资源描述
完美WORD格式
1-3
解:系统的工作原理为:当流出增加时,液位降低,浮球降落,控制器通过移动气动阀门的 开度,流入量增加,液位开始上。当流入量和流出量相等时达到平衡。当流出量减小时,系 统的变化过程则相反。
专业整理 知识分享
希望液位
流出量
高度 液位高度
控制器 气动阀 水箱
+ 流入量
-
浮球
图一
1-4
(1) 非线性系统
(2) 非线性时变系统
(3) 线性定常系统
(4) 线性定常系统
(5) 线性时变系统
(6) 线性定常系统
2-1 解:
显然,弹簧力为 kx(t ) ,根据牛顿第二运动定律有:
F (t ) − kx(t) = m
移项整理,得机械系统的微分方程为:
d 2 x(t )
dt 2
2
m d x(t ) + kx(t ) = F (t )
dt 2
对上述方程中各项求拉氏变换得:
ms 2 X (s) + kX (s) = F (s)
所以,机械系统的传递函数为:
G(s) =
X (s) =
F (s)
1
ms 2 + k
2-2 解一:
由图易得:
i1 (t )R1 = u1 (t ) − u2 (t )
uc (t ) + i1 (t )R2 = u2 (t )
duc (t )
i1 (t ) = C
dt
由上述方程组可得无源网络的运动方程为:
C ( R + R ) du2 (t )
u (t ) = CR
du1 (t )
u (t )
1 2 dt
+ 2 2 + 1
dt
对上述方程中各项求拉氏变换得:
C (R1 + R2 )sU 2 (s) + U 2 (s) = CR2 sU1 (s) + U1 (s)
所以,无源网络的传递函数为:
G(s) = U 2 (s) =
U1 (s)
1 + sCR2
1 + sC(R1 + R2 )
解二(运算阻抗法或复阻抗法):
U (s)
1
+ R2
1 + R Cs
2 = Cs = 2
U (s)
R + 1 + R
1 + ( R + R )Cs
1 1 2
1 Cs 2
2-5 解:按照上述方程的顺序,从输出量开始绘制系统的结构图,其绘制结果如下图所示:
依次消掉上述方程中的中间变量 X 1 , X 2 , X 3 , 可得系统传递函数为:
C(s) =
R(s)
G1 (s)G2 (s)G3 (s)G4 (s)
1 + G2 (s)G3 (s)G6 (s) + G3 (s)G4 (s)G5 (s) + G1 (s)G2 (s)G3 (s)G4 (s)[G7 (s) − G8 (s)]
2-6 解:
① 将 G1 (s) 与 G1 (s) 组成的并联环节和 G1 (s) 与 G1 (s) 组成的并联环节简化,它们的
等效传递函数和简化结构图为:
G12 (s) = G1 (s) + G2 (s)
G34 (s) = G3 (s) − G4 (s)
② 将 G12 (s), G34 (s) 组成的反馈回路简化便求得系统的闭环传递函数为:
2-7 解:
C(s) =
R(s)
G12 (s)
1 + G12 (s)G34 (s)
= G1 (s) + G2 (s)
1 + [G1 (s) + G2 (s)][G3 (s) − G4 (s)]
由上图可列方程组:
[E (s)G1 (s) − C (s)H 2 (s)]G2 (s) = C (s)
R(s) − H1
(s) C (s)
G2 (s)
= E (s)
联列上述两个方程,消掉 E (s) ,得传递函数为:
C(s) =
R(s)
G1 (s)G2 (s)
1 + H1 (s)G1 (s) + H 2 (s)G2 (s)
联列上述两个方程,消掉 C (s) ,得传递函数为:
E(s) =
R(s)
1 + H 2 (s)G2 (s)
1 + H1 (s)G1 (s) + H 2 (s)G2 (s)
2-8 解:
将①反馈回路简化,其等效传递函数和简化图为:
0.4
1
G (s) = 2s + 1 =
1 + 0.4 * 0.5
2s + 1
1
5s + 3
将②反馈回路简化,其等效传递函数和简化图为:
1
2
2
G (s) = s + 0.3s + 1 =
5s + 3
2
2
3
1 + 0.4
5s + 4.5s
+ 5.9s + 3.4
(s + 0.3s + 1)(5s + 3)
将③反馈回路简化便求得系统的闭环传递函数为:
0.7 * (5s + 3)
Θ o (s) = 5s 3 + 4.5s 2 + 5.9s + 3.4 =
