The analysis and design method of the sky-ground scaled similarity of aerodynamic characteristics for stratospheric airship were described in detail. The similarity criteria for the rigid and flexible models to complete the wind tunnel tests were given. Two kind of scaled models and wind tunnel test were completed. By analyzing the wind tunnel experimental data for scaled models, it was found that the aerodynamic characteristics of the stratospheric airship under different inflatable internal pressures were basically same, but the rigid body model was obviously different. The aerodynamic drag coefficient under flexible characteristics was significantly higher than that of rigid body, and even twice as high as that under zero attack angle, which lead to the essential changes of the rolling aerodynamic torque characteristics, such as stability and divergence. It has important engineering application value for evaluating flexible aerodynamic characteristics of stratospheric airship, especially under low pressure state. And it overcomes the disadvantages of using rigid body aerodynamic characteristics data or engineering estimation method in the airship overall design of "dynamic-resistance balance".

The current study focuses on the motion-pressure coupled control for a multicapsule stratospheric airship and transforms the path-tracking and heading-hold control of airships into guidance tracking with a time-varying weighted sum of longitudinal and lateral velocities by the definition of compound speed. Herein, an improved nonlinear predictive control method is provided to reduce the control energy consumption by the rolling optimization of controller parameters based on finite time intervals, ensuring infinite-time path-tracking tasks. Simultaneously, combined with the proposed cyclic regulation process of safe pressure between internal and external capsules, this study can fully reflect the force-thermal coupled rule of airships under the actions of atmospheric environment and maneuvering force, while evaluating the long-endurance capability of airships under the conditions of safe superheating and overpressure. The effectiveness of the motion-pressure coupled controller was verified through numerical simulations, which can overcome the influence of environmental wind and achieve a tracking effect for the desired cruise path and compound speed. The airspeed provided during the cyclic circadian time caused the maximum superheating of the helium controlled within 30 °C. The helium in the internal and external capsules achieved circadian regulation. The equivalent micropore diameter of the capsule of 5 mm can achieve 55 days of long-endurance flight. The controller satisfies the requirements of cruise-flight application modes for multicapsule stratospheric airships with important engineering value.