Optimal control and applications to aerospace problems

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Event details

Date 04.04.2014
Hour 10:15
Speaker Prof. Emmanuel Trélat, Université Pierre et Marie Curie
Location
Category Conferences - Seminars
I will first shortly report on some classical techniques of nonlinear optimal control such as the Pontryagin maximum principle and the conjugate point theory, and on their numerical implementation. I will illustrate these issues with problems coming from aerospace applications such as the orbit transfer problem which is taken as a motivating example. Such problems are encountered in a longstanding collaboration with the european space industry EADS Astrium.
On this kind of nonacademic problem it is shown that the knowledge resulting from the maximum principle is insufficient for solving adequately the problem, in particular due to the difficulty of initializing the shooting method, which is an approach for solving the boundary value problem resulting from the application of the maximum principle.

On the orbit transfer problem I will show how the shooting method can be successfully combined with a numerical continuation method in order to improve significantly its performances. I will comment on assumptions ensuring the feasibility of continuation or homotopy methods , which consist of deforming continuously a problem towards a simpler one, and then of solving a series of parametrized problems to end up with the solution of the initial problem. Finally, in view of designing low cost interplanetary space missions, I will show how optimal control can be also combined with dynamical system theory, which allows to put in evidence nice properties of the celestial dynamics around Lagrange points that are of great interest for mission design.


Bio:
Emmanuel Trélat is full professor with Univ. Pierre et Marie Curie (Paris 6), and member of the Institut Universitaire de France. He was previously professor with Univ. Orléans (2006--2011), and associate professor with Univ. Paris-Sud, Orsay (2001--2006). He is also member of the team GECO at INRIA Saclay. He has a number of research contracts with EADS Astrium, with the CNES and the CEA. He was one of the creating members of the pole OPALE (OPtimization Applied to European Launchers, 2005--2009) between CNES, EADS, Inria, ONERA and several universities, promoting the collaboration between academics and industrials on aerospace control problems.
He received in 2012 the Felix Klein Prize (EMS prize) for his contributions on Ariane launchers.
He is the author of around 45 articles, 20 proceedings, 2 books. He is editor in chief of the journal Acta Applicandae Mathematicae and associate editor of several international journals. He supervises currently 5 PhD theses.
His research fields are on control in finite and infinite dimension, in relation with other fields like sub-Riemannian geometry, PDE's or imaging.