Low bar or not
 

My team is wondering if the low bar is worth it or not and we want to hear from you.

Re: Low bar or not
 

It is very much late in the season for this kind of decision to be made in my opinion.

It's going to be a trade-off decision for your team, and many others. Can you accomplish the goals you need/want to to be able to compete effectively by going under the low-bar, or can you achieve your goals easier by not doing so.

There is definitely more of an engineering challenge to trying to scale with a short robot (low bar capable). Scaling is significantly easier with a tall robot (non low-bar capable).

Are you a rookie team? Can you contribute to your alliance in more ways if you do not go under the low bar? Do the math for how many points you could do with or without doing the low bar and go from there.

Re: Low bar or not
 

no we are not a rookie and the reason we were wondering is because we ran in to some problems with are some of are mechanisms

Re: Low bar or not
 

It's about the right time. Not from the design perspective but from the build perspective. Conceptually the low bar is worth it. But if there are other required components that can't fit in a low bar package then now is the time to decide if you want:

• A functional shooter or the ability to go under the bar.
  The ability to climb during the end game or to be able to go under the low bar.
  The ability for the drive train to negotiate other obstacles or go under the low bar.

Any one of those bullet points may be a reason to give up on the low bar. Certainly if all 3 are the case the low bar is holding you back.

Re: Low bar or not
 

It depends entirely on your game strategy. If it involves being able to breach the defenses solo or essentially so, yes. If it involves a rapid cycle time of getting boulders from your own secret passage to the courtyard for scoring, yes. Those two items are where most of the points are.

The only game goals which requires that you be tall are scaling the tower and defending/evading defense of boulder launches at the high goal. When you remember that you do not have to have all of your manipulators inside the frame perimeter when you go under the low bar, (only when scaling, launching, or defending), even these conflicts can be easily resolved.

Re: Low bar or not
 

We were faced with this decision early this week.

It was low bar or scale.

Essentially our scaling mechanism did not fit under the low bar (A large cylinder on an articulating shaft. We even went as far to have this manufactured.
http://imgur.com/r8dtvma

We looked at it this way
No low bar = loss of 10pts
No climb = loss of 10pts

But there are other advantages of the low bar including easier autonomous and faster cycle times. So, we decided to forget that climber.

Key word is that.

Since it was only the Monday of week 4 we decided to R&D a new climber in a day. We came up with a telescoping PVC design that deployed a hook.

We are also in talk of making the old climber some extreme cheesecake. I cheesecake worth a couple hundred dollars.

Re: Low bar or not
 

I would agree with JohnFogarty, it's pretty late in the season to be making the decision for such a crucial feature, as it basically defines how your robot will look.

The benefits for a Low Bot:
-Low Bar
* Your robot can feed balls to a shooter, making you a strong support robot
* significantly decreases time spent maneuvering other defenses if going for pure cycling
- Low robots tend to have low CoG, making them effective pushing robots, a strong consideration for any alliance's second pic
- Potentially better at crossing defenses than a High Robot due to CoG

cons of Low Bot:
-It's much harder to fit mechanisms in, and represents a very significant design challenge to fit a lot of features into a smaller space.
-Shooters are in general less effective, since the ball has to travel farther/you have to take a greater shot angle since you're so low
-Potentially faces robot defense issues, as they are unable to block shots and their own shots are easily blocked


Benefits of High Robot:
-Higher shooting platform may lead to better accuracy
-More space to put components and mechanisms, increasing versatility and value as an alliance captain's pick
-some defenses may be easier if you are able to manipulate the defense from the top
-It's almost impossible to block you from taking a shot
-possibly easier to climb, as your mechanism moves a lesser distance if you mount it high
-Significantly greater capability when loading balls AND playing courtyard defense, as your height will allow you to block

Cons of High Robot:
- Higher CoG means that you may face tipping issues against Cheval, Ramparts, Rough Terrain and Rock Wall if balance is not taken into consideration
- Higher CoG also means that tipping is a possibility against powerful drivetrains or collisions
- You are entirely unable to use the Low Bar, making it easier for opponents to plan their match
- Possible weight issues, due to extra mechanisms

Re: Low bar or not
 

How is the low bar worth 10pts?

Re: Low bar or not
 

Well its instantly worth 10pts for us in auto as its really the easiest defense to cross without throwing off all of our sensors and, crossing the defense twice is 10pts.

Effectively 20 possible points.

However, it is very likely another robot will be low bar capable so we took 5 points off. And, its also likely we can do an auto while breaching obstacles like rough terrain, ramparts, the moat, and the rock wall so we knocked down another 5 points.

It is not the most scientific way of thinking but imo its a decent rationalization of the point values up for grabs.

Re: Low bar or not
 

Actually, the MAX you can get out of the low bar is 15 points (solo, at any rate). You can't get crossing points twice in auto. One auto, one telop, after that it's Damaged and no more points are awarded.

But yes, I see how you're thinking. I kind of like that line of thought.

Re: Low bar or not
 

Our team decided to combine the best of both worlds, and create a robot that fits under the low bar, but unfolds upward to shoot and climb. So far, our clearance beneath the low bar is less than an inch, which is very problematic. It doesn't look like we're going to scrap the low design, for the simple sake of going underneath the low bar, but might have to alter some other mechanisms to gain that ability.

Re: Low bar or not
 

If you are making this decision at this point in the season, the answer is no. If you were making it earlier, the answer is maybe.