3.5s + 2.1
Θi (s)
1 + 0.7 * Ks(5s + 3)
5s 3
+ (4.5 + 3.5K )s 2
+ (5.9 + 2.1K )s + 3.4
5s
3-3 解:该二阶系统的最大超调量:
σ p = e
−ζπ /
1−ζ 2
*100%
当σ p
= 5% 时,可解上述方程得:
ζ = 0.69
当σ p
= 5% 时,该二阶系统的过渡时间为:
t s ≈
3
ζwn
所以,该二阶系统的无阻尼自振角频率 wn
3-4 解:
≈ 3
ζt s
= 3
0.69 * 2
= 2.17
由上图可得系统的传递函数:
10 * (1 + Ks)
C (s) =
R(s)
s(s + 2)
1 + 10 * (1 + Ks)
s(s + 2)
== 10 * (Ks + 1)
2
s + 2 * (1 + 5K )s + 10
所以 wn =
10 ,ζwn = 1 + 5K
⑴ 若ζ
= 0.5 时, K ≈ 0.116
所以 K ≈ 0.116 时,ζ
= 0.5
⑵ 系统单位阶跃响应的超调量和过渡过程时间分别为:
σ p = e
−ζπ /
1−ζ 2
*100% = e
−0.5*3.14 /
1−0.52
*100% ≈ 16.3%
ts =
3
ζwn
= 3
0.5 *
≈ 1.9
10
⑶ 加入 (1 + Ks ) 相当于加入了一个比例微分环节,将使系统的阻尼比增大,可以有效
地减小原系统的阶跃响应的超调量;同时由于微分的作用,使系统阶跃响应的速度(即变
化率)提高了,从而缩短了过渡时间:总之,加入 (1 + Ks ) 后,系统响应性能得到改善。
3-5 解:
由上图可得该控制系统的传递函数:
C(s) =
1
10K1
R(s)
二阶系统的标准形式为:
C (s)
R(s)
s 2 + (10τ + 1)s + 10K
w 2
= n
s 2 + 2ζw s + w2
n n
所以
w
2
n = 10K1
2ζwn = 10τ + 1
由
p
σ = e−ζπ /
π
1−ζ 2
*100%
t p =
wn
1 − ζ 2
σ p = 9.5%
t p = 0.5
可得
ζ = 0.6
2
wn = 10K1
ζ = 0.6
wn = 7.85
由 和
2ζwn = 10τ + 1
wn = 7.85
可得:
K1 = 6.16
τ = 0.84
t s ≈
3
ζwn
= 0.64
3-6 解:⑴ 列出劳斯表为:
因为劳斯表首列系数符号变号 2 次,所以系统不稳定。
⑵ 列出劳斯表为:
因为劳斯表首列系数全大于零,所以系统稳定。
⑶ 列出劳斯表为:
因为劳斯表首列系数符号变号 2 次,所以系统不稳定。
3-7 解:系统的闭环系统传递函数:
K (s +1)
C (s) =
R(s)
=
s(2s +1)(Ts +1) =
1 + K (s +1)
s(2s +1)(Ts +1)
K (s +1)
K (s +1)
s(2s +1)(Ts +1) + K (s +1)
2Ts3 + (T + 2)s 2 + (K +1)s + K
列出劳斯表为:
s3 2T K +1
s2 T + 2 K
s1 (K +1)(T + 2) − 2KT T + 2
s0 K
T > 0 ,T + 2 > 0 , (K + 1)(T + 2) − 2KT T + 2
> 0 , K > 0
T > 0
K > 0 , (K + 1)(T + 2) − 2KT > 0
(K +1)(T + 2) − 2KT = (T + 2) + KT + 2K − 2KT
= (T + 2) − KT + 2K = (T + 2) − K (T − 2) > 0
K (T − 2) < (T + 2)
3-9 解:
由上图可得闭环系统传递函数:
C (s) =
KK2 K3
2 3 2 3 2 3
R(s) (1 + KK K a)s2 − KK K bs − KK K
代入已知数据,得二阶系统特征方程:
(1 + 0.1K )s2 − 0.1Ks − K = 0
列出劳斯表为:
s2 1 + 0.1K − K
s1 − 0.1K
s0 − K
可见,只要放大器
−10 < K < 0 ,系统就是稳定的。
3-12 解:系统的稳态误差为:
ess
= lim e(t ) = lim sE (s) = lim s
R(s)
t →∞
s→0
s →0 1 + G0 (s)
