Ⅱ型PIO反馈与前馈抑制系统对比

 当舵机速率限制饱和时会产生附加时延,恶化飞行品质,触发Ⅱ型驾驶员诱发振荡（PIO）。运用描述函数法研究速率限制反馈（RLF）和死区增稳（DASA）Ⅱ型PIO抑制系统的开环相位补偿能力,提出RLF抑制系统的参数优化选择方法,分析了DASA抑制系统中死区和滤波器参数对相位补偿能力的影响。研究了两型抑制系统对正弦与偏差输入信号的开环响应特点。建立了含速率限制器的人机系统数学模型,基于描述函数法探究了Ⅱ型PIO的产生机理,推导了抑制Ⅱ型PIO发生的公式,应用连续信号相位补偿法抑制Ⅱ型PIO的发生。对阶跃、离散和正弦3种易于诱发PIO现象的跟踪任务进行数值仿真,对比了两种抑制系统的Ⅱ型PIO抑制能力。结果表明,反馈型RLF抑制系统对Ⅱ型PIO的抑制能力强于前馈型DASA抑制系统,有效降低了Ⅱ型PIO发生的可能性。

A Comparison of Feedback and Foreback Schemes to Prevent Category Ⅱ PIO

When rate limiter is saturated, the additional time delay would occur. It could deteriorate aircraft flying quality and cause category Ⅱ pilot-induced-oscillations(PIO). The rate-limited feedback(RLF) and the dead area stability augmentation(DASA) schemes prevent the category Ⅱ PIO from occurring. The open loop phase compensation capability of two schemes is studied based on describing functions method. The parameter optimization method of RLF scheme is provided. The influence of deadzone and filter parameters on DASA scheme phase compensation capability is analyzed. The responses of two schemes to sine wave input and bias input are examined. The pilot-vehicle system model with rate limiter is developed. The generation mechanism of category Ⅱ PIO is analyzed and the expression to avoid category Ⅱ PIO is derived. The continuous signal phase compensation method is applied to preventing category Ⅱ PIO. The step, discrete and sine tracking tasks which are easy to induce PIO are simulated, and the prevention capabilities of two schemes are compared. The results demonstrate that the RLF scheme has better capability for avoiding category Ⅱ PIO and decreases the occurrence possibility of category Ⅱ PIO.