The multi-variable control method was already used in the short take off/vertical landing (STOVL) aircraft engine. The research on outputs selection and control structure design for STOVL aircraft engines three-variable control system was carried out in different operating modes based on the analysis of robust stability
condition number and block relative gain array. As for normal operating mode
a three-variable block decoupling control method based on multi-ojective optimum was proposed. The dynamic tracking and coupling suppression properties were achieved through index definition. As for the transition control between normal operating mode and vertical landing operating mode
a compound controller with lift fan power feedforward was proposed to suppress the influence of the varying load. The simulation results show that the decoupling control effect can be ensured in normal operating mode
and the smooth transition between different operating modes also can be achieved by proposed methods
presenting the effectiveness of the control methods.