View Single Post
  #1   Spotlight this post!  
Unread 29-09-2014, 21:13
PhilBot's Avatar
PhilBot PhilBot is offline
Get a life? This IS my life!
AKA: Phil Malone
FRC #1629 (GaCo: The Garrett Coalition)
Team Role: Mentor
 
Join Date: Jan 2006
Rookie Year: 2006
Location: Maryland
Posts: 747
PhilBot has a reputation beyond reputePhilBot has a reputation beyond reputePhilBot has a reputation beyond reputePhilBot has a reputation beyond reputePhilBot has a reputation beyond reputePhilBot has a reputation beyond reputePhilBot has a reputation beyond reputePhilBot has a reputation beyond reputePhilBot has a reputation beyond reputePhilBot has a reputation beyond reputePhilBot has a reputation beyond repute
[FTC]: Encoders on new Andymark motors.

I was really excited about the new andymark motors that we are allowed to use this year (Game Manual 1).

However, I see that the encoders only give 280 pulses per shaft revolution (PPR). The old encoders give 1440 pulses per revolution.

So the old encoder would be giving 3600 pulses per second at full speed , and the new encoders will be giving 700 pulses per second at full speed.

By my reckoning this will totally mess up any chance that the motor controllers have of achieving the correct requested speed, and subsequently cause all sorts of overshoot when attempting to "run to position".

eg: if I ask for 10% speed, I'm going to get %51 speed. Because the motor will keep speeding up until the pulses get as fast as expected.

I guess if I limit my speed requests to 20%, I'll get a proportional range, but I KNOW it's going to mess up the PID position controller since the gain will essentially be 5 times higher.

Does anyone at Hitechnic know if we can use the "gain" settings in the motor controller to compensate for this much-reduced PPR?
__________________
Phil Malone
Garrett Engineering And Robotics Society (GEARS) founder.
http://www.GEARSinc.org

FRC1629 Mentor, FTC2818 Coach, FTC4240 Mentor, FLL NeXTGEN Mentor
Reply With Quote