A Study on Torsional Vibration Suppression Method for an Integrated Helicopter / Engine System

In order to solve the problem of torsional vibration instability of control unit in helicopter/engine system during maneuver flight, this paper has conducted the research on the integrated torsional vibration suppression of helicopter/engine system. Firstly, an integrated helicopter/engine model combined with torsional vibration is established based on the UH-60 helicopter model. Then the torsional vibration filter that is composed of a notch filter and a low-pass filter is applied to speed control loop of the engine to suppress the torsional vibration of power turbine speed. It is shown that the integrated helicopter/engine model combined with torsional vibration can simulate the torsional vibration characteristics under variable rotor speed, and both the low-order and high-order amplitudes of torsional vibration can be effectively eliminated below 0.04 & x2006;% at constant rotor speed through utilizing the torsional vibration filter. Meanwhile, when the helicopter operates under variable rotor speed, the fundamental frequency of torsional vibration varies from 1.30 Hz to 2.30 Hz. However, all torsional vibration amplitudes within this frequency range can be damped less than 0.05 & x2006;% through the notch filter whose bandwidth is 2.3 Hz, which proves the remarkable effect of torsional vibration suppression.