Control Law Design for the STOVL Aircraft Engine Using Variable Replacement Method

This paper presents a control law design method for the Short Takeoff and Vertical Landing (STOVL) aircraft engine. The objective is to achieve pitch and roll control of the STOVL aircraft by jointly adjusting multiple control variables, including the inlet guide vane angle of the lift fan, the nozzle exit area of the roll duct, and the engine exhaust nozzle throat area. The study begins with the development of a component-level simulation model for STOVL aircraft engines. The variable replacement method is then employed, wherein the desired values are assigned to the state variables that require iterative solution, and the corresponding number of control variables are replaced with iterative variables. This establishes a control law design model that is solved iteratively to derive the control law. Numerical simulations are conducted to validate the reliability and effectiveness of the proposed method under different input parameters. The results demonstrate that the designed control law achieves stable engine operation and meets the requirements of STOVL operations.