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| Projects Simulation Prototypes and Testing Systems
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Manufacturing Systems Integration Program
Simulation-based Manufacturing Interoperability Standards and Testing Annual FTEs: 6 NIST FTEs 5 Guest Researcher FTEs 11 Total FTEs Challenge: Manufacturing systems, often requiring large investments in capital equipment and supporting software, are costly and time-consuming to acquire, integrate, and operate. Simulation technology, which makes possible the construction of technically correct, dynamic models of organizations, systems, and processes, is a tool of proven effectiveness in reducing manufacturing costs and improving the efficiency of manufacturing system design, operation, and maintenance. Simulation models can be used to perform “what-if” analyses and make better-informed decisions. But because simulations take time as well as specialized expertise in both construction and analysis of results, they are not used as often or as effectively as they might be; manufacturing management makes decisions based on intuition or superficial analysis. Manufacturing simulations are often developed to address a narrow set of industrial issues, such as the purchase of new equipment or the improvement of an existing manufacturing process, with no thought given to reusability for other purposes. Overview Greater use of simulation technology and re-use of existing models can help U.S. industry improve its manufacturing systems and compete more effectively in world markets. The NIST Simulation Program focuses on simulation standards and testing issues that will enable the U.S. manufacturing industry to make more effective use of simulation technology. The Department of Homeland Security (DHS) has also recognized the value of NIST’s expertise in simulation, and is giving the Program additional support to provide guidance on standards and testing for DHS modeling, simulation, and analysis applications. There are three major components to the Program: Frameworks and Architectures; Data Models and Standards; and Simulation Prototypes and Testing Systems. Frameworks and Architectures - NIST has developed distributed integration frameworks and architectures for both manufacturing and homeland security applications. The frameworks and architectures have set the direction for NIST’s interface standardization, prototyping, and testing activities. As well as publishing journal articles, technical reports, and other papers, we were invited in 2007 to give the keynote at the Simulation Interoperability Standards Organization Conference (SISO) that addressed the NIST modeling and simulation architecture for incident management training. Data Models and Standards - NIST has provided leadership and technical expertise to the Simulation Interoperability Standards Organization (SISO) to develop a Core Manufacturing Simulation Data (CMSD) model. The CMSD provides neutral data interfaces for integrating job shop software applications with manufacturing simulators. CMSD is now being extended to address flow shop[17] simulation, plant layout, and other data types. A number of major organizations – manufacturers, software vendors, research institutions and government agencies – have supported and participated in the validation of the specifications, and have provided technical contributions and reviews. Current validation efforts are being conducted with Volvo’s truck engine plant, a division of the Ford Motor Company, and Chalmers University of Sweden. Unigraphics, Enterprise Dynamics, and Simul8 simulation systems are being used in the validation process. Simulation Prototypes and Testing Systems - NIST scientists and engineers involved in the Simulation Program are using simulation technology to gain first hand experience with the problems faced by industrial users, to validate standards solutions, and to establish interoperability and other testing capabilities. A major focus is the development of a new, dynamic, simulation-based interoperability testing facility for manufacturing software applications. NIST has developed a number of simulations to support simulation-based interoperability testing, including an automotive supply chain, a vehicle final assembly plant, and various shop floor operations. The interfaces that have so far been incorporated into these simulations include the SISO Core Manufacturing Simulation Data Model and the Open Application Group’s (OAGIS) specification supporting Inventory Visibility. Future work will focus on integrating manufacturing software applications with a virtual machine shop to support validation and interoperability testing. Key Accomplishments and Impacts:
Future Directions and Plans: The technical plan for this program is to develop manufacturing simulations that incorporate standard interfaces and instrumentation to support dynamic interoperability testing of manufacturing software applications for the automotive, aerospace, and other industries. Projects include:
Awards and Recognition: Board Memberships
Leadership
Excellence
Projects Simulation-based Manufacturing Interoperability Standards and Testing Frameworks and Architectures Today simulation analysts typically code simulators and models from scratch and build custom data translators to import required data. As a result, developers and analysts around the world are rebuilding over and over again the same basic analytical, programming, and modeling processes. Although a simulation analyst may think that each modeling problem is unique, the component elements of many problems often have a good deal in common. Classification of different types of modeling problems according to uniform schemes or frameworks could identify and exploit such, commonalties. Frameworks make possible the establishment of modular architectures that can minimize redundant code development. Architectures based on these frameworks divide larger systems into their component modules and identify the interfaces between those modules, allowing the assembly of more sophisticated systems from specialized modules that are independently developed by experts in each modeling area. Use of standard data input formats, as defined by commonly accepted architectures, would permit direct import of data with no need for translation. Challenge: Integration of simulators and other software applications and data-sharing among them are currently very difficult because no commonly accepted frameworks and architectures exist that define the simulation module functionality, boundaries, data requirements, and interfaces. Objective(s):
