View Single Post
  #6   Spotlight this post!  
Unread 11-11-2005, 07:47
Greg Needel's Avatar Unsung FIRST Hero
Greg Needel Greg Needel is offline
REVving up for a new season
FRC #2848 (All-sparks)
Team Role: Engineer
 
Join Date: Jan 2002
Rookie Year: 2002
Location: Dallas, TX
Posts: 3,104
Greg Needel has a reputation beyond reputeGreg Needel has a reputation beyond reputeGreg Needel has a reputation beyond reputeGreg Needel has a reputation beyond reputeGreg Needel has a reputation beyond reputeGreg Needel has a reputation beyond reputeGreg Needel has a reputation beyond reputeGreg Needel has a reputation beyond reputeGreg Needel has a reputation beyond reputeGreg Needel has a reputation beyond reputeGreg Needel has a reputation beyond repute
Re: Nintendo Style Speed Booster

Quote:
Originally Posted by Cory
It seems like a waste to limit the power of your motors when using this option as if it were a psuedo 2 speed transmission, however.
it really isn't limiting the power of the motors. since the IFI setup uses pwm(pulse width modulation) the motors are still receiving maximum voltage, it is just the pulse length that is shorter. and since
Torque(transmitted to the shaft) = (Horsepower*63000)/rpm

and since 1 HP = 745.699872 watts

and watts= voltage^2/ohms <--constant in this case because resistance of the motor doesn't change and neither does the voltage.

the total torque transmitted at a given rpm is the same, all that is being changed is your speed. This is the same thing that happens when you push the joysticks only a little bit forward.

we did this this past year and it works very well for precise movements on the field.


although to make a "speed boost" button you would have to be limiting your pwm the whole time except when you want to boost, which would be a waste.
__________________
Greg Needel│www.robogreg.com
Co-founder REV Robotics LLC www.REVrobotics.com
2014 FRC World Champions with 254, 469, & 74

Last edited by Greg Needel : 11-11-2005 at 07:51.