This paper is concerned with reliable fuzzy tracking control for near-space hypersonic vehicle (NSHV) subject to aperiodic measurement information and stochastic actuator failures. The NSHV dynamics is approximated by Takagi-Sugeno (T-S) fuzzy models and the stochastic failures are characterized by a Markov chain. Different with the existing tracking results on NSHV, only the aperiodic sampling measurements are available during system operation. To realize the tracking objective, a reliable fuzzy sampled-data tracking control strategy is presented. An appropriate time-dependent Lyapunov function is constructed to fully capture the real sampling pattern. The sampling-interval-dependent mean square exponential stability criterion with disturbance attenuation is then established. The solution of the tracking controller gains can be obtained by solving an optimization problem. Finally, the simulation studies on NSHV dynamics in entry phase are performed to verify the validity of the developed fuzzy tracking control strategy.

Electric propulsion technology has attracted much attention in the aviation industry at present. It has the advantages of environmental protection, safety, low noise, and high design freedom. An important research branch of electric propulsion aircraft is electric vertical takeoff and landing (VTOL) aircraft, which is expected to play an important role in urban traffic in the future. Limited by battery energy density, all electric unmanned aerial vehicles (UAVs) are unable to meet the longer voyage. Series/parallel hybrid-electric propulsion and turboelectric propulsion are considered to be applied to VTOL UAVs to improve performances. In this paper, the potential of these four configurations of electric propulsion systems for small VTOL UAVs are evaluated and compared. The main purpose is to analyze the maximum takeoff mass and fuel consumption of VTOL UAVs with different propulsion systems that meet the same performance requirements and designed mission profiles. The differences and advantages of the four types propulsion VTOL UAV in the maximum takeoff mass and fuel consumption are obtained, which provides a basis for the design and configuration selection of VTOL UAV propulsion system.

Stratospheric airships can perform long-duration, wide-area observation missions above a specific location. The conceptual design of streamlined stratospheric airships is researched in this paper. Multidisciplinary analysis models for stratospheric airships are established, including geometry, aerodynamics, propulsion, and renewable power systems. A conceptual design method focusing on the energy balance for stratospheric airships is proposed, taking minimum total mass as the objective function. A conceptual design of a stratospheric airship for area observation was achieved, and the feasibility of the design results was verified. In addition, the influence of the wind resistance strategy on the conceptual design was analyzed, and simulation results showed that, by adjusting power consumption during day and night with a maneuverable wind resistance strategy, the total mass and renewable power system mass of the stratospheric airship can be greatly reduced.

Trajectory control of the stratospheric airship is an important but challenging task due to the characteristics of large inertia, long time delay, and large disturbance with wind field. Based on six-degrees-of-freedom dynamic model and kinetic model, this paper proposes a model predictive control method for the trajectory control of stratospheric airship in wind field. The aerostatics, aerodynamics, and flight mechanics are incorporated into the model with consideration of wind interference. By linearization of the dynamics equations by small perturbations method, a trajectory controller is designed using model predictive control method. A simulation program is developed from the model and is applied to analyze the control response of the high altitude airship. Results show that the method has a fast response and high accuracy trajectory control in wind field. A simulation comparison of airship performance with model predictive control and traditional sliding mode control shows that model predictive control can give a higher tracking accuracy at initial stage.

Prediction of thermal behavior and trajectory plays an important role in design and operation of stratospheric balloons. First, a more rounded and improved thermal and vertical trajectory model for performance prediction of stratospheric super-pressure balloons is established, including thermal models for solar radiation, infrared radiation, heat convection, and vertical dynamic model. Meanwhile, mathematical models for gas expulsion and ballast drop are also established. The new model is suitable for both the ascent stage and floating condition of stratospheric super-pressure balloon. Then, a computer program is developed based on the improved model, and predicting accuracy of the model is verified using experimental results of a stratospheric balloon. In the end, performance parameters of a new concept stratospheric balloon in ascent stage and floating condition are obtained, including film temperature, helium gas temperature, pressure differential, altitude, and velocity. Simulation results sho...