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Unread 30-04-2010, 01:22
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FRC #1986 (Team Titanium)
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Re: Swerve Drive Idea

Quote:
Originally Posted by ajlapp View Post
It may be easier to make a hollow main pivot axle so that you can pass the wires out the top of the module.

A few teams did this sort of modification to Wild Swerve units this season.

frc20 is one that comes to mind.

That was the method in our module (see pic). Dealing with the connection at the center of rotation is much easier than dealing with it around some perimeter of the assembly. Many rotary contacts are available to connect wires at the center of rotation. Depending on how noise-free you need the connection to be, you may be able to fashion it yourself. Take a look at the rotary connection for the power cord of a typical woman's hair curling iron. Just a center pin in a socket, with another sleeve around the outside contacting a spring loaded contact. The brush contacts to the armature of almost any electic motor is another example. If you don't need a real clean signal, such a simple friction contact may suffice, but if you need a high quality signal such as an FRC CIM would require, I would suggest a commercial rotary contact. The mercury filled type I mentioned earlier worked beautifully on our CIM modules.

Take a serious look at whether you really need infinite rotation in your application. Team 1730 and 1986 learned that you can get several rotations if you route the wire properly, use high-flex wire (high strand count), and give it plenty of slack. We also covered our wire with woven braiding to help keep it under control. The right programming can deal with the rotational limit issue.
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