Penalizing mecanum wheeled robots durring alliance selection.
 

Over the years as mecanum drive robots increse in popularity its become incresingly common for teams that seed in the top 8 to penalize 1st round picks for having a mecanum drivetrain. So CD comunity, what does your team do when it comes to mecanum drive robots?

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

We built mecanum robots in both 2011 and 2012. We were (for give my narcissism) very good both years, and mecanums proved to be advantageous in both games.

The single only reason we didn't use them last or this year, is specifically because other teams don't like them immediately.

I have never seen a mecanum implementation (code etc) better than ours, but nonetheless, it is painful to be judged by stereotypes than performance

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

We have picked Mecanum wheeled robots in the past to be on our alliance. Most notably at Arkansas in 2013 when our 1st selection (Ubotics, FRC#3507) was a mecanum wheeled robot and our alliance made it to the finals.

However the biggest impact mecanum wheels have on our pick list is with 2nd round selections. Defense normally plays a bigger role in our choice for a 3rd member of our alliance and more often than not a kit bot drive base will beat a mecanum robot when it comes to standard defense techniques.

There are teams that have used mecanum wheels very effectively but similarly to crab/swerve if you are not one of the teams doing it at high level it rarely pays off. I often advise rookie and young teams from using them on their competition robots.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

Last year we had mechanum wheels and were the 15th highest OPR on our field but our robot was slow and could not go under the pyramid and could only load in station and we went unpicked.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

Maybe meccanums are less popular in NorCal, but I didn't have to make a decision about picking a team with meccanums all that often.

(The following is about how I helped choose picks for 100, so don't read anything about 971 into my statements.)

For first round picks (if you are in that position, we were only there once when I was helping choose our picks), it's often fairly obvious who the next best team is, or if not, it's a choice between two teams. Usually, the teams who are picking from the top 8 have done their homework, and base their picks off objective statistics at least in part. Most teams that have a good shot at getting picked first have already chosen not to use meccanums, so it's usually not an issue. But, if I was in the position of picking first, and there was a team that was clearly better than anyone else available who ran meccanums, I would pick them.

Second picks are a lot harder, because there's a larger pool of teams that it might make sense to pick, and frankly most of the teams left over really aren't that good. Of course, it depends on the game, but in my experience, you're looking for a team that has a strong drivetrain and knows how to drive it, and if possible can hit auto and help with the endgame. If there's a team with a reasonably well built WCD and good drivers left by the time that we can pick them, we'll go for them 4/5 times. Offensive ability (which meccanum bots may or may not possess) is secondary, as the captain and 1st pick will likely be doing essentially all of the scoring. You want a good defensive team for your second pick, and for whatever reason, in my experience a well built WCD works best for that.

I don't think there's some vast conspiracy to never ever pick meccanum bots, but I do think (from being there in the past) that given a few roughly equivalent robots, teams will usually pick tank drives over meccanum drives. Going meccanum is usually a decision based on coolness, and teams with meccanums are often kind of wild cards. It often just feels safer to pick a team without diagonal rollers on their wheels.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

Great poll and thread. I am very interested to see how the results turn out. As for me, I chose "does not affect position".

Interestingly enough, for some of the regionals I have attended, I might actually be more prone to select a mecanum bot than a tank bot for a defensive pick. The reason why is because a mecanum robot always* has 4 drive motors, while too many teams still use only 2 drive motors for tank drive. I would still pick the robot that is the best driven for a defensive pick, but all else equal, I would feel better about having a mecanum bot on my alliance than a 2-motor tank drive robot.

*Although I have heard of teams that try to drive a mecanum configuration with only 2 motors. *shudder*

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

Our alliance did this at Panther Prowl last year. We could not have been more pleased with the outcome.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

Generally, mecanum is a major detractor when my team is assembling the pick list. However, we will pick a mecanum robot if it offers us what we need. We picked 2 at the crossroads regional. Personally, I think mecanum is a poor drivetrain solution, but some teams do it very well.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

For our team, if a team has mechanum wheels on their robot or not is a feature that we check, but wheels in general are a feature to consider while picking. We don't judge just by one feature, we look at all aspects of the robot, then choose. Although our team commonly makes jokes about mechanum wheels as they don't have the best reputation, we have yet to penalize a bot on our pick list because of mechanum wheels.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

It honestly depends on if the team knows the limitations (reduced pushing capability, vulnerability in open spaces,) of their drivetrain, and if they use it effectively. I'd have no problem picking a team with a mecanum drive so long as they effectively take advantage of their drivetrain and play smart with it.

