapped into local optimum; and subsequently lead to a poor layout design due to the multiple-attribute decision making (MADM) nature of a layout design decision. The present study explores the use of MADM approaches in solving a layout design problem. The proposed methodology is illustrated through a practical application from an IC packaging company. Two methods are proposed in solving the case study problem: Technique for order preference by similarity to ideal solution (TOPSIS) and fuzzy TOPSIS. Empirical results showed that the proposed methods are viable approaches in solving a layout design problem. TOPSIS is a viable approach for the case study problem and is suitable for precise value performance ratings. When the performance ratings are vague and imprecise, the fuzzy TOPSIS is a preferred solution method.     

An integrated circuit layout design system

An integrated circuit layout design system is presented. The system is effectively combined with a combinatorial optimization technique and man/machine interaction. This optimization technique allows wiring and placement of components to be determined simultaneously. By means of a c.r.t. display, the layout design of an integrated circuit chip is finally improved.     

Facility layout design using virtual multi-agent system

This paper presents a novel approach to the facility layout design problem based on multi-agent society where agents’ interactions form the facility layout design. Each agent corresponds to a facility with inherent characteristics, emotions, and a certain amount of money, forming its utility function. An agent’s money is adjusted during the learning period by a manager agent while each agent tries to tune the parameters of its utility function in such a way that its total layout cost can be minimized in competition with others. The agents’ interactions are formed based on market mechanism. In each step, an unoccupied location is presented to all applicant agents, for which each agent proposes a price proportionate to its utility function. The agent proposing a higher price is selected as the winner and assigned to that location by an appropriate space-filling curve. The proposed method utilizes the fuzzy theory to establish each agent’s utility function. In addition, it provides a simulation environment using an evolutionary algorithm to form different interactions among the agents and makes it possible for them to experience various strategies. The experimental results show that the proposed approach achieves a lower total layout cost compared with state of the art methods.     

An intelligent system for automatic layout routing in aerospace design

This paper discusses the development of an intelligent routing system for automating design of electrical wiring harnesses and pipes in aircraft. The system employs knowledge based engineering (KBE) methods and technologies for capturing and implementing rules and engineering knowledge relating to the routing process. The system reads a mesh of three dimensional structure and obstacles falling within a given search space and connects source and target terminals satisfying a knowledge base of design rules and best practices. Routed paths are output as computer aided design (CAD) readable geometry, and a finite element (FE) mesh consisting of geometry, routed paths and a knowledge layer providing detail of the rules and knowledge implemented in the process. Use of this intelligent routing system provides structure to the routing design process and has potential to deliver significant savings in time and cost.     

An expert system to generate associativity data for layout design

In this paper we present an intelligent system which assists the layout designer in producing associativity data as input to an automated layout generation tool. The approach which we adopt combines techniques based on expert systems, object-based data structures and cluster analysis. The system eliminates manual input for the associativity data. The object data structure assures data consistency. The cluster analysis determines the strength of relationship between any two pieces of equipment. The expert system provides guidance for the subjective part of the layout design. This results in automation of associativity data generation, an improved user interface, and consistency and accuracy of data. The concept is illustrated by an example taken from the petrochemical industry.     

A revised electromagnetism-like mechanism for layout design of reconfigurable manufacturing system

The layout design problem is one of the most important issues for manufacturing system design and control. A revised electromagnetism-like mechanism (REM) is proposed in this paper for the layout design of reconfigurable manufacturing systems utilizing automated guided vehicle. First, the formal model considering both loaded and empty flows is given. Then the REM is developed to solve the proposed model. In the REM, particles are encoded discretely. The charge of a particle is calculated according the total material handling cost of the particle. In the local search procedure, variable neighbourhood search strategy based on Hamming distance is adopted. In the moving procedure, the particles are moved according to the ordering of each element. To verify the effect of the proposed method, several computation cases are carried out. The computation results show that the proposed method is able to get optimal solutions for small scale problems and near optimal solutions within limited computation time for large scale problems. This indicates that the proposed method is effective and efficient.     

