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

Input multiplied by one of the states-State Space Representation

Input multiplied by one of the states-State Space Representation

(OP)
Hello. I want to represent a mechanical system in state space form. It is a see-saw like device with a motor and propeller attached to the longer end, and a counterweight attached to the shorter end. When the motor spins the propeller the longer end rises. I have to control the position (height). When writing the equations I end up with:

theta=angular position

(angular momentum)=Sin(theta)(-90.8621+1.4797 u -fg+fc)/(moment of inertia)

(angular velocity)=d(angular position)/dt

My states are angular position and angular velocity.
My problem is my input is multiplied by one of my states(angular position) and when writing it in matrix form I don't know how to separate u and the state theta(angular position). What is the best solution to solve this problem?


RE: Input multiplied by one of the states-State Space Representation

Your equations do not look right to me. Angular momentum is angular velocity x inertia. You are dividing by inertia. Perhaps you mean angular acceleration. In this case the numerator should be torque. This way your states are angle and angular velocity and you are computing the derivative angular velocity and angular acceleration.

BTW, the sin() function is non-linear. You really should use differential equations and integrate them using Runge-Kutta. State space will work only if you continuously update your transition matrix as theta or angular position changes. In this case it is easier to use Runge-Kutta.

Peter Nachtwey
Delta Computer Systems
http://www.deltamotion.com
http://forum.deltamotion.com/

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