If you haven’t seen it enjoy, if you have seen it….well it is always a good show.

In actuality this tells you nothing about our robot, except that it will be black and made from sheet metal.

Just like most teasers that make their way to the web during this time of the year, for the most part they are a waste of time. If you are urgently trying to show off your thinking then you should post your whole robot design. Or at a minimum the complete mechanism. Posting a close up picture of a sprocket or gearbox (especially one purchased from andymark) is not really a good representation of your robot or your team. In retrospect I might consider a team who is extremely proud of something like this, to have questionable design abilities.

I understand the desire for teams to gain recognition, but this is the wrong way to draw attention to yourself. Post videos to youtube, full photos of mechanisms, or your whole robot. All of these things are great ways to showcase your work! Even I have fallen into this trap years ago, but I have since learned better, so consider this a lesson to you “youngsters.”

On a side note, as much as I tried, Jeff removed those words from the bottom of the sheet metal.

BUILD WITHIN YOUR MEANS!

This concept can be difficult because I believe it is everyone’s deep desire to be the best at very scenario, and sometimes building within your resources means making choices which can limit your potential.  Yet even limited your robot actions can actually make you a better competitor since you will be more optimized.

I had a conversation with another 10+ year mentor a few days ago about drives, and how difficult it was going to be without 2 speeds this year.  He was struggling with the fact that on his new young team they really can’t afford the ~$640 for a set of shifters but without them the team would be at a huge disadvantage at the competition. While I agree that having 2 speeds would be a benefit this year I can condone spending almost half his robot budget just on transmissions.

This is exactly the type of thing I wish teams would realize that if you don’t have the money for fancy robot parts, or you don’t have access to heavy fabrication equipment, you should approach the game in a different manor.  For example I know that many teams think it would be totally awesome to build a turreted top basket shooter, with camera tracking that can shoot from anywhere on the field and have a mystery device that can guarantee a 3 balance every time, and a drivetrain that can drive through defense while having excellent acceleration and top speed.  While this robot is possible for all teams is it feasible for most teams? I am not trying to discourage teams from pushing themselves, yet I am encouraging teams to take a hard look at their resources to they can make the best decisions.  Is it worth spending all of your time and money on a single portion of the robot while hurting the other subsystems.

At this point in the season, I am sure many of you are far along the path for whatever you decide, but when you run into issues or feel overwhelmed, take a step back and see if what you want to build is what you are actually capable of or if you are over reaching.

And now for your moment of zen.

Jack Bot – Normally the most common robot out there this is a robot that is a jack of all trades, but master of none. In 2012 The jack bot will be ones that have the ability to climb the barrier (if they are lined up perfect), Shoot a basketball (from a few specific spots on the field), and balance the bridge when the circumstances are right. Not a bad robot to have at many regionals, but I still believe in focusing on 1 or 2 things and being the best at them instead of spreading the skill around.

Flying Pig – This is the robot that is designed to pull off an impossible strategy, and since it is an impossible strategy the robot fails. This year the flying pig will be a robot who can score a basket from the other side of the field (like right infront of your human player) with good accuracy. (prove me wrong if you will)

Brick – Bricks don’t move, neither does this robot.

The man – The ultimate robot for any game, The one who diecets the game correctly and is the best robot on the field. When you hear teams reading the schedule in the pits and groaning when they see your team number, you know you have built “the man.” There are a few teams that are capable of this every year, but on any given year you can build that robot. This year the man will be…..ha ha, nobody knows until the game plays out.

The bucket – “there is a hole in your bucket dear Liza, dear Liza” A robot filled with good intentions but unfortunately those good intentions are leaking all over the floor. Alot of times this is a team with a really good idea, but without the resources to pull it off, so they use strange things to make it happen, such as the tote the KOP came in.

LineRobot – Being a lineman, means you like to hit people. Being the LineRobot Means you like to hit robots. All Defense, nothing else. The drivers on these teams are typically the most relaxed at the regional because they get to take out their aggression every match.

