Séminaire de Lucas Brivadis

Date : 06/12/2021
Catégorie(s) : ,

17/06/2021 – 14h00-15h00 – Online

Infinite-dimensional Luenberger observers: application to a crystallization process

Lucas Brivadis (LAGEPP, Université Lyon 1)

Abstract. During a crystallization process, the Particle Size Distribution (PSD) is a relevant information that needs to be estimated through other measurements, such as the Chord Length Distribution (CLD). The PSD-to-CLD mapping depends on particle geometry. We propose a model for spheroid particles. When crystals in the reactor share the same shape, we prove the injectivity of this mapping. However, in the multi-shape case (which is common due to polymorphism), additional information is required to recover the CLD from the PSD. We propose to combine the CLD measurement with an evolution model of the PSD (a transport equation) and to use an infinite-dimensional Luenberger observer.

More precisely, we apply the Back and Forth Nudging algorithm, based on forward and backward iterations of asymptotic observers on a finite time interval. We investigate in a more general framework the convergence properties of this algorithm, and derive observability conditions for the weak or strong
convergence. We check these observability conditions in various cases for the CLD-to-PSD problem.

Biography. Lucas Brivadis is an engineer from École Centrale de Lyon since 2018, and received his master’s degree in applied mathematics from Université Lyon 1. He defended his PhD in May 2021 at LAGEPP, Université Lyon 1, under the supervision of Vincent Andrieu, Ulysse Serres and Jean-Paul Gauthier. His research interests focus on infinite-dimensional observer design and output feedback stabilization of nonlinear systems, in particular in the context of observability singularities.

Practical details. The seminar will take place online, using Microsoft Teams. If you want to attend this seminar (or any of the forthcoming online Automatiques seminars), and if you do not already have access to the AutoSeminar group on Teams, simply send an email and you will be invited. Please specify which email address the invitation must be sent to (this has to be the address associated with your Teams account). You will find the link to the seminar on the « General » AutoSeminar channel on Teams, approximately 15 minutes before the beginning.

The technical side of things: you can use Teams either directly from you web browser or using the « fat client », which is available for most platforms (Windows, Linux, Mac, Android & iOS). We strongly recommend the latter option whenever possible. Please give it a try before the seminar to anticipate potential problems