Showing papers in "Robotics and Computer-integrated Manufacturing in 2003"

Optimization of cutting process by GA approach

Abstract: The paper proposes a new optimization technique based on genetic algorithms (GA) for the determination of the cutting parameters in machining operations. In metal cutting processes, cutting conditions have an influence on reducing the production cost and time and deciding the quality of a final product. This paper presents a new methodology for continual improvement of cutting conditions with GA. It performs the following: the modification of recommended cutting conditions obtained from a machining data, learning of obtained cutting conditions using neural networks and the substitution of better cutting conditions for those learned previously by a proposed GA. Experimental results show that the proposed genetic algorithm-based procedure for solving the optimization problem is both effective and efficient, and can be integrated into an intelligent manufacturing system for solving complex machining optimization problems.

Sustainable product development and manufacturing by considering environmental requirements

Abstract: Sustainability in the development and manufacture of new products is a strategy that is widely accepted in principle, although not yet widely practiced. The integration of environmental requirements throughout the entire lifetime of a product needs a new way of thinking and new decision tools to be applied. This paper describes the concept of an approach to product development, based on a paradigm for sustainable manufacturing. Four examples of methodologies and decision tools are discussed, representing the most important sources of environmental impacts of a product. The emphasis lies on the integrating concept rather than on the details of the methodologies.

E-manufacturing—fundamental, tools, and transformation

Abstract: Manufacturing industry worldwide has been facing unprecedented challenges brought by ever changing, global and competitive market conditions as well as changing social demands, regional, governmental and environmental regulations. E-commerce and Internet technologies injected “velocity” into the front business activities and enabled companies to shift their manufacturing operations from the traditional factory integration philosophy to a supply chain-based e-factory philosophy. It transforms companies from a local factory focus to a global enterprise and business focus. This paper introduces e-manufacturing as a new concept to answer the aforementioned needs of business strategies for complete integration of all business elements including suppliers, customer service network and manufacturing units by leveraging the Internet, web-enabling, tether-free technologies and computational tools. Enabling tools will be introduced to support e-manufacturing includes the ability to monitor the plant floor assets, and predict the variation and performance loss for dynamic rescheduling of production and maintenance operations, and synchronize with other related business actions to achieve a complete integration between manufacturing systems and upper-level enterprise applications. Finally, infotronics technologies for next-generation e-manufacturing transformation are discussed.

Optimization of cutting conditions during cutting by using neural networks

Abstract: Optimum selection of cutting conditions importantly contribute to the increase of productivity and the reduction of costs, therefore utmost attention is paid to this problem in this contribution. In this paper, a neural network-based approach to complex optimization of cutting parameters is proposed. It describes the multi-objective technique of optimization of cutting conditions by means of the neural networks taking into consideration the technological, economic and organizational limitations. To reach higher precision of the predicted results, a neural optimization algorithm is developed and presented to ensure simple, fast and efficient optimization of all important turning parameters. The approach is suitable for fast determination of optimum cutting parameters during machining, where there is not enough time for deep analysis. To demonstrate the procedure and performance of the neural network approach, an illustrative example is discussed in detail.

A web-enabled PDM system in a collaborative design environment

Abstract: For manufacturers, profitability always depends upon the orderly and efficient development, production and distribution of their products. Product Data Management (PDM) is a unique technology, which integrates and manages all applications, information and processes that define a product, from design to manufacture, and to end-user support. The recent advance in Web-based technologies has the potential to greatly enhance PDM's functionality and capability, and to overcome the obstacles that many traditional PDM systems are confronted. It is found in this research that a multi-tiered, collaborative environment with advanced Web technologies is well suited for a PDM system to operate in. In this research, the overall architecture of a Web-enabled PDM system in the Collaborative Design environment is proposed. The architecture is based on the use of open data standards to allow users on a wide variety of platforms to access the product data and other related information. It enables product visualisation using interactive 3-D graphics by the disparate members of a collaborative PDM team. Integral elements of the proposed architecture include object-oriented database (OODB), object-oriented DataBase management system, common gateway interface script and visualisation applications. The use of standard for the exchange of product model data standard effectively integrates different CAD and PDM systems. The advantage of OODB is its efficiency and effectiveness in handling complex data structures often found in engineering applications. Virtual reality modelling language provides a 3-D dynamic visualisation capability. The system, which is implemented using Microsoft Visual Basic, runs in the Windows environment with the basic Internet connections.

