Applications: Industry and Education
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Over the last decades engineered systems have reached a
tremendous level of complexity, involving expertise from many disciplines and
entailing a variety of implementation technologies (e.g., embedded software,
microelectromechanical systems, analog circuits, and digital circuits). The
heterogeneous nature of these systems invariably combines with an
architecture of different concurrent components that interact through continuous
signals or discrete message passing. The corresponding increased level of
complexity has led to the use of more formal approaches to system design through
realization. Efficient and effective approaches apply dedicated modeling
formalisms to different aspects of the system. Consequently, the complete system
specification process combines several modeling, design, implementation, and
realization paradigms (e.g., differential equation modeling, continuous time
signal processing, and discrete event controllers) and decomposition of the
entire specification task allows teams of experts to concurrently work on their
domain of expertise. In the area of computer aided control system design this
includes, e.g., control system design, simulation, optimization, modeling, and
verification.
Specialized computer automated tools for each of these
domains are very helpful or even indispensable to carry out the related tasks.
However, because these tools hardly ever are compatible, the sharing and
coordinating of information flow between project teams inevitably leads to a lot
of overhead in terms of collaboration and is very error prone, inefficient, and
expensive. Moreover, similar tasks may be carried out multiple times and even
simultaneously. For example, compared to control design approaches, fault
detection and isolation (FDI) methods often rely on different, more detailed,
models of the same system, which, as a consequence, is modeled by the control
design team as well as the FDI team.
Paper
1 [Simon Lacoste-Julien] discusses the ability to model and simulate complex
physical as well as control systems. Appropriate modeling formalisms need to be
available, depending on the type of system under study, on the aspects of the
structure and behaviour of the system one is interested in, and on the kind of
queries one wishes to make regarding the system. This paper presents a hybrid
formalism that combines event-scheduling with ordinary differential equations.
It shows how meta-modelling, the explicit modelling of a class of models, can be
used to describe the syntax of the hybrid formalism. Simulation of a
Personalized Rapid Transit vehicle is shown to consist of a series of model
transformations, modeled by graph grammars, that modify time as well as the
state.
Paper
2 [Hugh H. T. Liu] demonstrates the usage of a multi-paradigm simulation
framework for the requirement validation and verification of fly-by-wire (FBW)
flight control systems. The requirement validation and verification (V&V) is
an integrated part of systems engineering process, across different development
stages. In the meantime, simulation has been used quite extensively in aircraft
development and seems promising to serve as a tool in V&V. In order to make
the requirements and validation criteria consistent at different development
phases, teams that often use different simulation platforms, multi-paradigm
modeling and simulation strategy will come to play an important role. This paper
presents preliminary investigation in FBW flight control system V&V using a
proposed multi-paradigm simulation framework.
Paper
3 [Luciano Baresi] The correct behavior of hybrid systems depends on the
interactions between time-continuous and time-discrete subsystems, e.g., a
time-continuous plant and a time-discrete control. Complex interaction patterns
can be verified only with models that integrate both types of subsystems. This
paper presents a tool that uses Matlab/Simulink for modeling time-continuous
plants and timed Petri nets for modeling time-discrete controls, and support the
verification of the system design through integrated simulation of the models.
The control subsystem is specified with an IEC-compliant PLC editor integrated
in Matlab/Simulink. The tool automatically maps IEC 61131-3 FBD specifications
into timed Petri nets and integrates obtained models with the Simulink models of
the plant to allow for simulating the whole system based on event driven
discretization of the time-continuous components.
Paper
4 [Jin-Shyan Lee] In the past years, modeling and simulation of hybrid
dynamic systems (HDS) have attracted much attention. However, since
simultaneously dealing with the discrete and continuous variables is very
difficult, most of the models result in a unified, but more complicated and
unnatural format. Moreover, design engineers cannot be allowed to use their
preferred domain models. Based on the multi-paradigm modeling (MPaM) concept,
this paper proposed a Petri net (PN) framework with associated state equations
to model the HDS. In the presented approach, modeling schemes of the hybrid
systems are separated, but combined in a hierarchical way through specified
interfaces. Designers can still work in their familiar domain-specific modeling
paradigms and the heterogeneity is hidden when composing large systems. An
application to a rapid thermal process (RTP) in semiconductor manufacturing is
provided to demonstrate the practicability of the developed approach.
