I understand that you are encountering an error with the MD assignment in your code above and would like to know the reason behind it.
The error you're encountering when assigning U(4) and U(5) to the measured disturbances (MD) is likely due to a mismatch in the structure types between the manipulated variables (MV) and the measured disturbances (MD). In MATLAB, when you assign different types or structures to elements of the same array, it results in a "Subscripted assignment between dissimilar structures" error.
- Initial Assignment:
- When you assign nlobj.MV(1) to U(1), MATLAB initializes U as a structure array based on the structure of nlobj.MV(1). This works without issue because U is being defined for the first time.
2. Subsequent Assignments:
- Assignments like U(2) = nlobj.MV(2); continue to work as long as the structures are the same.
3. Error with Different Structures:
- The error occurs at U(4) = nlobj.MD(1); because nlobj.MD(1) might have a different structure than nlobj.MV(1). MATLAB requires all elements of a standard array to have the same structure.
To handle this, you should ensure that all elements in U are compatible. If nlobj.MV and nlobj.MD are fundamentally different structures, consider using a cell array instead. Cell arrays can hold different types of data:
% Use a cell array to store different structures
U = cell(1, 5);
U{1} = nlobj.MV(1); % Pbat
U{2} = nlobj.MV(2); % Psm
U{3} = nlobj.MV(3); % Pload
U{4} = nlobj.MD(1); % Ppv
U{5} = nlobj.MD(2); % Pwt
- By using a cell array (U = cell(1, 5);), you can mix different structures without encountering errors.
- Use curly braces (U{}) to assign and access elements in a cell array, allowing for flexible data storage.
Refer to the following documentation link to learn more about cell arrays:
This approach will enable you to assign both manipulated variables and measured disturbances without encountering structure-related errors.
I hope this helps.