Unrelated parallel machine scheduling with setup times and a total weighted tardiness objective

Abstract: This paper presents several search heuristics and their performance in batch scheduling of parallel, unrelated machines. Identical or similar jobs are typically processed in batches in order to decrease setup times and/or processing times. The problem accounts for allotting batched work parts into unrelated parallel machines, where each batch consists of a fixed number of jobs. Some batches may contain different jobs but all jobs within each batch should have an identical processing time and a common due date. Processing time of each job of a batch is determined according to the machine group as well as the batch group to which the job belongs. Major or minor setup times are required between two subsequent batches depending on batch sequence but are independent of machines. The objective of our study is to minimize the total weighted tardiness for the unrelated parallel machine scheduling. Four search heuristics are proposed to address the problem, namely (1) the earliest weighted due date, (2) the shortest weighted processing time, (3) the two-level batch scheduling heuristic, and (4) the simulated annealing method. These proposed local search heuristics are tested through computational experiments with data from dicing operations of a compound semiconductor manufacturing facility.

Cycle time management during production ramp-up

Abstract: Aggressive capacity ramp rate of a semiconductor wafer fabrication is vital for the commercial success of the enterprise. Basic requirements are short and stable production cycle times to timely qualify equipment and to provide acceptable yield. Therefore, in the ramp-up environment which is characterized by high variability and uncertainty, an adequate methodology is required to properly manage the conflict of short cycle times and fast throughput increase. This paper presents a methodology to manage cycle time by closely monitoring and limiting the work in process (WIP), by means of the so-called “WIP caps”. Used consequently, this methodology allows the ramp rate to accelerate as soon as the factory performance enables this while keeping cycle times under control.

An evaluation framework for deploying Web Services in the next generation manufacturing enterprise

Abstract: In today's competitive manufacturing environment, the ability to effectively and efficiently manage the flow of information is a vital competency. Manufacturing enterprises must be able to integrate their internal business processes horizontally and vertically, and they are increasingly required to support federated business processes with other members of their respective virtual value chains. Web Services, an emerging form of service-oriented architecture for distributed computing, have the potential to serve as a key enabling technology to support these requirements. Leveraging the inherent interoperability of Internet and Worldwide Web technologies, they enable cooperative processing across heterogeneous computing environments. This paper presents a framework for evaluating the viability of Web Services technologies to be incorporated into enterprise information architectures to support the business needs and requirements of next generation manufacturing enterprises. It examines economic, technical, and organizational contexts that will influence the ability of manufacturing-related enterprises to deploy advanced information architectures based on Web Services to support the complex business processes needed to collaborate with suppliers, customers, and other stakeholders in virtual enterprise environments.

Computer-aided RCM-based plant maintenance management system

Abstract: In most of the industries, classical reliability-centered maintenance (RCM) is employed to decide the maintenance strategies using reliability data without having adequate interaction with the design and operational systems. This means that the RCM process will be conducted with no or limited access to the design and operational data/knowledge. Commonly, the developed maintenance strategies are implemented and managed within the computerized maintenance management system (CMMS), which is usually separate from the RCM automated environment. This paper presents the detailed system design and mechanism of improved RCM process as integrated with CMMS. The proposed solution is integrated with design and operational systems and consolidates some successful maintainability approaches to formulate an effective solution for optimized plant maintenance. The major components of the enhanced RCM process are identified and a prototype system is implemented as integrated with the various modules of the adopted CMMS (MAXIMOt). A case study is used to show the effectiveness of the proposed RCM-based CMMS solution in optimizing plant maintenance over the traditional approaches. r 2003 Elsevier Ltd. All rights reserved.

