1、磁盤驅(qū)動(dòng)讀取系統(tǒng)的分析設(shè)計(jì)一、閉環(huán)系統(tǒng)的性能分析（1）確定使閉環(huán)系統(tǒng)穩(wěn)定的Ka的取值范圍 G1=tf(5000,1,1000); G2=tf(1,conv(1,0,1,20); G=series(G1,G2) Transfer function: 5000-s3 + 1020 s2 + 20000 sg3= 一一開環(huán)傳函G3= 一一閉環(huán)傳函 syms K den den=1 1020 20000 5000*K; K=den(2)*den(3)/den(1)/5000 K = 4080有勞斯判據(jù)可得k的范圍是0 K g=100*Gg1=feedback(g,1)C=dcgain(g1) Tran

2、sfer function: 500000-s3 + 1020 s2 + 20000 s Transfer function: 500000-s3 + 1020 s2 + 20000 s + 500000 C = 1c,t=step(g1); y,k=max(c); percentovershoot=100*(y-C)/Cpercentovershoot = 21.6918調(diào)節(jié)時(shí)間函數(shù)t=setllingtime(g1)t = 0.3697K=1000時(shí) g=1000*GTransfer function: 5e006-s3 + 1020 s2 + 20000 s g2=feedback(g,

3、1)Transfer function: 5e006-s3 + 1020 s2 + 20000 s + 5e006 c,t=step(g2); C=dcgain(g2)C = 1 y,k=max(c)y = 1.7109k = 11 percentovershoot=100*(y-C)/Cpercentovershoot = 71.0891t=setllingtime(g2)t = 0.4989超調(diào)量 調(diào)節(jié)時(shí)間0.3697(s)K=1000時(shí)超調(diào)量 調(diào)節(jié)時(shí)間0.4989 (s)（3）考察擾動(dòng)信號(hào)為單位階躍時(shí)，上述兩個(gè)Ka取值情況下，系統(tǒng)的抗干擾能力，并進(jìn)行分析 g2=tf(1,conv(1 0

4、,1 20) Transfer function: 1-s2 + 20 s g1=tf(5000,1 1000) Transfer function: 5000-s + 1000 syms k g3=feedback(g2,g1,1) Transfer function: s + 1000-s3 + 1020 s2 + 20000 s - 5000 g3=feedback(g2,-g1,1) Transfer function: s + 1000-s3 + 1020 s2 + 20000 s + 5000 g4=-g3 Transfer function: -s - 1000-s3 + 102

5、0 s2 + 20000 s + 5000 -擾動(dòng)輸入的傳遞函數(shù)當(dāng)K=100時(shí) g=tf(-1 -1000,1 1020 20000 500000)Transfer function: -s - 1000-s3 + 1020 s2 + 20000 s + 500000 c,t=step(g); y,k=min(c)y = -0.0024k = 15c（t）= 2.4*10-3（s）當(dāng)K=1000時(shí) g=tf(-1 -1000,1 1020 20000 5000000) Transfer function: -s - 1000-s3 + 1020 s2 + 20000 s + 5e006 c,t

6、=step(g); y,k=min(c)y = -3.4308e-004k = 11c（t）= 0.34*10-3（s）(4)針對(duì)如下的性能指標(biāo)要求，折中選取一個(gè)合適的Ka值取Ka=100二、速度反饋系統(tǒng)的性能分析（1）運(yùn)用第3章中所學(xué)的勞斯判據(jù)，確定要使閉環(huán)系統(tǒng)穩(wěn)定，Ka和K1應(yīng)如何選取？Ka=100，K1=0.03（2）針對(duì)你選取的Ka和K1，仿真閉環(huán)系統(tǒng)的階躍響應(yīng)，并計(jì)算超調(diào)量、調(diào)節(jié)時(shí)間和對(duì)單位階躍擾動(dòng)的最大響應(yīng)值。 g1=tf(5000,1 1000) Transfer function: 5000-s + 1000 g2=tf(1,1 20) Transfer function: 1

7、-s + 20 g3=tf(1,1 20) Transfer function: 1-s + 20 g0=feedback(g3*feedback(100*g1*g2,0.03,-1),1) Transfer function: 500000-s3 + 1020 s2 + 35000 s + 500000 t=setllingtime(g0)t = 0.2300 c,t=step(g0); C=dcgain(g0)C = 1 y,k=max(c)y = 1.0206k = 38 percentovershoot=100*(y-C)/Cpercentovershoot = 2.0650超調(diào)量 調(diào)

8、節(jié)時(shí)間0.2300 (s) g10=-feedback(g2*g3,-g1*100*(0.03*1/g3+1),1)Transfer function: -s - 1000- -擾動(dòng)輸入傳遞函數(shù)s3 + 1020 s2 + 35000 s + 500000 step(g10) c,t=step(g10); y,k=max(c)y = 0k = 1 y,k=min(c)y = -0.0020k =38對(duì)單位階躍擾動(dòng)的最大響應(yīng)值：c（t）= 2.0*10-3（s）。三、PD控制器的性能分析根軌跡法利用根軌跡圖，分析K3的變化對(duì)系統(tǒng)性能指標(biāo)的影響，選取能夠滿足下列指標(biāo)要求的K3值 G3=series(G,tf(1 1,1) Transfer