View Single Post
  #13   Spotlight this post!  
Unread 30-12-2013, 13:39
IKE's Avatar
IKE IKE is offline
Not so Custom User Title
AKA: Isaac Rife
no team (N/A)
Team Role: Mechanical
 
Join Date: Jan 2008
Rookie Year: 2003
Location: Michigan
Posts: 2,148
IKE has a reputation beyond reputeIKE has a reputation beyond reputeIKE has a reputation beyond reputeIKE has a reputation beyond reputeIKE has a reputation beyond reputeIKE has a reputation beyond reputeIKE has a reputation beyond reputeIKE has a reputation beyond reputeIKE has a reputation beyond reputeIKE has a reputation beyond reputeIKE has a reputation beyond repute
Re: Gearbox friction model

Quote:
Originally Posted by Ether View Post
The above is essentially what I used in the Drivetrain Acceleration Model, except that instead of c*speed^2 I used Kro+Krv*speed (line 85 in the C code). This one line of C code is easily changed to make it whatever function of speed you like. In FRC drivetrains, the Kro constant term is probably needed since even at very low speeds and output torque there is friction in the drivetrain (due to tension in the chains/belts, misalignment, etc).


While I agree that a certain amount of friction there initially, I think that value should go away once it is overcome, much like the delta between static and dynamic coefficients of friction. If you are pushing a block on a smooth surface, you need a certain amount of push to get it going, but once it is going, the term would reduce.
I will need to think about that one a bit more, and how it would effect an acceleration model.