Mecanum vs. Swerve Drive

[mega900997]

I'm doing some research for an offseason project this year. We have used mecanum wheels in the past to great success, however I want to know if a swerve drive would serve us better.

What are the main differences between mecanum and swerve drive and the pros/cons of each drive systems? Or if there is already a thread that discussed this, can someone link it in a post?

[Ether]

There are dozens of threads and hundreds of posts on this very subject. You can use the built-in forum search feature.

Or Google works too.

[jbsmithtx]

Prepare for the worst.

Nearly everyone on CD will tell you that mecanum wheels are completely awful, and have no pushing power.

That being said, there are several benefits to moving to swerve. It is much more efficient in power delivery, and so much more powerful. As a beginning team, mecanum is great for preliminaries. However, as a team that has used them for several years, it may be useful for you to transition into something else. Keep in mind, that swerve is always a work in progress. The best swerve drives are made over several seasons. But don't be afraid to continue with mecanum, if you determine your time should go elsewhere.

Pros to Swerve:
Several alternate control methods
Better power delivery (Speed and no slickness of rollers)

Cons to Swerve:
Not easy to slap onto a robot like mecanum
Requires the use of many motors
Can be unreliable, unless you spend a lot of time getting everything right
Can be expensive (but mecanum can be too)

Pros to Mecanum
Easy to implement
Reliable
Little development

Cons to Mecanum
Rollers
Costly
Can be unbalanced

[Ether]

Originally Posted by jbsmithtx

Pros to Swerve:
Several alternate control methods

What "alternate control methods" for swerve do you have in mind that cannot also be used for mecanum?

Originally Posted by jbsmithtx

Pros to Swerve:
no slickness of rollers

Mecanum rollers do not have to be slick.

[jbsmithtx]

Originally Posted by Ether

What "alternate control methods" for swerve do you have in mind that cannot also be used for mecanum?


Mecanum rollers do not have to be slick.

I meant control methods such as "car" steering, crab, swerve, etc.

And I meant the rollers were "slick" simply because they are a roller...

[buildmaster5000]

Link to a thread about this very subject. While it's been a few years, feel free to PM me with any questions you have. My team did implement a swerve back in 2011 (My senior year of HS) and I like to think I remember a thing or two from the good ol'e days.

Originally Posted by jbsmithtx

I meant control methods such as "car" steering, crab, swerve, etc.

And I meant the rollers were "slick" simply because they are a roller...

Theoretically, any movement that you can make with a swerve you can make with a mecanum, and vice versa.

[Walter Deitzler]

Why not build both?! Swervecanum drive!

Serious: We have built Mecanum. We loved the maneuverability we got, and ease of use. Yes, we could get pushed a lot, but the trick to that was to just go sideways around the defender. They are awesome to show off at science night and such, because everyone like a robot that moves like a crab, and you get questions about the wheels, how they work, etc, from people just looking at the bot.

We do have reason to believe that they we one of the reasons we failed to make eliminations at all in 2012, mostly because there is a stigma against them, and, if you are not first round pick, then there is a good chance you will be skipped second round.

Have fun choosing!

[Koko Ed]

Originally Posted by LedLover96

We do have reason to believe that they we one of the reasons we failed to make eliminations at all in 2012, mostly because there is a stigma against them, and, if you are not first round pick, then there is a good chance you will be skipped second round.
!

This happened to us this year.
There are teams that have policies of not picking teams with Mechanums no matter how good they have performed that weekend.

[Clem1640]

Both swerve and mecanum are equally agile when executed well.

Mecanum is easier to execute well and requires fewer resources ($s, mass,...) and less learning or insitutional knowledge to do so. The rollers, however, do compromise traction.

Swerve provides agility without compromising traction, but it is resource intensive. 1640 uses swerve and we are very pleased with the results, but this has come at a considerable investment in learning. We also have to deal with having a finished drive-train rather late in the build season due to long fabrication and assembly times. Control software is also non-trivial. So there is a price to pay for this traction.

It is clear that the investment and cost of swerve has imposed limitations on other systems and capabilities on our robots.

So, like all real design decisions, this one is about what is right for you and your situation. All good designs are good compromises.

More serve info is available at the following link to "swerve central":
http://wiki.team1640.com/index.php?title=Swerve_Central

[Gdeaver]

If for a moment you do not focus on the competition value of complex drive trains, but look at the FIRST mission to inspire students, go for it. Our students learn so much about design and fabrication from the swerve project. It is a complex project and requires a team to develop a design build process. This same process can also serve a team well in all other design build missions. The knowledge gained from going for a swerve project can be huge. Our team recently discussed manufacturing and selling some of the critical parts of our swerve module. Teams would have to make and purchase the rest. There would have to be some interest to make a run. Interest.

[Taylor]

Whichever way you decide to go, don't try to reinvent the wheel (pun intended). There are many resources out there - crab/swerve COTS modules, gearboxes built into chassis, programming code shared from others - that make life so much easier for you.

[Pault]

I'm not an expert on this (or just about anything, really), and I am going to echo Ether in saying that there are a million other threads about this already. But I just want to say 2 things.

1. People, please don't let this devolve into another thread arguing about whether mecanums are good or bad. Just stay focused on how mecanums compare to swerve. I think everyone can agree that swerve > mecanum, so lets keep this a simple discussion on why that is.

2. To the OP: don't just dive into swerve like nothing thinking that you will have instant success. Know that swerve is very complex and resource intensive, so be cautious. It's good that you want to test out these kinds of things in the offseason, but know your limits. Basically what I am trying to say is: don't underestimate the difficulty of swerve.

[Samwaldo]

We won the Boston Regional in 2011 with Mecanums, and we were playing the DEFENSIVE ROLE!!! If you know how to use them well, and have a full 120lb robot, defense is very possible with mecanums.

[Boe]

while as a drive system alone swerve always wins it is a lot more difficult and resource intensive and hard to program. Ive hated and thought meccanum drives were a bad idea for a while, but i believe that's because ive never seen a team use them to their full potential. Last weekend i got my first real chance to see KnightKrawler 2052 driving (we go to opposite MN regionals typically) and i was very impressed with their driving and how they used their meccanums to their full potential. I believe KnightKrawler has used meccanums for years (i believe one of my friends said almost every year except 09) and have really figured out how to get the most use out of them. Like all drivesystems the key to using it successfully is driver practice. You cant drive a meccanum like a tank drive which i unfortunately see a lot of teams do.

[Ether]

I think this may be some kind of record. We got through 9 entire posts before someone mangled the spelling of mecanum.