mecanum vs. omni

[Alex.Norton]

I've enjoyed using the omni's for the past few years just because they are "cool". Admittedly not as cool as mecanums but still...

To clarify what I said earlier (why I don't like mecanums), each wheel creates a vector of force in the direction that it moves but regardless of what direction the robot moves in it also creates a vector perpendicular to the wheel. When driving forward two of the wheels have this vector to the left and two have it to the right so the net is no lateral vector. When strafing these vectors point all in the same direction and the forward/reverse vectors cancel. so no matter how you build or program you robot, by the nature of mecanums there is extra force on the frame and extra sidewards force on the bearings.

In regard to the gyro. I really like to gyro because our bot would be unusable without it. Since there can be errors in the gyro code we have a way to turn that function off and the machine becomes completely uncontrollable just because of differences in the motors. With the gyro on it is so stable that one of the drive motors can be unplugged but the machine is still very much drivable.

For me I have never even begun to try and delude myself that an omni or mecanum could compete with a tank drive in a pushing match. We tried once in 2005 and got pushed around the field, however, the team that won our regional didn't actually get to win or even score against us simply because they couldn't get around us since we were too maneuverable. Traction has never been a factor in my reasoning. However, I do like the idea of the ability to change a mecanum into something else more easily.