pic: Omnibot

[AdamHeard]

Originally Posted by EricH

I'm pretty sure it was a kiwi-type system, like below. I tried to search, but no luck yet.

Nope, sorry Eric, but 67 definitely had a 3 wheeled crab in 2005.

[EricH]

Originally Posted by AdamHeard

Nope, sorry Eric, but 67 definitely had a 3 wheeled crab in 2005.

Actually, I found a picture... of 67 2005... in a match... on two wheels, showing the third. NOT a true swerve. Swerve, yes. Three wheeled robot, yes. But not a three-wheel swerve. One wheel steered, three drove. Zoom in on the picture. One wheel is turned; the others appear not to be able to.

[AdamHeard]

Originally Posted by EricH

Actually, I found a picture... of 67 2005... in a match... on two wheels, showing the third. NOT a true swerve. Swerve, yes. Three wheeled robot, yes. But not a three-wheel swerve. One wheel steered, three drove. Zoom in on the picture. One wheel is turned; the others appear not to be able to.

Actually, I found a picture... of 67 in 2005...during build... on the ground, showing all three wheels. A true swerve, with all three wheels able to rotate.

No hard feelings eric

[seanwitte]

If you move the wheels to opposite corners the math will work out exactly the same as it would for the configuration shown.

There are two advantages that a holonomic base built using this configuration has over a swerve drive:

1) The modules are lighter and less complex.
2) The robot can translate and rotate at the same time (I've seen this called "frisbee motion")

The programming is more complex, but there are plenty of examples available to get you started.

[EricH]

Originally Posted by AdamHeard

Actually, I found a picture... of 67 in 2005...during build... on the ground, showing all three wheels. A true swerve, with all three wheels able to rotate.

No hard feelings eric

And rotate independently... No wonder the code took so much space in the controller.

Back on topic: If you're going to do 3WD, plan it out first. Carefully. As noted, only one robot (to our knowledge) has had a 3WD omni system; most of the other 3WDs were crab/swerve systems.

[Andrew Schreiber]

Originally Posted by EricH

And rotate independently... No wonder the code took so much space in the controller.

Back on topic: If you're going to do 3WD, plan it out first. Carefully. As noted, only one robot (to our knowledge) has had a 3WD omni system; most of the other 3WDs were crab/swerve systems.

Also, the one robot that did a 3 wheeled omni (857) didn't use code to control their wheels, they used hardware (http://www.chiefdelphi.com/media/photos/16410) Dont forget that sometimes that solution works better than complex code. No reason to make the code more complex than it needs to be. Could it be done in code? Yes, is complex code always better? That is up to you.

[Dowjonesbotics]

Cooool, are those the robots that spin really really fast??