The nodes of the unmanned aircraft are fast maneuvering and confronting fiercely in the complex environment. There are bad conditions such as position change and link interference suppression. The robust routing technology adapted to wireless network is studied in order to solve the problem of network resource management caused by the frequent change of wireless network topology and the sharp increase of management and control cost, and realize the goal of tenacious, timely and accurate service carrying of wireless communication service in the specific environment. A lightweight hybrid routing scheme with layered management and control is constructed, and topology awareness and fault detection technologies are used to detect network changes quickly and accurately. The damaged residual network is quickly optimized scheduling and compensation through layered route construction, intra-segment route repair and inter-segment route repair, and the communication service capability of the damaged network is improved.

The missile cabin structure is used to form the shape, connect and install the subsystems, and bear various loads. The loads that the missile needs to bear in the flight stage mainly includes shear load, bending moment, axial load, external pressure, thermal load, ect. In order to verify the structural stability and strength performance of the missile cabin structure under multi-load cooperation, it is necessary to carry out the research on the structural strength test. The equivalent treatment method of test load and the design of coupled loading scheme are focused on. The study of structural strength test method of a certain missile cabin under multi-load is carried out, which provides a reliable test basis for the calculation, optimization and modification of the cabin structural strength.

Establishing an accurate aerodynamic model is of great significance for analyzing the aerodynamic characteristics of aircraft and designing reliable flight control systems during the aircraft design process. Multi-source data fusion of aerodynamic data from different sources, such as wind tunnel tests and flight tests, is currently a popular method for unsteady aerodynamic modeling by intelligent algorithms. However, traditional fusion algorithms have shortcomings such as high requirements for flight data sources and weak generalization capabilities. Thus an improved intelligent modeling method based on Physics-Informed Neural Networks (PINNs) is proposed to integrate static wind tunnel test data and flight data. Compared to traditional PINNs, the physical loss constraints in improved PINN are reversely constructed to enable feature extraction from different and discrete flight data. The static wind tunnel data are incorporated into both the input and loss function of neural network to construct residual estimates. So the differences between ground and flight aerodynamic data are effectively corrected. The predictive aerodynamic characteristics for different motion forms demonstrate that the improved PINN not only has high aerodynamic prediction accuracy but also exhibits excellent generalization capabilities.

Hydrogen-oxygen mixtures are widely used as aerospace propellant. Their thermodynamic properties, transport properties and chemical reaction processes are far more complex than pure air, and it is more difficult to analyze and predict their flow process. The self-developed device-detonation tunnel is used to provide high temperature hydrogen-oxygen combustion gas. Combined with CFD, the flow and aerodynamic heating characteristics of air and combustion gas under the same total temperature and total pressure are analyzed. It is found that, when flowing in the nozzle, the combustion gas has higher temperature, speed and smaller Mach number; the standoff distance and stagnation pressure of the combustion gas are smaller than air; the skin friction and wall heat flux are greater than air. Active chemical reactions in combustion gas make aerodynamic heating more serious.

To control the position of the windward side along the vehicle for reducing the impact of harsh re-entry force and thermal environment on the vehicle, an active continuous roll control method based on the aerodynamic coefficient fitting model is proposed. Firstly, an aerodynamic coefficient fitting model combining quadratic term and negative exponential term model is established, and the aerodynamic coefficients are fitted using the least squares method. Secondly, based on the coordinate system transformation relationship, the windward angle model and the windward error angle model are proposed to describe the trajectory of the windward side along the cone of the vehicle. Then, based on the BTT/STT composite control method, linear roll control commands are designed, and the effect of different roll control commands on the flight process is compared and analyzed. Furthermore, nonlinear rolling control commands are created based on the loads to ensure that the roll rate is consistent with the trend of the loads. Finally, the proposed roll control commands are verified to generate excellent roll control effect through six degrees of freedom simulation, and can make the windward side evenly distributed along the vehicle. The standard deviation of the load on each meridian of the vehicle in rolling condition is 20% of that without rolling.

The e ^N method based on linear stability analysis is currently one of the most widely used methods for transition prediction; however, the selection of the transition criterion N_T value shows significant scatter at high Mach numbers. The linear stability analysis and e ^N method are used to conduct stability analysis and N-factor envelope calculations for the lifting calibration model at Mach numbers of 5 and 8, and for Reentry F at a Mach number of 20. Combining the transition onset locations obtained from wind tunnel results and flight data, the calibration of the transition criterion N_T value at high Mach numbers is carried out. The results show that for the lifting calibration model, the transition criterion N_T is approximately 5.3 to 6.5 under different angles of attack at Mach number of 5, and approximately 4.8 to 5.3 at Mach number of 8. For Reentry F, the transition onset locations vary significantly at different altitudes, but the transition criterion N_T does not change significantly, being approximately 9.55 to 9.73.

