error while using iddata

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arash rad
arash rad 2021-1-8
评论： arash rad 2021-1-10
Hi i wrote the code below but when i run it i face two errors that i dont get it can anyone help me
Error using iddata/numArgumentsFromSubscript (line 8) The syntax "Data{...}" is not supported. Use the "getexp" command to extract individual experiments from an IDDATA object.
Error in arma (line 29)
plot(t,yhat1{1}.y,'--',t,y);
I have this two erros please help me
Thanks
%% Generate the data
N = 250;
Ts = 1;
u_var = 1;
noise_var = 1;
a = [1 -1.5 0.7];
b = [0 1 .5]; c = [1 -1 0.2];
u = sign(randn(2*N,1))*sqrt(u_var);
v = randn(2*N,1);
M = idpoly(a,b,c,1,1,noise_var,Ts);
y = sim(M,[u v]);
uv = u(N+1:end);
vv = v(N+1:end);
yv = y(N+1:end);
u = u(1:N);
v = v(1:N);
y = y(1:N);
DATe = iddata(y,u,Ts); DATv = iddata(yv,uv,Ts);
DATe1 = get(DATe); DATv1= get(DATv)
%% Identification
na = 2; nb = 2; nc = 2;
theta_pem = armax(DATe,[na nb nc 1]); % ARMAX using PEM
%% Compare the measured output and the model output
[yhat1,fit1] = compare(DATe,theta_pem);
[yhat2,fit2] = compare(DATv,theta_pem);
t = 1:N;
figure;
subplot(2,1,1);
plot(t,yhat1{1}.y,'--',t,y);
legend('model','measured');
title('Comparison on estimation data set','FontSize',16);
ylabel('y');xlabel('t');
subplot(2,1,2);
plot(t,yhat2{1}.y,'--',t,yv);
legend('y2','y');
legend('model','measured');
title('Comparison on validation data set','FontSize',16);
ylabel('y');xlabel('t');

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采纳的回答

Walter Roberson
Walter Roberson 2021-1-8
Is there a reason you are not using
plot(yhat1)
??
But if you insist...
plot(t, getexp(yhat1,1).y, '--', t, y);
  3 个评论
显示 1更早的评论
Walter Roberson
Walter Roberson 2021-1-9
Ran in:
Please try this code and see what you get.
%% Generate the data
N = 250;
Ts = 1;
u_var = 1;
noise_var = 1;
a = [1 -1.5 0.7];
b = [0 1 .5]; c = [1 -1 0.2];
u = sign(randn(2*N,1))*sqrt(u_var);
v = randn(2*N,1);
M = idpoly(a,b,c,1,1,noise_var,Ts);
y = sim(M,[u v]);
uv = u(N+1:end);
vv = v(N+1:end);
yv = y(N+1:end);
u = u(1:N);
v = v(1:N);
y = y(1:N);
DATe = iddata(y,u,Ts); DATv = iddata(yv,uv,Ts);
DATe1 = get(DATe); DATv1= get(DATv)
DATv1 = struct with fields:
Domain: 'Time' Name: '' OutputData: {[250×1 double]} OutputName: {'y1'} OutputUnit: {''} InputData: {[250×1 double]} InputName: {'u1'} InputUnit: {''} Period: {[Inf]} InterSample: {'zoh'} Ts: {[1]} Tstart: {[]} SamplingInstants: {[250×0 double]} TimeUnit: 'seconds' ExperimentName: {'Exp1'} Notes: {} UserData: []
%% Identification
na = 2; nb = 2; nc = 2;
theta_pem = armax(DATe,[na nb nc 1]); % ARMAX using PEM
%% Compare the measured output and the model output
[yhat1,fit1] = compare(DATe,theta_pem);
[yhat2,fit2] = compare(DATv,theta_pem);
t = 1:N;
figure;
subplot(2,1,1);
plot(t, getexp(yhat1,1).y, '--', t, y);
legend('model','measured');
title('Comparison on estimation data set','FontSize',16);
ylabel('y');xlabel('t');
subplot(2,1,2);
plot(t, getexp(yhat2,1).y, '--', t, yv);
legend('y2','y');
legend('model','measured');
title('Comparison on validation data set','FontSize',16);
ylabel('y');xlabel('t');
arash rad
arash rad 2021-1-10
thank you very much

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