The proportional integral differential (PID) controller is improved to meet control system requirements for the boost-glide rocket with difficulty in manual adjusting parameters. A method is proposed that directly takes the simulated results with the nonlinear six-degree-freedom model of the rocket as the objective function value, the genetic algorithm is adopted to adjust parameters adaptively for the global optimal control effect with a given range, and the convergence of the algorithm to search the global optimal value under given conditions is analyzed. This method introduces the measured angular velocity into the differential term of the PID controller, which is convenient to establish the system model and adjust control parameters. Parameter adjustment based on the nonlinear dynamic model can avoid deviations caused by model linearization and facilitate parallel search by genetic algorithm, then reasonable parameters can be quickly obtained with the specified value range. The proposed method is compared with the classical test method in time domain simulation. The simulated results indicate that the proposed method can adjust the parameters adaptively, the maximum deviation of attitude angle is less than 2°, the mean of deviation and the standard deviation of attitude angle deviation are less than 1°, and the control precision is obviously better than that of the classical test method. The experiments from the hardware-in-the-loop simulation show that the attitude control of the selected control parameters is stable, the deviation converges to 0°, and the control effect is good.

The fiber woven reinforced flexible composite film has been widely concerned in the fields of adjacent space aerostats, high air balls, etc. due to its excellent properties such as high strength, good toughness, light weight and good foldability. However, the temperature difference which is too large between day and night around the high-altitude environment causes the flexible composite film to undergo stress fatigue damage with the alternating change of the bearing pressure, which induces to form the damage microcrack and cause the air leakage damage of the flexible composite film, consequently, the damage seriously affects the normal service life of the aerostat and the airbag. Here, a typical Vectran fiber reinforced plain woven flexible composite film was taken as an example. The uniaxial warp stress fatigue damage evolution model of fiber reinforced plain weave flexible composites was constructed by using flexible film mechanics theory and progressive damage accumulation principle. And the uniaxial stress fatigue damage test and the SEM test of the damage mode were performed to identify the parameters of the uniaxial stress fatigue damage evolution model. It was found that the uniaxial warp-induced stress fatigue damage of flexible fiber reinforced plain woven composites was closely related to the properties, structure and stress state of the main load-bearing fiber bundles, and the damage mode was mainly represented by fiber bundle control, which synchronously induced the damage evolution of internal matrix and functional film layer. The fatigue test data of warp uniaxial fatigue damage under different fatigue loads showed good double logarithmic linear variation law, which could provide theoretical references for the structure optimization design and service life analysis of the fatigue damage mechanism.

The objective of this paper is to numerically investigate the three-dimensional side loads and associated flow physics of a conical nozzle during the fire-in-the-hole staging event of the multistage rocket. The transient flow in nozzle is examined by a three-dimensional time-accurate numerical method with the start-up process of the upper-stage motor and the prescribed nominal separating motion of the lower stage. The impacts of asymmetric lateral motion due to non-nominal staging movement on the nozzle side loads are also numerically analyzed. These motion deviations include the relative angle between axes of two stages, relative lateral displacement between two stages, superposition of relative angle with relative lateral displacement, and angle of thrust vector control. As presented in the simulation results, the flow separation in nozzle is significantly prolonged and intensified by the obstruction of the lower stage. With the location of shockwave reflection approaching the dome of lower stag...

Online identification of aerodynamic parameters of experimental rockets was completed based on unscented Kalman filtering (UKF). Numerical simulation, hardware-in-the-loop (HIL) simulation, and flight tests were conducted. The identification error of aerodynamic force in numerical simulation and HIL simulation is within 2%. For flight test data, trajectory reconstruction was performed using the identified aerodynamic forces, and the results showed that the identification results were more accurate than the interpolation table calculation results. The flight test identification results show that the identification method can complete parameter online identification under the conditions of limited performance of onboard computers, real sensor errors, and servo response. The approximate linear correlation between $\alpha$ and ${\delta }_e$ and the reason for their formation from the moment balance were analyzed. It was pointed out that when the recognition sampling period is long, this phenomenon will affect the identification of parameters, and a solution is proposed.

For aircraft which move in the atmosphere, the angle of attack and angle of sideslip cannot be measured precisely. This limits the precision of guidance and control systems, so the flush air data sensing system module with navigation and temperature information is designed for atmosphere parameter calculation. In this work the traditional parameter calculation method is improved, and a new algorithm which combines pressure data, temperature data and navigation data to calculate the atmosphere parameters is proposed. A ground experiment test scheme with a simulated flight environment is designed and the measured data is fitted and filtered to complete the experiments. The flush air data sensing module gets pressure data and temperature data of the atmosphere with sensors, and the measured data is integrated with navigation information to calculate the aircraft parameters of the angle of attack, angle of sideslip, dynamic pressure, static pressure, Mach number and so on. Calculated parameters can be transmitted to guidance and control systems to improve the attitude and trajectory precision for an aircraft. Experimental results show that the software and hardware of the flush air data system module with navigation and temperature information work well, and communication of various devices is normal. The flight status of aircraft can be precisely calculated online, which provides a useful reference for prospective wind tunnel experiments and flight tests.