Dynamic Properties Analysis And Optimazation Design Of The High Altitude Platform

The research object in the thesis is a high altitude platform taking the form of the stratospheric airship. The research focuses on the influences of dynamic properties caused by the mass changes and the fuselage flexibility. The optimization of the actuators placement is also investigated. The main research includes the following several aspects:Firstly, rigid-body dynamic model to be used for analysis is established. Based on the airship nonlinear model, the nonlinear model is linearized and then decoupled into models in longitudinal and lateral planes, as the foundation of further analysis. Secondly, flexible characteristic model is established by the theory of Euler beam. From the basic equations of the vibration, by solving the vibration equation, the relations between the elastic deformation and the kinetic parameters are obtained. The model in the longitudinal plane is used in the Simulink simulation, and the results show the influence of the flexible deformation on the dynamic characteristics under the external force disturbances.Thirdly, mass characteristic model is established. mass and additional mass of the platform change with the change of the platform in height, which results in possible changes of the dynamic characteristics of the platform. Through the simulation analysis of mass matrix changes, the influences on the dynamic characteristics are obtained.Finally, the placement of the actuators are optimized. The deficiency of the original actuators configuration is analyzed., With the tail propulsion kept unchanged, the layout of the abdominal propulsion is adjusted to improve efficiency, and two schemes are proposed. The feasibility of the two schemes are shown through simulation.