Place function

[Sorn Simatrang]

I used "place" function to compute the desired gain k for my closed loop system. Even though my system is controllable (full rank) , I still got an error as following

The "place" command could not place the poles at the specified locations. Probable
causes include:
* (A,B) is nearly uncontrollable
* The specified locations are too close to each other.

I guess that my system might be "nearly uncontrollable". So, I would like to ask you some advices how to deal with the system with "nearly uncontrollable" systems ? How to get a gain "k" to control the system in this case? (I have already calculated gain k manually but it didn't work and was very brute-force experience)

PS. For "nearly uncontrollable" definition, you can read it on the introduction part of this paper (URL : http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.55.8671)

Thank you so much in advance :)

[Jordan Kemguimatio]

Hello how did you finaly solved the probleme???
The "place" command could not place the poles at the specified locations. Probable causes include:
* (A,B) is nearly uncontrollable
* The specified locations are too close to each other.

Thanks
jordan