Modeling and compensation of piezoceramic actuator hysteresis for helicopter vibration control

Hysteresis in piezoceramic materials causes considerable complications in the use of piezo actuators in applications, such as vibration control. In this study, the classical Preisach model is used to characterize the hysteresis in a piezostack actuator used to move a trailing-edge flap for helicopter vibration control. The hysteresis in the actuator is primarily due to material nonlinearity and to a lesser extent due to losses in the amplification mechanism. Most helicopter vibration control studies ignore the effect of the hysteresis on the actuator performance. The desired motion of the flap for maximum reduction in vibration is determined using an aeroelastic analysis of the helicopter. Numerical results indicate that complete compensation of actuator hysteresis can result in up to 90% reduction in helicopter vibrations. The performance of the vibration control system deteriorates considerably when the actuator is represented by a linear model or when the compensator is based only on the primary material hysteresis of the actuator. Complete compensation of both material and mechanical hysteresis in the actuator is therefore critical to the performance of the trailing-edge flap vibration control system in a helicopter.