Adaptive Control and Predictive Control for Torsional Vibration Suppression in Helicopter/Engine System

In order to damp torsional vibrations in a helicopter, which would cause resonance in rotating components like engine, transmission, and rotor, an adaptive notch filter is proposed. Instead of fixed notch filter, the adaptive one, with FFT analyzer and sorting algorithm, can damp the low-order torsional vibration signal with natural frequency varying in a wide range. Then, in order to enhance the power following capability of the engine, a nonlinear model predictive controller based on the supported vector machine is designed to compensate for the dynamic control performance. Through the adaptive notch filter, the torsional vibration of the free turbine speed whose frequency is away from the set-point value can effectively be suppressed by 50% compared with the fixed notch filter. Furthermore, instead of conventional PID controller, the nonlinear model predictive controller based on the adaptive notch filter can reduce the sag of the free turbine to less than 0.4%. Therefore, the control strategy achieves fast high-quality response of the turbo-shaft engine.