Simulink Control Design: Linear Analysis

I'm using Simulink Control Design: Linear Analysis to get better result of my simulation (more stable output). But, When I tried to compute the operating point to the model, it gives me this kind of error (see attachment).

I was just wondering someone can help me this time. Maybe, some suggestion would be helpful.

Answer 1

[Muhd Firdause]

http://files.engineering.com/getfile.aspx?folder=25059154-1a2d-48a0-bc91-38035bb3ecba&file=untitled.JPG

[Muhd Firdause]

this is the error

[Walter Roberson]

'could not find a solution that satisfied all constraints.'

[Muhd Firdause]

do you have any suggestion?

Answer 2

[Guy Rouleau]

It looks like the constraint you specified on your operating point cannot be satisfied.

Did you consider getting an operating point from a Snapshot?

[Muhd Firdause]

I'll try that. I'll come back later

[Muhd Firdause]

I'm not sure how this 'Simulink Control Design' works. But, I have set the operating point at 6 sec (snapshot). Then, I get another form of error dialog:

http://www.facebook.com/photo.php?fbid=1860835757364&set=a.1708364025666.234724.1135021559&theater

[Guy Rouleau]

The error says that your model goes to ininity at time ~.9.

Very likely this is because your controler is unstable... this make sense since you want to use SCD to tune it ;-)

I don't know what is the system you simulate, but would it possible to start the simulation in the configuration where you want to control your system? that way you could take a snapshot at t=0;

[Muhd Firdause]

well..thx for the answer..now I'm doing my master in engineering, and taking control system subject...only then i understand that the system is unstable..after 3 years i accidentally found this question again..hahah..thx again for help.