Who is going over the bump? (A Pillar really)
 

I didnt see a thread for this (correct me if there is one), but anyway, what teams are having a drive base that will traverse the bump that is at mid-field? (As a normal occurrence anyway!)

My team is definitely, so how about yours?

Re: Who is going over the bump? (A Pillar really)
 

imo, a no brainer since we can't throw the balls onto the scoring side until the last 30 seconds.

Re: Who is going over the bump? (A Pillar really)
 

Yep. Not being able to cross the hump in 2010 didn't hurt us at FLR, but this year just plain isn't 2010... Zone management will be a big deal!

Re: Who is going over the bump? (A Pillar really)
 

My input here, is it really necesary to cross the bump? Especially when it may be faster for one to cross the bridge and also safer? Think about it, Bridge= no blocking, (if so fouls will be incurred) Bump=block crazy, I expect to see many robots stuck or prevented from crossing the bump due to just a little defense, anyone else see my point? Crossing the bridge seems like the way to go, and it makes the intake design much more simplistic. It could even be faster... Please confirm that my reasons for not going over the bump are logical...

Re: Who is going over the bump? (A Pillar really)
 

It really is more of a pillar

Re: Who is going over the bump? (A Pillar really)
 

I thinking going over the bump is a good thing to have in your design, even if you plan of using the bridge. If you came off the bridge in a match wouldn't it be bad to be stuck there the rest of the match?

Re: Who is going over the bump? (A Pillar really)
 

Well, as our team is finding out, it's a bit more difficult than they though to tip the bridge. If this statement is true, I'm not sure. But we're fairly certain we'll be traversing the barrier and saving the bridges for endgame.

Re: Who is going over the bump? (A Pillar really)
 

What if every robot on your alliance is a bridge-only robot? Nasty traffic jam, that. What if an alliance partner (or opponent) falls and blocks the bridge?

I personally know several teams that are going bridge only this year. I wouldn't recommend it.

Re: Who is going over the bump? (A Pillar really)
 

Occupy Chief Delphi... I am the 4 Percent!

Re: Who is going over the bump? (A Pillar really)
 

To the teams who are going over the bump: do you have a long or short base drive train. Our decision process went something like this:

-We need more than 12" to pick up an 8" ball easily, so we need a long base.
-A 4WD with 120lb on it, even with a short wheel base is pretty hard to turn, so we need a 6WD.
-A 6WD in short configuration would likely tip going over the barrier, so we need to go over the bridge.

Where in this process do others disagree, or come to a different conclusion?

Re: Who is going over the bump? (A Pillar really)
 

We've designed our robot around our strategies, and our strategies will only involve going to the other side maybe once or twice per round maximum, sometimes none at all. Because of this, we designed to use the bridge instead of the bump.

Re: Who is going over the bump? (A Pillar really)
 

My team is ready to cross the bump... technically?http://www.youtube.com/watch?v=dD8OUCOpnRo

Re: Who is going over the bump? (A Pillar really)
 

Here's what we came up with:
-We need more than 12" to pick up an 8" ball easily, so we need a ball-intake appendage that extends out of the front of our robot.
-A 4WD mecanum with 120lb on it turns on a dime but can be kept from the key, bridge, and alley, so we need an octocanum with preposterous torque.
-A 4WD octocanum in long configuration needs only passive mechanism help to make it over the barrier, so why not do that?

Are we right? Are you? I'm sure experience will tell us! :eek:

Re: Who is going over the bump? (A Pillar really)
 

My thoughts EXACTLY!!! if you can do it well and consistently, then why bother with the bump, and make sure before the match, if you send a team across, MAKE SURE they can do it without failing... I feel the perfomance boos gained by not adapting for the bump allows for a better performing (and better scoring) robot.

Re: Who is going over the bump? (A Pillar really)
 

Given two robots, identical in all aspects but one--one of them can cross the bump and the bridge and the other one can only cross the bridge. Which robot is better? The one that can cross the bridge, obviously.

However!

Crossing the bump is a tricky engineering proposition, and not all teams have the time to figure out how to do it. So what you need to weigh is whether or not crossing the bump is important enough to merit your engineering time. For teams with a lot of resources, the answer is yes! For teams with few resources, the answer may be no.

So let's do some bump analysis.

