Design and test of adaptive torsional vibration suppression method for helicopter power system with variable rotor speed.

In order to solve the problem of torsional vibration instability of the control system for turboshaft engine caused by low-order torsional vibration modal drift under variable rotor speed effectively, an adaptive torsional vibration suppression method based on the least mean square algorithm is proposed and designed. First, based on Lagrange equation and state space method, the structural dynamic model of torque transmission chain system is established, which takes into account fixed and variable gear ratio. It is beneficial to express the dynamic characteristics of torsional vibration in real time, so that the variation laws of low-order torsional vibration modal under variable rotor speed and gear ratio are revealed. Then, an adaptive torsional vibration filter based on least mean square algorithm is proposed and designed combined with the active control objective of helicopter power system. Finally, the effectiveness of adaptive torsional vibration suppression method is validated based on numerical simulation and hardware-in-loop simulation separately. The results show that compared with the conventional constant-coefficient notch filter, the adaptive torsional vibration filter can decrease the peaks of all low-order torsional vibration frequency by more than 50%. It proves better robustness, more remarkable effectiveness and superior adaptive ability of the adaptive torsional vibration suppression method. [ABSTRACT FROM AUTHOR]