Is there a dominant design style?
 

I wonder if the advances over the last several years in product availability and information sharing have resulted in major changes to the way teams design and build their drive bases and superstructures. Is WCD now dominant? Did vexpro revolutionize the sport with versaframe? Are more teams building swerve drives than ever before, thanks to products like andymark's? I'd love to see what people think of where their own teams are, and where they think things will go.

Re: Is there a dominant design style?
 

We've gone to the kit chassis the past couple years...it's really good these days. We used to build our own.

Re: Is there a dominant design style?
 

For our team, definitely. Versaplanetaries are really good, and probably dropped out weight 10+lbs in 2014 and 2015, WCP and Vex gearboxes drop our weight more compared to our old AM shifters.
CD has helped our team learn a lot more about mechanical design.
As far as swerve drive and versaframe go, I haven't seen many teams use either, excepting this year. But the Swerve And Steer might remain popular next year, as so many teams used it this year that it's easy to re-use.

Re: Is there a dominant design style?
 

At $325 a pop, and building two robots, we're looking at $2k for swerve or crab just for gearboxes and wheels. Unless we were reprising Tumbleweed, this would probably blow our budget.

We're with MrForbes above - we did our own chassis for our second and third year, but when we forgot to opt out last year, we realized just how versatile the 2014+ KoP chassis is. We opted out this year, but have ordered two AM14U2s (2015 chassis) and these are 95%+ likely to be the main part of our chassis this year. By using some Vex 1"x1" c-channel and a drill with a 3/16" bit, it is easy enough to use KoP below and VersaFrame above; that's our most likely construction for 2016.

WCD will buy you another inch or two of track width for the same robot width, but this has not been a major consideration in our last several robot designs. If it does prove to be one, we can always rearrange the wheels and sprockets on those shafts, and even bring the "outer plate" inside of the wheel if it seems necessary to do what I'm going to call a Gulf Coast drive. (and that's just the beginning of some of the weird things you can adapt the KoP to do.)

As far as COTS causing a style to become (or cease to be) dominant, I think that the COTS availability of omni and mecanum wheels has done more to open up the possibilities of something other than drop-center to teams with a $1k+ robot budget than anything else.

Re: Is there a dominant design style?
 

Versaplanetary gearboxes have definitely been a game changer for us, especially with the new Versaplanetery CIM adapter. It's just so much more convenient to be able to grab a couple of stages and put them together when you figure out what ratio you need instead of stocking many many gearboxes or ordering them in the mail and waiting. They're extremely reliable, relatively light(compared to p80s) and you can switch them out with each other as long as you keep the number of stages consistent.

Re: Is there a dominant design style?
 

We used the Versaplanetary for our 2014 drive train... That was wicked fast! Each wheel had its own CIM and gearbox :yikes:

Re: Is there a dominant design style?
 

We copy 254's drive train style. WCD every year.

We copy 973's mechanism style. Tube + Holes + Gussets (essentially versa-frame)

We use vex pro ball shifters in our drive train.

We use versaplanetaries for all of our mechanisms.

We expect to keep learning from the best teams in FRC.

We expect to continue to use the VexPRO product line almost exclusively.

We would not be where we are without these resources.

-Mike

Re: Is there a dominant design style?
 

We used the 2015 KoP frame last year, but adapted it to our own drivetrain (Toughbox Nanos with 6" mechanums).

It's worth mentioning that if you just want the KoP frame, they sell it separately from the drivetrain and it's $209 instead of $599. They also sell all the sheet metal, churros, and hardware separately.

http://www.andymark.com/AM14U2-p/am-2990.htm

Re: Is there a dominant design style?
 

Wow, we are on the same page, though we use WCP gearboxes half the time, and the Vex ball shifters the other half. This is really what I'm wondering, and why I posed the question. My suspicion is that these products, and the great teams whose ideas these products seek to emulate, are becoming the go-to for many teams. It sounds like the versaplanetaries also are huge for some teams (mine included), and that AndyMark has raised the kit bot to become a much better product, too. Thanks.

Re: Is there a dominant design style?
 

Sounds a lot like my team! Especially with VexPRO products. Also, VexPRO and other Vex products are great for our color scheme since their products generally come in schemes of black, dark green, and gold-ish (mainly from their gears), Aside from pretty colors, VexPRO products have been super reliable, and I've had no major issue yet. Like 1678, if a transmission is not a ball shifter on the WCD drive train, it's a versaplanetary somewhere else. I think the last time we attempted a custom transmission was in 2010. From 2013 on, it's been almost all VexPRO COTS transmissions.

Last year was an exception though, since we used mecanum drive instead of WCD, with no shifters. After competing against 1678, 254, and 118 in several playoff and finals matches, we saw that performance with a drop center 6 or 8 wheel drive in a game is just as good if not better for maneuverability than non-linear motion drives like swerve and mecanum. It's all about driver practice. This is especially important when considering the percieved advantage of these other drive systems in the context of a game like Recycle Rush.

