[转载]导纳圆法模态参数识别

%导纳圆法模态参数识别 .FK'TG  
clear /:dVW"A|  
clc nut;ohIh  
close all hidden X?$Eb  
format long GV)#>PL  
global mn bTC2Ya  
%fni=input('导纳圆法模态参数识别－输入数据文件名','s'); 2a*1q#MpAt  
%fid=fopen(fni,'r') IBl}.o&]B#  
%mn=fscanf(fid,'%f',1);     %模态阶数 ia|^>V>-  
%df=fscanf(fid,'%d',1);     %频率间隔 >j?5MIm03  
%f0=fscanf(fid,'%d',[1 mn]);     %模态频率初值数组 FVLXq0<Cj  
%fno=fscanf(fid,'%d',1);    %读入输出数据文件名 1DcYc-k#  
%H0=fscanf(fid,'%f',[2 inf]); %实测频响函数实部虚部数据 l ,)l"6OV  
%status=fclose(fid); yAEOn/.
~  
mn=3;df=0.02;f0=[5 10 20];fno='out8_1.mat'; sw*k(i  
%tt=0:0.01:20; xMg&>}5  
%y=(1-0.2*tt).*sin(2*pi*5*tt); mm%w0dOb"  
%yy=fft(y);y=yy(1:1000); P,AS`=z  
%H0=[real(y);imag(y)]; >rlQY>5pH  
load y OB3AZH$  
H0=[y(1:1000);y(1001:2000)]; _J&u{  
f=0:df:(length(H0(1,:))-1)*df; XboOvdt^|  
w=2*pi*f; aq"E@fb  
fds=zeros(1,3*mn); xt +fuL  
for n=1:4 )<
4o"R:*  
    for j=1:mn Tp~yn  
        l=3*(j-1); Cq1t[a  
        fds(l+1:l+3)=zeros(1,3); )Y~q6D K  
        H1=fun81(fds,w); Fy-nV%P  
        H=H0-H1; Rz`<E97-  
        k=round(f0(j)/df)+1; sAk~`(:4!  
        [m,kc]=max(abs(H(2,k-4:k+4))); #l
~d  
        kc=kc+k-5; /6F 1=O(c>  
        v=0.15*abs(H(2,kc)); [$3Zid  
        for k=1:30 ;3\Fb3d  
            l=kc-k; ,)V*xpp  
            if abs(H(2,l))>v&abs(H(2,l))<=abs(H(2,l+1)) g2C-)*'{yh  
                k1=l; 7=om /  
            else 5WP[-J)  
                break; R#tz"T@  
            end +YT/od1t7  
        end 6 6x} |7  
        for k=1:30 x=1G|<z%  
            l=kc+k; `]]gD EPG{  
            if abs(H(2,l))>v&abs(H(2,l))<=abs(H(2,l-1)) F~a5yW:R=)  
                k2=l; a[s%2>e  
            else k}>l+_*+7  
                break; wd*T"
V3  
            end ?>q=Nf^Q.  
        end .5L/<  
        x=H(1,k1:k2); &0f7>.y  
        y=H(2,k1:k2); z1!ya#,$  
        A=[sum(x.^2),sum(x.*y),sum(x);sum(x.*y),sum(y.^2),sum(y);sum(x),sum(y),length(x)]; [gzU/:  
        B=[-sum(x.^2+x.*y.^2);-sum(x.^2.*y+y.^3);-sum(x.^2+y.^2)]; mUr@w*kq|p  
        c=inv(A)*B; R2Tvo?xI7  
        x0=-c(1)/2; %H<w.]>  
        y0=-c(1)/2; KGi@H
%NN  
        r=sqrt(x0^2+y0^2-c(3)); ^'QcP5Fv  
        x1=f(kc-1); 9YHSL[  
        x2=f(kc); <Q\`2{  
        x3=f(kc+1); $';'MoS  
        y1=H(2,kc-1); S,AZrgh,"X  
        y2=H(2,kc); F)e*w:D  
        y3=H(2,kc+1); 2)RW*Qu;+  
        fc=((y2-y1)*(x3^2-x2^2)-(y3-y2)*(x2^2-x1^2))/(2*(2*y2-y1-y3)*(x2-x1)); avO+1<`4B  
        yc=(y1*(x2-fc)^2-y2*(x1-fc)^2)/((x2-fc)^2-(x1-fc)^2); toTAWT
D  
        if abs(y1)>abs(y3) )2YU|  
            xc=H(1,kc-1)+(H(1,kc)-H(1,kc-1))*(fc-x1)/(x2-x1); F&lc8  
        else oBqP^uT>a|  
            xc=H(1,kc)+(H(1,kc+1)-H(1,kc))*(fc-x2)/(x3-x2); qa^x4xZM  
        end !nV
X .m9  
        F(j)=fc; .j88=t0  
        [m,k]=max(abs(y)); d;lp^K M  
        a=(xc-x(k-1))^2+(yc-y(k-1))^2; /7S]%UY  
        b=(x0-xc)^2+(y0-yc)^2; o~P8=1t  
        c=(x0-x(k-1))^2+(y0-y(k-1))^2; |BH, H  
        a1=acos((b+c-a)/(2*sqrt(b)*sqrt(c)))/2; uNXh"?  
        a=(x(k+1)-xc)^2+(y(k+1)-yc)^2; 1I3u~J3]/  
        b=(x0-x(k+1))^2+(y0-y(k+1))^2; AG}' W  
        c=(x0-xc)^2+(y0-yc)^2; i04Sf^  
        a2=acos((b+c-a)/(2*sqrt(b)*sqrt(c)))/2; Z+t?ah00  
        D(j)=(f(l+1)-f(l-1))/(F(j)*(tan(a1)+tan(a2))); 1b3Lan_2  
        S(j)=yc*2*D(j); N_pJE?  
        l=3*(j-1); 8SAz,m!W)  
        fds(l+1:l+3)=[2*pi*F(j) D(j) S(j)]; n4."}DO  
    end 58e{WC  
end Cy6[p  
H1=fun81(fds,w); &[*<>  
figure(1) ::H jpM  
subplot(2,1,1); w#PaN83+  
plot(f,H0(1,:),':',f,H1(1,:)); .e.vh:Sz  
xlabel('频率(Hz)'); n^&QOII@>  
ylabel('实部'); jn}6yXB  
legend('实测','拟合'); cIM5;"gLP  
grid on; " "a+Nc  
subplot(2,1,2); qwFn(pK[  
plot(f,H0(2,:),' .. NBMY1Xgj  
=Bo0Oei  

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