Unless we're playing a full contact game like Aerial Assist. I would not pick a team that has a pure mecanum drive for a game like this. IMHO, drives with traction wheels were king, even octocanum/butterfly.

-Nick

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

For this year's game our team used mecanums and knew that we were slow and easily pushed. Seeing that, we preferred to have our alliance partners have a decent tank drive to not only keep our play at a decent speed, but also to have a good defense while they weren't handling the ball. It may be a little hypocritical, but defense was a major part of this year's game.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

For us it's all about performance. It doesn't matter what drive train a team has, so long as they effectively use it and are the best available team at that point in the selection process. If we need someone who can score, we look at the team that has best shown the ability to score the most points per match. If we need someone to play defense, we look at the team that has been able to decrease an opponents score the most. In the end, it's all about the bottom line - can you score more points than someone else. Ignoring a team who has proven they can affect the bottom line the most of everyone available just because you don't like a feature of the robot? We try to avoid that.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

I think it really comes down to how big your wheels are. In 2013 we bought big 8" diameter, 2" width wheels and were actually one of the better pushing robots out there (didn't get picked, but that was mainly because our shooter was awful). In contrast, we used 6" diameter, 1" width wheels in 2010 and got pushed all over the place.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

If they are the team that best meets my criteria I pick them. If they aren't, I don't. This is the same logic I apply to any other team.

So, no I don't penalize them. I just tend to rank features they traditionally lack as higher priority than the features they excel at.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

I have not personally been a part of selecting teams, but I have noticed that you have to have a strategy in your alliance that accommodates a mecanum drive bot. Mecanum is good for being evasive (if built and driven well) but is bad for being physical and getting in pushing matches. If you don't have a need for it don't pick it(mecanum drive).

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

Automatic DNP, unless there are too many mecanum bots for that to be possible.

It's not that mecanum wheels are inherently bad, just that 99% of the implementations we see are.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

If the team drives the mecanum drivetrain well, I see no reason to leave them off the list.
Then again, I don't do any scouting.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

In my fantasy world I would dearly love to see Teh Chezy Pofs do mecanum just one year so they can show us all how we have been doing it wrong all this time and then maybe everyone else would stop the mecanum bashing and shut up about how mecanums are never on Einstein.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

I think you'll see it when they decide that powdercoat looks kind of stupid, wires don't care if they're ziptied down or not, and that they should stop driver practice because it distracts from watching South Park.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

We're not penalizing anybody. We're picking robots that best complement our robot and the strategy we want to play in the elims.

In 2014, there was no place for a (pure) mecanum drive robot on our alliances. The ability to resist pushing was viewed by us as essential to forming a 3 assist cycle. Resisting pushing with traction allows for "wall" defense and also helps avoid being spun while shooting or ejecting. People argue about whether mecanum can push or not, but they're really missing the point - pushing resistance is where mecanum robots really struggle.

There were some robots at our events that were mecanum drive that played fairly well but without traction they just could not get into and hold position where they needed to be. Setting up truss shots or passes with them was just too difficult when they could be spun by defense. In spite of this, there was just one other robot on our list between our alliance's second pick and a mecanum drive robot at Finger Lakes.

In other years, the "cost" of a mecanum robot versus a traction robot varies. I feel it's worth noting that more often than not the best several teams at a regional are all tank drive. In this case the teams aren't being selected because they aren't mecanum, but because their robots are overall better than the mecanum robots are. In addition, in the somewhat rare event that the best teams at a regional include mecanum robots, these robots tend to have well driven and implemented mecanum drive systems.

To be quite frank, I think a lot of teams that aren't very good pick mecanum drive because they feel like the ability to strafe allows them to drive better with less practice. It seems more trivial to just gun the robot forward into a scoring zone, then strafe to where you actually wanted to be, than it is to drive in a smooth arc up to where you wanted to score. However, without plenty of drive practice, it doesn't matter what your wheels are, you're a lot less likely to be a first round pick at all.

In short, there's almost no situation where all other things equal, a mecanum drive is a net gain over a tank drive for our alliance, and I've observed a correlation between teams choosing mecanum wheels and teams dropping down our pick list due to poor manipulator design.

Also, if you're the kind of team that gives teams grief for making choices differently than you and assume teams were too stupid and biased to pick your obviously superior robot based on its wheels, maybe you're not the kind of alliance partner we would want to work with?

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

Despite formerly being on 1523 (who has used mecanums since 2011) with the OP for years I agree with all your statements except for the above, where is the data to support that statement since mecanums have nothing to do with a manipulator?

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

Purely anecdotal. My experience supports this claim but I cannot say that there is correlation with any sort of certainty.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

Correlation doesn't necessarily imply causation here, and mecanum robots aren't considered by us to have poor manipulators *because* of their wheel choice. I'm trying to say that many teams that have mecanum wheels didn't get picked for other reasons as well, not just their wheel choice.

