Mecanum Drivetrains

[Taylor]

Originally Posted by BBray_T1296

Several Very VERY critical points for a successful mecanum drive:

-SQUARE FRAME. Not as in length (though a square shape IS the most efficient for mecanum), but as in straightness and lack of vertical warping. That is, all 4 wheels need to be perfectly level to get ideal force distribution. If you are worried about having a lifted wheel, put some sort of rubber or spring mount to allow the robot to settle in a planar configuration. When you design the robot, try to create close to a square shape too. We did rectangles both years, but the only way that works is with a "narrow 'bot" configuration. ("wide 'bots" will not work well!)

I disagree with this. Many teams encountered difficulties when driving over uneven field. When field components are placed under the carpet, as they often can be, this takes your carefully tuned 'square' base and lifts up a corner or two. I'd recommend taking Nathan's advice and leaving the chassis 'loose' or having some sort of suspension to negate 'imperfections' in the field.

-DRIVER EXPERIENCE. your drivers need TONS of practice, even if that means playing around with just a base for a while. Know the ins-and-outs of mecanum, and it is advantages. As previously mentioned, mecanum has poor pushing power, but with a skillful driver and well made mecanum (coding is a major factor), you can use the agility to dodge even the toughest defensive 'bot. In 2011, we burned a jag mid competition, and had to compete a match with just 3 operating wheels. From a spectator's perspective, you would not have even known the difference. Of course, holding "up" on the joystick did some funky things, but it was easily correctable for a guy who knew what was going on.

We found quite the opposite during our offseason event - rookie drivers with very little practice driving a robot had no preconceived notions about how a tank-style drive handles, so they bobbed and weaved and spun around traffic with ease using our sensor-less and simply-programmed mecanum drive.