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Unread 10-01-2005, 08:01
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Tristan Lall Tristan Lall is offline
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FRC #0188 (Woburn Robotics)
 
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Re: 2005 Drivetrains

Quote:
Originally Posted by Greg Needel
this is not possible because you wont have the traction to transfer that force to the floor.... kinetic force = (coefficient of friction)*(the normal force)

since the coefficient of friction can;t be more then 1 and your normal force is essentially the weight of your robot (force that acts perpendicular to the surface)

therefore your max force can not reach 340 ft-lbs


i would recommend recalculating your theoretical force to a more reasonable value around the max weight of your robot but even that will be overkill and you will just end up spinning your tires
Greg, you're right about the wheel slip being the limiting factor, but with interlocking surfaces or certain combinations of materials, μ can exceed 1; it's a convenient approximate upper bound, but it isn't a physical limit. (See here.) Some FIRST teams have empirically determined the coefficient of friction of rubber tread on carpet to be around 1.2; it all depends on your particular wheels.