MIMOMH feed-forward adaptive vibration control of helicopter fuselage by using piezoelectric stack actuators

Abstract

The vibration of a helicopter fuselage is mainly produced by the rotor exciting loads which are three forces and three moments containing harmonics in three directions at rotor hub center, and has the characteristic of large, steady and harmonic vibration. The active control of helicopter fuselage vibration by using inertia actuator needs to pay a heavy weight cost for achieving a good control effect. In this paper, a method for multi-input multi-output multi-harmonic (MIMOMH) feed-forward adaptive control of helicopter fuselage vibration by using piezoelectric stack actuators is presented. The method is composed of the harmonic coefficients identification and the MIMOMH feed-forward adaptive filtering algorithm, and has excellent characteristics such as light weight, fast response, wide working frequency range, adaptive ability and high effect. The numerical simulations for a frame structure scaled by the Z11 helicopter fuselage floor with four actuating inputs, four vibration outputs, three rotor exciting loads and the first three harmonic frequencies contained in each exciting load were performed, indicating that the vibration levels at objective points are reduced by 99% by using the method and are much lower than the results by only controlling the first harmonic frequency. When the phases, amplitudes and frequencies of exciting loads are changed, the method demonstrates an excellent adaptability to control vibration.