Calculation And Analysis Of Rotor Vibration Load Based On Individual Blade Control

Rotor is the main vibration source of the helicopter.It is an effective method to actively control the rotor vibration load and reduce the level of helicopter vibration by applying high-order harmonic pitch to each blade of the rotor directly.Based on the Hamiltonian principle,the coupled equation of the blade flapping,bending,twisting and stretching is established.The dynamic equation of the rotor is obtained by finite element method using two-node 12-degree-of-freedom beam element.The validity and accuracy of the model are validated by comparing the properties of the Princeton beam with the published results of calculation and experiment abroad.Then the aeroelastic equation is established using Leishman-Beddoes semi-empirical unsteady/dynamic stall aerodynamic model and Glauert inflow model.The dynamic response of rotor blades in forward flight is solved by modal superposition method.The hub vibration load with high-order harmonic pitch is obtained by superposition of radial and circumferential discretes along the disc.On the base of these,the parameter influence analysis is carried out and the variation of the hub vibration load with the high-order pitch amplitude and phase is obtained.Finally,with the minimum vibration load of the hub as the objective,the optimum combination of impeller variable-pitch harmonics under different flight conditions is obtained by using Matlab minimum optimization function.The results of the paper can be used to guide the design of electro-mechanical-actuator rotor.