Research activities
Position
Together with my colleague Thierry POINOT, I am leading the "Automatique et Systèmes" (Control and Systems) team, one of the three teams in the LIAS. This team is devoted to identification and control of systems, intelligent networks.Research interests
I am studying automatic control in the Laboratoire d'Informatique des Systèmes (LIAS) which is born from the union of the (LAII) and the (LISI) in 2012. More precisely, the main topics I deal with are:Multidimensional (or nD) systems
I am trying to extend many wellknown results of the literature dedicated to LMI, robustness and so on to the realm of nD systems, including the continuous, discrete or hybrid Roesser models, the last ones encompassing the repetitive processes.
A particular attention has been paid to the KalmanYakubovichPopov (KYP) lemma and other Sprocedurelike results.
The research for sufficient nice and numerically tractable conditions for stabilisability and stabilisation of nD linear models which are close as possible to necessity is a hard but interesting challenge, especially in the 2D case.
The link between socalled strucutral (or spectral) stability and asymptotic or exponenential stability is particularly studied. We obtained interesting results in the discrete case and aim at further investigating the continuous and mixed continuousdiscrete case.
I am also interested in exploiting the socalled Algebraic analysis approach to the linear systems theory for the specific and peculiar study of 2D models such as Roesser and FornasiniMarchesini models. This elegant and quite general framework that my mathematician colleagues desperately try to teach me allows to look at the 2D linear models through an original lens. We are particularly interested in the notion of equivalence (in the sense of this approach) to study the possible preservation of structural stability from one model to an equivalent model and to enlarge the set of possibilities for stabilising a 2D model.
Another subtopic which is dear to me is how to study some PDE's or some chains of connected cells (subsystems) through the lens of nD (for the moment only 2D) systems.
THIS IS THE TOPIC I'M THE MOST INVOLVED IN!
Matrix rootclustering analysis
I am studying various conditions for the eigenvalues of a matrix (in practice the state matrix of a linear model) to lie in some specified region of the complex plane. This notion is also often referred to as Dstability.
I am particularly interested in the case where the clustering region is non convex and even non connected (for instance some unions of various subregions, possibly non symmetric with respect to the real axis). For such a purpose, the concepts of DUstability or dDregularity of a matrix (which can be generalised to the concept of Sregularity) can reveal as very useful. The necessary and sufficient conditions for Dstability are expressed in terms of linear matrix inequalities (LMI).
At this time, I am not so involved in this topic... but I can come back to it because it is not unconnected to the previous topic.
Robust matrix rootclustering
The considered uncertainty is the polytopic or the (normbounded) LFTbased uncertainty. It can also be any associations of boths. I aimed at finding sufficient conditions (as tight as possible to necessity) such that a matrix is Dstable with respect to the uncertainty. This leads to the concept of robust Dstability (as well as robust dDregularity or robust Sregularity).
At this time, I am not so involved in this topic... but I can come back to it.
Pole placement
Besides, it is also important to study under which conditions the abovementioned conditions can be exploited for the design of a control law. Nevertheless, not only the pole placement is some regions is investigated but I am also working on the derivation of some noniterative techniques to assign strict closedloop poles by a static output feedback control law, even when the socalled Kimura's condition does not hold. Of course the improvement of the robustness induced by such laws is a challenge.
At this time, I am not so involved in this topic... but I can come back to it.
Applications to other domains
I had the opportunity to propose various extensions of my work to some other descriptions of systems such as
Descriptor systems
I am trying to find strict LMIbased conditions for robust stability of uncertain systems with uncertainty on the derivative matrices.
Also, I am interested in the use of Descriptor LFTbased uncertainty for simplifying many robustness analyses.
Associating descriptor forms and nD systems is probably of high interest to suitably model some physical plants... but also lead to complicated theoretical challenges with previously many definitions to introduce and motivate... Coming soon ?
Sensorless control of a synchronous motor
Few years ago, I collaborated with my colleague Erik Etien on the sensorless control of the synchronous motor, using possibly robust or insensitive observers. I am no longer involved in this topic.
Establishment of control laws for mutisources energy devices
I started to collaborate with my colleague Slim Tnani on possible applications of some advanced automatic control techniques to improve the efficiency of some multisource (renewable) energy plants.