Q1) Do you need to be able to go on the bridge to win?
A1) Yes.

Q2) Is the bump as important as the bridge?
A2) Maybe! Let's see.

Q3) How much is balancing the bridge worth?
A3) Balancing the bridge is worth ten points.

Q4) How much is crossing the bump worth?
A4) Crossing the bump is not directly worth any points. It is worth as many points as you can score in the time you save crossing the bump vs. the bridge.

Q5) How much time do you save crossing the bump versus the bridge?
A5) Probably no less than two seconds and no more than five seconds per crossing (one way).

Q6) How many times per match do you need to cross midfield?
A6) Run some simulations and figure it out! Our simulations told us that scoring is fastest when you maximize efficiency, which is done by minimizing travel time, which is done by not crossing midfield. This means that two out of three robots in an alliance should only have to cross midfield once per match at most. Your simulations may tell you something different.

Q7) What is A5 * A6?
A7) Our team thinks it's between zero and ten seconds.

Q8) How many points can you score in A7?
A8) Do the math yourself. Our team says no more than 9.

Q9) Is A8 points per match worth the cost of engineering your robot for the bump?
A10) You tell me.

We'd love to be able to cross the bump as an insurance policy in case our analysis was wrong, but our robot is not specifically designed to do it because we have limited engineering resources. It's a mechanism that we'll make if we have the time.

Re: Who is going over the bump? (A Pillar really)
 

You left out in your analysis, how often is the bridge blocked and for how long. Think about all teams following your logic. How much bridge crossing is happening? It is just too dangerous for two bots to attempt to cross one bridge at once. Could it be done? yes, but not safely and quickly...

Re: Who is going over the bump? (A Pillar really)
 

On day one our team did a little simulation of the game and from that we found that most of the moves our team members made were going across the field to get a ball from the human player in a competitive match (several scores from each alliance). With that being said we played around with whether or not going over the bump was necessary. We thought through it some more and came up with that if we just went over the bridge it would take a few seconds longer to cross but we are limited to 2 bridges: one of which is our own alliance's shared with 2 robots and a common bridge which is shared with 5 other robots 3 of which would want to stop us. Additionally, what if one of our robots got stuck on either bridge or takes much longer than us to cross then we are now stuck in rush hour traffic at the tolls, and in a game with so few balls what if for some reason we there are several ball in our opponents zone constantly?

Conclusion, crossing the bump while another design challenge will pay off in the long run in that we can move across the field over multiple access points to maximize our ability to play the game. To accomplish this we have angles on the front of our frame that allow us to glide over the bump with a 6wd.

We were also torn between a long and wide drivebase. A wide robot would give us a large gap for pickup and have an easier time fitting on the bridge but comes a the cost of having a high chance of tipping if not designed properly due to the shorter wheel base. A long robot takes away our ability for a large pickup but is safer at going over the bump and fitting in our ball pickup and shooter.

Conclusion, make a long robot with a drop down harvester at full width and is heavily weighted towards one side to fit on the bridge for a triple balance.

Pretty lengthy but this is what our team came up with in the end. The biggest thing is making sure your team can accomplish what you intend to build.

Good luck!

Re: Who is going over the bump? (A Pillar really)
 

We don't know if we're going over the barrier. Hopefully we'll know in a week or two. But we are going to make the robot so it can attempt it.

Re: Who is going over the bump? (A Pillar really)
 

The students really wanted to go over the bump, so that is what we are doing even though some of the mentors still think this puts the schedule at risk. Our team has traditionally done track drive which takes more machining, expense, and tweaking, than other drive bases. Last year they had more difficulty (than usual) getting everything done on time. So for practice over the summer they decided to build a demo-bot using regular wheeled kit-bot parts. From that experience they seemed ready to build a normal wheeled robot this year so they could focus more on the other parts of the challange. Than they saw the barrier that seemed to call out for tracks. What to do!

What we came up with is a wheeled robot that still has some track like characteristics. In stead of chains in some places it has timing belts. These belts are supported in such a way as to act enough like a track to hopefully allow the robot to avoid high centering when crossing the barrier. It is not a real track and will not be good enough to use much, but hopefully it will work just enough to navigate the barrier.