As for data, the robots that are near the bottom of our pick lists or on our DNP lists are more likely to have mecanum wheels than the robots near the middle or top of our pick lists. I could publish our Finger Lakes pick list from this year if you really want hard numbers, but it's just a trend I've noticed. There are exceptions, and I'm reasonably sure that 1523 would be one.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

We saw a lot of mecanum-powered robots at the Pine Tree district event earlier this year. Generally, mecanum robots weren't really good at offense, but were crushing in defensive scenarios (important in an event where both teams in the finals relied on parking at the 1-goal and firing.) However, like most teams, we wanted offense over defense. Unless the mecanum bot isn't one dimensional, we don't really have them high up on our list.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

Maybe it is a region thing, for the most part in Florida the mecanum bots do not have poor manipulators, though a lot do follow your statement about drivers not being as well versed with driving as their traditional drive counterparts. Like you said their are exceptions to every rule though your offer of data does bring up something, if possible I think it would be interesting for someone to compile data from events and see if there is a correlation between drivetrains and their ranking, and elimination selection/performance.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

1065 has a SOLID robot this year, despite having mecanum wheels. We picked them during elimination matches and made it to semi-finals. :D

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

I think Moose had a drop down traction wheel on each side this year

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

1065 was not pure mecanum. They had jump drive which was powerful enough to push 233's 8WD sideways. Im shocked we where able to pick them in Orlando as the #4 seed.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

Yeah, they had 2 1" diameter traction wheels bolted together on each side. As fart as I know, they only used them during pushing matches though. *So when you tried to stop shots into the goal :p*

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

Who knows, Skystalker V2 may come equipped with 8 wheel drop center mecanum.

They where this year.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

All other things being equal, we would most likely pick a non mecanum drive over a mecanum drive.

However, I think it's important to point out that rarely are all other things equal. Like anything else, design to play the game well and be consistently contribute to the alliance in a positive manner.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

Yeah, but they never touched the carpet ;)

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

This year, the robot's drivetrain didn't matter to us nearly so much as how the robot was being driven. This was probably our biggest selection factor; I asked scouters specifically to note great or poor maneuvering (especially around defense). We even used our first pick as 2nd seed at North Carolina on a 44th seeded box bot, just because they drove very well. Likewise, plenty of drivers at champs proved that mecanum was no hinderance if utilized well.

Discriminating against robots for particular attributes should not be done if they can hold their own on the field, period. Unfortunately, teams with such attributes do have to prove themselves to overcome doubters, and even then, the tiniest of concerns might be enough for alliance captains to discredit them.... it's really unfortunate, but it happens, whether you're a mecanum bot, rookie team, or had no intake this year :( (cries in corner).

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

When teams were scouting our robot it seemed like they were penalizing us for having mecanums even when we told them we were using 4 cims and 4 mini cims.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

8 motor mecanum isn't bad

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

You have peaked my interest, was there any noticeable difference in performance in comparison to the traditional 4 motor? Specifically in terms of pushing power or resistance?

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

Not to call you out specifically, but you mentioned something that is frequently spread around, and not quite true. Mecanum is often touted as being good for being evasive, but due to the fact it must be geared slower (for more torque) to strafe well, they typically can't outmaneuver a tank drive (this is especially true in the 6 CIM era). If you want an example of this, look to Ultimate Ascent;

There was a very small handful of robots able to complete 7 cycles, which was a task that required nearly no pushing, and all maneuverability. If mecanum wheels were more maneuverable, you would expect the best cyclers to be mecanum robots, but this was not the case. 118, 469, 610, 245, 868, 11, etc., were all tank drive robots.

"Pushing Power," is a function of coefficient of friction with the floor, robot weight, and torque. Wheels sizes (widths) can influence coefficient of friction, but tread material is typically a more important factor. Wheel diameter can also affect coefficient of friction by changing the size of the flat patch you have on the carpet, but this has a pretty minor effect. Torque is a function of your gear ratios and wheel diameter together, as well as the efficiency of your transmission, but you can gear for as much toque as you want, regardless of wheel size.

TL;DR: You can push with small wheels if you want to, just be aware of the variables at play.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

As a team that went with mecanum this year (as much as I did not want to) I can say that it was a factor in teams selecting us. At TVR we had teams tell us they would pick us if we switched to traction wheels. I believe we had a great bot design for the game but the mecanum just made us a bot that could get pushed all over ( esp by 2791). Needless to say we have switched them out for offseason events, Im looking forward to seeing the results.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

Wait, being fed by human player doesn't count as an intake? ;)

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

Yes, if you have mecanum wheels it will lower you on my picklist. Especially for our third pick robot we try to avoid teams with mecanums because its very hard to play effective defense with mecanums. It is possible I have seen it done but most of the times these teams have a solid offensive strategy too meaning we wouldn't want them to play defense to begin with as we need them to score.

