A new design method for mode transition control law of variable cycle engine

Both the polar moment of inertia and volume dynamics of variable cycle engine were considered, the transition-state numerical simulation system for VCE is established. A new mode transition method with a ladder-type variation of thrust is proposed. The ladder-type mode transition method isolates the thrust variation from the traditional mode transition process The VCE thrust is kept constant during mode transition, making it easy to get smooth mode transition. Differential evolution algorithm is used to design the mode transition control law. Based on the designed mode transition control law, the transient simulation of mode transition performance is conducted. The result shows that the designed control law basically realizes the ladder-type mode transition. The parameters change smoothly throughout the entire mode transition process. Thrust changes dramatically with minor change in specific fuel consumption. The inlet mass flow ratio changes slightly which means that the control law can enable what is known as flow holding.