Section: New Results

Computer aided control system design

ScicosLab

Participants : J. Ph. Chancelier, F. Delebecque, J.P. Quadrat.

ScicosLab is a free environment for scientific computation similar in many respects to Matlab/Simulink, providing Matlab functionalities through Scilab 4, and, Simulink and Modelica functionalities via Scicos.

ScicosLab is a GTK version of Scilab, based on the Scilab BUILD4 distribution. ScicosLab includes, in addition to the Gtk2 GUI, the maxplus built-in toolbox. Scilab and its predecessor Basile have been developed in the Metalau (formerly Meta2) project. This work has been carried out in close collaboration with J. Ph. Chancelier of ENPC who has made major contributions to Scilab such as the development of the graphics and the port to the Windows platform.

ScicosLab is made available by the researchers of the Metalau team at INRIA and ENPC who originally developed Scilab. ScicosLab is used in particular for distributing software stemming from the research activities at Metalau, such as Scicos (http://www.scicos.org ) and the Maxplus algebra tool (http://www.maxplus.org ).

ScicosLab (ex-ScilabGTK) is available for most Windows, Linux and MacOSX operating systems, and can be downloaded from: http://www.scicoslab.org/ .

Scicos

Participants : R. Nikoukhah, S. Steer, M. Najafi, Fady Nassif, A. Layec, J. Ph. Chancelier, Abdellah Hijazi.

The development of Scicos continues. Our development strategy consists of actively participating in R& D projects (ANR, European). We choose the projects to support long term development of Scicos.

We have released Scicos 4.4 in December of 2009. This has been a major release. Scicos 4.4 (http://www.scicos.org ) is distributed with ScicosLab 4.4 (http://www.scicoslab.org ) which is currently available as beta release for most Windows, Linux and Mac operating systems.

This release of Scicos includes:

• a better coverage of the Modelica language (Modelica functionalities in Scicos are developed in collaboration with LMS-Imagine)

• a user interface for assistance in finding consistent initial conditions for large Modelica models

• a new more efficient Scicos compiler

• improved masking operations

• hierarchical palette structures

• major improvement in the C code generator allowing in particular code generation for a wider class of sub-systems.

• Efficient XML format for load and save (to be used for model exchange with other programs)

Scilab

Participant : S. Steer.

The development of Scilab has been taken over by the Scilab team since the creation of the Scilab consortium. We continue to have an action in this domain to help the knowledge transfer to the Scilab team. This transfer is mainly about the numerical computation, the Scilab language features and implementation subtelties. Since this year it also concerns the Scicos tool.

Until this year this action of transfer was made thanks to an assignment at mid time with the team of Scilab. Since June 2008 this action continues throught a support of the Metalau team.

On an other hand we continued updating the optimization contributed toolboxes (FSQP, CUTEr, LIPSOL, Quapro, ..) with the newest solvers available. In this context we started an overall evaluation of these solvers as well as the Scilab native one using the wide CUTEr problem set.

Hybrid system modeling and simulation

Participants : R. Nikoukhah, F. Delebecque, M. Najafi, A. Layec, D. Chapon, S. Mannori.

The research work on hybrid system modeling and simulation provides the backbone of the modeling and simulation software Scicos. Modeling hybrid systems in a rigorous fashion is the objective of the Scicos formalism.

Currently the major axes of research and development on Scicos formalism are:

• Modelica. Modelica is a programming language primarily devoted to continuous-time system modeling. We consider that the extension of the Modelica language to discrete time dynamics consistently with the Scicos formalism would lead to a very powerful and broad modeling paradigm. We have been involved in close collaboration with Modelica Association for the specification of the language in the spirit of Scicos formalism. We have developed a Modelica compiler with LMS-Imagine which is now included in Scicos and distributed with ScicosLab 4.3. We work closely with EDF, IFP and PSA through various research contracts (in particular Simpa2, Eurosyslib) and we are in close contact with the OpenModelica project at Linkoping University. This work will be supported by the European project OpenProd starting 2009. We also participate in the development of Modelica libraries for hybrid components in Modelica (collaboration with Dassault Systems).

• Code generation.We have made significant progress in the area of code generation. Scicos code generator now can be used in the asynchronous framework. This has been particularly important for the integration of Modelica.

• Parade. The ANR contract Parade, the purpose of which is the study of parallel techniques for system simulation has been . Mrs Nguyen, an ESIEE trainee has developed waveform simulation examples within Scicos, following the preceding work of D. Chapon. Our joint work with Lagep has been followed up, and in particular a preliminary Scicos toolbox for port Hamiltonian system has been started. An example of a transmission line has been developed using an Hamiltonian formalism, leading to discretization schemes which respect energy invariants. The collocation method used is based on ad-hoc interpolation polynomials and the quadrature have been performed numerically (the Matlab implementation made at Lagep use symbolic calculations). Simone Mannori has realized several examples of parallel solvers using the Sundials/Mpi environment. The purpose is to exploit the new code generator of Scicos 4.4, which is now compatible with the parallel solvers of Sundials. The Lagep adsorption column model has been simulated by a standalone Sundials solver, automatically generated.

• Applications. A modeling paradigm must respond to real needs. That is why we continue our close collaboration with industrial partners to better understand their problems. We have been involved in the development of a number of applications in the past few years with PSA, EDF, IFP, EADS, DGA and others.

Communication systems

Participant : A. Layec.

ModNum ("MODulations NUMériques") is an open source and free computational library for the modeling and the simulation of communication systems. It proposes scicos blocks, schematics and scilab in-line functions of base-band PSK/QAM modulations in order to build communication chains in the Scilab/Scicos environment. Components used to build spread-spectrum communication systems, such Pseudo Noise sequence generators (Quasi-Chaotic, PN and Gold sequence generators) are also included. ModNum also includes miscellaneous scopes for Scicos, such as a spectrum analyzer scope and other scopes used for analysis of digital transmissions (e.g. Eye Diagram Scope, Scattered Diagram ). Schematics and blocks of integer and fractional frequency synthesizer components (e.g. Phase/Frequency Detector, VCO, Delta-Sigma modulators,...) are provided. ModNum also focuses on the simulation of chaotic systems and gives schematics of simulation of Chua's, Rössler's, Van Der Pol's systems (and others). More information on ModNum is available on ModNum web site .

New releases have been realized during that year 2009 to take advantage of the new features available in the lastest ScicosLab/Scicos.