【作者】 李强；

【导师】 杨卫东；

【作者基本信息】 南京航空航天大学 ， 飞行器设计， 2021， 硕士

【摘要】 为提高直升机的操纵功效和飞行性能,简化桨毂结构,采用无轴承旋翼设计是现代直升机的发展趋势。但是无轴承旋翼直升机在气弹/机械稳定性方面存在着不足之处。无轴承旋翼直升机旋翼模态与机体的滚转模态有较强烈的气弹耦合,高速前飞状态下,摆振面内阻尼比较小,容易发生旋翼/机体耦合系统的不稳定现象,使其发展受到很大的限制。本文通过以机身运动角速度作为状态反馈量,周期变距作为控制输入对旋翼/机体气弹耦合系统实现主动控制增稳,为解决直升机动力学稳定性问题提供了方法。本文基于Hamilton原理,利用多体动力学描述无轴承旋翼直升机动力学部件的空间运动关系,建立旋翼/机体气弹耦合系统的动力学分析模型,所建立的模型保留了旋翼/机体的惯性/弹性/气动耦合。基于建立的旋翼/机体耦合系统的动力学模型,对其状态转换矩阵进行特征值分析求解其稳定性。并对旋翼/机体气弹耦合系统稳定性进行机体状态反馈控制增稳,通过计算机体滚转模态的瞬态响应对增稳效果进行观察。本文的研究分析可为旋翼/机体气弹耦合稳定性问题提供有效的增稳措施。基于所建立的旋翼/机体气弹耦合动力学分析模型,进行了直升机机体/桨叶的动特性计算,分析了悬停条件下样机旋翼/机体耦合系统的稳定性,实现了前飞状态下旋翼/机体耦合系统的机体状态反馈控制增稳,通过机体滚转模态的瞬态响应对反馈系数进行参数影响分析。分析得到了一些有意义的结论,有利于对直升机的“空中共振”稳定性问题进行进一步的分析研究。更多还原

【Abstract】 In order to improve control efficiency and flight performance of helicopters,the use of bearingless rotor design is the development trend of modern helicopters.But the bearingless rotor helicopter has shortcomings in terms of aeroelastic coupling stability.The rotor mode of the bearingless rotor helicopter has a strong aero-elastic coupling with the roll mode of the body.In the high-speed forward flight state,the damping in the swing plane is relatively small,and the instability of the rotor/body coupling system is prone to occur.Development is greatly restricted.This paper uses the angular velocity of the fuselage as the state feedback and the periodic variable pitch as the control input to realize the active control and stabilization of the rotor/airframe aeroelastic coupling system,which provides a method for solving the problem of helicopter dynamics stability.Based on the Hamilton principle,this paper uses multi-body dynamics to describe the spatial motion relationship of the dynamic components of a bearingless rotor helicopter,and establishes a dynamic analysis model of the rotor/body aero-elastic coupling system.The established model retains the inertia/elasticity of the rotor/body / Pneumatic coupling.Based on the established dynamic model of the rotor/airframe coupling system,the eigenvalue analysis of its state transition matrix is performed to solve its stability.The stability of the rotor/air-body aeroelastic coupling system is controlled by the body state feedback control to increase the stability,and the stabilization effect is observed through the transient response of the computer body’s rolling mode.The research and analysis in this paper can provide effective measures to increase the stability of the rotor/airframe coupling stability.Based on the established rotor/body aero-elastic coupling dynamics analysis model,the dynamic characteristics of the helicopter body/blade were calculated,the stability of the prototype rotor/body coupling system under hovering conditions was calculated,and the rotor was realized in forward flight.The airframe state feedback control of the airframe coupling system increases the stability,and the feedback coefficient is analyzed through the transient response of the airframe rolling mode.The analysis has obtained some meaningful conclusions,which is conducive to further analysis and research on the stability of the helicopter’s air resonance.更多还原