For higher reliability, higher efficiency and easier maintenance, three TVC actuators for a hydrolox launch vehicle block are studied comparatively, in aspects of designs, models and testing performances, namely, a Servo-Valve Controlled Electro-Hydraulic Actuator (SHA), an Electro-Mechanical Actuator (EMA) and an Electro-Hydrostatic Actuator (EHA), each outputting a peak power of 3 kW. A fully packaged duplex EHA design is proposed, lightweight and compact by means of innovating indepth integrations in the actuator, Electro-Hydrostatic Module (EHM), Servo Motor Pumps (SMPs) and Electronic Control Units (ECUs). The weight of a TVC system with four EHAs is 85 kg, reduced by 37%, compared to the SHA counterpart of 135 kg. The dynamic capability of three TVC actuators is almost on a par, with the first-order frequency bandwidth of greater than 30 rad/s. As to the overall efficiency of energy conversion, it is one order of magnitude higher for an EMA or an EHA than a SHA. In an operation profile on ground with a duration of 1 200 s, the efficiency is lowest for an SHA, less than 1%, and heated quickly, with the temperature reaching over 100 ℃ at the hydraulic pump. In contrast, as to the EMA and EHA,the efficiency is remarkably upgraded to over 20%, with the temperature only slightly increasing by 5 ℃ at the pump or the electric motor. It demonstrates that an EHA embodies both the heavy loading, high reliability of a SHA, and the high efficiency, good maintenance of an EMA, at the same time overcoming the weak points in dynamics, power density, oil sealing, etc., providing an intriguing option for highly reliable and secure launch vehicles. The EHA has finished its maiden flight as the first one for launch vehicles.

To address the issue of harmonic concentration near fixed switching frequencies caused by high-speed switching actions in traditional PWM strategy, the random modulation strategies in the PMSM servo drive system are studied. On the basis of conventional RSF-PWM strategy, DRM-PWM strategy enhances EMC by introducing randomization of the zero-vector action time. However, this strategy struggles to balance EMI suppression effectiveness with system control performance. Subsequently, MARSF-SVPWM strategy is investigated, with a focus on comparing and analyzing the two modulation strategies. Compared to DRM-PWM strategy, MARSF-SVPWM strategy maintains overall spread spectrum range and average switching frequency while narrowing the distribution range of differences between adjacent switching frequencies, thereby further reducing harmonic peaks. Simulation and experimental results demonstrate that MARSF-SVPWM strategy achieves better harmonic dispersion performance compared to DRM-PWM, and maintains a lower impact on system control performance, optimizing the EMI suppression effect.

The stability of lubricating grease performances is a significant factor that restricts the long-term storage reliability of aerospace electro-mechanical servo actuators. The rheological properties of lubricating grease can directly affect the transition characteristics of servo actuators. Accelerated degradation test at high temperature stresses is designed and carried out. Three grades of lubricating grease with different base oil systems, including soap based, non-soap based and mixed lubricating grease are investigated for their theological properties. The rheological properties of different lubricating grease changed in thermal aging time and temperature stress are analyzed. It is found that the viscosity of lubrication dose not change unidirectionally with the increase of thermal aging time. In addition, the rheological properties of mixed lubricating grease at high temperature is better than that of soap based lubricating grease and non-soap based lubricating grease, which is valuable to evaluate the properties of lubricating grease during long-term storage of aerospace electromechanical servo system.

The rolling screw transmission mechanism is a key transmission component of the servo mechanism. Monitoring its operating state is crucial for the normal operation of the servo control system. Currently, there are still difficulties in the state monitoring of rolling screw transmission mechanisms, such as low integration and wiring difficulties. A multi-parameter wireless micro-nano sensing monitoring system for rolling screw transmission mechanisms is designed. The sensing module, MCU module, wireless module and power management module are integrated in this system, which can be integrated with the nut of the rolling screw transmission mechanisms directly and flexibly, improving integration and reducing wiring complexity. The sensing module contains three types of MEMS sensors for temperature, acceleration, and acoustics to meet the condition monitoring requirements of multi-point distributed and multi-parameter sensing on the surface and interior of the nut. This system has advantages of small size, easy installation, flexibility and high integration, effectively monitoring the working state of rolling screw transmission mechanisms.