A modeling technique for loading and scheduling problems in FMS

Abstract: In recent years, due to highly competitive market conditions, it has become necessary for manufacturing systems to have quick response times and high flexibility. Flexible manufacturing systems (FMS's) have gained attention in response to this challenge. FMS has the ability to produce a variety of parts using the same system. However this flexibility comes at the price, which is the development of efficient and effective methods for integrated production planning, and control. In this paper, we analyze the production planning problem in flexible manufacturing systems. We address the problems of part loading, tool loading, and part scheduling. We assume that there is a set of tools with known life and a set of machines that can produce a variety of parts. A batch of various part types is routed through this system with the assumption that the processing time and cost vary with the assignment of parts to different machines and assignment of various tool sets to machines. We developed a mathematical model to select machines and assign operations and the required tools to machines in order to minimize the summation of maximum completion time, material handling time, and total processing time. We first integrate and formulate loading, and routing, two of the most important FMS planning problems, as a 0–1 mixed integer programming problem. We then take the output from the integrated planning model and generate a detailed operations schedule. The results reported in this paper demonstrate the model efficiency and examine the performance of the system with respect to measures such as production rate and utilization.

Vision-guided fixtureless assembly of automotive components

Abstract: Assembly operations in many industries make extensive use of fixtures that are costly and inflexible The goal of “robotic fixtureless assembly” (RFA) is to replace these fixtures with sensor-guided robots In this paper, the development of a vision-guided RFA workcell for automotive components is described Each robot is equipped with a multiple degree-of-freedom programmable gripper, allowing it to hold a wide range of part shapes without tool changing A 2D computer vision is used to achieve part pickup which is robust to positioning errors A novel 3D computer vision system is used to align the parts prior to joining them The actions of the workcell devices are coordinated using a flexible distributed object-oriented approach Experimental results are presented for the RFA of four automotive body components

MRP-controlled manufacturing environment disturbed by uncertainty

Abstract: Most identified research on uncertainty in material requirements planning (M RP)-controlled manufacturing environment, while purporting to represent such environment, does not truly model a multi-level dependent demand system, with multi-product and controlled by planned order release (POR) schedule based on planned lead times. This research has developed an MRP-controlled batch manufacturing simulation model using ARENA simulation software to represent such environment. In this paper, the delivery performance of the environment, measured with parts delivered late (PDL) and finished products delivered late (FPDL), when disturbed by uncertainty is examined. Design of experiments and simulation studies are carried out for these uncertainties: external late supply, internal late supply, planned set-up time exceeded, machine breakdowns, labour unavailability, tooling unavailability, demand batch size enlargement and customer design changes. Analysis of Variance (ANOVA) results identify significant effects from individual uncertainty as well as combination of uncertainties. The knock-on and the compound effects cause more PDL and FPDL. The main finding is that the higher is the level of the significant uncertainties, tile higher is the level of PDL and FPDL. It is suggested that MRP-controlled manufacturing enterprise must diagnose for the significant uncertainties, so that optimum use of buffer or slack can be implemented. Some practical implications of this work and required further work arc also discussed. (C) 2003 Elsevier Science Ltd. All rights reserved.

Advanced Resource Planning

Abstract: Advanced Resources Planning hits the bottom of what we know as aggregate planning. This approach differs from other approaches in that it explicitly recognizes the stochastic nature of manufacturing systems. Therefore, it is an ideal high-level tuning and planning tool which can be used in various planning environments like MRP, ERP, JIT, Load-Oriented Planning, Theory of Constraints, Finite Scheduling, POLCA systems, and perhaps many more. The main purpose is to set aggregate planning parameters right before diving into any other operational planning decision. In this sense, we opt to offer realistic lead time estimations, lot sizes, utilization levels, customer service levels and quoted delivery times. The underlying approach is a waiting line network, which is heavily adapted in order to make it useful for planning purposes. The main feature is that both input parameters and output parameters are considered as stochastic variables. In this way it allows us to model manufacturing environments in a more realistic and intuitive way, including all kinds of uncertainty and variability. As a consequence, the output of the planning effort is also a stochastic variable: it has an average, a variance and the entire lead time distribution. The latter makes it possible to obtain high customer service levels or to establish realistic delivery times, which can be met with a high probability. This mathematical approach as such is not suited for people operating a manufacturing system. We illustrate the approach with software, named i-CLIPS, and we review some implementations and their results.