If everything works out, and that still seems like a big if right now, we will have a robot that drives around most of the time like a wheeled robot with just a little assistance from the pseudo tracks only when needed. We are using custom wheel mounting plates, but believe the design could ultimately be adapted to a kit of parts frame to allow teams to experiment with track drive without a lot of machining or expense.

The design is lower cost than traditional track drive and requires less machining because it uses the standard Gates timing belts with off the shelf pulleys. But that means you only get part of the advantages of track drive. The students are calling this variation Corvallis Spartan Drive because they do not know if it has ever been tried before. We will need to post some pictures if we ever get it working. Too soon to say if it has any advantage, or will even be competitive, but that is what happens when you try something new.

Re: Who is going over the bump? (A Pillar really)
 

I know for our team being able to get anywhere on the field rather quickly has always been beneficial to us. This is a lesson we have learned by looking at the robots that you routinely see in the finals at championships. Generally speaking they are able to easily transition from different zones of the field quickly. This allows them to acquire game pieces quickly and score them regardless of where the game pieces are on the field.

Therefore, I think that we will attempt that approach again this year but I can see where robots that can't transition the barrier are useful. If they are a really good shooting robot they can stay in their scoring zone while other robots on their alliance cross over to the other side to feed them ball.

Re: Who is going over the bump? (A Pillar really)
 

Our robot is designed to focus on bridge crossing since we've been able to cross it fairly quickly and easily with a prototype mechanism we built. The plan is to build in the ability to cross the barrier as a last resort but it's not a part of our regular strategy and would probably cause damage to our drivetrain if used on a regular basis (we're using mecanum wheels that we don't want to ram into the barrier repeatedly).

Really we're hoping to end up in a feeder/shooter alliance setup and avoid crossing the barrier as much as possible for all teams involved.

Re: Who is going over the bump? (A Pillar really)
 

I think that all teams will avoid crossing the barrier as much as possible -- but really great teams will be able to cross it as necessary.

We're going octocanum this year, but have something in place to keep the shock of the barrier off of the drive train.

Re: Who is going over the bump? (A Pillar really)
 

Ooh, you're right.

I suppose we should conclude that our answer to that question was "never".

1) Not very much bridge crossing is happening.*
2) Opponents are not stupid enough to block your bridge and risk a technical foul.
3) Even if they block your bridge, the Coopertition bridge is open and blocking you there is a technical foul under the blockading rule.
4) That leaves two allies who can block your bridge at a time.
5) One of those allies will likely be playing defense and will thus cross midfield only once, right at the beginning.
6) That leaves one ally who can block your bridge at a time.
7) If both of you cross the bridge at the same time, neither of you is scoring.
8) If neither of you is scoring, you are losing.
9) You should never be crossing the bridge at the same time as your partner.

*This could be a flawed assumption, in which case the bump is much more important than we think. However, all of our simulations and logic back this up.

This sounds like sketchy logic. Did your simulating players try bouncing the ball from the inbounder station? What about dedicating one robot on the other side of the field to play defense AND to return scored balls? In your simulations, did you ever come across a situation where more than one robot needed to use a bridge at a time? "We'd be screwed if our partner breaks down loses some validity because if your partner breaks down on the bridge (thus rendering it unbalanceable) it's probably already over. The flaw here is "for some reason". Think about the reasons this would happen.

Q1) Why do they have a lot of balls?
A1) There are two possibilities.

P1) They are receiving a lot of balls.
P2) They are not scoring any balls.

C1) If P2 is true, they are losing.

Q2) From where are they receiving these balls?
A2) There are several possibilities.

P3) They are receiving them from their feeder station faster than they can score them.
P4) They are receiving them from the ground on your side of the field faster than they can score them.
P5) Some combination of P3 and P4

C2) If P3 is true, you are scoring at a faster rate than they are and therefore winning.
C3) If P4 is true, your aim is bad and their defensive robot is amazing at stealing rebounds.
C4) If P5 is true, the result is likely a combination of C2 and C3.

O1) If P4 is true, stop that defensive robot! (Or, alternately, build a robot that is accurate.)
O2) If P5 is true, stop that defensive robot! (Or, alternately, build a robot that is accurate.) (Or, if P3 > P4, don't worry!)

C4) If they have a lot of balls on their side of the field, either you are winning or one robot is responsible for their success or your alliance is so wildly inaccurate that you have no hope of winning anyways.

