INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Jobs

How to make fmincon search through the all domain of definition?

How to make fmincon search through the all domain of definition?

(OP)
Hello to everyone,
i am implementing a driver model with look-ahead function. Herefore, i have to use an optimization algorithm, which look in a finite future horizont, to define Np optimal control signals, so that a specific Cost function J(trade off between deviation to reference trajectory and Consumption), can be minimized. That means if for example i am only minimizing J over the acceleration pedal Ua, then i call fmincon from a level 2 s-function within the main Car-model like this for example:
Uopt = fmincon(@(u)fun(u),U0,[],[],[],[],-100,100,@nonlcon,options).
whereby U0 is a vector of size = [Npx1]. Within teh function fun a simplified vehicle model, is then called with u as input and the velocities over the Np time steps as output!
My questions are then:
1) since i set DiffMinChange=0.1 and DiffMaxChange = 100, why does fmincon only try pulses of u=0.1 at different time steps, and doesn't try bigger values within the range [0.1 ,100]??? Fmincon then stops since(i think) with a single input of 0.1 as pedal position the cost function doesn't vary very much. It would be something else if it would ahve tried u = [100 50 80 10 9] in case Np = 5 for example.

2) the all process of calling the simulink model is really, really slow. Is there a more convenient way to implement predictive control, when i don't have the predictive control toolbox???
I am new to the site and i hope we will have some great discussions.
Thanks for your time and help.
Armand

RE: How to make fmincon search through the all domain of definition?

(OP)
well the prediction will actually also controls the shifting-strategy for the manual gearbox(that was just a small part of the problems) and since i'am simulating an hybid driveline, i tought it was the right forum.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close