Active Whirl Flutter Suppression Using Control Surfaces

Abstract

Whirl flutter is a stability problem caused by the interaction between aerodynamic, inertial, elastic forces, and gyroscopic effects from rotating propellers or rotor blades. Detailed analyses and flight tests are conducted to ensure stability; however, additional flutter control measures can be implemented to enhance stability further. For this purpose, active control strategies offer adaptive and effective solutions, dynamically adjusting to real-time flight conditions. This study presents an active control application designed to enhance the critical whirl flutter speed of an aircraft by utilizing existing primary control surfaces, eliminating the need for additional actuators or surfaces. To demonstrate this approach, a numerical simulation is performed using a 6-DoF dynamics of a model aircraft, modified by incorporating a twin prop-rotor engine, formulated using Reed’s model equations. Then, a PID-based active control system is implemented, which utilizes angular rate feedback from the proprotor thrust system to generate control commands for the ailerons and rudder. Numerical simulation results show that this approach can successfully increase the aircraft’s critical whirl flutter speed by 14.6%