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Simulation-based Manufacturing Interoperability Standards and Testing Data Models and Standards The primary reason for building manufacturing simulations is to provide support tools that aid decision-making in manufacturing processes. Simulations are typically a part of a case study that has been commissioned by manufacturing management to address a particular set of problems. The objectives of the case study determine the appropriate types of simulation models, input and output data. Translation of real world manufacturing problems into the language of manufacturing simulators requires a considerable degree of abstraction. Commercial manufacturing simulators are usually based on discrete event modeling paradigms (e.g., stations, queues, resources, processes) and do not have data interfaces that are consistent with commonly used manufacturing terminology or data structures (e.g., process plans, bill of materials, schedules). The analysis, acquisition, formatting, and translation of required data is often the most difficult part of the simulation analyst’s job. Standard data interfaces for manufacturing simulators simplify and significantly improve the inclusion of simulations in typical case studies. Standard interfaces help reduce the costs of model construction and data exchange between simulators and other software applications, and thus make simulation technology more affordable and accessible to a wide range of potential industrial users. Currently, many small manufacturers do not use simulation technology because of the difficulties of model development and data translation. These businesses typically do not have staff with the technical qualifications to develop custom simulations of their operations or custom translators to import their data from other software applications. Challenge: Commercially-developed simulators are typically constructed as general purpose modeling tools that require considerable efforts to input and process real world data, in part due to a lack of agreement on how to represent real world systems and data. Objective:
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Simulation-based Manufacturing Interoperability Standards and Testing Simulation Prototypes and Manufacturing systems developed by different software vendors typically cannot work together. Development of custom integrations of manufacturing software incurs costs and delays that hurt U.S. productivity and competitiveness. As software applications continue to evolve interoperability is expected to remain a problem. Although NIST has developed static testing tools that, for example, check data formats, software applications must ultimately be tested in live operational systems. It is impractical to use real industrial systems to support dynamic interoperability testing and research due to: 1) access issues - manufacturing facilities are not open to outsiders, as proprietary data and processes may be compromised; 2) technical issues - operational systems are not instrumented to support testing; and 3) cost issues - productivity suffers when actual production systems are taken offline to allow testing. No publicly available facility with open interfaces currently exists to support dynamic interoperability testing for a broad range of manufacturing interface standards and software applications. Prohibitive development costs and other priorities prevent most software vendors, research, and standards organizations from developing systems to support interoperability testing. Software applications from the supply chain to the shop floor must be supported. New standards now being developed to address interoperability issues often overlap and conflict with each other. Adequate testing facilities are not available for evaluating the suitability and effectiveness of existing and candidate standards for application to specific manufacturing domain areas. New, dynamic, manufacturing domain-specific testing capabilities are needed to evaluate the suitability of standards for selected applications, identify and resolve conflicts between standards, and evaluate compliance of vendor implementations with standards. Non-proprietary systems and neutral test case data sets are needed to support fair and open competition. Challenge: Publicly available simulations do not exist to demonstrate simulation integration issues, validate potential standards solutions, or dynamically test the interoperability of simulation systems and other software applications. Objective(s):
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[17] The flow structure of the process used to make or deliver a product or service impacts facility layout, resources, technology decisions, and work methods. When characterized by its flow structure, a process broadly can be classified either as a job shop or a flow shop. A job shop process uses general purpose resources and is highly flexible. A flow shop process uses specialized resources and the work follows a fixed path. Consequently, a flow shop is less flexible than a job shop. [http://www.netmba.com/operations/process/structure/]
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