Nacim Ramdani

Cyber-Physical Systems - Humanoid Robots - Human Robot Interaction - Interval Methods

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Dr Nacim Ramdani when awarded the HabilitationDr Nacim Ramdani has been with the Networking & Telecoms Dep. and the CERTES lab. of the Université Paris-Est Créteil, since 1996. He currently holds the rank of Maître de Conférence - HDR (Associate Professor). He has also been affiliated with the Robotics Dep. LIRMM CNRS Univ. Montpellier 2 since 2005. His current research interests include modelling and analysis of cyber-physical systems in presence of uncertainty, set membership estimation with applications to robotics and human movement science, safe motion planning for humanoid robots, and modelling efficient / deficient human movement and posture control with applications to healthcare and human-robot interaction.

 

Latest News:
 

Newly accepted for publication in the International Journal of Adaptive Control and Signal Processing 2010

Interval observer design based on nonlinear hybridization and practical stability analysis, by N.Meslem & N.Ramdani, accepted for publication in the International Journal of Adaptive Control and Signal Processing.

Abstract: In this paper we design an interval observer for nonlinear uncertain continuous-time dynamical systems, in the unknown-but-bounded error framework. We show how to generate two coupled hybrid observers, which yield the best conservative upper and lower component-wise bounds for the state,  provided bounds are available for initial conditions and uncertainties. The interval observer depends on a tuning gain, which is chosen in order to satisfy the practical stability of a given hybrid dynamical system. An example is studied to emphasize the performance of our method.

Copies are available upon request. The original publication will be available at www3.interscience.wiley.com, here doi:

Last Updated on Monday, 26 July 2010 09:56
 

Newly accepted for publication in Nonlinear Analysis: Hybrid Systems 2010

Computing reachable sets for uncertain nonlinear hybrid systems using interval constraint propagation techniques, by N.Ramdani & N.S. Nedialkov, accepted for publication in Nonlinear Analysis: Hybrid Systems.

Abstract: We investigate solution techniques for numerical constraint satisfaction problems and validated numerical set integration methods for computing reachable sets of nonlinear hybrid dynamical systems in presence of uncertainty. To use interval simulation tools with higher dimensional hybrid systems, while assuming large domains for either initial continuous state or model parameter vectors, we need to solve the problem of flow/sets intersection in an effective and reliable way. The main idea developed in this paper is first to derive an analytical expression for the boundaries of continuous flows, using interval Taylor methods and techniques for controlling the wrapping effect. Then, the event detection and localization problems underlying flow/sets intersection are expressed as numerical constraint satisfaction problems, which are solved using global search methods based on branch-and-prune algorithms, interval analysis and consistency techniques. The method is illustrated with hybrid systems with uncertain nonlinear continuous dynamics and nonlinear invariants and guards..

The original publication will be available at www.sciencedirect.com, here doi: 10.1016/j.nahs.2010.05.010

Last Updated on Friday, 09 July 2010 14:57