⑴ G0 (s) =
10
s(0.1s + 1)(0.5s + 1)
系统的静态位置误差系数:
K = lim G
(s) = lim 10 = ∞
p s →0 0
s →0 s(0.1s + 1)(0.5s + 1)
系统的静态速度误差系数:
K = lim sG
(s) = lim
10s
= 10
v s →0 0
s →0 s(0.1s + 1)(0.5s + 1)
系统的静态加速度误差系数:
K = lim s 2 G
(s) = lim
10s 2
= 0
a s→0 0
s→0 s(0.1s + 1)(0.5s + 1)
当 r (t ) = 1(t ) 时, R(s) = 1
s
ess
= lim s
* 1 = 0
当 r (t ) = 4t 时, R(s) =
s→0 10 s
1 +
s(0.1s + 1)(0.5s + 1)
4
s 2
e = lim s
* 4 = 0.4
ss s →0 s 2
当 r (t ) = t 2 时, R(s) =
1 + 10
s(0.1s + 1)(0.5s + 1)
2
s 3
ess
= lim
s →0
1 +
s * 2 = ∞
10 s 3
s(0.1s + 1)(0.5s + 1)
当 r(t) = 1(t) + 4t + t 2 时, R(s) = 1 + 4 + 2
s s 2 s 3
3-14 解:
ess = 0 + 0.4 + ∞ = ∞
由于单位斜坡输入下系统稳态误差为常值=2,所以系统为 I 型系统
设开环传递函数 G(s) =
K
s(s2 + as + b)
⇒ K = 0.5 b
闭环传递函数
φ(s) = G(s) = K
1 + G(s) s3 + as2 + bs + K
Q s = −1 ± j 是系统闭环极点,因此
s3 + as2 + bs + K = (s + c)(s2 + 2s + 2) = s3 + (2 + c)s2 + (2c + 2)s + 2c
⎧K = 0.5b
⎪
⎪K = 2c
⎪
⎨b = 2c + 2 ⇒
⎪⎩a = 2 + c
⎧K = 2
⎪
⎪a = 3
⎪
⎨b = 4
⎪⎩c = 1
所以 G(s) =
2 。
s(s2 + 3s + 4)
4-1
jω [s]
jω [s]
k →∞
k = 0
×
k →∞
k = 0
0×
σ k = 0
×
k →∞
k →∞
k = 0 σ
0×
(a) (b)
jω [ s ]
jω [s]
σ
× × 0 ×
σ
× 0×
(c) (d)
4-2
j ω [ s ]
×
p 3 = − 1
0 ××
p 1 = 0 σ
p 2 = 0
p1 = 0,
p2 = 0,
p3 = −1
1. 实轴上的根轨迹 (−∞, −1) (0, 0)
1
2. n − m = 3
3 条根轨迹趋向无穷远处的渐近线相角为
=±
ϕ 180°(2q + 1) = ±60°,180°
a 3
(q = 0,1)
渐近线与实轴的交点为
n m
∑ pi − ∑ zi
i =1
j =1 0 − 0 −1 1
σ a =
3. 系统的特征方程为
n − m
= = −
3 3
1+G(s) = 1 +
K = 0
s2 (s +1)
即 K = − s2 (s +1) = −s3 − s2
dK = − 3s2 − 2s = 0
ds
s(3s + 2) = 0
根 s1 = 0
(舍去)
s2 = −0.667
4. 令 s = jω
代入特征方程
1+G(s) = 1 +
K = 0
s2 (s +1)
s2 (s +1) + K =0
( jω )2 ( jω +1) + K =0
−ω 2 ( jω +1) + K =0
K − ω 2 − jω =0
⎧K − ω 2 =0
⎨
⎩ω = 0
ω=0
(舍去)
与虚轴没有交点,即只有根轨迹上的起点,也即开环极点
p1,2 = 0
在虚轴上。
2
5-1
G(s) =
5
0.25s +1
G( jω ) =
5
0.25 jω +1
A(ω ) =
5 (0.25ω )2 +1
ϕ(ω) = − arctan(0.25ω)
输入 r(t) = 5 cos(4t − 30°) = 5 sin(4t + 60°)
ω=4
A(4) =
5
(0.25 * 4)2 +1
= 2.5 2
ϕ(4) = − arctan(0.25 * 4) = −45°
系统的稳态输出为
