Research On Rotor Control And Vibration Reduction Based On Individual Blade Control

Vibration is an important factor which limited helicopter use and development, rotor is the main source of helicopter vibration. High order harmonic pitch control for each blade of the rotor is an important method to reduce the vibration load of the rotor, and it is also an effective way to simplify the helicopter control. In this paper, the research object is a three bladed articulated rotor, on the base of first order harmonic(1/rev) cyclic pitch, the independent high order harmonic pitch have applied to each blade too, research on rotor vibration reduction based on single blade control.This paper established the blade rigid flap and lag dynamic equations and hub load functions, on account of the Leishman-Beddoes semi-empirical unsteady/dynamic stall aerodynamic model and the Pitt-Peters rotor dynamic inflow model. Then verified the L-B model and the hub load functions by example respectively. On the base of first-order harmonic cycle pitch, the second-order and third-order harmonic pitch applied on the blade respectively, and second/third-order harmonic combination pitch also studied, under different flight speed, harmonic phase/amplitude and harmonic combination influence on hub loads have been researched. Finally, this paper also analyzed rotor hub vibration loads in condition of the high harmonic components differences of each blade.The results show that phase and the amplitude of higher harmonics can substantially affect the rotor hub vibration loads; with the appropriate amplitude and phase, some elements of hub vibration can be reduced by more than 80% under each harmonic order. In apply of second-order and third-order harmonic combination, each direction of hub vibration load can be reduced significantly, and amplitude of harmonic combination can be much smaller than single high harmonic, it can be achieved easier in engineering.