Knowledge-based tool for planning of enterprise resources in ASEAN SMEs

Abstract: Manufacturing has been identified as a key pillar of growth in many Southeast Asian (ASEAN) economies. However, in the last decade many countries have become keen competitors for foreign direct investments. Many countries are trying to improve their total business capabilities by encouraging computerisation of small and medium sized enterprises (SME). Manufacturing SMEs (M-SMEs) are tasked to adopt technologically advanced programmes. With an improving public education system and more literate work force, more SMEs are better positioned to tap into the knowledge-based economy. There is tremendous amount of knowledge intensive activities within the multi-flows of the M-SMEs. Although the concept of ERP systems and artificial intelligence (AI) techniques have been around for more than two decades, this has largely remained the domain of the larger companies. ASEAN M-SMEs have been slow to implement it. In this paper, the various strategic and operational requirements of regional M-SMEs are presented and a knowledge-based resources planning model making use of AI techniques is proposed. This improved AI model makes use of the large amount of accumulated knowledge typically found in the M-SMEs, especially those in the electronics and precision engineering sectors. This includes a case study of how an electronics precision engineering company adopted the proposed AI model.

A study on the quality improvement of robotic GMA welding process

Abstract: With the advance of the robotic welding process, procedure optimisation that selects the welding procedure and predicts bead geometry that will be deposited has increased. Amajor concern involving procedure optimisation should define a welding procedure that can be shown to be the best with respect to some standard, and chosen combination of process parameters, which give an acceptable balance between production rate and the scope of defects for a given situation. This paper represents a new algorithm to establish a mathematical model for predicting top-bead width through a neural network and multiple regression methods, to understand relationships between process parameters and top-bead width, and to predict process parameters on top-bead width in robotic gas metal arc (GMA) welding process. Using a series of robotic GMA welding, additional multi-pass butt welds were carried out in order to verify the performance of the multiple regression and neural network models as well as to select the most suitable model. The results show that not only the proposed models can predict the top-bead width with reasonable accuracy and guarantee the uniform weld quality, but also a neural network model could be better than the empirical models.

Emergence of intelligence in next-generation manufacturing systems

Abstract: In the paper we propose a fundamental shift from the present manufacturing concepts and problem solving approaches towards new manufacturing paradigms involving phenomena such as emergence, intelligence, non-determinism, complexity, self-organization, bottom-up organization, and coexistence with the ecosystem. In the first part of the paper we study the characteristics of the past and the present manufacturing concepts and the problems they caused. According to the analogy with the terms in cognitive psychology four types of problems occurring in complex manufacturing systems are identified. Then, appropriateness of various intelligent systems for solving of these four types of problems is analyzed. In the second part of the paper, we study two completely different problems. These two problems are (1) identification of system in metal forming industry and (2) autonomous robot system in manufacturing environment. A genetic-based approach that imitates integration of living cells into tissues, organs, and organisms is used. The paper clearly shows how the state of the stable global order (i.e., the intelligence) of the overall system gradually emerges as a result of low-level interactions between entities of which the system consists and the environment.

Product information systems engineering: an approach for building product models by reuse of patterns

Abstract: This paper deals with an approach for Product Information Systems (PIS) engineering by reuse of patterns. Patterns form generic solutions to problems frequently occurring during PIS specification and implementation. The pattern approach provides an engineering guide to model data by organizing hierarchically and functionally modeling problems and the manner to resolve them. Their use would contribute to accelerate building and implementing product and process models during PIS specification and implementation. Two kind of patterns are distinguished: business patterns used for specification and providing solutions for application field problems and software patterns used for implementation and providing solutions for technical problems (software). A special interest is given to identify and specify different business patterns for product modeling during PIS specification. However, a pattern-based approach can be developed only for disciplines which acquired a certain maturity, i.e. those for which there is both a consensus around a finite set of problems and a variety of known solutions for solving these problems. There is no universal agreement on the knowledge needed in product information systems, let alone on the representation of this knowledge and we therefore find it impossible to discuss product information systems without reference to what kind of knowledge is being managed. The first step consisted thus of constructing a general reference framework based on PIS concepts, providing a common terminology and a semantic of the principal concepts managed in PIS and proposing various models to fix these concepts. It forms a basis for exploring the problems frequently occurring during PIS specification. A pattern language is thus defined to resolve the identified problems, basing partially on existing design pattern catalogues.