Re: Who is going over the bump? (A Pillar really)
 

We plan to slide right over the bump like it wasn't even there...

:ahh:

Re: Who is going over the bump? (A Pillar really)
 

Hoverbot? Or teleport bot?

Re: Who is going over the bump? (A Pillar really)
 

Are you gonna go Wildstang 2004 on us?

Re: Who is going over the bump? (A Pillar really)
 

Since we did not have a full field we did a table top simulation. I also got a chance to play with the field that morning. Our simulation assumed that no balls would be thrown or bounced over the field (we may play around with this but unless you have an inbound station, bridge, and bump you can't rule it possible).

While it may seem like, "sketchy logic" it is perfectly resonable to me. We participate in a week one regional where many teams are just getting up and running and driver skill is on the lower side unless they have practiced. All you need is one robot to have a hard time going over the bridge and you have yourself a mess. I never assume that my robot or the robots at my event will be stellar at one thing or doing something will be easy like crossing the bump or even driving. That isn't mean or saying everyone else is horrible, I'm just saying that I'm not going to assume my regional has 50 robots that can cross a bridge in 2 seconds. Following that same train of though while having one robot to funnel balls across the field is a good partner, I'm not going to assume that robot will be at my regional or in my matches. If I designed around this what am I going to do when I'm stuck with 2 other robots just like me or can't do anything?

If a partner breaks down on the ramp/is hanging off the side I'm not going to touch it unless it is absolutaly necessary out of respect for that teams robot. I will however design to go over the bump so I don't have to worry about the bridge until the end. Our design should take around 1 second to cross the bump, unless I can make a bridge cross that fast including dropping the bridge I'd do it. Again I'm not going to assume the bridge is open the entire match. To say my partners are going to stay in one zone is out there because I can't control what they do.

Assuming you are correct and they are outscoring me does that mean I stop scoring? The way I see this game is that there are 18 balls which equates to 3 per robot which is all I can have. Each inbounder can hold 2 balls which means up to 6 on each side. If you take a moment and think that over and over you'll realize that there aren't going to be a lot of balls on the field (I'm not saying 3 balls will be in each robot at all times and each inbounder will have 2 at all times). Collecting the few balls that are on the field will be a huge factor in this years game which is another reason why we see the bump as a strategic point. If it is faster to cross the bump then the bridge we will cross the bump as much as we can.

In short I'm not assuming the bridge is open all the time and I'm not going design my robot around what I think other teams can do.

Re: Who is going over the bump? (A Pillar really)
 

This is where strategy comes to play... talking to your alliance partners before matches is key... you should never have a bridge jam!

Re: Who is going over the bump? (A Pillar really)
 

One thought to consider with the bridges is that the center bridge 'exit' location is pretty close to the key. If you come off of the bridge too quicly you have a high risk of contacting an opposing alliance robot that is in that zone.

Re: Who is going over the bump? (A Pillar really)
 

That's a hugely important incorrect assumption. When running your simulations, you should always simulate the real game, not change the rules to your liking. There's no point in simulating a game that you won't be playing. Well, not quite. All you need to have a mess is one robot that breaks down on your bridge (as discussed earlier, game over already). If it has a hard time, you can and should design a strategy to minimize its crossings. Neither did we; I mentioned earlier that our analysis allots quite a chunk of extra time for bridge crossing compared to bump crossing. Just as you can't assume bridge crossing time will be zero, I can't assume bump crossing time will be. I think a five second differential for every crossing is probably reasonable. You can go higher... but as per our team's analysis, a ten-second differential (whoa!) is still only ten wasted seconds per match at most. I should hope that there will be a robot like that at your competition--all it has to be able to do is pick up balls and throw them across the midfield gap for you to pick them up. Start making bounce passes from the inbounder station or only send one at a time to cross the bridge. See, the difference here is that you think you have to cross the bump in order to not have to worry about the bridge, and I think you can ignore them both altogether if your scoring mechanism is accurate enough. What it boils down to is that I assumed people would be throwing balls across the field and you assumed that they would not. See again my earlier point: A bump crossing mechanism makes any robot better, and of course you'd rather cross the bump than the bridge if you can, but for some teams it may not be worth the requisite engineering time. You can't? This is where pre-match discussions need to come in. Why wouldn't you tell your alliance partners to default to the most efficient possible configuration?
In none of my scenarios were they outscoring you, expect the one in which you are inaccurate. If you are inaccurate you haven't even started scoring, so I'm not sure this makes sense... No, you won't... you will cross the bump as much as you need to. Crossing midfield for its own sake is silly because it's wasted time. If you think you need to retrieve balls from the other side of the field, why not have one robot stay on the other side of the field to retrieve them? We didn't assume it either; we simulated it. Then, based on our simulation, we decided what was and what wasn't an important design objective and decided to postpone pursuing a seemingly unimportant objective that would have required meaningful investment of time on our part.

