Anlysis And Test Research Of Smart Rotor System With Active Trailing-edge Flaps

Vibration control is focus all through the development of helicopter. Smart rotor with trailing edge flaps and high effective actuators is a new technique for vibration active control and it arouses people’s wide concern. The vibration loads of the rotor can be reduced by the distribution changed of the high harmonic aerodynamic loads of blades under deflection of active controlled trailing edge flap. This paper presents the analyses and tests of a smart rotor model with trailing edge flaps used for active vibration control of the rotor.The aero-elastically dynamic analysis model of the smart rotor with trailing edge flaps is developed for active vibration control of the rotor. The derivation of the coupled actuator/trailing-edge flap/ blade equations of motion is based on Hamilton’s variation principle. The actuator and flap are modeled as two separate structural dynamic elements. The actuator and flap dynamics and their influence on the blade deformation are concerned. An unsteady aerodynamic model of flap based on the Hariahan-Leishman flap theory is established to analysis the flap’s influence on blade aerodynamic force. The hub loads are estimated using a force integration method and a summation process.Based on the coupled analysis model, parametric studies have been conducted to investigate the impact of flap and actuator design on control authority and power consumption. Key flap design parameters, such as flap span-wise length and chord, span-wise location, have been examined. Simulation and analysis based on the smart rotor model are conducted to demonstrate the vibration reduction effect of the hub loads. One of the objects of this research is to investigate the influence of active flap control on the vertical loads of the hub especially on the high-order harmonic loads. Simulation results showed that it is viable to use the ACF smart rotor to reduce the hub vibration through active control.Several actuators based on the piezo electric and ferroelectric material are designed, analyzed and tested to compare their performance. The rotor blades with trailing edge flaps and high effective actuators are designed and fabricated with the hub, measurement system and control system. At last, a smart rotor system with trailing edge flaps used for active vibration control is built.The open-loop test has been conducted to demonstrate whether the actuators can effectively drive the flap at the rotor operating speeds. Rotor rotating speed, drive frequency and voltage influences on actuator performance are studied. At last, the variations of vertical hub loads are researched by the flap angels and frequencies changed. There is a good agreement between the analysis and the test. Test result shows that piezoelectric actuators can effectively actuate the flaps and the movement of flaps has significant effect on the vertical hub loads at the rotor operating speeds. The effectiveness of the active flap control vibration is conclusively demonstrated from the closed-loop test. Result shows that the vertical loads of the hub have a sufficient reduction.