Variable phase control of wing rock

This paper addresses a variable phase control issue for suppressing wing rock with hysteresis. In free-to-roll tests, as the angle of attack (AOA) is increased, the roll angle versus the rolling moment indicates hysteresis and provides clues about where wing rock motion is being driven and where the motion is being damped. We present the analysis method of wing rock energy to explain the mechanism of wing rock and the formation of hysteresis, and then develop a variable phase control (VPC) scheme to compensate the phase and magnitude distortions. The effectiveness and robustness of the proposed scheme are demonstrated by suppressing wing rock phenomenon at various AOA and any initial conditions.