Re: Low bar or not
 

Are you an inch under 16, or an inch under 14? The low bar is located at the neutral zone end of the defense, which means that you will need to be significantly shorter than 16 inches on your leading edge as you pass under hte low bar.

(I use the term leading because we have tried to eschew use of front and back for our robot. It will cross different defenses in different directions. We have a boulder launch that projects the boulder at the high goal from the opposite end of the pickup. Our robot ends are "pickup" and "launch" rather than "front" and "back".

Re: Low bar or not
 

Depends on how good your packaging guru's are. ;)

It is possible to fit everything you need to play the game under the low bar. You just have to plan for the space for each mechanism beforehand rather than look for space when you get around to it.

Re: Low bar or not
 

Our height is 14.9 inches, give or take. We have a definite front and back to our robot because of our use of an arm, but we're alternatively looking at approaching the low bar from the back while going in to the courtyard, and the opposite for exiting the courtyard.
Since the defense isn't all that big, how big is the difference in a structure being closer or farther to the neutral zone? And will it make that much of a difference trying to pass underneath it?

Re: Low bar or not
 

On the contrary, I expect the majority of teams in FRC to make this decision in Week 5 or Week 6 of build season.

I think most teams have decided to go for it, but many, many teams will learn during testing that they are not very good at it, that Mechanism X interferes, that they have to drive slowly / in a specific way to go through it. At this point, some teams will see an opportunity to be better at X / Y / Z aspect of the game in exchange for not being able to go under the low bar. For many it will be hanging. For others perhaps a more accurate shooter will work with extra height. Maybe the mechanism teams use to go through other obstacles just can't tackle the low bar for some reason.

Now is when teams need to be thinking about "is it worth it", because the end of the season is when teams tend to break from their strategic objectives. Teams who "should" be keeping low bar functionality WILL give it up for the sake of keeping a "cool" mechanism, and teams who "shouldn't" be keeping the functionality will at the expense of the rest of their robot. It'll happen for sure, so we should have an informed discussion as to what robots should keep this capability and why rather than shutting down people for being "too late".

(The painful thing about this decision is that, if teams that abandon the low bar decided to abandon it from Day 1, they would be much better at every other aspect of the game simply because of the loosened constraints. The jack of all trades is the master of none, after all, and this is a classic case where over-reaching can hurt a team's season)

Re: Low bar or not
 

It is on the cusp of maddening insanity to attempt to fit EVERY mechanism under the 15" while designing and working to being the BEST at something*. I will have a lot of respect for a team which stays under ~15" and can play every aspect of this game with any level of repeat-ability.

The really nice side effect is that even with large 8" wheels and a high ground clearance, c.g. is very low given the decision to attempt the low bar. In fact, I can move our battery from it lowest-mountable point in the frame to above the drive train transmissions and shift c.g. up by only about 1/8" (according to CAD...).

*Something being pick one: Scaling ; High Goal ; Low Goal ; Defense (point prevention) ; breaching ; Autonomous

Re: Low bar or not
 

Call us insane then. (we are at 14.5" right now) :)

Re: Low bar or not
 

We're right there with you.

We pushed to 15". Slowing down a bit to go under is our tradeoff for the extra critical 0.5" of height for a certain mechanism.

On the plus side, the portcullis doesn't have to be raised that far :rolleyes:

Re: Low bar or not
 

Yuuuup. We're a bunch of madmen also. The 2016 robot will certainly be our most dense robot ever.

Re: Low bar or not
 

We are currently at 13". No climber yet, but we will see.

Re: Low bar or not
 

we finally got the robot mostly working today...and tried it on the low bar. It fit.

https://youtu.be/8ZeExbmZBVA

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Re: Low bar or not
 

LOL, we were constantly arguing over which end is which. We finally came to the same kind of terminology compromise, although ours is "intake" and "shooter"

Very nice. We look like we have similar bots. Except we have an articulating shooter and a climber. See you in NYC.

Re: Low bar or not
 

I have a hard time finding somethings value or worth until I either have overwhelming evidence that indicates how a scenario will run, or I have run the scenario and just found out that it is worth.
The big thing though is if you pin yourself to this big (or technically small) of a constraint, then you better be utilizing it fully to your advantage otherwise you might be making sacrifices for nothing.

Re: Low bar or not
 

Those are good points. However for my team at least, we found that we could fit everything under the height limit and still perform well. At times I have wanted to completely rework the design, but working through it has definitely paid off.
At the very least it gives us the option of going under, and to change our strategy. It's easy to get tall, but it's hard to stay short.

Re: Low bar or not
 

Yup, lots of nuts in the nuthouse. We are definitely nuts. Another camera angle...

Low robots force discipline. You are either going to have a rats nest which is unreliable or a very tight robot which can survive. This is going to be a rough game. Sadly, no printed robot for 3824 this year...:( Cracked the frame week 1. If this is a fast game, loads on structural members will be the highest we've ever experienced.

Re: Low bar or not
 

We have figured out the low bar and Groups A,B and D and have a shooter that can go high or low. Still working out and working on our climber concepts but that was the lowest our list of to dos .

Re: Low bar or not
 

Depending on your wheelbase and where the high spots are, this may be too tall because of the ramps coming and going. See this thread for details.

Re: Low bar or not
 

We just mounted our arm on our robot and when it is folded down, it is like 11.5" in the front and 13.5" in the back. We pushed it under the low bar by hand (not done wiring yet) and we aren't even close to touching it right now.