Thread: 6WD vs 8WD
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Unread 06-01-2011, 11:42
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Re: 6WD vs 8WD

Quote:
Originally Posted by Lil' Lavery View Post
The frictional force is calculated as Ff=μN, where μ is the coefficient of friction and N is the normal force. Subbing this back into the first equation, we now have:
μN=ma
The equation is actually Ff <= μN, which brings us back to the question of traction limitted drive trains. Because 67 used traction wheels that would be driven and in contact with the ground at all times, I highly doubt that they would be fraction limited. Let's assume that the coefficient of friction of their wheels is .8 (conservative estimate), then their force of friction would be .8 x 90 <= 72 lbs. That means that they would have up to 72 pounds of force moving them forward. This lead to the acceleration of a 90lbs robot up to:
mass = 40.82 kg
force = 320.27 N
acelleration = 320.27N / 40.82 kg = 7.846 m/s2 = 25.74 ft/s2

Given that no robots can get up to 25.74 ft/s in a single second (or at all for that matter), the acceleration is clearly limited by gearing/motors, not the traction of the wheels. So in this case 67 would in fact accelerate about at about 4/3 the rate of the 120 robots that they compete against.
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