Seminars Winter 2005

Le Laboratoire d’Automatique de l’EPFL a le plaisir de vous inviter aux séminaires selon la liste ci-après. Une mise à jour régulière des informations concernant ces séminaires est disponible à l’adresse sur cette page. En particulier, il est conseillé aux visiteurs externes de vérifier que les séminaires soient dispensés comme prévu ci-dessous.

Where: Salle de séminaire LA-EPFL, ME C2 405 (2è étage), 1015 Lausanne

When: Friday at 10h15

Winter 2005 – 2006 seminars

Iterative Learning Control: Theory and Applications

04.11.2005 – Prof. D.H. Owens – Automatic Control & Systems Engineering, University of Sheffield, UK

The area of Iterative Learning Control (ILC) has emerged from robotics to form a new and exciting challenge for control theorists and practitioners. There is great potential for applications to systems with a naturally repetitive action where the transfer of data from repetition (trial or iteration) can lead to substantial improvements in tracking performance. Although many of the challenges met in control systems design are familiar, there are several serious issues arising from the “2D” structure of ILC and a number of new problems requiring new ways of thinking and design. This seminar will introduce some of these issues from the point of view of the research group at Sheffield University and concentrates on linear systems and the potential for the use of optimization methods to achieve effective control. An indication of potential application areas will be included.

Haptic Devices for Surgery Simulators, a Challenge in Mechatronics

25.11.2005 – U. Spaelter, Prof. H. Bleuler – Laboratoire de Systèmes Robotiques (LSRO1), EPFL

Haptic or force-feedback devices are human-machine interfaces that reproduce contact forces to the human operator during manipulation. They play a key role in both teleoperation and simulator technology and are of growing interest as input device for computers in various domains such as games, vehicle control, instrumentation and especially in medicine as surgery assist-devices and simulators. In this talk, we will focus on haptic devices for surgery simulators. They are in-tended for training, education and evaluation of surgeons and, in the future, also for pre-operative planning. Among the most important quality criteria for haptic devices are rendering realism and stability. Key components are mechanical design, sensors and actuators, the control strategy, and, last but essential, the human operator. The interdependency of these subsystems including the human behavior makes haptic devices a rich engineering topic with increasing relevance for future applications.

Design of Observer Bundles for Biotechnological Processes with High Uncertainties

02.12.2005 – Dr. O. Bernard – COMORE, National Institute for Research in Computer Science & Control (INRIA), Sophia-Antipolis, France

State observers are extremely useful in the monitoring and control of biotechnological processes to supplement the lack of cheap and reliable sensors. This seminar will discuss recent advances in the design of nonlinear observers for such processes. An extension of the traditional open-loop asymptotic observers (observers with unknown inputs) will be presented that takes advantage of additional outputs to achieve closed-loop observers. Interval-based observers, which predict the intervals into which the state is lying in the presence of uncertainty, will then be described, and it will be shown how tight enclosures can be obtained by running a broad set of such interval observers in parallel and selecting the best ones. A number of applications will be presented.

Dynamic Optimization Approach in Simulation, Design and Operation of a Pressure Swing Adsorption Process

16.12.2005 – Prof. M.A. Latifi – Laboratoire des Sciences du Génie Chimique (LSGC-CNRS), INPL, Nancy, France

Pressure Swing Adsorption (PSA) processes are commonly used in the separation of gas mixtures (such as air separation and hydrogen purification) as an alternative to traditional separation processes such as distillation and absorption. Despite their large utilization in industry, optimization has not been extensively used in the design and operation of PSA processes so far. This presentation will give an overview of how simulation and optimization tools can be used to improve these processes. PSA processes are typically described by partial differential-algebraic equations (PDAEs). Based on these models, it will be shown how dynamic optimization can be used for the determination of cyclic steady-state (CSS) regimes in PSA operation. A number of design parameters such as adsorption and purge phase durations and fixed-bed length can also be determined for optimizing a key product yield or productivity, while satisfying specified product purity constraints and the CSS conditions.

A Novel Approach to Data-driven Controller Design: Correlation-based Tuning

27.01.2006 – L. Miskovic – Laboratoire d’Automatique (LA), EPFL

The essential ingredients of any control design procedure include the acquisition of process knowledge and its efficient integration into the controller. In many practical control applications, a reliable mathematical description of the plant is often difficult or impossible to obtain, and the controller has to be designed on the basis of measurements. Recently, a new data-driven method labeled Correlation-based Tuning has been proposed. The underlying idea of this method is inspired from the well-known correlation approach in system identification. The controller parameters are tuned iteratively to decorrelate the closed-loop output error between designed and achieved closed-loop systems with the external reference signal. Ideally, the achieved closed-loop system captures the dynamics of the designed one. In this talk, the principal idea of this method, some extensions and recent developments will be presented.

Automatic Control for the new 100m Telescope

03.02.2006 – Dr. M. Dimmler & Dr. B. Sedghi – European Southern Observatory (ESO), München, Germany

The European Southern Observatory (ESO) has undertaken a concept study for the next generation of ground-based optical telescopes. The planned ESO 100m Telescope (OWL) has a segmented mirror structure of more than 3000 hexagonal 1.6m segments on the primary mirror and 300 on its secondary. In addition, the telescope will host several other active mirrors in order to achieve diffraction limited image quality considering various perturbations (e.g. wind, thermal, atmospheric turbulences). Regardless of its opto-mechanical design, a telescope of this size must inevitably integrate extensive control systems. The slow main axes and wavefront control system must bring the telescope into a state where the fast adaptive control loops can be closed reliably. In this presentation we will give an overview of OWL from an automatic control point of view. We will derive requirements for the individual control subsystems, and discuss challenges regarding their interactions.