'Error in default port dimensions function of S-function', 'This function does not fully set the dimensions of output port 2'

Hi there, I have created a manoeuvring prediction code and am trying to just read an excel document within the matlab function. The errors 'Error in default port dimensions function of S-function', 'This function does not fully set the dimensions of output port 2' come up when I try to do this. It works perfectly fine when I just input the coefficients and parameters in manually, but I want the user to just be able to use an excel sheet to put in their variables for this code.

Does anyone know how I can get this to work?

Sorry for the lack of knowledge, I'm not exactly a Matlab wizard.

Thanks in advance.

[Walter Roberson]

Please show all of fcn

[Michael Dunn]

Here it is Walter,

Thanks.

[Walter Roberson]

It would be easier if you attached the .m instead of having to work with pictures of the code.

[Michael Dunn]

Here it is.

[Divya Gaddipati]

Hi,

Could you provide the excel file as well? The could be a mistake in the excel format.

[Michael Dunn]

Hi there Divya,

Thanks for your response, I will attach it with this message. I do not think it is an excel issue though, as I have written a seperate script which can receive the desired data from the excel file perfectly, just something wrong with the actual MATLAB function. However, I will still attach it for your reference.

Thanks,

[Divya Gaddipati]

Could you attach the script for reading the excel file as well?

[Michael Dunn]

I have attached it. Just to clarify, this script is not the issue at all. I can import any values from the excel sheet fine using this script, so there is not issue with that. I simply desire to import the excel values within the function as previously described.

Thanks.

Answer 1

[Divya Gaddipati]

In line 50 of your ManoeuvringCode.m, the variable X_u is defined as an expression which is present in your excel sheet in row 45 as well. When you are reading your excel file using xlsread, it is extracting that expression as NaN. Hence, your output port 2, which is v_dot is not defined properly as it depends on X_u, which could be NaN in some cases (u >= 0.1). Try defining X_u in the code itself and not from the excel.

[Michael Dunn]

Thanks for your response Divya,

However, I require to be able to define them in an excel document.

[Walter Roberson]

What output is required if the excel entry is read as nan?

[Michael Dunn]

I require to be able to read the coefficients from an excel document so that the code will not ever have to be touched. So that the user will only need to modify the excel document for the code to run.

[Walter Roberson]

X_u is defined by a formula in row 45,not by a numeric constant. When you read the spreadsheet then the reader automatically replaces formula with nan. You need to change how you read X_u so that you can get out a formula that you can apply.

[Walter Roberson]

It looks like you are not reading as far as row 45, so that would not appear to be the problem.

I was concerned that the GOTO for several variables might not have been initialized, but I see that you are using memory blocks set to 0 to define initial conditions to the integrators whose output is GOTO over to the inputs, so that should be okay.

[Michael Dunn]

Yeah, I am unsure what is wrong with it.

[Walter Roberson]

It just might help to use block parameters or an initial conditions block to initialize all the values that you GOTO into the function.

[Michael Dunn]

I apologise for my lack of knowledge, but I am unsure how I would do this. Would I complete this in the Simulink model or within the MATLAB function?

Answer 2

[Michael Dunn]

I think I have not communicated something correctly. In the excel sheet I have provided, the coefficients 'Y_dr', K_dr', N_dr', etc. are shown. The user is required to provide the coefficients only, not as a formula. The MATLAB code will use this numeric constants to define the formula by multiplying them by their respective velocities. I have attached an updated script that shows what I mean with this. This script works perfectly by itself, but I cannot put it into the 'AUV_mathemanical_model_ver7.slx', it simply does not work within this and runs the error as shown previously.