A superelement formulation for the efficient layout design of complex multi-component system

In view of the prohibited computing time and the complexity of design procedure, a superelement formulation (SEF) is proposed to deal with the simultaneous optimization of component placement and the framework topology. In the iterative design process, each component is modelled as a movable superelement so that the sensitivity analysis with respect to the location design variables can be largely simplified by the SEF. Moreover, based on the Kuhn–Tucker optimality condition, two decomposition strategies are developed as variant approaches for the simultaneous design of multi-component system. By means of numerical examples, these approaches are compared to show their capability and efficiency for the system compliance minimization.     

Automatic layout design of plastic injection mould cooling system

This research extends our previous investigation of the automation of the preliminary design stage to the layout design stage of the cooling system design process. While the functional aspects of the cooling system are considered during the preliminary design stage, the layout design stage addresses both the functionality and manufacturability of the design. A graph structure is devised to capture a given preliminary design and a graph traversal algorithm is developed to generate candidate cooling circuits from the graph structure. Heuristic search is employed to develop the cooling circuits into the layout designs by generation of tentative manufacturing plans. A framework for fuzzy evaluation of the layout designs is developed to rate the various design alternatives generated. An experimental system is implemented to verify the feasibility of the approach, and examples generated from the system are presented to illustrate the major steps of the automatic design process.     

A -based layout design for gratings allocation

In the design process of gratings, the grating layout design is the most important activity influencing manufacturing cost. In the grating layout design, the key to saving manufacturing cost is to find a design with a minimal number of cutting operations. This paper presents an application of the A^* algorithm in grating layout design. The design problem is represented as the space search problem of design alternatives. A^* explores the feasible alternatives within the space, until an optimal solution is obtained.     

Efficient simplex computation for fixture layout design

Fixture, to hold an object by making multiple contacts, is a fundamental tool in manufacturing. A fixture layout is an arrangement of contacts on an object’s surface. Designing a fixture layout of an object can be reduced to computing the largest simplex and the resulting simplex is classified using the radius of the largest inscribed ball centered at the origin. We present three different algorithms to compute such a simplex: a simple randomized algorithm, an interchange algorithm, and a branch-and-bound algorithm. We also present methods to combine different algorithms to improve the performance and highlight their performance on complex 3D models consisting of thousands of triangles. Our randomized algorithm computes a feasible fixture layout in linear time and is well-suited for real-time applications. The interchange algorithm computes an optimal simplex in linear time such that no single vertex can be changed to enlarge the simplex, and it provides a practical method for complex 3D objects. The branch-and-bound algorithm computes the largest simplex by using lower and upper bounds on the radius of the inscribed ball, by which the computation time is reduced by a factor of five in comparison with the brute-force search.     

Computerized facility layout design

The paper describes a computerized facility layout designer, COMLAD II, for plant layout development. Besides developing an efficient layout, COMLAD II has useful features which allow fixing the departments, changing the shape of the departments and changing the length and width dimensions of the overall layout.     

CLASS: An algorithm for cellular manufacturing system and layout design using sequence data

Cell formation problem in CMS design has received the attention of researchers for more than three decades. However, use of sequence data for cell formation has been a least researched area. Sequence data provides valuable information about the flow patterns of various jobs in a manufacturing system. Therefore, it is only natural to expect that use of sequence data must result in not only identifying the part families and machine groups but also the layout (sequence) of the machines within each cell. Unfortunately, such an approach has not been taken in the past while solving CMS design problem using sequence data. In this paper, we fill this gap in the literature by developing an algorithm that not only identifies the cells but also the sequence of machines in the cells in a simultaneous fashion. The numerical computations of the algorithm with the available problems in the literature indicate the usefulness of the algorithm. Further, it also points to the untapped potential of such an approach to solve CMS design and layout problem using sequence data.     

Application of a cascade BAM neural expert system to conceptual design for facility layout

The major contribution of this novel application is the pilot development and feasibility study for a bank of cascade BAM (Bidirectional Associative Memories) neural networks. This improved BAM structure functions as an expert system for conceptual facility layout or for preliminary construction layout design. This application, rather than being a better analytical algorithm or a better production expert system, builds a neural expert system with the capability of incrementally learning layout design examples for a given set of constraints. The cascade BAM incremental learning methodology, which distinguishes this system from the more frequently used Backpropagation Network (BPN) learning system, creates effective multibidirectional generalization behavior from qualitative, goal-driven layout design experience. The initial tests of learnability are presented by its applicability to conceptual layout design problems, and their solutions are assessed and compared with the learning ability of a standard BAM. Issues deserving further investigation are addressed as well.     