We have picked/accepted invitations from teams with mecanums more notably this year we allied twice with 58 and once with 126 both were very effective robots on the field with mecanums. If there were identical robots to them just with tank drives I would have rather gone with the tank drive.

You might call it "penalizing" but I see it as a weakness if the other alliance can push you around as much as they please.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

Our mecanums this year were the best i've ever seen. We had 4 CIMs and 4 mini-CIMs.

We ended up pushing practically everyone. Yes, there are a few battles that we lost, but we just spun around them and continued. I was surprised by the amount of power that we could put down.

We pushed a whole bunch of 6 CIM 6/8 wheel drivetrains.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

Well it definitely made for a heavy robot(~22 pounds in motors and motor controllers). It had quite a bit of torque but it was still hard keeping 6 wheel drives off us.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

Any videos of this?

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

Not quite the same thing, but reminds me of this thread.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

2220 has been picked by a certain MN team that has used mecanum for the last few years-- 2052 (who has also won three regionals in a row now).

However, frankly, they're the only team I've ever seen that was successful with mecanum-- and that's because a whole lot of driver practice (they're also the only mecanum bot I've seen that actually "runs circles" around others in terms of evasiveness), and just generally the great quality that they build into their robots.

It's all performance/quality based. I will admit that I tend to scrutinize mecanum more than tank, just because I've seen more subpar, problematic, or nonfunctional mecanum bots than "conventional" NWD bots.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

I checked out a few of their videos, and in qual 89 of MSC there are a few moments when they cause noticeable forced lateral motion of an opposing robot.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

2052 completed 7 cycles with a mecanum drive train, so the 7-disk cycle club was not exclusively made up of tank drive robots.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

This is my opinion and should not reflect on my current or any former teams.

Before I state anything, I understand that there have been successful teams running mecanum wheels or some form of mecanum-traction combos, locally 126 and 230 have had successful seasons on these wheels.

Far too many teams pick mecanum wheels for the "cool factor" without a solid understanding of the pro's and con's of the system. I would in fact rather pick a partner running an off the self kitbot then a mecanum drive robot.

Generally speaking, drivetrain quality (like bumper quality) can be an indicator of overall robot performance or in the case of our current pre-match scouting and point of interest to determine an alliances strengths and weakness.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

At a real event.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

Are you implying that the Minnesota State Championship is not a real event because it doesn't occur during the regular season?

Realize that all robots attending the state championship must be bagged between their final event and the championship, minus a short unbag perior similar to a district championship. The event uses a real field with the FMS, an FTA, and all the workings of a standard FIRST event. It also includes only the best teams in the state, which makes it more competitive than the "real events" that happen in the state.

I'm curious as to how it isn't a "real event."

I would argue that this is an effect of the inherent bias against mecanums by all of the teams that regularly make it to Einstein more than evidence that robots with mecanum wheels are inherently worse than traditional tank drive robots.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

It's an off season event. I treat it like all other off season events. Just like post/pre season performance doesn't factor into stats in sports.

Or, put a really simple way, if it's not an official event it's not real, it's just for play.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

Yup, there's an international conspiracy of discrimination against mecanum robots by the perennial Einstein teams. These teams have foregone maximizing their utility and competitiveness by collectively (or coincidentally) making the same inefficient alliance selection decisions. Right.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

You forgot the collaboration with the Shadow Government. Clearly this is their insidious work.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

I don't think mecanum wheels are a great drivetrain. That said, I think a lot of teams who choose mecanum wheels also make other poor choices for their robot, and that is the real reason they aren't on Einstein.

The Einstein level teams pick teams who have high quality and reliable robots, which are generally made by teams who don't use mecanum wheels.

That is not meant to be a blanket statement, but my general view and opinion.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

Thanks for the complements! (We've actually won 4 regionals in a row, and 2 state championships, but who's counting :) )

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

I can see that when talking about rankings and official stats (IRI winners will never be truly be considered FRC world champions), but I think when we are discussing the subjective capabilities of a drive train, we can take into account all of the data available to us.

If I came across as conspiratorial, I apologize. I'm not trying to claim that there's a conspiracy against mecanum wheels- I'm just saying that it is unlikely that a team with mecanum wheels will make it to Einstein as a second or third (or fourth) pick by one of the perennial Einstein teams because mecanum is an automatic DNP for many of those teams.

