To swerve or not to swerve
 

What do you guys think about swerve drive in this years game?

Re: To swerve or not to swerve
 

Swerve is a good option, but if a team doesn't have experience making swerve drives than they shouldn't attempt to make it for the first time during the build season.

Re: To swerve or not to swerve
 

If you have built it before and can pull it off then the maneuverability, speed, and power that it offers should be advantageous. I think that swerve is almost always a great choice if you can build it but the question is just if you can build it.

Re: To swerve or not to swerve
 

We're not using it, due to lack of resources, but I think that the increased maneuverability will be really helpful for avoiding defense and catching balls.

Re: To swerve or not to swerve
 

I think there is no need of a swerve drive because you can have the same movement using a mecanum drive and if you can pull it off you can have a jump drive so you have agility and still been able to push other robots away.

Re: To swerve or not to swerve
 

I've always liked 175's clever drive trains. Their 2007 strafing bot was so hard to stop.

To repeat almost everyone above... If you've done swerve before, it's just a matter of justifying the weight of the system. If you haven't done swerve before, design and build one in the off season before using it in a game.

Re: To swerve or not to swerve
 

I would be tempted to utilize the advantages of 2spd transmissions over a swerve drive given that many robots will have to both play defense and avoid defense, i.e. I want the ability to go faster than anyone who can push me, and push anyone who can go faster than me (assuming I can get a hold of them in high gear).

I see the advantages with a 2 speed being able to our run defense bots and push around others but if you get someone who can operate swerve drive you can practically get out of all sorts of situations as seen with 195 in 2012 and 1717 D'Penguineers... in almost every year recently

Re: To swerve or not to swerve
 

I'll be interested to see if some of the top teams that usually run tank drive will choose swerve this year. Some of them have done swerve before, so they could presumably bring it back and still get their other business done. For example: 67, 111, 973, 1114, 1986.

Re: To swerve or not to swerve
 

If your team is using swerve, are you using continuous rotation or fixed rotation swerve modules?

Re: To swerve or not to swerve
 

There's no argument against swerve being the most agile drive style, but the combination of acceleration and top-speed offered by a 2-spd+4cim drive is paralleled only by a 6cim drive, and that costs you two motors and a lot of current capacity when you're pushing hard.

Despite constant debate with myself I can't find a better 'bang for buck' than using a 2spd drivetrain. They're light, COTS that won't break the bank, proven, and generally available. Everything you'd want in a drivetrain.

Do you guys think that this is a solid game for one or no?

Re: To swerve or not to swerve
 

That's up to you and your team. Do the math, weigh the pros and cons, and maybe even take a vote.

Whether it's swerve, tank, mecanum, or something else, the important part is the engineering.

Re: To swerve or not to swerve
 

We are running it.
No matter what running a swerve drive will always be a hard decision to make just from the resource draw it has. We go really lucky that we have been prototyping it(making modulates and improving on them) for almost a year. We had planed on making it for a off season event but our mill broke down causing us to have all of the peaces to make 6 modules sitting around. After resetting the modules in a new gear box configuration we are set to start machining it, In fact the mill is set to go live tonight. if we were not to have already to have 80% of the stuff to make it we would not even have thought of running it.

Re: To swerve or not to swerve
 

#SwerveSoHard

I haven't built one, but I have always wanted to (ask my team). I looked into it quite a bit in the offseason. One of the items that is required (for a Revolution Swerve Style) is a bevel gear set per wheel. I haven't seen these at FRC type stores (AM & VEX). The cheapest place I found them is on Amazon

http://www.amazon.com/dp/B005AVUCJ8/ (straight bore)
http://www.amazon.com/dp/B005AVU6T4 (keyed)

There are a lot of sizes and bores there.

My cautions after doing some research. Compared with other drive styles, Swerve :
- Is more expensive (count up all the miter gears, bearings and sprockets)
- Is heavier
- Is not in the standard WPI library (probably not in LabVIEW either)
- Takes up quite a bit of room in your chassis corners (you have to be able to rotate the whole wheel and all the hardware with it 360 degrees) (it's tall too!)
- Forces a smaller wheel track

A swerve is a significant undertaking and is a potential season breaker (imagine if you can't drive at all!). Make sure you have a backup plan.

Consider your budget and number of team members before committing. Unless you are a huge team it is likely that the effort expended on learning how to build, program and drive a swerve will take away from your other game mechanisms. Essentially the drive train is your main mechanism. Luckily there are some examples (BuildBlitz & Ri3d) to help you build a quick shooter and pickup.

Also not a bad idea to read this from 1114. They address the swerve in some detail http://simbotics.org/files/pdf/drivetraindesign.pdf

I am basing this on the experience of a friend of mine from 1296 who described his experience making a swerve during the build season. It essentially took most of the season's effort. In following years it was easy to do, but the first year and all the lessons learned were tough.

Good luck

-matto-

Re: To swerve or not to swerve
 

I think that this sums up pretty well many team's experience with swerve.
http://www.chiefdelphi.com/forums/sh...1&postcount=28

Seriously, the team that posted this has 70+ members, a couple of good years under their belt, and this still happened to them. Don't do swerve if you haven't already prototyped it over the pre-season. I don't really care how big your team is or how much FRC experience you have. Just don't do it.