We also found that strafing with the mecanum was only important when lining up with the chute. Originally we only needed mecanum to do our autonomous which was supposed to grab all 3 totes while strafing along the alliance station so the robot was in between the totes and wall. That didn't work out, so we didn't need strafing for the majority of the game.

After seeing the championship being won by 1678 with WCD in a game thought to favor strafing motion, 701 will probably not stray from WCD again for competition, with only exceptions in the extreme.

I think what 701 should try is tube+hole+gusset design. We do this for prototypes, but our practice and final frames are welded. I was discussing with Doug about the advantages of the mechanism versatility for making changes over the competition season up to champs, and the welded frame doesn't give as much versatility as a tube+hole+gusset frame.

*see signature below* WCD FTW!

While I agree with your point, I don't think 1678's WCD is what made them world champion caliber.

Re: Is there a dominant design style?
 

"Because they do it" shouldn't be your rationale. Yes, all the top teams doing something is generally a indicator that it's a smart decision. However, blindly following them without figuring out the rationale behind their decisions is a bad idea; there might be variables at play that made WCD the right choice for them but not for you.

Note how Corsetto said that 1678 is going to keep learning from the teams they're inspired by. Copying 254 or 973 probably had some sort of analysis of their resources and what direction was best for them.

There are successful teams that do WCD, there are successful teams that do omnidirectional drives. There are successful tube and gusset teams, there are successful sheet metal teams. Which one is right is completely dependent on the resources available to your team.

Re: Is there a dominant design style?
 

Totally agree! Well put.

"Blindly following" and "not figuring out rationale" are pretty poor ways to approach the problem.

The OP is asking the right questions. You need to start by looking out, then shift your focus to looking in. In other words, "steal from the best, invent the rest".

Start by knowing as much of the existing knowledge base as possible (steal from the best).

Then take that knowledge, apply the things that make sense for your team (resources, experience, yada yada), and tweak/customize/throw out the things that don't (aka invent the rest).

Too many teams flip the process, spend too much time focused inward (inventing solutions to already solved problems), and don't realize that the competition has already left them in the dust.

-Mike

Re: Is there a dominant design style?
 

6 WD is the most common design style, I challenge the OP to find a game where swerve drive was necessary/needed.

Re: Is there a dominant design style?
 

If people are interested, 5188 put a decent amount of effort into figuring out what drive direction to pursue for 2016, and came to a conclusion of a chain-in-tube WCD. This was an attempt to balance several factors, including cost, weight, performance, maintenance time, and machine time. I'll see if we can publish a white paper on our decision process before build season starts.

Re: Is there a dominant design style?
 

I really like this post in that it illustrates something that is hard to understand.

There are successful teams who use WCD, Sheet metal, swerve, kitbots, and every other style in-between.

The success comes not from using a particular style of drivetrain, but from building the right kind for your team. That goes for most mechanisms too.

5254 and 20 are both probably going to use shifting 6 Wheel WCD's in 2016. 5254 will use Versaframe and gusset one together, 20 will use stock tubing and weld it together.
5254 will likely use a lot of COTS parts and gearboxes for everything and try to build something incredibly simple and then iterate on it. 20 will likely have a detailed CAD drawing of a robot we hope will be able to compete at the highest levels, then work with it until it works like expected.

Both have the potential to be successful in 2016, despite varied styles of build and materials available.

Use what's right for your team. Do a detailed engineering analysis of what makes sense for you. Don't be dissuaded by people who say you can't win without this resource or that resources- they're wrong.

Re: Is there a dominant design style?
 

Since the modern kit chassis/drivetrain is pretty good, if you use it you can spend more of your effort on figuring out the game and building great mechanisms. Great teams can win with whatever drivetrain they pick...it's really not that important.

Re: Is there a dominant design style?
 

Also known as the pot roast rule.

Re: Is there a dominant design style?
 

In my experience, I have seen the highest correlation between robot performance and quality bumper design*.


*obviously not valid in 2015 or before 2008

Re: Is there a dominant design style?
 

We used to use the vexpro ball shifters until last year. We stopped using them, because we broke several in 2014, and ultimately went through 4-5 total in 2014. We not use the wc products ss gearboxes. We will go with an 8 wheel WCD this season, barring some very odd game. We are will likely also to chain in tube. We went through an extensive drivetrain research last season and decided WCD is the drive of the future for us.

We use vexpro versaplanetarys for everything else.

Re: Is there a dominant design style?
 

I always use this rule for third bots. But there're plenty of robots that have been decent but had TERRIBLE bumpers. Ok, actually this is just an excuse to pull out one of my favorite pictures:

https://scontent.xx.fbcdn.net/hphoto...10&oe=56DB5819

Re: Is there a dominant design style?
 

This also has to be one of my favorites. Especially since it won a regional.

http://archive.firstinspires.org/sit...?itok=dMTXO-FG

Re: Is there a dominant design style?
 