c(t ) = A(4) * 5 cos[4t − 30° + ϕ(4)]
= 2.5 2 * 5 cos(4t − 30° − 45°)
= 17.68 cos(4t − 75°) = 17.68 sin(4t +15°)
sin α = cos(90° −α ) = cos(α − 90°) = cos(α + 270°)
5-3
或者,
c(t ) = A(4) * 5 sin[4t + 60° + ϕ(4)]
= 2.5 2 * 5 sin(4t + 60° − 45°)
= 17.68 sin(4t +15°)
1 1
(2)
G(s) =
(1 + s)(1 + 2s)
G( jω ) =
(1 + jω )(1 + j 2ω )
A(ω ) =
1
(1 + ω 2 )(1 + 4ω 2 )
ϕ(ω) = − arctan ω − arctan 2ω
ϕ(ω) = − arctan ω − arctan 2ω = −90° arctan ω + arctan 2ω = 90°
ω = 1/(2ω)
ω 2 = 1/ 2
A(ω ) =
1 =
(1 +1 / 2)(1 + 4 *1/ 2)
2 = 0.47
3
与虚轴的交点为(0,-j0.47)
jY(ω)
0 ω =∞
-j0.47
ω = 0
1
X (ω)
ω
1
(3) G(s) =
1
s(1 + s)(1 + 2s)
G( jω ) =
1
jω (1 + jω )(1 + j2ω )
A(ω ) =
ω
1
(1 + ω 2 )(1 + 4ω 2 )
ϕ(ω) = −90° − arctan ω − arctan 2ω
ϕ(ω) = −90° − arctan ω − arctan 2ω = −180° arctan ω + arctan 2ω = 90°
ω = 1/(2ω)
ω 2 = 1/ 2
A(ω ) =
1
1/2 (1 +1/ 2)(1 + 4 *1/ 2)
= 2 = 0.67
3
与实轴的交点为(-0.67,-j0)
-0.67
0
ω = 0.707
ω
ω = 0
jY (ω)
ω =∞
X (ω)
(4) G(s) =
1
s2 (1 + s)(1 + 2s)
G( jω ) =
1
( jω )2 (1 + jω )(1 + j 2ω )
A(ω ) =
ω 2
1
(1 + ω 2 )(1 + 4ω 2 )
ϕ(ω ) = −180° − arctan ω − arctan 2ω
ϕ(ω) = −180° − arctan ω − arctan 2ω = −270° arctan ω + arctan 2ω = 90°
ω = 1/(2ω)
ω 2 = 1/ 2
A(ω ) =
1 = 2 (1/ 2) (1 +1/ 2)(1 + 4 *1/ 2) 3
2 = 0.94
与虚轴的交点为(0,j0.94)
ω = 0.707
ω = 0 ω
0.94
0
jY(ω)
ω = ∞
X (ω)
2
5-4
(2)ω1 = 0.5 ,ω2 = 1 , k = 1 ,υ = 0
L (ω ) ( d B )
0
0.01
-20dB
0.1
0.5
-20dB /dec
ω
1 10
-40dB /dec
-40dB
(3)ω1 = 0.5 ,ω2 = 1 , k = 1 ,υ = 1
L (ω ) ( d B )
-20dB /dec
20dB -40dB /dec
ω
0
0.01
0.1
0.5
1 10
-20dB
-40dB
-60dB /dec
(4)ω1 = 0.5 ,ω2 = 1 , k = 1 ,υ = 2
L (ω )(d B )
60dB
-40dB /dec
40dB
20dB -60dB /dec
ω
0
0.01
0.1
0.5
1 10
-20dB
-40dB
-80dB /dec
5-6
G(s) =
1
s −1
是一个非最小相位系统
3
G( jω ) = 1 =
1 (−1 − jω ) =
1 e j ( −180o +arctgω )
jω −1 1 + ω 2
1 + ω 2
G(s) =
1
s +1
是一个最小相位系统
G( jω ) = 1 =
1 (1 − jω ) =
1 e− jarctgω
jω +1 1 + ω 2
1 + ω 2
5-8(a)
ω = 0 −
ω = ∞
-1 0
X (ω )
ω = 0 +