It wastes money in administrative procedures and staff, which is of crucial importance in a period where money is available in overabundance.

It wastes energy but this is human energy so it has absolutely no impact on the climate change. Isn't it marvelous to spend so much energy but not to contribute to the future floods? By creating a system which consumes so much energy to produce almost nothing, we give insights into (if not pave the way to) the creation, one day, of a kind of reverse system which would consume very little energy for a huge effect. This is maybe what some clever decision makers have bet on.

It prevents us from doing research and thus from falling in deep addiction to science.

The abovementioned loss of energy and time(=money) has actually a kind of retroactive effect: Indeed, think about all the time all those researchers spent studying tough scientific disciplines. This investment is no longer exploited. This is just magic! Not only the currently supplied energy is wasted but also the past one. This is a NON CAUSAL feedback control law, i.e. a phenomenum that many scientists whould have thought impossible.

While soliciting new funds, we write long texts on the economic impacts of our non existing research on the markets. It has a double interest: It gives us the opportunity to write on something we just don't know at all and moreover, someone else will read it. This is what is called SYNERGY. The time you loose can be lost again by someone else. Magic once again!

As all these applications are timeconsuming (so nice, really!), they also prevent us from improving our teaching documents and methods. So the benefits go far beyond the research world, it has a non negligible impact on the quality of the teachings. The students will soon thank us for that.

We have now hundreds of versions of ours CVs (one page, two pages, four pages with font size 11pt, half a line, two hundred pages, 143.5 block capitals and so on).

