问题 I am trying to to a non linear grey box model identification and I am using the following code. I have my measurements for the input in input vector, output vector and time stamps in time. input = output_data(2:3,:)'; output = output_data(4:5,:)'; time = output_data(1,:)'; data = iddata(output, input, [], 'SamplingInstants', time); data.TimeUnit = 's'; %create model Order = [2 2 4]; % Model orders [ny nu nx].cha Parameters = [1; 1; 1; 1; 1; 0.1]; % Initial parameter vector. InitialStates = [0