Mecanum. What's Best

[jamie_1930]

My opinion is
- Use a long frame, so that the wheels are square with one another. Having the wheels, in a "long" or "wide" orientation can cause the robots rotation to be skewed from the center due to a different force being applied in rotation of the robot due to an irregular center of gravity.
- Direct driven will be better to use because the signals sent to the motor will be better applied to the wheel, especially in changes in direction due to any slack in the chain causing the wheel to not move for a short interval of time, while the slack shifts.
- During this years game we had the option of using both field-centric and robo-centric drives and switching between both during the same match. Even though we had that option we never switched from robo-centric. field centric can be thrown off and change completely the direction the robot will travel relative to the joystick, this can occur during quick changes in direction due to fast turning, bumping into the field or with other robots. Therefore I would endorse robo-centric, however field centric would be a good thing for your programmers to learn how to do, but I wouldn't implement it until your drivers feel confident with it.

Also as Ether said the wheels can be a major concern. you want to have the sub-wheels all freely spinning, but ideally wheels of this design would be the most prefered, http://www.chiefdelphi.com/media/photos/25159, because they will prevent the wheel from bumping up and down. Similar to the difference in performance between single and double omni wheels.