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To achieve the attitude control of air-breathing hypersonic vehicle, it's necessary to analyze its complex aerodynamic characteristics, and complete the control system design. Aerodynamic characteristic of air-breathing hypersonic vehicle, namely, the variations of lift coefficient, lift-drag ratio and pitch-moment coefficient with that of attack angle at different Mach numbers, is explored by the data from wind tunnel test. The longitudinal dynamic coefficients are calculated to analyze its stability. Two different control strategies are designed based on aerodynamic analysis, one is attack angle feedback control and the other is normal overload control, and their time domain and frequency domain characteristics are calculated respectively. Experiment result shows that air-breathing hypersonic vehicle not only satisfies longitudinal dynamic stability, but also demonstrates good flight control performance. [ABSTRACT FROM AUTHOR]

To reduce the influence of deflection and time lag of control force during the dispersion of tether on trajectory control precision, this paper designed stratospheric satellite control system. According to the system composition this paper established the trajectory control system and the longitude motion model of balloon system; Based on sliding mode variable structure control, according to deflection between the actual instruct position and instruct position in north-south direction, the methods of exponent reaching law and the flutter reduction around boundary layers are used to design the control system of trajectory controller. The simulation results have shown that the control system can overcome the disturbance and time lag caused by tether effectively, and complete the stratosphere satellite east and west direction motion control with the error of 80 m. [ABSTRACT FROM AUTHOR]