A cascaded optimization scheme by which the main rotor speed can be changed was proposed to solve helicopter/turbo-shaft engine hybrid control problem.Firstly

the minimal power demand of main rotor was found by Levenberg-Marquarat(L-M)algorithm and one-dimensional search optimization algorithm under the helicopter's stable flying state.And secondly

the engine's optimum operating point

i.e.:least fuel consumption state or lowest inlet turbine temperature state

was calculated by optimizing engine's manipulate variables

provided that the engine's constraints were not violated.At last

specific fuel consumption mode control was simulated based on UH-60 helicopter/turbo-shaft engine hybrid control platform;the simulation results show that the cascade optimization scheme is feasible and valid.