VHDL-AMS to support DAE-PDE coupling and multilevel modeling

International audienceWith the increasingly high level of electrical system integration, the modeling of both the system behavior, and the detailed physics of its elements becomes necessary. VHDL-AMS language allows to describe a range of physical systems, such as electromagnetic devices, using a unified design approach to simulate a complete system. In the paper, the behavioral modeling of multiple energy domains is achieved using VHDL-AMS. This illustrated how the interactions between domains take place with an electromagnetic actuator. Then, a multi-level hierarchical modeling methodology, using a V-shaped-based design approach, allows functional modeling, structural behavioral modeling and detailed component modeling

Virtual Prototyping Methodology for Power Automation Cyber-Physical-Systems

In this thesis, the author proposes a circular system development model which considers all the stages in a typical development process for industrial systems. In particular, the present work shows that the use of virtual prototyping at early stages of the system development may reduce the overall design and verification effort by allowing the exploration of the complete system architecture, and uncovering integration issues early on. The modeling techniques of this research are based on VHDL-AMS, yet supporting other modeling languages such as C/C++, SPICE, and Verilog-AMS, together with integrated simulation tools. Contrasting with conventional approaches, it is shown that the proposed methodology is adapted for small-scale Cyber-Physical Systems (CPS) design and verification thanks to the modularity and scalability of the modeling approach. The proposed modeling techniques enable seamlessly the CPS design together with the implementation of their subsystems. In particular, the contribution of this work improves the virtual prototyping approach that has been successfully used during the development of smart electrical sensors and monitoring equipment for high and medium voltage applications. The design of the measurement and self-calibration circuits of a medium voltage current sensor based on the Rogowski coil transducer is presented as an example. The proposed small-scale CPS design methodology based on virtual prototyping, namely VP-based design methodology, uses important theoretical concepts from layered design, component-based design, and platform-based design. These foundations are the basis to build a modeling methodology that provides a vehicle that can be used to improve system verification towards correct-by-design systems. The main contributions of this research are: the re-definition of the system development lifecycle by using a virtual prototyping methodology; the design and implementation of a model library that maximizes the reuse of computational models and their related IP; and a set of VHDL-AMS modeling guidelines established with the purpose of improving the modularity and scalability of virtual prototypes. These elements are key for supporting the introduction of virtual prototyping into industrial companies that can thoroughly profit from this approach, but cannot commit a specific team to the creation, support, and maintenance of computational models and its dedicated infrastructure. Thanks to the progressive nature of the proposed methodology, virtual prototypes can indeed be introduced with relatively low initial effort and enhanced over time. The presented methodology and its infrastructure may grow into a bidirectional communication medium between non-expert system designers (i.e. system architects and virtual integrators) and domain specialists such as mechanical designers, power electrical designers, embedded-electronics designers, and software designers. The proposed design methodology advocates the reduction of the CPS design complexity by the implementation of a meet-in-the-middle approach for system-level modeling. In this direction, the modeling techniques introduced in this work facilitate the architectural design space exploration, critical cross-domain variable analysis (especially important in the component interfaces), and system-level optimization and verification

A Problem-Oriented Approach for Dynamic Verification of Heterogeneous Embedded Systems

This work presents a virtual prototyping methodology for the design and verification of industrial devices in the field level of industrial automation systems. This work demonstrates that virtual prototypes can help increase the confidence in the correctness of a design thanks to a deeper understanding of the complex interactions between hardware, software, analog and mixed-signal components of embedded systems and the physical processes they interact with

UNIFIED MODELLING TECHNIQUE USING VHDL-AMS AND SOFTWARE COMPONENTS

International audienceThe paper deals with the dynamic modeling of mechatronic devices, which usually need detailed modeling to be described and to take into account the physical properties of the system. VHDL-AMS 1 , which is a powerful unified modeling language for mixed system, allows to describe a large range of physical systems, for their dynamic simulation. It allows to describe models of physical components and then to connect them to obtain the model of a system.. However, this language cannot support the description of some physical phenomena, such local ones, defined by numerical methods (e.g.: finite element method, special numerical integrals). When an aspect of a model cannot be described in VHDL-AMS, the paper proposes to use software components. So, the aim of the paper is to propose a generic way to extend the computation capability of VHDL-AMS, by coupling the models described in VHDL-AMS with external ones specified as software components (where VHDL-AMS fails). The approach has been applied on several applications, among them the time simulation of an electrical plunge

On mixed abstraction, languages and simulation approach to refinement with SystemC AMS

Executable specifications and simulations arecornerstone to system design flows. Complex mixed signalembedded systems can be specified with SystemC AMSwhich supports abstraction and extensible models of computation. The language contains semantics for moduleconnections and synchronization required in analog anddigital interaction. Through the synchronization layer, user defined models of computation, solvers and simulators can be unified in the SystemC AMS simulator for achieving low level abstraction and model refinement. These improvements assist in amplifying model aspects and their contribution to the overall system behavior. This work presents cosimulating refined models with timed data flow paradigm of SystemC AMS. The methodology uses Cbased interaction between simulators. An RTL model ofdata encryption standard is demonstrated as an example.The methodology is flexible and can be applied in earlydesign decision trade off, architecture experimentation and particularly for model refinement and critical behavior analysis

Abstract State Machines 1988-1998: Commented ASM Bibliography

An annotated bibliography of papers which deal with or use Abstract State Machines (ASMs), as of January 1998.Comment: Also maintained as a BibTeX file at http://www.eecs.umich.edu/gasm

A Holistic Approach to Functional Safety for Networked Cyber-Physical Systems

Functional safety is a significant concern in today's networked cyber-physical systems such as connected machines, autonomous vehicles, and intelligent environments. Simulation is a well-known methodology for the assessment of functional safety. Simulation models of networked cyber-physical systems are very heterogeneous relying on digital hardware, analog hardware, and network domains. Current functional safety assessment is mainly focused on digital hardware failures while minor attention is devoted to analog hardware and not at all to the interconnecting network. In this work we believe that in networked cyber-physical systems, the dependability must be verified not only for the nodes in isolation but also by taking into account their interaction through the communication channel. For this reason, this work proposes a holistic methodology for simulation-based safety assessment in which safety mechanisms are tested in a simulation environment reproducing the high-level behavior of digital hardware, analog hardware, and network communication. The methodology relies on three main automatic processes: 1) abstraction of analog models to transform them into system-level descriptions, 2) synthesis of network infrastructures to combine multiple cyber-physical systems, and 3) multi-domain fault injection in digital, analog, and network. Ultimately, the flow produces a homogeneous optimized description written in C++ for fast and reliable simulation which can have many applications. The focus of this thesis is performing extensive fault simulation and evaluating different functional safety metrics, \eg, fault and diagnostic coverage of all the safety mechanisms