For a mecanum team to make it to Einstein, I think they will have to be an alliance captain. That is the point I was trying to make.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

So your saying alot teams that choose X drivetrain will also choose Y gamepiece minipulation design? Are you also implying that that mechanism is inferrior? If so my eyes and statistics disagree.

Sure looks like one.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

"Quarterback X is the worst quarterback ever"

"Why?"

"Their completion percentage is crap if you include all the practice games they played in"

See the problem with including all data?

Of the teams that completed 7 cycles DURING THE COMPETITION SEASON not a single one of them was mecanum wheeled.

Why is this? If they are touted as more mobile why were these "inferior" drivetrains able to accomplish something that they were not?

What did 2052 do after the season to be able to accomplish 7 cycles? Why did they not accomplish it during the season?

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

It totally depends on the game. FIRST has given us games where defense was nonexistent (2001), and they could do so again. But every game in the three-team alliance era has involved physical contact between opposing robots in any role (scoring, defense, or counter-defense) once the level of play gets sufficiently high. In such situations, pure mecanum drives are clearly at a disadvantage. Depending on the game and the machine, perhaps good driving or superior scoring functions more than make up the difference. But in my experience this is the exception rather than the rule, especially once you get to Champs and there is a large pool of effective robots.

So I agree with you, unless FIRST really departs from recent game design trends.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

The fact that no mecanum wheeled robots on Einstein has occurred means any number of these 4 things.

1. Mecanum wheels somehow prevent teams from going to Einstein
2. Teams who chose mecanum wheels also do things that prevent them from going to Einstein
3. Teams who build robots who are capable of going to Einstein do not chose mecanum wheels
4. Einstein has gotten unlucky. This is unlikely, as we've seen an incredible number of robots on Einstein since mecanum wheels first entered FIRST, and none of them have mecanum wheels.

I will rewrite my statement with more disclaimers.

From events in a specific region that I have attended since 2011 and robot that I have seen on the field, I have seen that the majority of mecanum wheeled robots make other decisions that I do not agree with. On a world wide scale, I have yet to see more than one or two mecanum wheeled teams be very successful and claim it had to do with their mecanum wheels.

Also, in the year that mecanum was most useful (IMO, 2011), 254 won with a simple 6WD, proving that you don't need mecanum. In fact, every single Einstein match ever proves that you don't need mecanum to be a very successful team. Personally, I prefer to work with a team that realizes that something like mecanum drive is not something needed to be the very best and spent more time on other parts of their robot.

This is an opinion, and only applies to robots that have only mecanum wheels on drive.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

Guys, mecanum wheels were on Einstein this year.

:cool:

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

My one defense for mecanum is, when done right, they can be extremely intuitive to drive. Our 2011 robot that made it into the Curie elimination rounds was an extremely easy robot to drive, and I believe that help us succeed that year.

With that said, we have not used mecanum since, including *winning* Galileo this season.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

In my experience, I have only competed with 2 robots that stick out in my mind as having implemented a mecanum drive in a fashion that in some way improved their overall strategic design and were executed well: Team 230 in 2010 and Team 58 in 2012. Both of these teams had creative ways to use their mecanum drives to do something that a standard tank drive could not (or at least not as simply or with the same resources). 230 used theirs to strafe sideways once atop the bumps in the field so they could engage their hooks and climb the tower, knowing they were lined up as they did so and not having to climb as far. 58 used their mecanum drive to position themselves against field elements in auto, moving along multiple axes to ensure they were in the proper location to consistently score their 10 point autonomous.

I often ask a team with a mecanum drive in the pits what their drive train allows them to do that the kit drive train cannot achieve. If the answer is a blank stare or simply "strafing" for no well thought out reason, then I am obviously going to deem their drive as a disadvantage when I see them using it to no advantage on the field. This is because there are then plenty of things that an all else equal robot with a traction drive CAN achieve that this mecanum drive robot cannot. Even the two teams mentioned above did have their limitations owed to their mecanum drive trains, but at least their mecanum gained them something (hey look, points). I'm sure there are more examples of this, but for most mecanum bots I am left thinking that the robot would be at least as effective with a traction drive.

TL;DR consider the marginal gain of your mecanum drive. If one does not exist, why bother?

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

I'm curious, do people move octocanum drives lower on their list/ automatic dnp in a similar fashion to mecanum drives?