Alley-Oop - A robot that is designed for a co-op strategy, and needs a good partner to pull it off. Many times teams will try something so outside the box that they can’t do it themselves, but when they are successful, the world takes notices. In recent memory 469 in 2010 was both the “alley oop”and “the man” all wrapped in one.

Hungry Hippo - Also Known As a horder, this robot’s job is to collect as many game pieces as is legally (or illegally) possible and drive around with them hoping to make the game changing move. In some games it is great to hord game objects, and I believe this is one of them. With 18 balls on the field and the ability for the human players to hold 12 (6 on each side) if you can defensively hold 3 of them, you leave the 3 extras for all other teams to fight over. How many matches will reach a “ball-less state” by about 1 min in?

As my previous post indicated we had been busy trying to make sure our practice field is as true to reality as possible. We made some giant leaps forward when we got the basketball hoops in and our sheet metal barriers back from the shop.  The last thing left to do was the ramps and more directly how to make sure the ramps function like the ones on the real field.

I noticed a bit of conversation on www.chiefdelphi.com on how to do this so I thought I would share our method.

On Kickoff FIRST posted this video.

If you ignore the extremely dry puns the most important info comes when they talk about the balance test. 2 FRC batteries 28″ from one side should not tip the bridge, while moving them to 30″ will. We found that our bridge as built to the plans was no where close, so we brainstormed and figured out how to fix it.

Our bridge had 2 distinct problems. 1) the balancing point on each side of center was not the same on either side of the bridge and 2) the tip points were totally off from the FIRST spec.

To fix problem one we took 2 FRC batteries and determined the point away from the center which would cause the ramp to tip (ours was something like a single battery 14 inches from center on one side and a single battery 22 inches away on the other side. This inequality is simply a Torque balancing problem. Distance X Force (battery Weight) of the larger side – the smaller side Then divide by 2, That number is your difference. If you remove the weight of the battery by dividing it out Subtract that number from the side that has the higher torque value and you will get the amount which you must adjust the ramp.

In our case 22 inches X 13.5lbs = 297 in-lbs and 14 inches x 13.5 lbs = 189 in-lbs Difference = 108 in-lbs Difference/2 = 54 in-lbs removing the weight 54/13.5= 4 inches. So we needed to add 13.5 lbs to the ramp 4 inches from the central pivot. In actuality you can assume that the weight is just 1 unit and figure it all out with just the distance differences. ((22-14)/2)=4  But then you don’t have the amount of weight to use, so even if the weight gets canceled out in your equation, it is still a constant that you need. We used batteries and calculated this with 1 BMU  (battery mass unit)

Once we got the ramp balancing correctly we still had the issue of it tipping too quickly. This is due to the entire system being too light.  The system mass is important because balanced weight will impact how much force is required to initiate movement. This is a system dynamics problem where you are trying to solve a problem at the edge of equilibrium.  I wish I could give you a formula to work on your bridge but our solution was much simpler than that, we cut steel plates and kept adding them to the underside of the bridge until it balanced like the video. Nothing special, just some trial and error.  Ours took about 20lbs.

Hope this helps you out.

On a side note, the way  that the real bridges are designed will have this same inequality from left to right, does anyone know if FIRST will balance the ramps out?

Over the past few years the drawing package for the field has gotten much better and the addition of the low cost team field really helps to get things going quickly. Every year I will never follow the plans exactly mainly because there is normally a better way to do things. My only isse with these plans is that it is obvious that nobody at FIRST who reviews these knows how to build with wood in the practical sense and there are always organization problems with the packet. I don’t mean to gripe because without these plans many teams would not have anything to practice with, but it is always enjoyable to poke some fun at small things.

Here are a few Gems from this year.

To build a 4 hoop assembly, Build a 3 hoop assembly

then add the 4th hoop. Why not just build a frame for all 4 from the start and decide if you want to add them all?

Non-functional fillets, just a waste of time.

This one is TOTALLY on me. I was in a wood cutting frenzy and saw the below drawing and cut 4 pieces 88″ x 4″ out of the half in plywood I was using for almost everything. I just wish I had seen that it was a print for a velcro strip.

