Adaptive Vibration Control for Helicopter with Active Rotor Using Double-Acting Piezoelectric Actuator

Active rotors with trailing-edge flaps (TEFs) are a promising method applied to the main-rotor blades of the helicopter for vibration suppression. For active rotors, both the TEF actuator and the corresponding deflection control law determine their overall performance and effectiveness for vibration reduction. In this study, a double-acting piezoelectric actuator is designed to actuate the TEFs, where bidirectional push/pull output is achieved by two groups of piezoelectric stacks operating in opposite directions. Benchtop tests indicate that the TEF deflection angle of the active rotor equipped with this actuator can reach ±4.3°. Subsequently, based on the controlled autoregressive moving average (CARMA) model, an adaptive controller is developed to reduce vibrations in the active rotor by using a minimum variance direct self-tuning regulator (MVSTDR). Finally, an unmanned helicopter is retrofitted with the active rotor, and vibration control experiments are performed under tethered hover conditions with vertical cabin vibration as the control target. Experimental results demonstrate the effectiveness of the designed actuator and the MVSTDR for vibration reduction on the helicopter equipped with an active rotor, which also validates the feasibility of active rotors for practical engineering applications in helicopter vibration control.