Showing papers by "Yasmina Bestaoui published in 2002"

Stabilization of a nonlinear underactuated autonomous airship-a combined averaging and backstepping approach

Abstract: A strategy to design a time-varying stabilizing controller of the position and the orientation of an underactuated autonomous airship is proposed. The dynamic modelling of the airship involves six equations with only three inputs. This airship cannot be stabilized to a point using continuous pure-state feedback law. However, the stabilization problem is solved with an explicit homogeneous time-varying control law, based on an averaging approach. We prove that the origin of the system is locally exponentially stable.

Dynamic analysis of airships with small deformations

Abstract: The theory of modelling and control of airships was mostly imported from the fields of science and engineering of underwater vehicles. However the main hypothesis of rigidity of the structure may be improved to take into account the flexibility of the hull of an airship. We present an approach for analysing dynamic elastic deformable airships in an ideal fluid. Our model uses the updated Lagrangian method in combination with a large displacement and small deformation (Green) strain tensor formulation. Analogy is made with classical structural dynamics. The description of the behaviour of the airship consists of a continuous differential equation that is solved using a Rayleigh-Ritz technique combined with the finite element method. The method proposes also to take into account the coupling between the rigid body motion and the deformation as well as the interaction and coupling with the fluid surrounding.