Research On Adaptive Individual Blade Control Of Helicopter Vibration

The rotor vibration is the main resources of the helicopter vibration.In order to reduce the vibration to a lower level,the active control approaches have been widely developed.One of the approaches is individual blade control(IBC),where each blade can be controlled independently mainly by an actuator with higher harmonic pitch.It can reduce the rotor hub loads effectively which has been proved by many tests and experiments.The purpose of the paper is to conduct the simulation of individual blade control based on the aeroelastic model of rotor and study the fundamental law of control.Combined with adaptive control algorithm,the vibration reduction with IBC can be analyzed.Based on the Halmiton variational principle and the moderate deflection beam theory,the blade finite element model of structure dynamics can be established.Combined with Leishaman-Beddoes unsteady aerodynamic model and dynamic inflow model,the rotor aeroelastic model can be built.Using 3-blades model rotor at forward flight and IBC pitch control formula,the simulation can be conducted by loading 2/rev,3/rev,4/rev harmonic to the pitch.The basic rule with different harmonic pitch amplitudes and phases on vibration reduction control can be analyzed.The adaptive control algorithm with Kalman filter online identification is added,and the local model is adopted to simulate the single input and single output closed loop IBC The simulation results are compared with the control law derived from different performance functions.The multi input and single output method is used to simulate the IBC adaptive control,and the effect of multiple harmonic control on simultaneous vibration control is studied.The multi input and multi output method is used to simulate the IBC adaptive control,and the effect of simultaneous vibration damping for multiple hub components is studied.It is shown that the optimal combination of harmonic amplitude and phase can be found to make the vibration load to a minimum under the IBC loading of single harmonic.In single input single output system with adaptive control,vibration control can realize automatic control,by adjusting the control parameters to make the control process achieve satisfactory stability and convergence.On this basis,multi input and multi output adaptive control can simultaneously reduce vibration loads of multiple hub loads with multiple harmonic control.The effect of vibration reduction can achieve better expectations.