Multi-purpose computer graphics system SMOG-85

This paper describes the SMOG-85 system, a set of software components for graphical and geometric data processing. One may distinguish among the parts of the system functional components implementing main capabilities of the system and technological components providing a local operating environment for functional components. A general structure of the system and interfaces between separate components, or processors, are described. Also described are structures and main capabilities of functional components—an illustration processor, a drafting processor, a 3D modelling processor—and main parameters of technological components—a graphical output processor, an interaction processor and a data base processor. The system could be applied to preparation of documents containing graphic illustrations; construction of geometric 2D and 3D objects, their visual analysis and computation of mass properties; and preparation and editing of draft documentation.     

Network layout procedure for printed - circuit design

This paper describes a heuristic solution procedure for laying out the conductors of a printed circuit on the two sides of a plate of nonconducting material. There must be no overlap between conductors on the same side of the plate as they are uninsulated. For certain layouts it is necessary to drill holes in the plate and pass conductors through the holes to avoid overlap. The problem is to identify the layout which requires the minimum number of holes. The solution procedure uses a computer subroutine in conjunction with an iconic model of the plate. The subroutine is based on a method of Nicholson¹ which attempts to lay out a given circuit on one side of a plate to minimize the number of overlaps. The iconic model of the plate used in this research consisted of a pair of plastic sheets, representing the two sides of the plate, overlaid one on top of the other. The nodes and connections were drawn on them with felt-tip pens. The procedure is iterative and takes advantage of the fact that the problem can be viewed in terms of graph theory. The procedure is suitable for an interactive computer terminal system. Computational experience is limited but encouraging. However there is no guarantee that solutions produced by the procedure will be optimal in the sense that an absolute minimum number of holes will be required to be drilled.     

Object knowledge environment for manufacturing systems layout design

This article proposes an object knowledge environment to support manufacturing systems layout design, as an alternative to classical functional softwares. It justifies this transition to an object-oriented paradigm by the advantages in openness of the system, as well as increased flexibility and modularity, and higher potential for abstraction and hierarchical structure formation. the implemented environment uses the SMALLTALK-80 language. It supports hierarchical classes of objects such as cell, aisle set, facilities structure, flow, set, relationship set, flow networks, independent objects, evaluators, and optimizers. the layout designer can interact directly with all defined objects through the use of individual model-view-controller triads.     

Intelligent approach to a CAD system for the layout design of a ship engine room

The current layout design of a ship engine room not only depends on a skilled designer but also has many design constraints and regulations to be considered. At preliminary design stage CAD systems need to be intelligent in the sense that they must be able to use knowledge to achieve the designer’s goal. In this paper, we present an approach to implement a practical knowledge-based system for the machinery layout design of a ship engine room. The knowledge-base is implemented and verified in the actual CAD environment of a ship engine room, named MADES (Machinery ArrangementDesign Expert System), which we develop in this study. Design knowledge is represented byobject-oriented concept, and nonmonotonic reasoning enables the values of closely related objects to be consistent. The approaches presented in this paper provide a practical example of a knowledge-based system for complex design problems, and can also provide guidance on implementing an integrateddesign expert system that extends the capability of existing CAD systems.     

An integrated model and a decomposition-based approach for concurrent layout and material handling system design

This paper presents an integer programming formulation that integrates decisions concerning the layout of the resource groups on the shop floor with the design of the material handling system. The model reflects critical practical concerns, including the capacity of the material flow network and of the handling transporters, as well as the tradeoff between fixed (construction and acquisition) and variable (operational) costs. For realistic industrial cases, the size of the problem prevents the solution using explicit or implicit enumeration methods. Instead, the global model is decomposed into standard optimization problems: quadratic assignment, fixed charge capacitated network design, and non-depot distance-constrained vehicle routing. An integrated solution method, guided by a simulated annealing scheme, solves the global shop design problem. The algorithm takes advantage of the proposed decomposition and converges to a final design which is feasible with respect to all problem constraints. The method is applied to redesign the facility of a large manufacturer of radar antennas. The resulting shop configuration exhibits substantially decreased material handling effort, and requires significantly smaller investment costs compared to the existing facility.