Quote:
Originally Posted by Abhishek R
I searched some old threads but couldn't find a clear answer.
What is it about a single speed drive train that allows it to accelerate faster than a two gear one? I don't see why it does, but it seems like there should be a technical reason that I'm missing as to why it does accelerate faster.
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Try this - find a friend with a manual shift car. Try to start the car from a complete stop in 2nd gear. Now try it in 1st gear but shift quickly to 2nd gear. This is kind of what the robot is doing.
With a lower gear ratio the top speed is less but the torque is better at lower speeds thus you accelerate faster. Then you shift into 2nd gear at the correct time and enjoy power in another band and a higher top speed. It would be faster (than a single speed) unless it takes too long to shift.
In FRC it seems most teams with 2 speeds run around in 2nd gear most of the time and only shift into low gear when they need more torque for low speed maneuvers or when pushing against something.
Our teams gears for 4.5 and 14.5 fps when using 2 speed transmissions and 10-12 fps when using single speed transmissions. We use either setup depending on the game requirements. For example this year there were no obstacles on the field so a high top speed was desirable and low speed was desirable due to the brutal play - so dual speed transmissions helped. Some years the field is divided into sections so high top speeds are less desirable, maneuverability is more important.
HTH