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为了抑制直升机机动飞行时涡轴发动机自由涡轮、燃油调节系统出现的耦合扭振不稳定性,充分考虑了由旋翼、桨毂、传动系统、发动机以及机身组成的扭矩动力传递链的动态响应过程,建立了具有一定置信度的直升机综合扭振模型;并根据扭矩动力传递链特点,设计了作用于发动机转速控制回路的附加相移小的陷波滤波器以抑制综合扭振模型中涡轴发动机扭振。数字仿真表明,所建立的直升机综合扭振模型,在时域中,不同高度、马赫数下均可见低频扭振和高频扭振,与频域计算得到的低阶扭振频率1.92Hz,高阶扭振频率52.52Hz相符。同时,设计的扭振滤波器滤波幅值约-20d B,相角变化在±50°范围内,通频带附加相移小,能较为显著地抑制自由涡轮、燃油调节系统耦合扭振。
In order to restrain the instability of the coupled torsional vibration of the turbine and the fuel regulating system of the turboshaft during the flight of the helicopter, the dynamic response process of the torque transmission chain consisting of the rotor, the hub, the transmission system, the engine and the fuselage is sufficiently considered , A comprehensive torsional vibration model of helicopter with a certain degree of confidence is established. According to the characteristics of torque power transmission chain, a notch filter with small additional phase shift acting on the engine speed control loop is designed to restrain the turboshaft engine in the integrated torsional vibration model Torsional vibration. The numerical simulation shows that the established torsional torsional vibration model of helicopter shows low-frequency torsional vibration and high-frequency torsional vibration in the time domain, at different heights and Mach numbers. Compared with the calculated low-order torsional vibration frequency of 1.92 Hz in the frequency domain, Torsional vibration frequency of 52.52Hz match. At the same time, the designed torsional vibration filter filter amplitude is about -20d B, the phase angle change is within ± 50 °, and the additional phase shift of the passband is small, which can significantly suppress the coupling of torsional vibration of free turbine and fuel regulating system.