James Allison

Alexandru: Perhaps there is another function 'ss' on your path that is superseding the built-in ss function:

http://www.mathworks.com/help/control/ref/ss.html

You can use the 'which' command to find out if this is the issue.

Another possibility is the ss is part of the control system toolbox. If you don't have that toolbox, then ss will not work.

You can watch a video lecture that explains the basics of analytical target cascading by going to:

http://vimeo.com/21809054

Alexandru: Perhaps there is another function 'ss' on your path that is superseding the built-in ss function:

http://www.mathworks.com/help/control/ref/ss.html

You can use the 'which' command to find out if this is the issue.

Another possibility is the ss is part of the control system toolbox. If you don't have that toolbox, then ss will not work.

Very helpful model, I have two comments though:
1. I think umf should be set to 1 (or removed)
2. on line 62 the division by dt should be changed to a division by dt2

These two details made the script output inaccurate results; the script otherwise gives consistent results.