Starship is a new generation of reusable space transportation system developed by Space Exploration Technologies Corporation (SpaceX). The landing process of this type of spacecraft, which has the characteristics of large attitude maneuver, multiple constraints, and high accuracy requirements, is different from that of traditional spacecraft. The dynamics of the flipping and landing phase of the Starship-like aircraft is studied firstly, and the response of engine gimbal angle is introduced into the dynamics to suppress the oscillation of engine gimbal angle. Then, based on the convex optimization method, an optimization algorithm for the free-final-time flipping and landing trajectory of Starship-like vehicles is designed, which can consider the attitude maneuver and typical constraints. In order to improve the convergence of the algorithm, virtual control and penalized trust region are used, and a method for initial value selection is given. Finally, numerical examples are provided to analyze the influences of initial value selection method, the response of engine gimbal angle, engine number, and the selection of optimization objective functions on the flipping and landing phase.

The use of sinusoidal scanning vibration to simulate low-frequency transient vibration environment is a traditional testing method in the aerospace industry, and its environmental assessment of products may have both under testing and over testing simultaneously. Firstly, the equivalence between the two is analyzed, and then relevant theories such as impact response spectrum and maximum response spectrum are used to study the scanning rate and damping coefficient in the formulation of equivalent sinusoidal scanning vibration test conditions, and parameter selection suggestions are provided. Finally, steps are proposed to establish the testing conditions for sinusoidal scanning vibration environment, providing reference for the low-frequency transient environment adaptability assessment using sinusoidal scanning testing.

In allusion to the technique requirements such as reliably open, enough and greatly open-angle, automatically open or lock for the pressure tank, a method using function cycle time combination, and spatial multi-link coupled actuating strategy is proposed to develop a spatial multi-link Mechanism with a variable revolution axis to ensure of perpendicular inside out opening rapidly. A parametric dynamic model is established, the opening angle, horizontal size of the opening mechanism, and erecting cylinder load are used as outputs, and the Hinge-point parameters of the links are taken as inputs. Nondominated sorting genetic algorithm is used to solve the multiobjective problem and the max-min criterion is adopted to select a solution from the Pareto front. The optimized effect is compared with the results of ADMAS dynamic simulation, scale experiment and product experiment tests. The result shows that the proposed method provided a certain reference for optimization of perpendicular inside out opening mechanism.

In order to achieve lightweight, low cost and refined thermal design, the refined design method of coating thermal protection structure based on ablation mechanism is proposed. It can calculate the thickness of ablative carbon layer with using ablation mechanism, build thermal simulation model of ablation refinement and calculat accurate thermal simulation results. The application of this method can provide an effective and scientific theoretical analysis method for the demonstration of coating thermal protection scheme. It can guide the design of thermal protection scheme, reduce the design cost and shorten the development period.

Under the background of networked hypersonic weapon platforms, the research on hypersonic glide vehicles is no longer limited to the guidance methods under multiple constraint, but urgently needs to break through the technical difficulties of multiple vehicles cooperative guidance and control. Firstly, in order to lead to the necessity of research on multiple vehicles cooperative guidance and control, the development process of hypersonic glide vehicles of major military powers is summarized, and the development status and trend of multiple vehicles are analyzed. Secondly, to explore ideas for multiple hypersonic vehicles cooperative operations, the research status of formation communication maintenance control, collaborative guidance control with flight time constraint, and collaborative guidance control with flight angle constraint are summarized. Finally, the future development direction of multiple vehicles collaborative guidance and control is prospected.

The flow regulator is the key component to realize the thrust regulation of liquid propellant rocket engine. The dynamic model of the flow regulator is established according to the structure and working principle of the flow regulator of a hydrogen-oxygen engine, and the simulation calculation model of the flow regulator is established by using AMESim software. The simulation work is carried out by using the simulation model of the flow regulator: calculating the flow characteristics of the regulator under different working conditions, verifying the steady-flow characteristics of the regulator, simulating and analyzing the dynamic characteristics of the regulator, and analyzing the influence of the structural parameters on the dynamic characteristics of the regulator. The simulation results reveal the flow and dynamic characteristics of the flow regulator, and provide a direction for the improvement and optimization of the flow regulator.

In order to obtain the load-bearing characteristics of large diameter bolt under typical connection structure, ground test research on the basis of finite element analysis is carried out, which obtains the axial force and additional bending moment of large diameter bolt and revealsits failure mechanism. Analysis and test show that the additional bending moment is an important factor affecting the load-bearing capacity of large diameter bolts. After considering the additional bending moment, the equivalent axial force is several times of the initial axial force, which must be paid attention to in the design work. The formula for calculating the strength of large diameter bolt considering the influence of additional bending moment is proposed, which improves the accuracy. In addition, the method of reducing the additional bending moment of large diameter bolt is studied, and the direction of structural optimization is pointed out.

Considering the dispersion of small signal flow characteristics of servo valve, the control parameters of electro-hydraulic servo system need to be matched and adjusted. An off-line self-optimizing method for electro-hydraulic servo system control parameters based on particle swarm optimization is proposed. The control system task book and manual debugging results decide optimization target characteristics, and the parameter optimization range is determined by the analysis results of servo system stability and statistics of batch production data envelopment. This parameter optimization method takes about 100-240 seconds. Compared with manual approaches, it can greatly improve the mass production debugging efficiency of the control parameters for electro-hydraulic servo system.

For the hypersonic vehicle nonlinear attitude mode in reentry process with a strong coupling, aerodynamic parameter perturbations and non-deterministic, the hypersonic vehicle MIMO-ESO ADRC attitude controller is designed. Extended state observer and nonlinear law state error feedback are conbined, interference such as uncertainty, coupling and parameter perturbations as is put "the sum of interference", the extended state observer is used to estimate and dynamic feedback compensation, nonlinear law state error feedback is used to inhibit residual of compensation. ADRC controller is charged without a precise model of vehicle, and without precise perturbation boundaries of aerodynamic parameters. Simulation results show that the MIMO-ESO ADRC attitude controller can overcome the impact of large-scale perturbations of interference and aerodynamic parameters, have good dynamic qualities and tracking capabilities, also have strong robustness. It overcomes the difficulty of establishing accurate controlled model and obtaining parameter perturbation range in practical engineering, and has engineering application value.

The reusable launch vehicle based on liquid oxygen methane engine has excellent performance in reuse and maintenance, and is easier to achieve low cost. Countries around the world are accelerating relevant research and engineering development. Typical representatives include the Vulcan launch vehicle of the United States, and the ZhuQue-2 launch vehicle of LandSpace. The technical characteristics and technical challenges of the reusable launch vehicle based on liquid oxygen methane engine are analyzed. The following key research contents are proposed, including the overall design and evaluation of reuse, GNC technology for ascent and reentry and return landing, large-scale lightweight structure and manufacturing technology, reuse of LOX engine, health prediction management and reuse operation and maintenance technology, reuse thermal protection technology etc. It will lay a foundation for further development of liquid oxygen methane reusable launch vehicle.