Algorithmic selection of a disassembly sequence of a component by a wave propagation method

Abstract: The design of a product for its entire life-cycle is becoming more and more important. Nowadays, a product is designed with significant considerations for its manufacturability, serviceability, its functionality and even for its disassemblability. This is due to the fact that the modern consumers demand products that are not only functional, but also reliable, easy to repair and also environmentally friendly. For maintenance and re-use, the operation sequencing in disassembly process planning needs of reversible operation selecting. We present a new wave propagation disassembly algorithm of the determined component of a product; the given data are the immediate predecessors of each component. We show that the solution exists and that she is unique in the following conditions: the binary matrix of the immediate predecessors is non-symmetrical and the data does not contain a cycle. A tracked down cycle method in the data is also proposed.

Coordination policies to support decision making in distributed production planning

Abstract: Distributed production networks are considered organizational structures able to match agility and efficiency necessary to compete in the global market. Performances of such organization structures heavily depend on the ability of the network actors of coordinating their activities. The research proposes to model and design coordination problems within production network by using the Multiple Agent Technology. In particular, the paper proposes new strategies for coordinating production-planning activities within production networks. Such models have been developed and tested by using a proper simulation environment developed by using open source code and architecture. The results of the research can be located at two levels: (a) concerning the specific coordination problem addressed, the research provides some insights to make decisions about the choice of coordination approaches to be used in distributed production planning problems; (b) at more strategic level, the paper shows how Agent Technology and discrete event simulation can be used to build up efficient coordination structures for production networks.

An efficient multi-camera, multi-target scheme for the three-dimensional control of robots using uncalibrated vision

Abstract: A vision-based control methodology is presented in this paper that can perform accurate, three-dimensional (3D), positioning and path-tracking tasks. Tested with the challenging manufacturing task of welding in an unstructured environment, the proposed methodology has proven to be highly reliable, consistently achieving terminal precision of 1 mm . A key limiting factor for this high precision is camera–space resolution per unit physical space. This paper also presents a means of preserving and even increasing this ratio over a large region of the robot's workspace by using data from multiple vision sensors. In the experiments reported in this paper, a laser is used to facilitate the image processing aspect of the vision-based control strategy. The laser projects “laser spots” over the workpiece in order to gather information about the workpiece geometry. Previous applications of the control method were limited to considering only local, geometric information of the workpiece, close to the region where the robot's tool is going to be placed. This paper presents a methodology to consider all available information about the geometry of the workpiece. This data is represented in a compact matrix format that is used within the algorithm to evaluate an optimal robot configuration. The proposed strategy processes and stores the information that comes from various vision sensors in an efficient manner. An important goal of the proposed methodology is to facilitate the use of industrial robots in unstructured environments. A graphical-user-interface (GUI) has been developed that simplifies the use of the robot/vision system. With this GUI, complex tasks such as welding can be successfully performed by users with limited experience in the control of robots and welding techniques.

Calibration of multi-beam laser tracking systems

Abstract: Laser tracking systems (LTSs) employ tracking laser interferometers for coordinate measuring of precision machine tools and robots. Such coordinate measuring machines, if properly calibrated, are potentially fast, very accurate and can cover a large workspace. LTS devices must be self-calibrated, using redundancy or constraint surfaces. A methodology for self-calibration of a multi-beam LTS utilizing planar constraints is formulated and demonstrated. A kinematic model of a multi-beam LTS is derived. Model error analysis demonstrates that the use of angular measurement of the gimbal joint positions, relatively inaccurate as these are, does improve the overall system calibration accuracy. Self-calibration model parameters observability of the multi-beam LTS is studied. The results reveal the applicability of planar constraints to system self-calibration. Simulation and experimentation results obtained on a prototype system are reported demonstrating the applicability of the calibration strategies.

