| The control system of generator gas regulation is a key technology for ducted rockets. The performance of gas flow capacity have a significant impact on the performance and safety of solid rocket ramjet. With the aircraft engine performance requirements continue to increase, research on the gas flow regulation and control technology has been enhanced in recently years. The gas regulation control for variable flow ducted rockets was investigated in this paper.Firstly, the principles of gas flow regulation has been investigation according to the principle of solid rocket motor. The main influence factors on gas flow adjusting character of gas generator were summarized. The influence of burning rate exponent and throat diameter on gas flow was analysed and think of propellant burning rate exponent should normally be in the range of0.7-0.8. The experimental system was establish including gas generator, electric needle-type valve, measurement and control system, the needle-type valve structure and dynamic seal as a key part among them designed in detail.Secondly, the mathematical model of gas regulating system was established based on small perturbation theory. Gas regulation dynamic model with fixed gain was instead of a variable gain to reduce error. The inverse relationship between the undershoot and setting time was analysed according to the dynamic model and the minimum settling time was given subject to undershoot constraint. The mathematical model of electric needle-type valve and servo drive section was established.Then, we studied the open-loop control and feedback control, establish a comprehensive control method. The simulation model was established according to mathematic model of interior ballistic with MATLAB/Simulink and simulation studied various control algorithms. Numerical simulation results illustrate the optimum feed-forward controller based on ideal response signals can achieve minimize the settling time subject to undershoot constraint. Compared with PID control, two-stage PI/PD controller have excellent performance and simple implementation, PI controller is mainly used to decrease the system undershoot and PD controller is mainly used to improve the transient response of the system and decrease peak overshoot. Aiming at the influence of the uncertainty and nonlinear in the system, a two-stage fuzzy adaptive PID controller was proposed. A comprehensive control method was proposed based on open-loop control and feedback control, using the open loop control constrained negative, and feedback control eliminate the influence of disturbance as a supplement.Finally, cold experiments and hot experiments of gas regulation system were implement. The cold experiments verify the reliability of dynamic seal structure and the servo driven system dynamic performance. Hot experiments confirm the ignition performance and the valve head can ensure the surface integrity in the short-time work, but may be broken, should increase the diameter of cone first stage. Elastic piston rings and O-ring seals can effectively achieve the gas seal for regulation valve dynamic seal. The results of experiment shows that electric needle-type gas control valve can effectively control the pressure in gas generator, and gas control system has good performance. The test data consistent with the results of the mathematical model simulation, modifications model has higher accuracy. |
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