Engine Control Design Using Compressor Guided Vanes During Autorotation Power Recovery

Abstract

In order to improve the helicopter responsive ability during autorotation power recovery maneuvers, a new turbo-shaft engine control scheme is proposed in this paper. Using rotor flapping/lagging dynamics and an induced velocity model which is capable of capturing vortex ring characteristics, an integrated helicopter and engine model was developed to simulate autorotation process. By introducing a closed-loop with compressor guided vanes, a novel two-variable engine control law is devised using Linear Matrix Inequality Pole Placement method. This allows for a rapid adaptation of the helicopter to a large and fast needed torque variation required in autorotation power recovery. The transient performances and the robustness for the closedloop helicopter-pilot system are validated for some examples appropriated to autorotation training procedure. Simulation results illustrate that, with this novel control law, the helicopter's ability to respond during autorotation is strongly enhanced when compared to traditional cases.