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

When we go through our picking process, the first thing is always going to be the best robot in the category we seem.to need first will be brought up first for discussion. After that, we will look at the limitations that pick would have for our alliance and the strategy we want to play. Unfortunately, I will say I hate most mecanum bots because they almost always lack the driver experience needed to make them affective. Granted, there is always that occasional team but not often. Through my experience, I have always been able to find a better robot with some sort of traction setup. Even if that team with traction capability had not shown much, I would feel more confident for example sticking them in the corner and leaving them their for the whole match to inbound and spit out and not move. Where if I had a mecanum bot, I couldn't believe as much that they wouldn't be pushed out of position. (Examples from Arial assist; obviously will vary upon game). I am typing from my phone so excuse any errors haha.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

There are a lot of people dealing in absolutes here, which we should all know is dangerous. (Frankly, the only reason to issue an absolute blanket Do Not Pick rank on a team is for a demonstrated pattern of dishonest and unethical behaviour. This is an absolute that even a Jedi would get behind.)

I echo many of the thoughts said by others in this thread. Each team should be evaluated on a case by case basis, on how their design and level of demonstrated functionality would complement your own robot and your desired elimination strategy. From my own personal experiences, I would say that most mecanum robots we've competed with have not been fit to be included on a picklist. Sometimes this is because their drivetrain makes them easy to defend against or unable to defend others. Other times it's been because the robot is just not generally very good. However, this is not an absolute. In 2010 at GTR, we were very close to picking a mecanum robot (Team 188) over a team who has never lost a regional (Team 2056), and ended up winning the event with a mecanum robot as our third alliance member (Team 1547). So it's not impossible for teams to use mecanum wheels with a great degree of success, albeit the frequency seems to be much lower. As for any talk of an inherent bias against mecanum wheels that isn't precipitated by actual robot performance, this is just dumb. The only inherent bias I've seen from teams when it comes to alliance selection is a bias against inferior robots, which is exactly what the picking process is based around.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

Super duper ditto.

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Re: Penalizing mecanum wheeled robots durring alliance selection.
 

I think we would actually move octoncanums higher on the list with of course overall performance of the robot taken fully. That drive definetely isn't that simple and takes a lot of effort and machining. More often than not, if a team can do a good octocanum, the rest of their bot is probably pretty solid. Of course this is just speculation and I do not have any statistics to back this up.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

Team 145 has made it to the finals at FLR and TVR respectively the last two years with mecanum wheels.

I think the driver has a lot to do with it also. If the mecanums help you avoid getting pushed or pinned then they are an advantage.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

In our experience the teams that are able to execute highly maneuverable drive trains build swerve drives, so we don't see top-end mecanum drive trains. So we're left choosing our second robot and the mecanum drives haven't been as well executed as the available tank drives for the specific roles we're looking for.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

Friends don't let friends drive mecanum. Enough said...

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

My take on this is simple. A well-executed mecanum, including driver practice, is not something to overlook/automatically DNP. A poorly-executed mecanum is something to be aware of in terms of "we don't want to pick them unless they offer some other benefit", same as any other poorly-executed drivetrain.

Therefore, drivetrain shouldn't matter, the execution of that drivetrain's capabilities on the field should.


Unfortunately, many mecanum teams haven't figured out how to build and operate that drivetrain properly yet. Therein lies the perception problem. There are teams out there that are more consistently successful with a mecanum drivetrain than with a tank drive. They are a minority...

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

I don't think it's much of a stretch to say that while you can't say the mecanum as a drive system is dead on arrival, it seems to be invariably used by teams who are "in too deep" and would have more than likely struck gold with a 6-wheel tank instead of mining for limestone.

One time mecanum user, first time caller: never again. There were some minor maintenance kerfuffles at Alamo this year with an experimental drive train* but it pales in comparison to the constant retooling of the mecanum wheels and code to get the dadgum thing to drive 4 years ago. Finalist trophy, tell the haters to buzz off and whatever, not worth.

15 years later and we're finding plenty of fun ways to retool the 6WD in new and exciting ways to tailor our team. If you want to drive a mecanum, your call. You want to change drive train design on your team from the ground up annually or bi-annually? Ok.

If it a) goes out and executes a valid strategy and b) an alliance captain sees your valid strategy meshing well with theirs, then there's no reason to not do it.

The fact still remains that seeing a well-executed strategy being driven on 4 mecanum wheels isn't something that comes up too often in the history of FRC, and smart people in FRC love their FRC history. If you want to do a case study on wildly successful mecanum drives, go check out the fantasy section of the library because it's as wild a tale as Dean Kamen in a tux (well, not that wild).

*(but Wil, why did your team run an experimental drive train at an official FRC regional? GREAT QUESTION!)

