Multivariable Control Coupling Analysis and ALQR Thrust Controller Design of Liquid Rocket Engine

In this paper, for a certain type of liquid oxygen methane gas generator cycle rocket engine, the internal and external structure is used to establish the main stage nonlinear dynamic simulation model, and the relative gain matrix (RGA) is used to analyze the coupling relationship between the opening of the two oxygen loop valves and the pressure and mixing ratio of the thrust chamber during thrust control. On this basis, the ALQR multi-variable controller is designed, and the thrust control effect of the single-variable controller is analyzed and compared. The results show that the use of the ALQR multivariable control method reduces the overshoot by 17.9% compared with the PI control method, and the fluctuation of the valve opening is smaller, and the design of the thrust adjustment control system can be realized simply and quickly.