Re: Who is going over the bump? (A Pillar really)
 

You and I obviously have different opinions on this years game.

In a short and final response.

1. We aren't twisting the rules of the game it is a simulation which isn't the real game either and we aren't the only ones who do table top simulations.

2. It isn't game over if the bridge is blocked. If that is your thinking then start shooting your heart out.

3. Our design is literally driving over the bump which makes it 1 second and very easy for us so crossing the bump is effecient to get balls.

4. I'm sure there will be a robot at my competition who can spit balls out but I'm not going to wait for balls from another robot if my robot can get them faster. Again I don't plan my design around other teams robots unless I see they are GOOD at it.

5. Haven't tried that yet but with how few balls there are i'm not going to risk us losing one by a missed bounce shot if it is possible. Again if us driving to the other side of the field is faster we will.

6. I have human feeding next to picking up on the floor in order of importance. Can't throw over the wall until 30 secs remember!

7. Us crossing the bump has required a custom base that not everyone is capable of but it is still our decision to go with our design.

8. In every match I have been something from pre-match discussions have had to change mid match whether someone else on our alliance did something we didn't discuss or we had to change due to changes on the field. Sometimes you have to change your strategy, other times it is just humans reacting in the way they believe they need to react. Its not that I don't trust our partners, but I know that something will change. Being a drive coach last year and driving at a few off-seasons have showed me this.

9. My point was that if balls are on the other side of the field for WHATEVER reason we will still get them and going over the bump is faster for us.

10. It is not wasted time for us.

11. Good that you guys know how to prioritize based on your capabilities it pays off when you can weigh the pros and cons. Personally I can see the bridges being empty at some points but if we need to move zones I can see someone on one or both bridge. Might be extreme cases but going over the bump is faster.

Sorry for the lengthy post this is all I have on the topic. Good luck this season!

Re: Who is going over the bump? (A Pillar really)
 

We are in concurrence on all points, except that I think that travel time to cross the field, even if your robot can instantly cross the bump, is always going to be slower than an ally passing the ball across the field, that I think that bounce passing is viable, and that I think that when a robot breaks down on your bridge and prevents you from balancing it you have lost.

Given all of the arguing we were doing, that's relatively few points of contention. :o Besides, even though I don't agree with your logic all of the way through, I agree that a team with resources (like yours) is perfectly correct and justified in designing to cross the bump.

Good luck in the FRC season, and may your robot always drive straight!

Re: Who is going over the bump? (A Pillar really)
 

You can still get balls across to the other side with your human player. A bounce pass through the slot will make it over the bridge or the bump.

Re: Who is going over the bump? (A Pillar really)
 

No, they won't... Have you tried? They don't bounce, they just die after the first time they hit the ground.

Re: Who is going over the bump? (A Pillar really)
 

The blockading rule [G23] only applies to multiple robots blocking progress. One on one blocking is allowed. And via the official Q&A, blocking exit from the center bridge, in either direction (e.g. by preventing the bridge to lower with a robot already on it), is not considered a pin.

Not sure that a blocking robot would win many battles against a robot with an elevation advantage, but we'll see... I expect to see some interesting collisions at mid-field, and some heated arguments about whether damage to either robot should draw a technical foul or a yellow card.

However, I expect to see just as much blocking at the barrier. Should be a regular wrecking yard in some matches.

Re: Who is going over the bump? (A Pillar really)
 

Our Drive Train is designed to go over the barrier, whether or not we do will be decided based on the current situation.

"Better to be able to do something and chose not to than to need to do something and not be able to" is a common design mentality on 816.

