考虑助力器动力学的舵系统结构非线性颤振特性分析
Analyzing Structural Nonlinear Flutter Characteristics for a Rudder with Dynamic Stiffness Considered

针对操纵系统的结构非线性问题,提出了2种考虑动刚度特性的舵系统(助力器系统和舵面耦合系统)颤振分析方法。利用分支模态法建立了以助力器系统动力学方程为基础的时域和频域非线性控制方程。使用描述函数法和一种改进的迭代方法得到系统控制命令为0时的预载间隙非线性颤振特性,比较了时域和频域结果。结果显示,在非线性条件下,控制命令的幅值和相位对颤振特性都有影响。
Two new methods which can analyze the rudder's flutter characteristics are used respectively for structurally nonlinear hydraulic booster with its dynamic stiffness considered. The component mode substitution method is used to establish the nonlinear governing equations respectively in time domain and frequency domain based on the fundamental dynamic equations of the hydraulic booster and rocker arm. The flutter characteristics containing preload freeplay nonlinearity are obtained respectively with the existing describing function method and a proposed iterative method when control command is zero. A comparison between the results of time domain and those of frequency domain is studied. The results show that the amplitude and phase of the control command have also an influence on the flutter characteristics under the nonlinear condition