Need Help with Nonlinear System ID

Dear Control System Group List Subscribers:

    I have two things I need help with:

    (1) I need software for Mac or Power PC that does nonlinear system ID,

    (2) I have a control system I'd like some comments on. It's a high
order (4+) system with a dead zone in the feedback loop. I have a short
writeup on the system (that has a block diagram) in both RTF and Level 1
Postscript. These files are available via anonymous FTP from or in the directory
pub/balance. The file names are VMODEL.RTF (the RTF file) and VMODEL.PS
(the Postscript (Level 1) file).

Thank you very much