clear all
m=1365;
m1=46.8;
m2=46.8;
m3=41.4;
m4=41.4;
jx=498;
jy=1831;
k1=22428;
k2=k1;
k3=27022;
k4=k3;
kt1=232342;
kt2=kt1;
kt3=292982;
kt4=kt3;
c1=20.26e2;
c2=c1;
c3=1916;
c4=c1;
l1=0.7165;l2=0.7165;
l3=1.1135;l4=1.5415;
M=[m 0 0 0 0 0 0;
0 jy 0 0 0 0 0;
0 0 jx 0 0 0 0;
0 0 0 m1 0 0 0;
0 0 0 0 m2 0 0;
0 0 0 0 0 m3 0;
0 0 0 0 0 0 m4];
c=[c1+c2+c3+c4,-c1*l1+l2*c2-l1*c3+l2*c4,-l3*c1-l3*c2+l4*c3+l4*c4,-c1 -c2 -c3 -c4;
-c1*l1+l2*c2-l1*c3+l2*c4,l1^2*c1+l2^2*c2+l1^2*c3+l2^2*c4,
l1*l3*c1-l2*l3*c2-l1*l4*c3+l2*l4*c4,
l1*c1 -l2*c2 l1*c3 -l2*c4;
-l3*c1-l3*c2+l4*c3+l4*c4,
l1*l3*c1-l2*l3*c2-l1*l4*c3+l2*l4*c4,
l3*c2 l3*c2 -l4*c3 -l4*c4;
-c1 l1*c1 l3*c1 c1 0 0 0;
-c2 -l2*c2 l3*c2 0 c2 0 0;
-c3 l1*c3 -l4*c3 0 0 c3 0;
-c4 -l2*c4 -l4*c4 0 0 0 c4];
k=[k1+k2+k3+k4,-k1*l1+l2*k2-l1*k3+l2*k4-l3*k1, -l3*k2+l4*k3+
l4*k4,-k1 -k2 -k3 -k4;
-k1*k1+l2*k2-l1*k3+l2*k4,l1^2*k1+l2^2*k2+l1^2*k3+l2^2*k4,
l1*l3*k1-l2*l3*k2,
-l1*l4*k3+l2*l4*k4,
l1*k1-l2*k2 l1*k3 -l2*k4;
-l3*k1-l3*k2+l4*k3+l4*k4,
l1*l3*k1-l2*l3*k2-l1-l4*k3+l2*l4*k4,
l3^2*k1+l3^2*k2+l4^2*k3+l4^2*k4,
l3*k2 l3*k2 -l4*k3 l4*k4
-k1 l1*k1 l3*k1 k1+kt1 0 0 0
-k2 -l2*k2 l3*k2 0 k2+kt2 0 0;
-k3 l1*k3 -l4*k3 0 0 k3+kt3 0;
-k4 -l2*k4 -l4*k4 0 0 0 k4+kt4];
Q=[0 0 0 0;
0 0 0 0;
kt1 0 0 0;
0 kt2 0 0;
0 0 kt3 0;
0 0 0 kt4];
l7=zeros(7,7);
a=[C M;M l7];
b=[K l7;l7 -M];
A=-inv(a)*b
134=zeros(3,4)
174=zeros(7,4)
KT=[134;kt1 0 0 0;
0 kt2 0 0;
0 0 0 kt4;
174];
B=inv(a)*KT
C=[0 0 0 1 1 1 1,0 0 0 0 0 0 0]
D=[0];
sy=ss(A,B,C,D)
sys=tf(sy)
figure(1)
bode(sys(1))
hold on
w=0.1:0.1:100;
[mag,phase]=bode(sys(4),w);
j=0;
for i=1;length(w) -1;
if(mag(i+1)-mag(i))<0&(mag(i)-mag(i-1))>0;
j=j+1;
magmax(j)=mag(i);
wm(j)=w(i);
end
end
wm1=wm(1)/2/pi;
wm2=wm(2)/2/pi;
[w,A]=eigfre(M,K);
w=sqrt(w)/2/pi;
disp'计算结果'
disp'一阶车身跳动'
fprintf('一阶固有频率f1=%3.4Hz\n',w(1))
disp'二阶车身俯仰'
fprintf('二阶固有频率f1=%3.4Hz\n',w(2))
disp'三阶车身侧倾'
fprintf('三阶固有频率f1=%3.4Hz\n',w(3))
disp'四阶右前轮跳动'
fprintf('四阶固有频率f1=%3.4Hz\n',w(4))
disp'五阶左后轮跳动'
fprintf('五阶固有频率f1=%3.4Hz\n',w(5))
disp'六阶右后轮跳动'
fprintf('六阶固有频率f1=%3.4Hz\n',w(6))
disp'七阶左前轮跳动'
fprintf('七阶固有频率f1=%3.4Hz\n',w(7))
disp'系统幅频特性分析结果'
fprintf('由系统得到的共振低频fm1=%3.4f Hz\n',wm1)
fprintf('由系统得到的共振低频fm2=%3.4f Hz\n',wm2)
figure(2)
impulse(sys(1))
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