Analysis and verification of the coupling between FCS and helicopter vibration postprint

Abstract: The coupling between flight control system(FCS)and helicopters can induce or aggravate the vibrations of the helicopter.For the lack of systemic understanding of the problems at home,much more human resource and time have been wasted to do some troubleshooting from the beginning when the vibration problems caused by coupling between FCS and helicopter appear,thus delaying the model development progress.In this paper,two coupling models between FCS and helicopters are presented from the perspective of helicopter vibrations,according to which two categories are formed and the frequency characteristics are analyzed.The mechanisms as well as the critical factors in the interconnection are summarized.Aiming at two coupling paths,general resolutions are addressed to avoid the vibration problems caused by coupling between FCS and helicopters.Further analyses are made of the critical pathway and the associated frequency range,based on a practical problem of a certain helicopter model,which indicates the severity of the problem caused by coupling between FCS and the helicopters.The results prove the effectiveness of the resolutions presented,and can serve as the reference for dealing with the analogous vibration problems caused by coupling between FCS and helicopters.