Research On Dynamical Modeling And Nonlinear Control Of A Stratospheric Autonomous Airship

Stratospheric airship has an enormous, yet untapped potential as low-speed, oreven steady platform for telecommunication, aerial exploration, monitoring, and surveil-lance, as well as for transportation purposes.The development of an autonomous system of stratospheric airship demands aworkable dynamical model characterizing the intrinsic physical properties of the airship,and a state-of-art control system design based on the model. This thesis is devoted tothe two important issues in crafting an autonomous airship, dynamical modeling andcontrol design.The work about dynamical modeling lies in the following aspects.First, couple effects of the airship body and the ambient fluid are derived fromNavier-Stokes equation, continuity equation, Reynolds'second transport equation, andrigid body equation, plus some necessary and rational assumptions to simplify the for-mulation and obviate from falling into studying solutions to partial di?erential equa-tions. The wind disturbance is analyzed and formulated via two di?erent methodswhich are both based on Helmholtz velocity decomposition theorem. In the procedures,terms of mass and inertia variation caused by ballast motion and gasbag-ballonetsinflation-deflation, added inertial effects, viscous dissipation, other aerodynamical ef-fects, gravity, buoyancy, and wind disturbance arise naturally. Though we can't providea completely precise description of the fluid flow field around the airship body, we givea framework description of the integral dynamics of the airship body-ballasts-ambientfluid-coming flow composite system, which is wieldy in control design and tractable forparameters identification.Second, Lagrangian and Hamiltonian reduction theory are exploited to work outthe Euler-Poincar′e and Lie-Poisson descriptions of the dynamics. These descriptions...