封面图为试验飞行中的M28共轴式无人直升机,该直升机由北京航空航天大学航空科学与工程学院设计研制.直升机旋翼/机体耦合系统的动不稳定性问题是直升机两大动力学问题之一,涉及复杂的旋翼非定常气动力与振动,以及难以进行试验研究,由于问题的复杂性,所以至今对其的研究仍遗留许多理论问题,需进一步深入,论文总结了这类动不稳定性问题的研究 The cover image shows the experimental M28 co-axial unmanned helicopter designed and developed by the School of Aeronautic Science and Engineering at Beijing University of Aeronautics and Astronautics.The problem of dynamic instability of a helicopter rotor / body-coupled system is related to the two major dynamics of helicopters Because of the complexities of the problems, there are still many theoretical problems left over from the research on the unsteady aerodynamic forces and vibrations of the rotor, which require further study. The dissertation summarizes such instabilities Study of the problem