Swerve Drive vs Mecanum Wheel drive?

[lcoreyl]

Originally Posted by Abhishek R

In my opinion only, I feel there will always be exceptions, but mecanum just doesn't have any appealing aspects. Whenever I see a competitive team with mecanum I just wonder what they could have done with tank, butterfly/nonadrive (I've heard this is called TexCoast Drive now...) or swerve. The idea of using rollers on wheels is very unappealing to me.

zero appealing aspects? How about the tiny fraction of time to design and implement compared to the other holonomic drives (some with “unappealing” rollers) which receive your blessing? I’m not sure how giving such a strong opinion without mentioning any characteristics or tradeoffs is useful.

Originally Posted by fox46

I like mechanum, Omni and swerve drives- it makes it real easy to bulldoze through them and get to where you want to go on the field!

by this logic, if robot A has 6WD and bulldozes robot B with 6WD, then robot A has just proven their own drivetrain sucks. There’s more to it than this.

Originally Posted by fox46

Secondly, don't even bother with Omni if you aren't using a gyro and accelerometer to take some of the work away from the driver. DC motors always run better in one direction than another and to try and pull off one of these drivetrains without some sort of logic to make sure it is doing what the driver tells it is just setting yourself up for an extremely difficult to drive robot.

Yes, sensors make driving mecanum easier, but you can be successful without them. For example, a mentor from 2996, Cougars gone wired, told me their mecanum drive encoders and gyro were not working in Utah. They still have a shiny blue banner they brought home, however.

Originally Posted by fox46

Swerve drive- People think that with a swerve drive you have the tractive capabilities of a tank with the maneuverability of Omni- you do not. Each wheel has (at least) one motor. When you start pushing against something, all your weight transfers to your rear wheels leaving your front wheels spinning in the air. Hence, in a shoving match, typically you are only using half your available drive power.

How about discussing the actual tradeoffs of swerve vs. tank tractive capabilities instead of saying tipping to 2 wheels is somehow inherent in swerves design? “typically” you are using only half power? Really?

Originally Posted by fox46

Furthermore, the lag time associated with steering your modules is painful. Any lag time slows down your ability to utilize your maneuverability to its maximum advantage and if you don't utilize it to its maximum advantage you WILL be outgunned by a skid steer/tank.

You make me want to create a verb form of hyperbole.

Never built or driven a swerve, but wouldn’t lag depend on how it’s built and programmed? Are you saying it’s impossible to build one with acceptably small lag? In watching swerve used in competitions, I can’t say I’ve noticed lag as a “painful” problem. Hopefully someone with good swerve experience can speak on this.