View Single Post
  #13   Spotlight this post!  
Unread 29-09-2016, 15:26
Jared Russell's Avatar
Jared Russell Jared Russell is offline
Taking a year (mostly) off
FRC #0254 (The Cheesy Poofs), FRC #0341 (Miss Daisy)
Team Role: Engineer
 
Join Date: Nov 2002
Rookie Year: 2001
Location: San Francisco, CA
Posts: 3,078
Jared Russell has a reputation beyond reputeJared Russell has a reputation beyond reputeJared Russell has a reputation beyond reputeJared Russell has a reputation beyond reputeJared Russell has a reputation beyond reputeJared Russell has a reputation beyond reputeJared Russell has a reputation beyond reputeJared Russell has a reputation beyond reputeJared Russell has a reputation beyond reputeJared Russell has a reputation beyond reputeJared Russell has a reputation beyond repute
Re: Tuning PID Constants Over a Range

Quote:
Originally Posted by Ether View Post
For a robot with center of mass located at center of rectangle formed by the 4 wheels, I think that should be:

S = (1+f2)(W/2)ω

S is drive wheel linear speed
W is trackwidth
ω is desired turning rate in radians per second
f the the ratio L/W, where L is wheelbase


Yep, and this is the equation we actually used as our starting point (using the track width and wheelbase length of our inner four wheels). Our CoG was within an inch or two of the geometric center (ignoring dynamics). We found that even with this correction, we were ~50% off of the true value (a bit unsurprising since even though our outside wheels were raised, they still bore some weight because of deflection of our 15-20 PSI inner wheels).
Reply With Quote