Dynamic hysteresis of piezoceramic stack actuators used in helicopter vibration control:experiments and simulations

Abstract

This study investigates the effect of piezoceramic actuator hysteresis on helicoptervibration control using dual trailing-edge flaps. Piezoceramic stack actuators arepromising candidates for trailing-edge flap actuation in full-scale helicopters. However,they are inherently nonlinear in response to an applied electric field and exhibithysteretic behavior between the applied electric field and displacement. In this study,bench-top tests are conducted on a commercially available piezoceramic stackactuator, and its dynamic hysteretic behavior is studied. A Preisach-type dynamichysteresis model is used to describe the hysteresis in the stack actuator. The unknowncoefficients in the model are obtained through identification from experimental data.An aeroelastic model of the helicopter with multiple trailing-edge flaps is thenused to predict the hub vibration levels under different flight conditions. Theoptimal actuator control input for hub vibration suppression in the presence ofactuator hysteresis is considerably different from the case of an ideal-linear actuator.Numerical results show the importance of modeling actuator hysteresis in helicoptervibration control using trailing-edge flaps. Ignoring or inaccurate modeling ofhysteresis in the piezoceramic actuator can lead to inaccurate phasing of thetrailing-edge flap motion which directly affects the performance of the vibration controlsystem.