Re: To swerve or not to swerve
 

Vexpro has 3/8" hex broached 15T 12DP bevel gears that are kind of the standard for FRC swerves (starting with 118, then spreading to 1625, 1717, 973, etc...) for a great price.

Re: To swerve or not to swerve
 

We (1736) had a similar situation in 2012. I wasn't on the team but we ended up locking the swerve modules in place on the Thursday of the regional and driving it tank style.

Re: To swerve or not to swerve
 

I would imagine you are not the only one, my guess would be the teams with experience are strongly considering swerve. (i.e. 111, 118 , 973 , 1625, 1717)

If they are not doing swerve, many of the top teams are considering butterfly , octocanum and beyond.

Swerve modules are available from 221 if people are interested.
http://www.team221.com/viewproduct.php?id=89

Re: To swerve or not to swerve
 

A swerve drive gives faster strafing and more traction than Mecanum. Depending on what your priorities are, it could be a very good option. If you don't have experience with building swerve drives, then it's a bit too late to start developing one for this season. The only thing that swerve falls short is with potential pushing power. A 6 CIM-6 wheel drive with a ball shifter in low gear will out push a swerve. If the Pro's of a swerve drive outweigh the difficulty of making one, then a swerve drive, in my opinion, is a very good choice.

Re: To swerve or not to swerve
 

We won't be doing swerve, as fun as it would be. I can guarantee (off assumptions) that 1717 will be doing swerve though because they're crazy and dance like penguins.

All things equal (motors, rollout ratio, tread, weight, etc...) swerve and 6wd are the same in pushing power.

Re: To swerve or not to swerve
 

We built swerve our first year (Rebound Rumble) and didn't really use it since our drivers didn't get much time to learn it. Plus, our drive was kinda glitchy (which could be improved), but I would suggest to pick something with less parts (ie. Butterfly).

Re: To swerve or not to swerve
 

I was on team. Disaster. Mentors trying to save it, students disengaged. Even tank drive was disappointing.

Re: To swerve or not to swerve
 

Re: To swerve or not to swerve
 

As that team, I can tell you that our performance that year was tough for a lot of us to swallow-- especially the juniors and seniors who spent countless hours not only during the season, but also prototyping and designing before hand. Your team is the only ones who can realistically assess whether you can pull off a swerve drive. We made that assessment and thought we could pull it off, but we were wrong. Be prepared for that if you do end up going with swerve having never tried it before.

If your priority isn't to win competitions and you have little to no experience actually building and programming a swerve drive, it's still a completely valid option for this year's game. Just understand that what you might be gaining in knowledge you will most likely lose in terms of being competitive on the field.

In summary I guess, I can say "Been there, done that, got burned." But sometimes it's necessary to get a bit burned in order to learn a lesson.

Re: To swerve or not to swerve
 

The year before i joined my team they tried running swerve or more of a "crab drive". It ended in a way that those member of the team then are still scared to death of trying to run it. We ended up with it falling apart on the field...
Running a swerve is probably the most risky thing you can do but it has great rewards if done right. If you don't have 1000 hours of meeting time to make program and test it in the build season it will be a nightmare to run. If you do try to pull it off have a back up plan and look at the teams who have mastered it and see how they pulled it off some of them even release cad. Even if they do give out cad some times copying it will not work you will not understand why little things were decided apon and may end up costing you dearly in the end.
They also cost a lot of money to buy and the parts can take weeks to arrive even if you built it, but did not have the belts to run it you may not have the programming to make it the best possible.

=No matter what your team is the only one who can decide if you can run it.

Re: To swerve or not to swerve
 

The best swerves (1717 and 16) are the best drive trains in theory I've seen in first. The 4 downsides to these are reliability, time, weight, driver comfort. If you think you can finish a reliable swerve that fits your weight constraints in enough time to get your drivers used to driving it, I don't see why you wouldn't.

Re: To swerve or not to swerve
 

I doubt you'll see many top teams using a swerve (or mecanum) this year. With a wide-open field, symmetrical game pieces, and many different spots to score from, the additional control and motions you gain from swerve really won't be a significant advantage.

Swerve is a major engineering task, especially for teams who aren't intimately familiar with it (at least one or two successful implementations). The way I see it, you have to be either extremely comfortable with building/programming/maintaining/driving a swerve robot, or you have to be 100% sure that it's going to be a major advantage to have it on your robot. Preferably both.

<3

Glad to see people from other teams like it and remember it! Swerve is pretty crazy to drive.

Re: To swerve or not to swerve
 

Team 2471 made the decision to go with a swerve drive system this year.
In short, we decided that in this years game it's important to put the robot in the right place on the field facing the right direction, as quickly and efficiently as possible.

It will be a tough rode to go down, but we did have a successful off-season bot with swerve drive this year. we also did a somewhat successful crab drive in 2012.

Some of the disadvantages people have mentioned earlier in this thread not a big issue with the design we are using. We also did a drop center drive bot this off-season. The drop center drive base weighed in at about 36 lbs and the swerve drive base was about 37 lbs. The modules weigh 7.5 lbs each, only take up a 6" by 6" square, the wheels touch the carpet 2" in from the edge of the robot, and they only cost 222$ per corner.