Rapid and flexible prototyping through a dual-robot workcell

Abstract: With the advancement of CAD/CAM and robot technologies, applying robots for rapid prototyping applications has become a growing trend. However, a single robot can only perform limited prototyping tasks. Compared to a single robot, a dual-robot workcell can have greater structure flexibility, production efficiency, and system reliability due to the inherent parallelism and duality of robots. This paper presents the development and implementation of a dual-robot workcell for prototyping of 3D models. First, kinematic models of both robots in the workcell are established. Then, the concepts of five-axis machining configurations, postprocessing, off-line robot path generation and the dual-robot control scheme are presented. Finally, details of cutting experiments are provided to demonstrate the effectiveness of the system. The results show that the proposed dual-robot workcell is flexible and efficient for prototyping complex components in the current industrial environment.

Modeling, scheduling and simulation of product development process by extended stochastic high-level evaluation Petri nets

Abstract: This paper presents a methodology for modeling and simulating product development process-based on the extended stochastic high-level evaluation Petri nets (ESHLEP-N). A product development process is composed of many design activities and the ESHLEP-N model can describe some special features of design activity in detail, such as randomness of its duration, uncertainty of its interruption and complexity of design iteration. Therefore, the ESHLEP-N model is employed to simulate a product development process. The initial product development plan obtained by a mathematical method beforehand is taken as the input of the simulation. Then the simulation procedure is proposed, along with four types of rules, i.e. activity-sequencing rules, resource-assigning rules, state-changing rules and the simulation-terminating rule, for scheduling the design activities. An example of the development process of an automobile drive system in concurrent engineering environment is presented to illustrate the method of the ESHLEP-N-based modeling, simulation procedure and scheduling rules. The simulation results show that the simulation procedure and the scheduling rules are effective.

Simulation of cutting forces in ball-end milling

Abstract: The paper presents a simulation system (SCP) that determines the cutting forces in the ball-end milling process. The system is based on numerical methods, computer programme, theoretical knowledge of technological processes, machining and tests performed. The system for simulation of the cutting process combines the technological data base, the analytical and experimental model and the data base SCP. The experimental model contains a collection of variables of the cutting process by means of sensors and transformation of those data into numerical values, which are a starting point for data calculation of characteristic coefficients of materials. The analytical model is used to estimate the tangential, radial and axial cutting forces, along with a material data base obtained from cutting experiments. Ball-end milling test has been conducted to verify simulation results. The simulation results, are the basis for the development of the tool-designing model and for the model of optimization of the machining process cutting parameters.

Integrating Java 3D model and sensor data for remote monitoring and control

Abstract: This paper presents a novel approach and a framework for web-based systems that can be used in distributed manufacturing environments. A prototype is developed to demonstrate its application to remote monitoring and control of a Tripod—one type of parallel kinematic machine. It utilizes the latest Java technologies (Java 3D and Java Servlets) as enabling technologies for system implementation. Instead of using a camera for monitoring, the Tripod is modeled using Java 3D with behavioral control nodes embedded. Once downloaded from its server, the 3D model behaves in the same way of its counterpart at client side. It remains alive by connecting with the Tripod through message passing, e.g., sensor signals and control commands transmissions. The goal of this research is to eliminate network traffic with Java 3D models, while still providing users with intuitive environments. In the near future, open-architecture devices will be web-ready having Java virtual machines embedded. This will make the approach more effective for web-based device monitoring and control.

Just-in-sequence material supply—a simulation based solution in electronics production

Abstract: Just-in-time and just-in-sequence (JIS) concepts have been presented by the automotive industries in the past years. Today, where customer-oriented manufacturing is more and more demanded, electronics production is in a similar situation. The integral organizational means at Diehl AKO Nuremberg have been realized to achieve JIS material supply in the electronics sector. The right cooperation of software solutions from SAP (ERP), LES (logistics) to BOFOS (manufacturing planning) results in a set of improvements in material flow, scheduling, and document flow. The following paper shows the concepts, realizations, and achievements of the partners Diehl AKO and ETL. The main interest lies on the general approach, not on a particular detail.

