Quote:
Originally Posted by peter_p
hello, my team and i are trying to put together a crab drive in the off season, and i just had a quick question:
for crab drives with 2 wheels per housing (8 wheels total) what is the average size of each wheel. from what I've noticed they look small and wide.
any help is appriciated
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Some advice:
A crab drive will only be advantageous if it can change direction faster than a conventional "tank" style drive train. If a tank drive can turn 90* faster than your crab can swivel sideways... why bother?
The speed with which you can change direction will be proportional to how fast you can turn your modules, which will depend on the gearing on the rotation motor.
The gearing on the "module orientation motor" will depend on the torque of the modules. Torque=ForcexRadius, so if your wheels are very wide (or far apart, in this case) and have a high CoF, it will take a lot of torque to turn them. This will mean you will have to gear your rotation motor down, resulting in slower maneuvering.
So to answer your question:
-The dual wheels ought to be very close together and have little friction.
-Radius is entirely dependent on your gearing and how fast you want to go. But I might suggest you go with very small wheels (3-4”), since this will put less torque on the vertical bearings.
Hope this helps.