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

in my own personal opinion as the driver and alliance selector, I avoid mecanum wheeled robots all together. I don't see the use for them. They are too easy to block and push around. and with no real advantage, I don't see our team using them any where in the near or distant future.
we were the number one seed at an event this year and the pick list was given to me with a tie for my first pick, I went over to both teams discussed examined there robot ext. and when it came to picking the main reason I picked the team I did was they had hi grips while the other had mecanums.
it turned out that in the next event they had swapped there wheels out for hi-grips and were able to play more aggressively on the field. just my opinion.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

boooya

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

Has anyone considered picking a mecanum robot after talking to the team about switching the wheels to traction for eliminations? Or do you think the lack of drive practice would offset any benefits from the traction wheels?

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

that could end up being a lot of work

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

True, WCD has spoiled me in terms of pit repair/wheel replacement.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

I'd say that the lack of drive practice would effectively disqualify that option. Along with:

--You now have a 4WD all-traction setup. Generally speaking, those don't turn easily. (With the shorter wheelbases we've seen the last couple of years, though, that's less of an issue.)
--You really need to make a major change to the programming, like eliminating the sideways motion part. Otherwise the robot will act really funny on the field. (Alan Anderson has a story about that somewhere...) But changing the program requires some testing, which you probably won't have time to do...

In short, not a good option. Either you take a mecanum robot as a mecanum robot or you leave them for someone else to take.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

It's interesting to see that different regions may have different takes on drivetrain choices. I noticed a lot more mecanum robots in Orlando than I did in Texas (it seemed like 1/3 of all the competition used mecanum).

I figure this might have to do with the mentality of the teams. Again, this is just from my observation, and it's not a blanket statement. But in Orlando, it looked like everyone is more focused on outscoring the opponent rather than denying points from the opponent (which isn't bad, as long as your alliance has more points at the end is all that matters) - in short, offense > defense. For many teams, this was their first regional, yet the finals saw scores around 180 on both sides.

At our first regional, Alamo, the finals never saw a score above 100 points. I attribute that towards a more defensive focused play in Texas, rather than offense. While teams still build and gear towards scoring points, when it comes down to strategy, there's an emphasis on locking down the opponent so they can't score any more points.

Because of this, and the reputation most mecanum driven robots have for getting pushed around, it seems teams in our region stay away from them, and instead focus on tank drives or, even further, butterfly drives to escape pins more easily.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

This may have to do with Alamo being earlier, and teams not being sure about offensive strategies at that point in time. By world champs, teams scored over 250 points even during the finals, due to solid offensive strategies being made over the 6 weeks of comp.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

I attribute that more to about 8 teams at Alamo knowing how to play the game and about 5 or 6 of them actually able to play it.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

I would assert that it is safe to say this is not a view or an opinion, but an objectively observable trend. Of course the only way to prove this; You need a database directly comparing average win/loss ratio of different classes of robots by drivetrain.

This is not likely to happen any time soon, but that doesn't mean we can't recognize that it is true that robots of similar ability level have similar qualities. Mecanum robots historically are not as good as non-mecanum robots. We don't have to like it, but that is how it is.

I think I may coin a term "mecanum-apologist"...

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

49 tank, 10 mecanum, 2 jump drives and 1 swerve.
This is why you see mecanum drive in Florida. Defense is not played nearly as much as in other places and most alliances go for the outscoring strategy. Just look at QF 2-2 at South Florida in 2013. The match had 3 mecanum drive robots, no defense and a 149-103 score.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

Right, but I know it was the first regional for most of the teams there. Our alliance ran the same strategy that we ran at Alamo (2 assist cycles, the 3rd robot being focused on defense) yet the scores were significantly different.

Again, just an observation.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

I believe that it is very well known New England is where some of the heaviest defensive play occurs. watching events all over the US I noticed that in the west its offense offense offense. even in Texas the robots were made to play a purely offensive games, example 148 118, yes they play defense but there robot designs were more offensive. therefore I believe its true that mecanum wheels would be more common in those areas then up in new England.

Re: Penalizing mecanum wheeled robots during alliance selection.
 

Sorry to go a little off-topic here, but these are questions I had relating to this thread.

1) An add-on to the question for those who said automatic DNP: Instead of pick list, if you are a top 8 seed and a team with mecanum wheels above you picks you, do you automatically decline, or is it dependent on performance?

2) Are the same penalties made towards teams with:
a)4WD Omni
b)Slide/H Drive
c)Kiwi Drive

Re: Penalizing mecanum wheeled robots during alliance selection.
 

It depends on performance. I don't think to many teams were declining 33 this year even though they were a 4WD omni robot. However, I assume that their drivetrain choice was a consideration when teams were putting together pick lists.

Re: Penalizing mecanum wheeled robots during alliance selection.
 

