Quote:
Originally Posted by dtengineering
Okay... seeing as how my other car is still on this planet, I'm a bit hesitant to question these numbers, but I was doing some calculations with our programmers this evening to figure out peak velocities and such and have to question the assumed closure velocity cited here.
We used the published value of static coefficient (.06) of friction to determine that a 150 lb (68kg) robot would have a normal force of 668n and a peak forward force of 40N. The mass of the robot, plus trailer, is 186lb, or 84kg, giving a peak accelleration of 0.47 m/s/s...
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Jason-
Some of my numbers are based on empirical observations rather than theoretical values. During early development, we used standard kit-bots with prototype trailers for concept testing. We were regularly able to make the robots accelerate from the end of the field to reach top speed (9-11 fps, depending on the gearing installed) well before reaching the mid-field line. I understand that these observations may not agree with the theoretical performance calculated with the given COF. But the observed results were consistent and repeatable. So I am going to go with those.
There is one mistake in my calculations. I forgot to add the mass of the trailer into the impact calculations. With the trailer included, the localized instantaneous impact pressure is in the range of 12,300 psi.
-dave
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