Global Multichannel Control Method for Helicopter Active Vibration Isolation

Since the support struts of the helicopter main gearbox are the main transmission path for the excitation force from the main rotor to the fuselage, vibration transmission can be suppressed effectively by embedding actuators in the support struts. A new helicopter active vibration isolation system with hydraulic actuators embedded into the helicopter main gearbox support struts is proposed. A dynamic model of the helicopter active vibration isolation system with an eight-strut centralized configuration is established using the frequency response function synthesis method. Based on this model, the characteristics of vibration transmission in the system are analyzed. Considering the influence of coupling crosstalk of control channels, a feedback global multichannel (FGMC) adaptive controller based on the filtered-x least mean square (FxLMS) algorithm is proposed. The simulation and experimental results indicate that the convergence rate and stability of an FGMC controller are better than those of conventional decentralized multichannel (DMC) FxLMS controllers. In the experiment, the root-mean-square value attenuations are over 63% and 40% for the FGMC and DMC controllers, respectively. The experimental results of variable amplitude disturbing force further verify that the FGMC controller has strong convergence and robustness.