1. It would depend on the team.

2.
A: Until a larger amount of teams use them I shovel them into the same pile as mecanum. that being said, i would pick 33 at just about every opportunity.

B: mecanum pile.

C: DNP. it can not push and has a smaller wheel base.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

Strategy can also describe how the 2 assists are obtained such as utilizing the human player and in which zones.

Re: Penalizing mecanum wheeled robots during alliance selection.
 

If a mecanum robot is in the top 8 and picking, either they are that good or they got a good schedule. If they are consistently in the top 8, they're that good. Therefore, automatically declining them--to me at least--is a really bad move unless the team's strategy does not mesh well with my team's strategy. (OR if they're playing scorched-earth and I know about it, in which case, I may decide to accept anyways...)

I'll take 'em based on performance. Again, it's not the type of drive you have, it's how you use it.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

I don't think you can really compare off season professional sports games to off season FRC competitions. For example, in NFL preseason games teams avoid playing their starters and when they are on the field they don't always play at 100% to avoid risking injury. In FRC off season events teams compete with one robot and they usually give it their all since injury/damage is not nearly as big a concern. Off season FRC events can be just as competitive as events that are "for real", so I don't think you should ignore the data.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

You don't see teams making many groundbreaking additions or non-critical upkeep on the machines and there likely isn't a lot of scouting either.

However, your example meant to provide contrary evidence of an FRC offseason event being comparable to an NFL preseason game cites something that happens consistently at FRC offseasons: teams don't put in their top drive team for every offseason match of every event they attend.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

2052 had another 6 hours of unbag time (Minnesota teams must bag their entire robot after their last regional of the season, they are then allowed 6 total hours to work on it out of the bag prior to the Minnesota State Tournament). During that time our driver got more driving practice, along with fixing an issue that caused jams in our hopper. If we had made a practice robot, had a practice field using real carpet, another event, or had just finished the robot sooner we did during the build season, I am confident we would have been at that level of driving earlier. Our driver that season was amazing, but he definitely got better every competition with practice. We went from 3 cycles in our first regional, to 4 at our second, to 6 at worlds during eliminations, and 7 at State. Mostly thanks to driver practice. Mecanum also helped us line up at the feeding station as we had one of the narrower loaders out there.

Clearly everyone is not familiar with the Minnesota State Championship. Teams from Minnesota earn points at their first regional they attend, with point amounts being similar to how teams qualify for the Michigan State Champs. I assure you everyone in Minnesota takes this event extremely seriously, and all teams brought their best drive teams, and their A-game.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

I would actually argue the opposite. Teams have greater freedom to modify their robot during the off season because the rules are more relaxed and the robot isn't in a crate so you can make changes more easily. Teams can also put the competition into perspective and make a much more competitive robot.

Also, I'm talking from experience and I remember my team put a lot of effort into off season events. Maybe not all teams do, but my team competed like it was any competition and I'm sure many other teams have a similar mindset. Also I know some off season events are taken very seriously. IRI is the first one that comes to mind.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

Sounds like you haven't been to a Cali offseason then.

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

More professional sports analogies:

LeBron James can take the opportunity to retool the starting 5 he plays on when he calls up 9 of his closest contemporaries on the court for a rousing game of basketball at his house. While ESPN may want to carry the feed, the Elias Sports Bureau probably has better, more official things to do.

Even the FIBA Gold Cup is an event held by a major sanctioning body, but Anthony Davis' FIBA stats aren't coming up in the NBA books.

You want to bring up IRI? MLB doesn't count any statistics in official books for their all-star game either, even if some people walk home with special hardware.

If you want to challenge my anecdote of "not everyone is going out there with every resource they can muster to win the Alliterative Offseason of the week" with "my team does", that's your prerogative. Still doesn't make any of these events FRC-sanctioned events with any official meeting, which is the point Andrew was making earlier.

What was this thread about again?

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

I live in Virginia and am a full time college student. I'd appreciate it if you can fly me out to Chezy Champs :)

Re: Penalizing mecanum wheeled robots durring alliance selection.
 

The way that our team operates in terms of picking is that the first pick will be based primarily on ability. If a team complements our strategy of play well and will put the most points on the board then they will be the first pick regardless of drive train (usual caveats for reliability, etc). The first metric that we use for our second pick is drivetrain. We essentially just want a strong drive( traction wheels, 2 speed preferred) and then after that we will look at their scoring potential.

For us drive train can certainly brake a second round pick but it is highly situational. If we are an 8th seed or a similar position where we need to take risks and try a robot with a huge upside then we might go with a mecanum robot for the second pick to try and outscore the higher alliances.