Review of vibration and noise suppression technologies for helicopter transmission systems

The helicopter transmission system is the key source of cabin noise, which significantly affects the flight quality and ride comfort. Systematically combing its vibration/noise suppression technology can provide technical basis and path reference for engineering design, system integration and localization replacement. This article provides a review of the research progress on vibration/noise suppression technology for helicopter transmission systems both domestically and internationally. Passive vibration suppression techniques (including structural optimization, damping, absorption, and isolation) and active vibration suppression techniques (covering actuators and active control algorithms) have been elucidated in this review. The research status of vibration suppression technology for transmission systems of special configurations of helicopters with high-speed flight characteristics, such as coaxial reverse twin rotor helicopters and tilt rotor helicopters, has been summarized. At the same time, the vibration reduction mechanism of new transmission components such as magnetic gears, ceramic bearings, composite shafts, and casings has been explored, as well as the research progress of revolutionary electric drive technologies such as electric tail rotor and fully electric drive. Finally, based on the current research status in China, suggestions are proposed for multidimensional optimization of active vibration suppression technology, technological innovation to promote the upgrading of new transmission components, and the development of new energy helicopters, in order to enhance the international competitiveness of China's helicopters.