Requirements for object-oriented systems modeling with STEAMS

Proceedings Design, Automation and Test in Europe

After the IEEE ballot accepted the first draft language reference manual for VHDL-AMS (IEEE PAR 1076.1) in October 1997, we now can spend time and effort on applying the new arising methodology to real world problems outside the electronic domain. In automotive engineering we have system design problems dealing with hydraulic or mechanic components and their controlling units, for which we expect a major advantage by introducing unified modelling to all domains. With the Brite/EuRam-Project TOOLSYS (a joined effort of automotive industry and tool makers to apply VHDL-AMS as unified modelling language on mixeddomain applications) we prove the suitability as unified modelling and interchange language for real-world systems and components. First experiments with hydraulic components reveal numerical problems on analog circuit simulators. None of the available strategies for these particularly hard problems are included by the electronic simulator makers. With VHDL-AMS multi-domain modelling seems possible, now we need multi-domain simulation environments.

1997

VHDL 1076.1 is an extension to the well-established VHDL 1076 language to support the description and simulation of continuous and mixed continuous/discrete systems. We provide an overview of the extended language.

Computer Science and Information Systems, 2008

In the context of the INTEGRA project, compilation and code generation features for behavior definition are to be integrated in an existing model-based engineering environment for control systems. The devised compiler architecture is domain-specific and provides support for multiple input languages and multiple target platforms. In this paper we discuss an architectural approach in which the compiling process is organized in two different stages: the compiling stage and the linking stage. The compiling stage generates target independent code from possibly multiple input languages. The linking stage assembles precompiled code modules and generates a target specific executable code for a given virtual machine. To be more specific this paper describes the integration of the ST language in the tool core meta-model and the ST compiler is presented as an application case study.

2000

Proceedings of the IEEE

Hybrid systems modeling languages that mix discrete and continuous time signals and systems are widely used to develop Cyber-Physical systems where control software interacts with physical devices. Compilers play a central role, statically checking source models, generating intermediate representations for testing and verification, and producing sequential code for simulation and execution on target platforms. This paper presents a novel approach to the design and implementation of a hybrid systems language, built on synchronous language principles and their proven compilation techniques. The result is a hybrid systems modeling language in which synchronous programming constructs can be mixed with Ordinary Differential Equations (ODEs) and zero-crossing events, and a runtime that delegates their approximation to an off-the-shelf numerical solver. We propose an ideal semantics based on non standard analysis, which defines the execution of a hybrid model as an infinite sequence of infinitesimally small time steps. It is used to specify and prove correct three essential compilation steps: (1) a type system that guarantees that a continuous-time signal is never used where a discrete-time one is expected and conversely; (2) a type system that ensures the absence of combinatorial loops; (3) the generation of statically scheduled code for efficient execution. Our approach has been evaluated in two implementations: the academic language Zélus, which extends a language reminiscent of Lustre with ODEs and zero-crossing events, and the industrial prototype Scade Hybrid, a conservative extension of Scade 6.

In the context of the INTEGRA project, compilation and code generation features for behavior definition are to be integrated in an existing model-based engineering environment for control systems. The devised compiler architecture is domain-specific and provides support for multiple input languages and multiple target platforms.

Model-based control system design improves quality, shortens development time, lowers engineering cost, and reduces rework. Evaluating a control system's performance, functionality, and robustness in a simulation environment avoids the time and expense of developing hardware and software for each design iteration. Simulating the performance of a design can be straightforward (though sometimes tedious, depending on the complexity of the system being developed) with mathematical models for the hardware components of the system (plant models) and control algorithms for embedded controllers. This paper describes a software tool and a methodology that not only allows a complete system simulation to be performed early in the design cycle, but also greatly facilitates the construction of the model by automatically connecting the components and subsystems that comprise it. A key element of this technique is the software-in-the-loop (SIL) capability, which permits compiled legacy source ...

IFIP X International Conference on VLSI, Lisbon, 1999

Abstract: This paper presents the modeling and co-simulation capabilities of S3E2S, a design environment for electronic systems that can be built as a combination of analog and digital parts and software. S3E2S is based on a distributed, object-oriented system model, where abstract objects are initially used to express complex behavior and may be later refined into digital or analog hardware and software. Co-simulation of any heterogeneous model developed during a stepwise refinement process is supported. These capabilities ...