This. So much this. I was just discussing with my friends how it seemed that the most popular things teams are taking from the latest Behind The Lines episode were drill drives and tape, and not the processes that these great teams used.

Drill drives and tape will not make a good team, and probably not even a good robot. Understanding that 118 has a well defined and thought out prototyping process, and working to develop one for your own team, will go miles further toward improving your team and robot.

That's not to say you shouldn't use drill drives and fancy tape. Go right ahead. But don't miss the forest through the trees.

Re: Is there a dominant design style?
 

Yep. I call this phenomenon "Cargo Cult Robotics".

Re: Is there a dominant design style?
 

Okay, so what am I missing? A lot of folks here are saying basically the same thing: don't be slavish. Fine. Bu,t we built our first WCD as an off season project a year ago and loved it; we are on our fourth WCD build right now. Is it wrong that we took inspiration from teams we admire (including 254)? Is it bad that we are planning on using this construction style for all future projects, barring some radical reinventing of the FRC game?

A far as vexpro gussets are concerned, that one is a no brainier. I actually contacted a company in Russia four years ago in hopes of buying exactly the product that Vex now produces. We have no welding capability, so riveting works for us.

Re: Is there a dominant design style?
 

The important part is that you tried it as an offseason project instead of blindly doing it because a team you admire does it. You saw that a team did something a certain way, then tested it to see if it worked for your team. You figured out the "why" and the "how" behind the "what".

Re: Is there a dominant design style?
 

Not at all!

1. Off-season project: This indicates that you acknowledged that there were potentially variables or aspects of a WCD that you didn't fully understand, and that these caused an inheriant risk if you tried this out during build season. Building it during the offseason meant you wanted the opportunity to find out what these variables were, so that you could isolate and control them when you first built a WCD for competition use.

2. Iteration: You say that you're on your 4th WCD build. I'll go out on a limb and assume that it's not exactly the same as your first one. I'm sure you have tried to make improvements upon each design, and that these improvements are tailored towards your experiences with the drive and resources available to you. I'm sure that some of the details of your implementation are not exactly identical to that of 254.

Due to these, you've definitely gone through some sort of learning process and gained some lessons during your work on your WCD.

I'll explain my original post with an example of what I would recommend to avoid; I talked to a team during this season that wanted to improve their intake. Their solution was to plug in a 2nd monitor, pull up the best picture they could find of 1114s intake, and copy it as perfectly as they could given the information they had. While I'm a fan of doing anything you can within the rules to be as competitive as possible, I think that you lose out on a lot if you attack a problem with this approach. What I would recommend doing instead is building a quick prototype of the intake, figuring out all the critical aspects of it, and implementing it in your own team's construction style. While it might take a bit more time, you probably end up with a system that performs just as well, but is easier for you to manufacture and easier to integrate with your robot than a carbon copy. In addition, you learned a lot more than if you just copied everything you can see, including some tips and tricks that you could use on a future robot as well. Win-win.

Sure, you stole a concept from 254. But you took the time to implement it yourself and tailor some of the details to your liking, which IMO is where the real learning happens. You don't reinvent the wheel in the real world either; innovation is what drives engineering.

Re: Is there a dominant design style?
 

I may not have provided enough context. Of course WCD is not what made them champs, there's a lot more that goes into it. The situation with my team was at the beginning of the season, we had experimented with a slide H drive and found that was not a good for going over the platform since our middle omni wheel made the robot bottom out and lose contact of the floor with some of the outer wheels. We then moved on to mecanum since we still wanted to try the strafing autonomous.

Looking back on the season, we realized how much time and material we wasted manufacturing plates for the H drive that was never used and the near uselessness of our mecanum strafing since the auto never played out. We could have just kept with what we already have made the past three seasons in a row.

WCD is a good choice for us because we either will be able to make one quickly or have one one pre built for prototyping early in the season. Since this is a drive system we can easily produce, it's a good choice to stick to for prototyping at the very least.

I use the example of 1678 since we had anticipated early on that the better teams might use strafing to make landfilling or chute lining easier. The whole point is that regardless of the style and layout of the game, some form of WCD is likely not a bad choice for us and other teams who also regularly use it, as long as drivers are well practiced.

Re: Is there a dominant design style?
 

it seemed useful in lunacy...

Re: Is there a dominant design style?
 

While it seemed useful, 2/3 (971 and 67) of the World Champs had 6WD.
And just for reference, check out this article posted on FRCDesigns.

Dominant styles of design also vary by region.
Ultimately it is most important for teams to choose a strategy and design that they can build within their resources.

Re: Is there a dominant design style?
 

2001 was my first First season. As far as design styles the biggest change I have seen is that back in 2001 most teams were kludging up robots with almost no 3d modeling and cnc machining. Now many great teams design in modeling software and use cnc machining in house or by sponsors. Great teams build machines not kludge bots.