Scheduling algorithm based on evolutionary computing in identical parallel machine production line

Abstract: Evolutionary programming is a kind of evolutionary computing method based on stochastic search suitable for solving system optimization. In this paper, evolutionary programming method is applied to the identical parallel machine production line scheduling problem of minimizing the number of tardy jobs, which is a very important optimization problem in the field of research on CIMS and industrial engineering, and researches on problem formulation, expression of feasible solution, methods for the generation of the initial population, the mutation and improvement on the local search ability of evolutionary programming. Computational results of different scales of problems show that the evolutionary programming algorithm proposed in this paper is efficient, and that it is fit for solving large-scale identical parallel machine production line scheduling problems, and that the quality of its solution has advantage over so far the best heuristic procedure.

STEP-based product modeling system for remote collaborative reverse engineering

Abstract: Production of high-quality products with lower cost and shorter time-to-market is an important challenge in the face of increased global competition, and reverse engineering plays an important role in accelerating product and process development. With the advent of new technologies such as network, multimedia and product data exchange standard STEP (STandard for Exchange of Product model data), there are many advantages to adopt these technologies to enhance the competitiveness of an enterprise. In this paper, a product information recording module for reverse engineering is developed to enhance the performance of product development. A STEP development tool, ST-Developer, and Visual C++ were used to develop this module, which can be used to record key information expeditiously during a collaborative process, and can also be used for further exchange of information, or as the basis for manufacturability evaluation. In this paper, the developed STEP-based information recording system is further integrated with the conventional Computer Supported Cooperative Work methods such as videoconferencing and application-sharing to form a remote collaborative reverse engineering system, which can provides a new strategy for an enterprise to speed up the product development cycle, reducing production cost, as well as sharing knowledge and experience.

A re-configurable multi-agent system architecture for error recovery in production systems

Abstract: Multi-agent systems for manufacturing systems appear to provide adequate response to abrupt disturbances on the shop floor. To date, most of the work has been focused on planning and scheduling but very little work has been done on issues pertaining to monitoring, diagnostics and error recovery. Our approach addresses the issue of combining the discipline of hierarchical systems with the agility of multi-agent systems. Within the context of a hierarchy, the focus is on the workstation level and, in particular, the construction of a re-configurable system having production agents, error recovery agents, and a mediator agent structure connecting production and recovery agent hierarchies. In addition, the relationship to a multi-level, multi-layer hierarchy control is established. This latter hierarchy, based on Petri Net constructs, serves, in one sense, as a retrieval based resource for process planning and generation of recovery plans for production and recovery agents within the proposed multi-agent system. An objective of this effort is to provide a test-bed for comparison of hierarchical systems, heterarchical, and a hybrid combination which is the focus of the investigation presented here.

Design and performances of a one-degree-of-freedom guided nano-actuator

Abstract: The aim of the research presented in this paper was to propose a simple and cheap system, able to produce a macroscopic (centimetric) travel with a very high (nano-metric) resolution. The solution principle described yields a theoretically infinite travel range based on the accumulation of successive steps. The travel range of the prototype realised is equal to 2 cm , the size of the steps being about 20 nm . The actuation is based on the stick–slip effect: during the first stage of a step, the legs of the actuator slowly translate the carried structure; in the second stage the legs are moved back in their initial position very quickly, so that, thanks to their inertia, the structure stays at the same place. Each leg of the system, glued on a main frame, consists in a piezoelectric device working in shear mode, ended by a ruby hemisphere. The structure itself is in steel to get a sufficiently high inertia. An originality of the proposed translator is that the guiding elements of the structure (guiding grooves) are also used to transmit the motion. The friction force between the legs and the grooves can be tuned thanks to a magnet placed in the main frame, allowing to adjust the normal load on the legs. The paper presents the different functional elements of the translator and its electronic command system, and explains its functioning. The influence of several parameters (supported load, friction, resistive axial load) on the step size and thus on both the resolution, hence the speed of the system is then studied. Finally, the power losses are identified and estimated.