Research On A Rotor Hub Mounted Active Vibration Absorber

As the main vibration source of a helicopter,the rotor brings so many dynamic problems.How to reduce the impact of the rotor to the vibration of a helicopter has become a focused dynamic subject of helicopters.The vibration level of the helicopter can be effectively reduced by installing a frequencytunable absorber on the rotor hub,so the project has broad prospects for development.This paper presents an active vibration absorber that generates centrifugal force by rotating two eccentric masses which mounted on the rotor hub head,used for reducing the helicopter vibration load in the rotor rotation plane.Firstly,the vibration reduction principle of the vibration absorber is described,taking a helicopter as the application object,the DC torque motor is chosen as the driving mechanism,and using classical PID control its speed,the initiative of the hub mounted absorber of the design is completed,and the turntable,connecting bolts and other key bearing parts of the strength are checked.Then the control algorithm of active vibration absorber is studied,the encapsulated normalized LMS algorithm is used in the filtering x-LMS algorithm of on-line identification of secondary channels.The influence of the key parameters and the control process on the eccentric mass rotating speed is analyzed by the model established in Matlab / Simulink.On this basis of that,the stability of the control algorithm and the damping efficiency of the vibration absorber are studied when the helicopter flight status is changed.Finally,in order to verify the validity,high efficiency and stability of the vibration absorber,a set of test model system is designed.And the principle of the vibration absorber and the effectiveness of the control algorithm are verified by simulating the experimental model system co-simulation with Virtual.Lab and Matlab / Simulink.The results show that the simulation results are in good agreement with those obtained in Matlab/Simulink.