Paper
5 [Fernando Barros] Complex systems exhibiting structural changes can be
better represented by models that can mimic these transformations. The
Heterogeneous Flow System Specification (HFSS) is a comprehensive formalism that
can represent a large variety of models using a unifying representation. The
HFSS formalism represents models in a hierarchical and modular form. The
explicit representation of structure makes possible to alter it dynamically.
Among hybrid models, the most important include digital controllers and hybrid
integrators. The HFSS ability to provide a common ground to represent these
elements permits to model complex systems in a simple framework. We present a
detailed model of a PID controller and we show how this digital controller can
be merged with other types of components. To illustrate formalism application we
model a 2-stage rocket system, whose velocity is set by a PI digital controller,
by a dynamic structure network of hybrid components. Simulation results for the
rocket system are presented.
Paper
6 [Klaus D. Mueller-Glaser] Up to 70 electronic control units (ECUs) serve
for safety and comfort functions in a car. Communicating over different bus
systems most ECU's perform closed loop control functions and reactive functions
and have to fulfill hard real time constraints. The challenge for the design of
those distributed and networked control units is to define all requirements and
constraints, understand and analyze those manifold interactions between the
control units, the car and the environment (driver, road, weather) in normal as
well as stress situations (crash). To design within a development process which
is concurrent and distributed between the automotive manufacturer and several
suppliers requires a well understood life-cycle model, a strictly controlled
design methodology and using computer aided engineering tools to its largest
extent. The CASE-tool integration platform "GeneralStore" has been developed to
support the design of automotive ECU's. In addition, GeneralStore is also used
for the design of industrial automation systems and biomedical systems.
"Meta-Modelling
Hybrid Formalisms", slides
- Simon Lacoste-Julien
- Computer Science Division, University of California, Berkeley, CA
- Hans Vangheluwe
- School of Computer Science, McGill University, Montreal, Canada
- Juan de Lara
- Departamento de Ingeniería Informática, Universidad Autónoma de
Madrid, Spain
- Pieter J. Mosterman
- The MathWorks, Inc., Natick, MA
- "Multiparadigm
Design, Validation and Verification by Simulation in Flight Control System
Development", slides
- Hugh H. T. Liu
- Institute for Aerospace Studies, University of Toronto, Toronto,
Canada
- "On
Verifying Hybrid Systems with Simulink and Timed Petri Nets"1
- Luciano Baresi
- Dipartimento di Elettronica e Informazione, Politecnico di Milano,
Milano, Italy
- Marco Mauri
- Dipartimento di Meccanica, Politecnico di Milano, Milano, Italy
- Mauro Pezzč
- Dipartimento di Informatica, Sistemistica e Comunicazione, Universitŕ
degli Studi di Milano Bicocca
- "A
Multi-Paradigm Modeling Approach for Hybrid Dynamic Systems", slides
- Jin-Shyan Lee
- Department of Electrical and Control Engineering, National Chiao-Tung
University, Hsinchu, Taiwan
- Meng-Chu Zhou
- Department of Electrical and Computer Engineering, New Jersey Institute
of Technology, Newark, NJ
- Pau-Lo Hsu
- Department of Electrical and Control Engineering, National Chiao-Tung
University, Hsinchu, Taiwan
- "Modeling
and Simulation of Digital Controllers for Hybrid Dynamic Structure
Systems",2
slides
- Fernando J. Barros
- Dept. Eng. Informática, Universidade de Coimbra, Coimbra, Portugal
- "Heterogeneous
Modeling for Automotive Electronic Control Units using a CASE-Tool Integration
Platform", slides
- Klaus D. Müller-Glaser, Clemens Reichmann, Philipp Graf
- Institut für Technik der Informationsverarbeitung, University of
Karlsruhe, Karlsruhe, Germany
- Markus Kühl, and Klaus Ritter
- Forschungszentrum Informatik, Karlsruhe, Germany
1This is the version of the
paper submitted for review. It was not presented at the symposium.
2This paper was presented at the Conference on
Conceptual Modeling and Simulation, Genoa, Italy, October 28-30, 2004, and
published in its proceedings.