Effect of piezoelectric hysteresis on helicopter vibration control using trailing-edge flaps

This study investigates the effect of piezoelectric actuator hysteresis on helicopter vibration control using trailing-edge flaps. An aeroelastic analysis is used represent the helicopter with trailing-edge flaps. A compressible unsteady aerodynamic model is used to predict the incremental airloads due to trailing-edge flap motion. The material and mechanical hysteresis in the piezoelectric actuator is modeled using the classical Preisach model. Experimental data from the literature are used to estimate the weighting function through geometric interpretation and numerical implementation. Results are obtained from vibration control studies performed using a trailing-edge flap with 1) ideal linear actuator and 2) real actuator with hysteresis modeled. Multicyclic control input gives 90 and 81% reduction in hub vibration at high-speed flight (mu = 0.30) for the ideal and real actuator, respectively. In low-speed flight (mu = 0.15), the hub vibration is reduced by 99 and 86% for ideal and real actuator, respectively. Results indicate that the presence of actuator hysteresis nonlinearity leads to deterioration in controller performance and lower vibration reductions in both high- and low-speed forward flight.