2003

Abstract A critical review of some of the languages used to describe and analyze hybrid systems is provided. Simulink, Stateflow, CheckMate, Charon, Masaccio, and SHIFT are presented after an introductory chapter where the main issues surrounding representation languages are described. The goal is to set the stage for the recommendation of a hybrid system interchange format that could facilitate the integration of different tools to form an environment for embedded system design.

2005 IEEE International Symposium on Circuits and Systems

Systems on chip are more and more heterogeneous and include software, analog/RF and digital hardware, and non-electronic components such as sensors or actuators. The design and the verification of such systems require appropriate modeling means to deal with the increasing complexity and to achieve efficient simulation. SystemC is providing a modeling and simulation framework that supports digital (discrete) hardware and software systems from abstract specifications to register transfer level models. In the paper, we are proposing a way to extend the capabilities of SystemC to support mixed discrete-continuous systems by implementing a synchronous dataflow (SDF) model of computation (MoC). The SDF MoC is used to embed continuous-time behavior in SDF modules and to support the synchronization with the existing SystemC kernel. The paper presents an overview of the architecture and the syntax of the proposed extensions and gives modeling examples with simulation results. I.

1995

This paper presents a methodology for a unified cosimulation and co-synthesis of hardware-software systems. This approach addresses the modeling of communication between the hardware and software modules at different abstraction levels and for different design tools. The main contribution is the use of a multi-view library concept in order to hide specific hardware/software implementation details and communication schemes. A system is viewed as a set of communicating hardware(VHDL) and software(C) sub-systems. The same C, VHDL descriptions can be used for both co-simulation and hardware-software co-synthesis. This approach is ilustrated by an example. SW/HW COM. UNIT HW/HW COM. UNIT Hardware Ports Communication Controller Control_Interface Access Procedures Distribution_Interface Access Procedures Hardware Ports Communication Controller Motor_Interface Access Procedures Motor Abstract Model Hardware Speed Control Sub-system Abstract Model Software Distribution Sub-system Abstract Model Figure 5: The Adaptative Motor Controller: HW/SW communicating sub-systems communication primitives used by this subsystem. It activates the Speed Control sub-system of the motor by specifying the maximum position value and the maximum number of speed-pulses.

The 9th IEEE Real-Time and Embedded Technology and Applications Symposium, 2003. Proceedings.

In this paper, we discuss a synchronous, componentbased approach to the modeling of avionics applications. The specification of the components relies on the avionics standard ARINC 653 and the synchronous language SIGNAL is considered as modeling formalism. The POLY-CHRONY tool-set allows for a seamless design process based on the SIGNAL model, which provides possibilities of high level specifications, verification and analysis of the specifications at very early stages of the design, and finally automatic code generation through formal transformations of these specifications. This suits the basic stringent requirements that should be met by any design environment for embedded applications in general, and avionics applications in particular.

2007

The work presented here is on setting up methodological support, including (prototype) tools, for the design of distributed hard real-time embedded control software for mechatronic products. The use of parallel hardware (CPUs, FPGAs) and parallel software is investigated, to exploit the inherent parallel nature of embedded systems and their control. Two core models of computation are used to describe the behavior of the total mechatronic system (plant, control, software and I/O): discrete event system (DES) and continuous time system (CTS). These models of computation are coupled via co-simulation, to be able to do consistency checking at the boundaries. This allows for integration of discipline-specific parts on the model level (during design phases) instead of on the code level (during realization and test phases). Crossview design-change influences get specific attention, to allow for relaxation of the tension between several dependability issues (like reliability and robustness), while keeping design time (and thus design costs) under control. Furthermore, the design work can be done as a stepwise refinement process. This yields a shorter design time, and a better quality product. The method is illustrated with a case using the tools being prototyped.

Modeling and simulation have been established as fundamental facilities in the development of analog and analog-digital systems. Essential advances have been achieved by the usage of behavioral modeling languages. These languages can be considered as a link between the technical problem and the mathematical model that can be evaluated by computational methods. The paper outlines the various possibilities that are offered by the language VHDL-AMS – standardized by the IEEE to describe analog and mixed-signal systems – and the language Modelica. The underlying modeling approaches are compared. Last but not least, the potential to transform models written in one language into models of the other language is discussed.

2002

Abstract The goal of this paper is to evaluate the performance of digital systems generated from a high-level description language. The target language in this work is SDL. The SDL description is automatically synthesized with a codesign tool, resulting in a VHDL description. The codesign tool is responsible for software, hardware and communication synthesis.