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

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