Last but not least. To test the robustness of such a system to disturbances, few applications are successful, hence they swallow a large amount of money, fortunately only leaving a very weak fraction to the majority of researchers who do not suffer from this arrival of money. The magic is that  yes!  the system is robust. Nevertheless, to avoid a broad geographical distribution of the victims, the money attacks (disturbances) are only performed in large cities, large universities, where people are already very used to face such events. It is a very subtle and gently way to impoverish some regions in which some non educated people could have a vague desire to study science and do research (Oh my God!) whereas they should stay in their caves.
For all these reasons, I am so much enthusiastic about the evolution of research in my country.
Societal and economic impacts of my research (JOKE!!!)
Sense of a doubt!
Rich of a MBA, a PhD in sociology as well as a master in linguistics that I mysterioulsy forgot to mention in the first tab of this page, I am currently trying to answer this fundamental question to get funds. I am especially looking for the linguistic rules the word "societal" complies with.Energy and money loss in Research (Joke? Not so sure)
I am currently leading a joint experiment with thousands of other researchers in France on the impact of our applications for funds. It is a very exciting new topic which has been continuously growing in importance in the wide community of researchers. The idea is very simple: We spend a large amount of time (and time is money!) as well as much energy to prepare sophisticated documents in order to get funds while being aware that the application is very unlikely to be successful. It has several major advantages:FINALLY, UNLIKE WHAT IS CLAIMED ABOVE, THIS IS THE TOPIC I'M THE MOST INVOLVED IN!
It's a kind of magic... (Freddy Mercury)
Message to students abroad
Unfortunately, I do not reply to sollicitations of students aiming at doing a project or a master period with me. (I neither reply to PhD students who want to spend some journey in our laboratory.) Indeed, I receive far too many requests.What I suggest is to consider the possibility to apply for the Master Energie, parcours Automatique et Energie Electrique (M2)!.
This implies to spend one year in Poitiers. Once the master obtained, possibilities to candidate for a PhD thesis can be offered depending on the results during the master year. The application must be made through Campus france . For further information, you can contact Miss Sandrine Moreau who is responsible for the parcours ``Automatique et Energie Electrique'' of the master. Note that the teachings are in French.
Main collaborations
Ph.D. students
 Jérôme BOSCHE (currently assistant professor at the University of Amiens, France)
Analysis and control by pole placement and robust DUstability.
Defended in December 2003.  Ouiem REJICHI (currently assistant professor in Monastir, Tunisia)
(Thesis in collaboration with the University of Sfax, Tunisia)
DUstability and singular systems.
Defended in December 2008.  Bilal SARI (currently engineer in an R&D department of Alstom, in Grenoble, France)
Robust DUstability and Sprocedure.
Defended in December 2009.  Ines OMRANE
Sensorless speed control of a synchornous motor.
Started in October 2010. Defended in January 2014.  Ronan DAVID
On nD Systems and their stability (title to improve).
Defended in February 2018.  Sabri MANSOURI
On the conception and control of multisources systems.
Defended in December 2020.  Alexandre RIGAUD
Stability of nD models.
Started in September 2019.  KhalilErrhamane SARI
Advanced control of Electrical plants.
Started in September 2016.  Driss MEHDI (LIAS), a friendly "chief",
 Bernard PRADIN (INSA and LAASCNRS), my Ph.D. superviser to whom I am very grateful,
 Nima YEGANEFAR (LIAS), a young promising researcher,
 Didier HENRION (LAASCNRS), for sure a bright searcher and a friend... but remember La oveja negra Didier! You can do as much excellent research as you want, receive as many medals from the CNRS as you want, I cannot forget it!
 Jérôme BOSCHE (CREA) (Thank you for having worked with me!),
 Krzysztof GALKOWSKI (University of Zielona Gora, Poland), who converted me to the nD systems,
 Pawel DABKOWSKI (University of Torun, Poland),
 Wojciech PASZKE (University of Zielona Gora, Poland),
 Mohammed CHAABANE (University of Sfax),
 Jamal DAAFOUZ (CRANENSEM), another friend,
 Denis ARZELIER (LAASCNRS),
 Dimitri PEAUCELLE (LAASCNRS),
 Bilal SARI (colleague in Setif, Algeria, my former PhD Student),
 Erik Etien (LIAS), artistic mentor and office designer,
 Slim TNANI and Gérard CHAMPENOIS (LIAS), who desperately try to convert me to Electrical Engineering,
 Eric ROGERS (University of Southampton),
 Anton KUMMERT (University of Wuppertal),
 Mariem GHAMGUI (University of Sfax),
 Thomas CLUZEAU (XlimDMI and University of Limoges), a nice running guy, far better than Nima on a tennis court, who speaks about strange mathematical (algebraic) objects that curiously find their utility in automatic control,
 Francisco José Silva Alvarez (XlimDMI and University of Limoges), another mathematician who does not consider algebraic objects but who can manipulate some epsilons and deltas as few can,
 Thierry POINOT (LIAS), who helps me to lead the research team or the other way around (I don't really know) and who can make beautiful MScompatible slides... unlike me,
 many others that, I hope, will forgive me not to list them,
 and of course all the members of the LIAS, including its excellent head, Patrick COIRAULT (be always laudatory to your manager... but this one really deserves it!).
 Since January 2011, I am associate editor of Multidimensional Systems and Signal Processing
 Recurring member of the International Scientific Committe (ISC) of the International Workshop on Multidimensional Systems (nDS).
 Recurring associate editor of the International Conference on Systems and Control (ICSC).
Main associates (former or current)
Events
I was the organiser and local chairman of the 7th International Workshop on Multidimensional Systems (nDS'11) which was held in Poitiers in September 2011.Project
I was in charge of leading the ANR project MSDOS (20132017) which is dedicated to the study of the properties of multidimensional systems. A great thank to Nima YEGANEFAR who made a big amount of work to obtain the funds. He was in charge of this project from September 2015 to 2017. Many thanks also to Alban QUADRAT and all the colleagues involved in this adventure.This ANR project has later led to many MIRES projects in collaboration with our colleagues from Limoges. Those projects are dedicated to nD systems showing that this topic is still very active in our team.