Research On Pressure Closed-loop Feedback System For Variable Flow Gas Generator Of Ducted Rocket

The solid rocket ramjet has become an ideal power device for tactical missiles due to its simple structure,high specific impulse,and reliable performance.Gas flow regulation can not only control the air-fuel ratio within the set range,improving engine performance and safety,but also adjust the thrust of the engine,improving the mobility and penetration capability of the missile.So far,it has become a hot research topic in major military powers.This paper focused on the choke-type flow adjustable gas generator,and the research was carried out on the related gas flow adjustment technology and control method.Firstly,the principle and the composition of the choke-type gas flow adjusting system were analyed with detail.The sliding discal valve gas generator was designed and its working principle was investigated.The component of the the electric mechanism which drived the valve was briefly described.The design of Embedded software and hardware based on STM32 controller and display acquisition system based on Labview were introduced.Secondly,the steady and dynamic model of the gas flow adjusting system were established,along with the characteristics were analyzed.Based on the steady model of gas generator when pressure was at equilibrium,the influence of throat area and pressure exponent on flow adjustment static characteristics was studied through simulation.The analysis of the dynamic model during dynamic response showed that the flow adjusting system had two major characteristics: time-varying nonlinearity and negative regulation.The gas generator free volume,pressure,motor speed and other factors which influenced the dynamic characteristics were analyzed.Then,research on the control algorithm of gas flow adjustment system was conducted.In order to achieve stable regulation of gas flow,a design method of P-F-PI(proportional,fuzzy,proportional and integral)controller,whose parameters could be adjusted optimally by immune particle swarm optimization was introduced.This compound controller combined the rapidity of the proportional controller with the robustness and adaptability of the fuzzy controller.At the same time,the proportional-integral controller was used to compensate the fuzzy defects of the fuzzy controller in the blind zone.The coefficients of P and PI controllers and the quantization factors and scale factor of the Fuzzy controller were optimized by immune particle swarm optimization.Simulational results showed that the traditional PID controller was not suitable for the gas flow adjusting system.On the contrary,the designed algorithm was more suitable for the gas flow regulating system in terms of fastness,stability,suppression of negative regulation and anti-interference.Finally,experiments on gas flow regulation were conducted.The high-pressure cold air experimental system verified the air-tightness of the device and the reliability of the control algorithm.The firing test of gas flow regulation verified the reliability of the entire gas flow regulation system in high temperature and high pressure harsh environments.The experimental results showed that the control system had good adaptability and stability,also reflected the characteristics of the gas flow regulating system.