Effect of Piezoceramic Actuator Hysteresis on Helicopter Vibration and Noise Reduction

Abstract

The objective of this studywas to assess the importance of actuator hysteresis on vibration and noise reduction in a rotorcraft equippedwith an actively controlledflap (ACF) system.Ahysteresismodel, based ona generalized formof the classical Preisach model, was developed using experimental data. The model displays good agreement with experimental data for inputs representative of those used for vibration and noise reduction in full-scale rotors. The hysteresis model has been incorporated into the AVINOR code to determine the effect of actuator hysteresis on vibration and noise reduction in both open and closed-loop modes of operation. It was found that the hysteresis level of a representative piezoceramic actuator does not produce a significant performance degradation of theACF system for vibration reduction under blade-vortex interaction (BVI) and dynamic stall conditions. For open-loop BVI noise control, the presence of hysteresis produces a significant effect on themaximumnoise reduction obtained using 2 per revolution (rev) and 5=rev harmonic inputs. For closed-loop BVI noise control, hysteresis introduces a substantial difference inflap deflection time histories; however, the overall noise reduction performance of theACF system is not affected because the controller compensates for actuator hysteresis.