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Unread 21-03-2011, 00:49
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Re: Swerve Drivetrain.

Quote:
Originally Posted by Joe G. View Post
The revolution module that you linked is what is known as a coaxial swerve module, meaning that the motors are mounted vertically, parallel to the module's rotation axis. The wild swerve module contains the CIM motor, and gear reduction, within the swerve module itself. The primary advantage of coaxial modules is infinite rotation, as there are no electrical components within the modules. Wild swerve style modules are limited by the wires running to the motors, and must use sensors to limit their rotation. This limited rotation can also cause changing orientation to take more time than it might otherwise.

Non-coaxial modules, by nature, are independently powered, which can open up some flexibility in how the swerve is operated. For example, tank style turning will be much easier to accomplish in any orientation on a non-coaxial setup.

Finally, here are some teams that have produced quality crab and swerve drives over the years. Look into some of their past robots, its a great way to learn!

16 (most years)
71 (most years)
111 (most years)
118 (most years, but not the past couple)
148 (2008)
1114 (2004)
1640
1717
I was under the impression that coaxial module swerve was (usually*) the more flexible of the two due to the deletion of electrical connections to the module thus allowing the module to rotate directly to the desired position (for example, a 10 degree rotation in a coaxial setup could translate into a 350 degree rotation in a MOM (motor on module) setup). I am currently working independently on coaxial swerve and how to unlock it's full potential. Technically, due to the allowance of slip rings this year, MOM swerve is superior due to the greater efficiency that can be gained by eliminating the 90 degree transmission necessary for coaxial modules and the removal of MOM's limitations by the slip rings allowing unlimited rotation of the modules. One key design feature to fully utilize the abilities that swerve can give you is the independent steering and drive of all modules. After venturing into the 'branch' of swerve that I have, It is difficult to look at front/back // left/right linked swerve and say that it is even approaching all of the benefits that a fully functional swerve drive train has to offer. (NOTE: I plan on releasing that white paper I promised eventually).
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