系统开环传递函数有一极点在 s 平面的原点处,因此乃氏回线中半径为无穷小量ε 的半圆弧 对应的映射曲线是一个半径为无穷大的圆弧:
ω :0− → 0+ ;θ :-90°→ 0°→ +90°; ϕ(ω) :+90°→ 0°→ -90°
N=P-Z, Z=P-N=0-(-2)=2
闭环系统有 2 个极点在右半平面,所以闭环系统不稳定
(b)
jY (ω )
ω = 0−
ω = 0+
ω = ∞
-1 0
X (ω )
4
系统开环传递函数有 2 个极点在 s 平面的原点处,因此乃氏回线中半径为无穷小量ε 的半圆
弧对应的映射曲线是一个半径为无穷大的圆弧:
ω :0− → 0+ ;θ :-90°→ 0°→ +90°; ϕ(ω) :+180°→ 0°→ -180°
N=P-Z, Z=P-N=0-0=0
闭环系统有 0 个极点在右半平面,所以闭环系统稳定
5-10
K K 2.28K
(1)
G(s)H (s) = =
Ts +1
ϕ(ω)(°)
1
2.28
s +1
=
s + 2.28
ω1 = 2.28
0°
ω
−90°
ϕ (ω )
G s H s = K
1 = K
1 = 2.28K
(2)
( ) ( )
ϕ (ω )(°)
s Ts +1
s 1
2.28
s +1
s(s + 2.28)
−90°
ω1 = 2.28
ω
−180°
ϕ (ω )
K τ s +1
1
K 0.5
s +1
4K (s + 0.5)
(3)
G(s)H (s) = =
s Ts +1 s 1
=
s (s + 2)
2 2 2
s +1
2
L (ω )( d B )
-40dB /dec
-20dB /dec
a ω
b 0 0.5
1 2
-40dB /dec
5
20 lg 1
= a −20 lg K + 20 lg 1
= 40 lg 1
−20 lg K = 20 lg 1
0.5
20 lg(K )−1 = 20 lg 2
0.5 0.5
K = 1/ 2 = 0.5
0.5
G(s)H (s) = 4K (s + 0.5) = 2(s + 0.5)
s2 (s + 2)
s2 (s + 2)
−90°
ϕ(ω)(°)
ω1 = 0.5
ω2 = 2
ω
−180°
ϕ (ω )
5-11
ω = 0−
jY (ω)
ω = +∞
0 ω = −∞
(-1,j0)
X (ω)
ω
ω = 0+
G(s)H (s) =
K
s(s +1)(3s +1)
⇒ G( jω )H ( jω ) =
K
jω ( jω +1)(3 jω +1)
ϕ(ω ) = −90° − arctan ω − arctan 3ω = −180° arctan ω + arctan 3ω = 90°
ω = 1/(3ω)
ω 2 = 1/ 3
A(ω ) =
K
1 /3 (1 +1 / 3)(1 + 9 *1/ 3)
= 3 K = 1
4
Kc = 4/3 = 1.33
6
6-2 (1)
6 ω 2
G(s) = = n
n n
s(s2 + 4s + 6)
s(s2 + 2ξω s + ω 2 )
ω 2 = 6
ω = 6 =2.45, 2ξω =4 ξ =
4 = 2
= 0.816
n n n
2ωn 6
K = 1
所以,ωc = 1 20lgK = 0
⎛ 2ξω / ω
ϕ (ω ) = −90° − arctg c n
⎞ ⎛ 2 * 0.816 *1/ 2.45 ⎞
= −90° − arctg
c ⎜ 1 − ω 2 / ω 2 ⎟ ⎜
1 −1/ 2.452 ⎟
⎝ c n ⎠ ⎝ ⎠
= −90° − arctg ⎛ 2 * 0.816 *1 / 2.45 ⎞ = −90° − arctg ⎛ 0.666 ⎞ = −90° − arctg 0.7995
⎜ 1 −1 / 2.452
⎟ ⎜ 0.833 ⎟
⎝ ⎠ ⎝ ⎠
= −90° − 38.64° = −128.64°
γ = 180° + ϕ (ωc ) = 180° −128.64° = 51.36°
L(ω )(dB)
50
40
30
20
10
0
-10
-20
-30
-40
0.01
-20dB /dec
0.1
ωn
1 2.45
ω
10
-60dB /dec
(2)
ω1 = 1,
ω2 =1/0.2=5
⎛ 2ξω / ω
ϕ (ω ) = −90° − arctg c n
⎞ ⎛ ω ⎞ ⎛ ω ⎞
+ arctg c − arctg c
