Objective: To develop general design principles useful to all cyber-physical systems testbed developers and specific design concepts to guide development, operation, and evolution of NIST’s CPS testbed; and to establish a cross-sector CPS testbed (in the basement of Building 220) that enables remote federation with other NIST labs and external testbeds to support NIST CPS measurement science work.
What is the new technical idea? The technical approach relies on three key ideas: (1) to integrate “best-of-breed” tools from multiple domains, and (2) to do so using well-established standards for federated communications, and (3) to define the components of an experiment in a granular form that allow experiments to be composed of well-defined and tested parts.
First, the testbed design will be based on the NIST CPS Framework methodology and reference architecture concepts that promote convergence and synergy across all CPS domains. Second, the testbed’s integrative, reconfigurable, reproducible, scalable and usable design requirements will make the system a powerful platform for testing concepts for composability and standards, protocols, and test methods for interoperability. Third, the testbed’s interchangeable modules allow agile reconfiguration of the testbed for varying experimental and specific-domain applications. Access to a range of physical testbeds is a unique strength at NIST, and NIST’s smart grid, SCADA, robotics, net-zero energy, building control systems, and other test facilities provide a range of candidates for remote federated experiments that allow testing of CPS concepts in a spectrum of realistic, domain-specific settings.
What is the research plan? The research plan has several components: CPS testbed measurement science research and development; CPS applications and multi-domain experimentation; and development of a CPS testbed community of practice.
In CPS testbed measurement science, the research plan is to develop foundational principles for CPS testbeds, to develop tools for implementing and operating testbeds, and to advance standards for CPS testbeds including enhancements of IEEE Standard (Std.) 1516: High-Level Architecture (HLA), testbed federate descriptors and federate libraries. Strong interconnections with the Reference Architecture/Foundations project will ensure that CPS Framework concepts of “facets” and “aspects” serve as holistic, concern-driven guiding principles for testbed conceptualization, realization and operation. These principles will guide the development of a universal “federate descriptor” as a data structure that will allow analytical tools to determine the ability to compose independently developed “federates” into meaningful experiments where measurements of figures of merit for CPS can be obtained.
Tools for performing such an analysis of CPS, including co-simulation and emulation, and hardware-in-the-loop, have been developed by the CPS Program. These compose a complete software package that enables the creation and management of configurations, of experimental components of the system under test (SUT), that is called the Universal CPS Environment for Federation (UCEF), as well as the physical infrastructure for experimentation. This includes testing both virtual experimental components as well as physical components. The software package UCEF, which is an experiment design tool suite, together with the physical experimental infrastructure, will be referred to as an instance of the CPS Testbed.
In the second research plan component, the project focuses on constructing and demonstrating this unique (UCEF+hardware) multi-domain federated CPS testbed with multiple integrated and reconfigurable domain-specific components. Federation provides an ability to combine equipment that is unique or can’t be collocated, and proprietary components can be integrated without exposing intellectual property by designed experiment interfaces. The NIST approach allows leveraging existing and disparate simulation tools and hardware in the loop and rapid experiment design and configuration. Based on its design requirements to be integrative, reconfigurable, reproducible, scalable and usable, the NIST CPS testbed will enable domain-specific (smart transportation, smart manufacturing, etc.) and multi-domain (smart cities, smart energy including smart grid, etc.) applications and experiments. In addition, control center functionality and human-machine interactions will also available for research in the CPS testbed environment. The CPS testbed includes a control room as a focal point for experimentation, providing situational awareness through visualization of operations on multiple screens for monitoring testbed modules and experiments. It also will provide emulation of control rooms for domains such as smart cities, energy management/grid control, emergency response, transportation and others, and will served as a common demonstration platform for the testbed. The activities that will be performed in the CPS testbed include developing experimental design and test methods, performing experiments or running tests, monitoring testbed function, and analyzing testbed function and data. These activities are implemented under an internal governance document “System Development Plan for the UCEF and CPS Testbed.”
Third, the CPS testbed project is designed to collaborate with other testbed research efforts and laboratories both on and off the NIST campus. To engage stakeholders in the CPS testbed research plan, NIST is leading and encouraging the formation of a CPS testbed community of practice of testbed users and developers in the industrial and academic sectors. Building on initial NIST activities including leading a public workshop on CPS testbed design, developing an inventory of existing collaborating CPS testbeds and providing an analysis of concepts, concerns and gaps, the NIST CPS Program is now developing an open source testbed community (available via a NIST-organized GitHub project) which will be launched at a planned July 2017 workshop at NIST.
An additional activity involves collaboration with the transportation sector on scoping an autonomous vehicle testbed as an application of the NIST federated testbed model, with a focus on trustworthiness (e.g., security and safety). The NIST-SAE collaborators will work with transportation original equipment manufacturers and suppliers to represent the component systems of an autonomous, connected vehicle system as hardware or emulated hardware or simulated software components for purposes of configuring an autonomous vehicle testbed. ‘Federated’ into a testbed, these collaborators will pilot virtual testing and assessment of the system’s performance. Based on this work, a publication is planned to summarize the use of this pilot and testbed technology for transportation systems and describing the new measurement science needed for future autonomous systems.