Re: Who is going over the bump? (A Pillar really)
 

Well I dont know what balls you are bouncing because we have gotten them over through the slot.

Re: Who is going over the bump? (A Pillar really)
 

It depends on the ball. We have some we have been playing with since week one and brand new out of the bag and the difference is huge! The new ones have a nice bounce to them while the used ones tend to bounce less. When we put them in our shooter the distance can vary several feet.

Re: Who is going over the bump? (A Pillar really)
 

I dont believe you need to be a team with resources to cross the bump.
There are many possible designs that teams can come up with to do so, and still be able to design a bot that score baskets.
Being that your team has come up with decent bots in the past, I'm sure you folks will come up with something to do so.
Despite simulations and trying to determine to what extent its important, one fact remains true......being able to effectively cross the bump is better than not being able to at all.

Re: Who is going over the bump? (A Pillar really)
 

I agree. My team does not have extensive resources, but we still came up with a pretty good way to cross the bump I think! Plus we have a good scoring mechanism with it.

Re: Who is going over the bump? (A Pillar really)
 

For many teams picking up balls off the ground, such as ours, going over the bump could potentially damage our bot's intaker. Also, the wheels needed to cross the bump are relatively large, so some teams may just find it more convienient to go bridge.

On the other hand, the bump would provide faster mobility that is also very spacious. With the bump and the bridge together, a bot can be very mobile in this field.

The point is, the bump has its advantages and disadvantages.

Re: Who is going over the bump? (A Pillar really)
 

This is simply not true.

There are some extremely simple ways to cross the bump with wheels as small as 4".

Larger wheels make it 'easier' to cross the bump but they aren't absolutely needed.

Re: Who is going over the bump? (A Pillar really)
 

I'd be impressed if the same robot could block you at both your bridge and the other bridge, but it's kind of beside the point because blocking's not really a concern at the time in the match when you'd be most likely to cross over (i.e. really early).

I definitely agree with you there. Our thought process is that, while being able to cross the bump effectively is better than not being able to cross it at all, being able to cross the bump effectively with a mediocre scoring mechanism is worse than having a great scorer and not being able to cross the bump. First things first!

Despite what my posts may imply, our team has not ruled out a bump-crossing mechanism. It's just lower on our list of priorities than perfecting the scorer, which means that it won't get started on until late in the build season. We'll see how it turns out. Right now it looks like we're going to have more time than we initially thought.

Thanks for the input and we'll see you at the regional!

Re: Who is going over the bump? (A Pillar really)
 

Or 2.9" wheels :D

Re: Who is going over the bump? (A Pillar really)
 

Sounds like something Aren Hill challenged you to haha.

Looking forward to seeing that.

Re: Who is going over the bump? (A Pillar really)
 

TEAM 2185 IS GOING OVER THE BUMP

Re: Who is going over the bump? (A Pillar really)
 

We just like to have the option. A rugged chassis didn't hurt any other parts of our design. If we find that it's taking too much wear and tear on the robot, we can just as effectively cross the bridge. But from what we've seen, no downsides to crossing the bump.

Re: Who is going over the bump? (A Pillar really)
 

Team 1939 is going over the bump. Were using 2 normal rubber wheels and 2 pnematic wheels in the back with an unpowered middle caster to prevent us from getting stuck :p. I would think that mechanum would have a much harder time trying to get over it because of its 45▲ angled wheels.

Although, our frame had to be cut back inorder for the wheel to contact the bump first and not the frame first :/

Re: Who is going over the bump? (A Pillar really)
 

My team is planning to go over the bump. Scratch that, we can go over the bump. We just tested out drive train last night, and at speed it can cross!

In our brainstorming session, we concluded that going over the bump would be critical to traversing the field quickly and to avoiding potential bridge defenders. That said, we might still prefer to cross the bridge to be a bit more gentle on the robot, and to avoid the chance of getting stuck on top of the bump.

Re: Who is going over the bump? (A Pillar really)
 

http://www.youtube.com/watch?v=7GbrprUtC4o

We are. :D

Re: Who is going over the bump? (A Pillar really)
 

Same. pneumatic wheels rule.

Re: Who is going over the bump? (A Pillar really)
 

We built a small ramp on our robot that should allow us to traverse the barrier. I think it's a good idea to be able to go over the barrier as the bridges could become bottlenecks.