c ⎜ 1 − ω 2 / ω 2 ⎟ ⎜ ω
⎟ ⎜ ω ⎟
⎝ c n ⎠
⎝ 1 ⎠ ⎝ 2 ⎠
1 5
⎜ ⎟ ⎜ ⎟
= −128.64° + arctg ⎛ 1 ⎞ − arctg ⎛ 1 ⎞ = −128.64° + 45° −11.31° = −94.95°
⎝ ⎠ ⎝ ⎠
γ = 180° + ϕ (ωc ) = 180° − 94.95° = 85.05°
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课后答案网
L(ω) (dB )
50
40
30
20
10
0
-10
-20
0.01
-20dB /dec
0.1
ωn
1 2.45
20dB /dec
G c
ω
5 10
-30
-40
-40dB /dec -60dB /dec
-60dB /dec
6-5 (1)
G(s) =
10
s(0.5s +1)(0.1s +1)
ω = 1, 20 lg K =20lg10=20dB
ω1 = 1/ 0.5 = 2,
ω2 = 1 / 0.1 = 10
ω1 = 2
时, L(ω1 ) = 20 − 20(lg 2 − lg1) = 20lg10 − 20 lg 2 = 20lg5 = 14dB
ω2 = 10
时, L(ω2 ) = 14 − 40(lg10 − lg 2) = −13.96dB
所以,ω1 < ωc < ω2
L(ω1 ) = 40(lg ωc − lg 2) = 40(lg ωc / 2) = 14dB
ωc = 4.48
ϕ (ωc ) = −90° − arctg 0.5ωc − arctg 0.1ωc = −90° − arctg 2.24 − arctg 0.448
= −90°− 65.94°− 24.13° = −180.07°
γ = 180° + ϕ (ωc ) = 180° −180.07° = −0.07°
L (ω )(dB)
50
40
30
20
10
0
-10
-20
-30
-40
0.1
-20dB /dec
1 2
-40dB /dec
ω c 10
-60dB /dec
ω
100
2
(2)
G(s)Gc (s) =
10(0.33s +1)
s(0.5s +1)(0.1s +1)(0.033s +1)
ω = 1, 20 lg K =20lg10=20dB
ω1 = 1 / 0.5 = 2,
ω2 = 1/ 0.33 = 3,
ω3 = 1 / 0.1 = 10,
ω4 = 1/ 0.033 = 30
ω2 = 3
时, L(ω1 ) − L(ω2 ) = 40(lg ω2 − lg ω1 ) 14 − L(ω2 ) = 40(lg 4.35 − lg 2)
L(ω2 ) = 7dB
L(ω3 = 10) − L(ω2 = 3) = −20(lg ω3 − lg ω2 ) = −3.37dB
所以ω2 < ωc 2 < ω3
L(ω2 ) = 20(lg ωc 2 − lg ω2 ) = 20(lg ωc 2 / 3) = 7dB
ωc 2 = 6.72
ϕ (ωc ) = −90° − arctg 0.5ωc 2 − arctg 0.1ωc 2 + arctg 0.33ωc 2 − arctg 0.033ωc 2
= −90° − arctg 3.36 − arctg 0.672 + arctg 2.22 − arctg 0.222
= −90°− 73.43°− 33.90°+ 65.75°−12.52° = −144.1°
γ 2 = 180° + ϕ (ωc 2 ) = 180° −144.1° = 35.9°
L(ω )(dB)
50
40
30 -20dB /dec
20
10
0
-40dB /dec
ωc 2
20dB /dec
G c
10 ω
-10
-20
0.1
1 2 3
ωc1
30
G cG
100
-30
-40
-20dB /dec
-40dB /dec -60dB /dec
-60dB /dec
校正环节为相位超前校正,校正后系统的相角裕量增加,系统又不稳定变为稳定,且有一定
的稳定裕度,降低系统响应的超调量;剪切频率增加,系统快速性提高;但是高频段增益提 高,系统抑制噪声能力下降。
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