Research on Integrated Control Method for Helicopter/Turboshaft Engine with Variable Rotor Speed Based on the Error Between Engine Required and Real Output Torque

In order to achieve more rapid response control for integrated helicopter/turboshaft engine system with variable rotor speed, an integrated control method based on the error feedforward between engine required and real output torque is proposed. Firstly, based on the principle of incremental nonlinear dynamic inversion, an online acceleration estimation method of gas turbine speed (Ngdot) is proposed to realize the cascade control for turboshaft engine based on Ngdot. Then, a rotor demanded torque predicted model is developed through min-batch gradient descent-neural network. Meanwhile, a feedforward compensation method based on the error between engine required and real output torque is proposed according to the rotor dynamics characteristics of engine output shaft with variable rotor speed to suppress the interference of the rotor demanded power during variable rotor speed. The simulation results show that under different flight conditions, compared with the collective pitch feedforward and the rotor predicted torque feedforward control, the feedforward control method based on the error between engine required and real output torque can effectively reduce the overshoot of the relative speed of power turbine by about 14%. In addition, the settling time of power turbine speed is shorter, and the dynamic performance is superior, which can realize the rapid response control of turboshaft engine better.