Chainless Mecanum Drive

[AdamHeard]

Originally Posted by JesseK

I've toyed with a concept that uses 5 wheels in nonadrive's pentadrive configuration with the middle wheel being a traction crab module that pivots via pneumatic linkage (pneumatic to keep the code simple). This concept gives a mid-grade complexity while also potentially providing some of the agile+tractive advantages of nonadrive without the weight. Of course it doesn't have the natural anti-turn capability of nonadrive, but that's the trade off. The concept was inspired by nonadrive and the limited pictures I've seen of 330's 2009 bot.

Unfortunately I've been overruled for our offseason prototype due to team survivability, so maybe another team will prototype it?

I don't think this would work at as well as you'd hope. The crab module would only have so much normal force on it, based on CG location. On top of that, if someone to to try to rotate the robot, it wouldn't be nearly as difficult as trying to rotate a 4wd/6wd, etc... You'd also have to design carefully to ensure that when the module rotates, the module rotates relative to the floor, not the module stays in place and the robot rotates around it.

I'm making the assumption that the crab module would raise under normal operation.

Really, the best way to answer the question without building it is to do a full Free body diagram and look at the forces involved.