[转载]导纳圆法模态参数识别

%导纳圆法模态参数识别 % yw?s0  
clear K57&y
VX  
clc \ZkA>oO".  
close all hidden b}"N`,0dO  
format long (=om,g}  
global mn yPal
<c  
%fni=input('导纳圆法模态参数识别－输入数据文件名','s'); }R{
ts  
%fid=fopen(fni,'r') ,LnII  
%mn=fscanf(fid,'%f',1);     %模态阶数 ZusEfh?  
%df=fscanf(fid,'%d',1);     %频率间隔 <_-hRbS  
%f0=fscanf(fid,'%d',[1 mn]);     %模态频率初值数组 sr{a(4*\  
%fno=fscanf(fid,'%d',1);    %读入输出数据文件名 S Em Q@1  
%H0=fscanf(fid,'%f',[2 inf]); %实测频响函数实部虚部数据 h-[VH%  
%status=fclose(fid);
xsD(
$_  
mn=3;df=0.02;f0=[5 10 20];fno='out8_1.mat'; rogT~G}q  
%tt=0:0.01:20; ax<?GjpM  
%y=(1-0.2*tt).*sin(2*pi*5*tt); y]f"@9G#  
%yy=fft(y);y=yy(1:1000); +8R
gF   
%H0=[real(y);imag(y)];  B\o Mn  
load y ):[7E(F=  
H0=[y(1:1000);y(1001:2000)]; :s7m4!E
F  
f=0:df:(length(H0(1,:))-1)*df; B&n<M]7  
w=2*pi*f; V)[@98T_4?  
fds=zeros(1,3*mn);  A|<jX}  
for n=1:4 IhVO@KJI  
    for j=1:mn 0"pAN[=K@  
        l=3*(j-1); sG92XJ  
        fds(l+1:l+3)=zeros(1,3); NeE
t  
        H1=fun81(fds,w); %yv<y+yP~  
        H=H0-H1; *=V~YF:Qb  
        k=round(f0(j)/df)+1; Tu).K.p:  
        [m,kc]=max(abs(H(2,k-4:k+4))); ;5659!;  
        kc=kc+k-5; =ACVE;L?  
        v=0.15*abs(H(2,kc)); T9Nb`sbV]  
        for k=1:30 f}9zgWU  
            l=kc-k; G?Q3/y(  
            if abs(H(2,l))>v&abs(H(2,l))<=abs(H(2,l+1)) ']2E {V  
                k1=l; u=`L
)  
            else e?8HgiP-  
                break; (pv+c,  
            end t%E!o0+8Z  
        end $\X[@E S0  
        for k=1:30 `)T13Xv  
            l=kc+k; xHD=\,{ig  
            if abs(H(2,l))>v&abs(H(2,l))<=abs(H(2,l-1)) xLK<W"%
0  
                k2=l; hpO`]  
            else ^c9t'V`IWQ  
                break; d?A 0MKnl  
            end uM_wjP  
        end 5\]Sv]s)R  
        x=H(1,k1:k2); AP'*Nh@Ik(  
        y=H(2,k1:k2); K<>oa[B9  
        A=[sum(x.^2),sum(x.*y),sum(x);sum(x.*y),sum(y.^2),sum(y);sum(x),sum(y),length(x)]; w5Y04J  
        B=[-sum(x.^2+x.*y.^2);-sum(x.^2.*y+y.^3);-sum(x.^2+y.^2)]; 6\g cFfo  
        c=inv(A)*B; cj$[E]B3V*  
        x0=-c(1)/2; iOW#>66d  
        y0=-c(1)/2; v>Q#B  
        r=sqrt(x0^2+y0^2-c(3)); &m-PC(W+  
        x1=f(kc-1); v|dBSX9k0  
        x2=f(kc); xc=b |:A  
        x3=f(kc+1); e4?>-  
        y1=H(2,kc-1); &L'Dqew,*  
        y2=H(2,kc); < t,zaIi  
        y3=H(2,kc+1); Y^$X*U/q%U  
        fc=((y2-y1)*(x3^2-x2^2)-(y3-y2)*(x2^2-x1^2))/(2*(2*y2-y1-y3)*(x2-x1)); Vex{.Vh,"  
        yc=(y1*(x2-fc)^2-y2*(x1-fc)^2)/((x2-fc)^2-(x1-fc)^2); t/VD31  
        if abs(y1)>abs(y3) W3MJr&p  
            xc=H(1,kc-1)+(H(1,kc)-H(1,kc-1))*(fc-x1)/(x2-x1); J  IUx  
        else g/CSGII
T  
            xc=H(1,kc)+(H(1,kc+1)-H(1,kc))*(fc-x2)/(x3-x2); Vl&?U  
        end 0jy2H2  
        F(j)=fc; n\*!CXc  
        [m,k]=max(abs(y)); 8%A#`)fb  
        a=(xc-x(k-1))^2+(yc-y(k-1))^2; _`&m\Qe>  
        b=(x0-xc)^2+(y0-yc)^2; u{['<r;I  
        c=(x0-x(k-1))^2+(y0-y(k-1))^2; -zOdU}91Ao  
        a1=acos((b+c-a)/(2*sqrt(b)*sqrt(c)))/2; A%KDiIA  
        a=(x(k+1)-xc)^2+(y(k+1)-yc)^2; nn@-W]  
        b=(x0-x(k+1))^2+(y0-y(k+1))^2; tX_R_]v3  
        c=(x0-xc)^2+(y0-yc)^2; f4 P8Oz  
        a2=acos((b+c-a)/(2*sqrt(b)*sqrt(c)))/2; Lr$go6s  
        D(j)=(f(l+1)-f(l-1))/(F(j)*(tan(a1)+tan(a2))); TO]@ Zu1  
        S(j)=yc*2*D(j); PQ5QA61  
        l=3*(j-1); \Q0[?k  
        fds(l+1:l+3)=[2*pi*F(j) D(j) S(j)]; C~2F9Pg  
    end |$8~?7Jv  
end QdF5Cwf4  
H1=fun81(fds,w); %4et&zRC  
figure(1) M2OIBH4!  
subplot(2,1,1); }$SavB#SBP  
plot(f,H0(1,:),':',f,H1(1,:)); TaKLzd2  
xlabel('频率(Hz)'); cW@Zd5&0S  
ylabel('实部'); 49GkPy#]L=  
legend('实测','拟合'); ON=@O  
grid on; J8uLJ  
subplot(2,1,2); %5M/s'O?i  
plot(f,H0(2,:),' .. 9K{%vK  
;z}i-cNae  

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