Smart Spring Impedance Control Algorithm for Helicopter Blade Harmonic Vibration Suppression

Abstract

In this paper, an adaptive impedance control algorithm is developed for the Smart Spring to suppress helicopter rotor vibration through individual blade control. The harmonic frequencies of the blade response were estimated using parametric methods, which were used to synthesize the reference signal. Multiple equivalent notches were formed at corresponding frequencies to selectively suppress the blade vibration modes. To improve the adaptability of the algorithm, an on-line control path identification method is presented. The algorithm was implemented on a MATLAB xPC platform using the hardware-in-the-loop concept. Closed-loop experiments, conducted using a fixed helicopter blade section in both shaker and wind tunnel tests, have achieved significant vibration suppressions. Experimental results demonstrate that the algorithm, which is able to select the blade vibration modes and track the variations in vibration due to changes in flight condition, is promising for helicopter individual blade control applications.