考研851 自动控制原理
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\[\frac{C(s)}{R(s)} = \frac{5K_0K_1}{(s+5)(s^2+s)+5K_0K_1}\]

(3)

由劳斯判据可知系统稳定

\[G(s) = \frac{5K_0K_1}{s(s+1)(s+5)}, K_v = \lim_{s\to0} sG(s) = K_0K_1 \Rightarrow e_{ssr} = \frac{2}{K_0K_1}\]

\(n(t) = n_1 + n_2t\)

\[\frac{E(s)}{N(s)} = \frac{C(s)}{N(s)} = \frac{\dfrac{k_0k_2}{s^2+s}}{1+\dfrac{5k_0k_1}{s(s^2+s)}+\dfrac{5}{s}}\]
\[= \frac{k_0k_2s}{s(s^2+s)+5(s^2+s)+5k_0k_1}\]
\[e_{ssn} = \lim_{s\to0} sNE/N = \frac{k_2n_2}{5k_1}\]

(4)

对扰动端前馈校正

五、

(1)

\[G(s)H(s) = \frac{k(s+2)}{s(s+1)}\]

开环极点0,-1,开环零点-2

实轴上的根轨迹:\((-\infty,-2]\)\([-1,0]\)

分离点:\(\dfrac{dG(s)}{ds} = 0 \Rightarrow s_1 = -0.59, s_2 = -3.41\)

渐进线:\(\sigma_a = \dfrac{-1-(-2)}{2-1} = 1\)\(\Phi_a = \dfrac{(2k+1)\pi}{2-1}(k=0)\)

根轨迹如图: