With the development of data bus technology and the increasing demand for low-cost and high-reliability electrical systems in "flight-based transportation", Field Bus(FB) is gradually favored by the aerospace field. Controller Area Network(CAN), one of the most widely used field buses, has been researched and applied in missiles and tactical rockets. Considering the differences between launch vehicles and missiles, the application of CAN bus in launch vehicle control systems is expounded. The necessity of research is firstly analyzed, then typical CAN topologies suitable for medium and large-scale launch vehicles are given respectively. For the aim of practical use, two corresponding technologies are introduced which are the CAN relay technology and the CAN bus reconstruction. The efficiency and load rate of CAN bus are calculated which are then compared with the ones derived by 1553B data transmission under the same conditions. These results can be referenced by designers in a more accurate sense.

The geometrically non-linear stiffness response of morphing aircraft structures is crucial for applications with large deformations. In order to study the nonlinear mechanical behavior of zero Poisson's ratio honeycomb structure with sinusoidal corrugated walls during large deformation in plane, a nonlinear mechanic model with consideration for geometric nonlinear is established based on nonlinear beam theory. It is verified by comparison with non-linear structural analysis with FEM. The stress-strain relationships with different parameters are obtained. The results show that the geometric nonlinear increases the equivalent stiffness with the increase in strain, and the stress-strain curves are greatly affected by corrugation ratio, thickness ratio, and inclination angle, but not by height ratio.

The structure of S-shaped cable is complex. When S-shaped cable is separated at high speed, it has large deformation and complex nonlinear contact. The analysis of dynamic deformation and mechanical characteristics of S-shaped cable is one of the difficulties in engineering design. ABAQUS is used to establish the dynamic simulation separation model of separation cable. The dynamic deformation mechanism and mechanical characteristics of S-shaped cable are analyzed, and the correctness of the modeling method is further verified by the ground experiment. The influence of various sensitive factors, such as length, section diameter, tail length and separation speed of S-shaped cable is studied, which can provide analysis method and reference for engineering application.

The hanging process is one of the key links in the Mid-Air retrieval of launch vehicle. According to the whole process of the launch vehicle tail cabin hanging in the air, the design of the hanging device based on the helicopter as the recovery platform is carried out. The hanging device includes tension sensor, load shedding device, overload protection device and the actuator in the end of the hanging device. Parafoil and parachute eject from the bottom of the tail cabin of launch vehicle. The hanging device can realize the hanging operation of the retrieval by hanging attached apex drogue on the top of parafoil. Through the simulation analysis of the hanging process, it can be seen that when the weight of the retrieval increases, the overload increases significantly. When the parachute retraction time increases, the load reduction effect is obvious

Trans-media aircraft refers to a new concept special aircraft with both air flight capabilities and underwater submarine capabilities, which includes submersible aircraft and submarine-launched drones. Aircraft that can span multiple domains is focused on. Through literature research, this study elaborates on trans-media aircraft and their characteristics and applications, introduces in detail the development status of trans-media aircraft at home and abroad, analyzes the technical difficulties of achieving trans-media flight, and summarizes the key technologies required for trans-media aircraft. Finally, based on the investigation and the current development at home and abroad, the prospects of the trans-media aircraft are prospected and development suggestions are put forward.

Focusing on the main working phase of liquid rocket engine, with the aid of multivariate non-linear time series analysis, and based on Dual Stage Attention Based Recurrent Neural Networks (DA-RNN), a new time series analysis tool, Convolutional Dual Stage Attention Based Recurrent Neural Networks (CDA-RNN), is proposed, by which a fault trend prediction model is established. Compared with LSTM, DA-RNN, etc, this model shows higher prediction accuracy. Combined with autocorrelation analysis of the prediction residual, a quantitative basis of fault detection is proposed after introducing failure confidence probability. Using hot test data with weak fault to validate the model, result shows that the CDA-RNN model enables robust weak fault muti-parameter detection in unsteady working process. This strategy is so effective that it calls for direct engineering application.

The flow field simulation and scanning electron microscope observation methods are used to analyze the surface micromorphology of a certain type of turbine blade before and after operation, and the effect of high temperature and high pressure environment on the surface morphology of the blade is investigated. First, in order to improve the calculation efficiency, according to the blade form, a periodic symmetric CFD model of the turbine blade flow field is established, and the temperature and pressure of the flow field are calculated and analyzed by the finite volume method. Then, the surface of the working blade is measured by scanning electron microscope. The morphology is observed to analyze the form of micro-defects on the blade surface. Finally, based on the results of simulation and experimental observations, the reasons for the blade defects and the factors affecting the changes of the blade surface microstructure are analyzed. The results show that the temperature of the leading edge of the blade reaches the highest ${860}\mathrm{\;K}$. Under the combined effect of geometric structure and wave system, the flow characteristics of the flow field near the leading and trailing edge, blade tip, and hub are complicated, and the temperature and pressure distribution in the flow channel is inhomogeneous. The hub near the trailing edge of the blade appears with a cross-grain/inter-grain mixed mode of microcracks about ${180\mu }\mathrm{m}$ in length, and an inclusion crack with a length of about ${30\mu }\mathrm{m}$ appears at the tip of the trailing edge. This is due to the thermal stress of the blade, the metallographic transformation of the blade surface, and the oxidation, hydrogen embrittlement and other effects. According to the actual task of the turbopump, the turbopump ground hot test program should be reasonably arranged, especially in the shutdown stage, consider whether to take atmospheric environmental isolation measures for the cooling of the turbine blades. The current work can provide a reference for the life evaluation of liquid rocket engine turbine blades.

In order to solve the issue of missing high-frequency information of flight data in servo system of launch vehicles, a high-frequency feature restoration method based on wavelet multi-resolution analysis is proposed. Initially, features are extracted from ground hot firing test data through wavelet multi-resolution analysis. Subsequently, leveraging the correlation between the angular velocity signal and high-frequency features, a feature matching approach is put forward for predicting the high-frequency features of the flight data. Finally, the linear superposition method is conducted to achieve feature fusion, thus completing the feature restoration process of the flight data. The experimental verification is carried out. It shows that, compared to the baseline data, the restoration results have a consistent commutation frequency pattern, which imply that the proposed feature restoration method is feasible and effective. The study can provide data support for obtaining the characteristics of actual flight profile for aerospace servo products.

The active aircraft defense problem with unknown attacking missile's guidance law is considered, and the one-way and two-way cooperation modes for a target aircraft and a defending missile are introduced. Cooperative guidance laws for the target and defender are proposed by using sliding mode control, which can enhance the measurement observability and meanwhile guarantee the successful defensive interception. A sliding surface is firstly constructed, considering both the requirements of estimation enhancement and successful interception. And then the one-way and two-way cooperative guidance laws are derived, by adopting the double-power reaching law and the state-feedback based exponential reaching law respectively. Compared with one-way cooperative guidance law, the two-way cooperative guidance law is optimized by introducing the cost function of control effort for the target and defender. Meanwhile, in two-way cooperation mode, the target aircraft can take the cooperative maneuver to help defender impact the attacking missile with less control effort. Simulation results show that the proposed cooperative guidance law can guarantee both the good measurement observability and the well defensive guidance accuracy.

There are many capacitive loads in airborne equipment, the safety and stability of power supply are negatively affected by the surge at the moment of switch closing of power distribution facility. The causes and hazards of surge are analyzed, and the scheme of surge restrain is introduced. The parameters of transistor scheme are studied. The experiments of high and low ambient temperature and wide input voltage range are carried out, simulated and tested to verify the function and effectiveness of the design.