Active flutter suppression of an airfoil model using ultrasonic motor

This paper presents the use of the ultrasonic motor, which features high torque at low speed, small size and low weight, as an actuator in the flutter control of a two-dimensional airfoil section with control surface. The paper starts with the design of a two-dimensional airfoil model with a control surface driven by an ultrasonic motor. Then, it gives the experimental modelling of the servo. Afterwards, the paper establishes the dynamic equation of the aeroservoelastic system based on Theodoson's aerodynamic load, and presents the numerical simulations for the sub-optimal control of flutter. Finally, the paper outlines the experimental study of the flutter control of the airfoil section in a wind tunnel test, where the critical flutter speed of the controlled system is increased by 13.4%, and the flutter is effectively suppressed when the flow velocity exceeded the critical flutter velocity of the uncontrolled system.