Btw if anyone wants some ultra thick velcro stripcs that don’t not stick to anything and resembles plywood, all you have to do is come by and pick them up. No Charge.

And Finally my favorite, how do you add this feature to the bottom of a piece of plywood?

I understand that this is to make the bridge more flush with the ground, but putting a 1/4 inch 15deg chamfer on a 1/2″ thick piece of board is silly. It is really two parts for me.

1) The only way I could accurately think of doing this is on a shaper, which i don’t believe many teams have and the specific bit would be expensive. You could also stand the part up on end and cut it with a table saw but it would be extremely dangerous (Please Please Please don’t do this!!). If you really want to do this give a freshman a sander and tell them to go at it. A belt sander if you are nice, sand paper if you are not.

2) If your robot needs this to climb the ramp you have more problems then how to make this part, so don’t worry about it anyway.

Some other minor things…

• Control your decimal points. Why show 2 decimals in inches and 1 in metric? Last time I checked .1mm =.0039in so why are you going to display 1/8 as .13 instead of .125″ Either drop the metric decimal or add the 3rd place in inches.

• If you are designing for people to make things out of wood, showing dimensions in fractions is a really nice gesture.

• Please don’t reference drawings not included in the specific package I am looking at. While I understand that sometimes the team field drawings are exactly the same as the real field drawings, it is annoying to try and track down a sheet which is in a different pdf. (ie. The lexan used for the top of the bridge) it doesn’t cost extra to include that sheet where needed.

• It would be awesome if FIRST also provided a spreadsheet BOM for these so it would be really easy to figure out all the fasteners and materials needed as it would make home depot runs easier.

• It would be even more awesome if there were some recommended part nesting layouts on plywood so you could minimize the sheets needed. I feel we did a good job today, but we still ended up with a load of scrap or as I call it the first week of build season “prototype materials”

We didn’t get finished but everything is cut and ready to go for some serious assembly tomorrow. And now for your moment of zen.

I know that everyone is probably overwhelmed with ideas and discussions about the best robot to build here is some more food for thought and some of my impressions after day 1.  No real order just a brain dump.

• This is a game for veterans teams who normally compete at a relatively high level.  Rookie and Mid-level teams are going to have a serious problem accomplishing all the game objectives.
• There will be many matches this season where the majority of the points for an alliance will be penalties committed by the other team.
• There are many subtle challenges to this game, that seem easy but are actually very difficult.  To paraphrase Shrek this game is like an onion, many layers, most of which will make some teams cry.  Don’t underestimate anything on the field, no matter how easy it seems.
• Some games look hard but are actually easy, I don’t think this is one of those games.
• Motors – FIRST realized that there inspection teams were not capable of catching the differences between many versions of the same motors so they just made them easy.  Too much choice exists, and while you can basically do whatever you want with motors this, restraint  will be key.  And btw if you use that rare motor  where exactly do you think you are going to find a replacement…oh that’s right FIRST cut a deal with junk yards…WHAT?!
• Banebots already has a 6 business day delay in shipping parts out….C’mon Man!
• The GDC put in a rule that they reserve the right to change a rule for championship, atleast this year we know it is coming.   Any takers on my bet already that they lower the ramp points?
• There will be many robots on their backs this season, half on the ramps, half on the barricade.
• I like the cooperation bonus, it allows you to make up for a loss in ranking.  I still don’t think it will happen much at regional events, it will surly happen at championships.
• Double balances will be rare. Many will try few will be successful.
• Triple Balances will be extremely rare.  Probably less than 50 times the while season.
• Many teams will forget that the ramps self level and won’t put a device which changes the direction of the ramp on their robot. They will either have to brave the bump with their kitbot or stay on that side of the field.
• I was really hoping for a multi-game piece game and was really excited when they were teasing all the old game pieces.
• Why were Kate and Colin in Elf costumes during kickoff? Did they loose a bet?
• Thank god there are no mini-bots

I am tired, and that is enough. I really don’t mean to sound like I don’t like this game, because I think it has potential. I just think that the challenge is going to be a bit much for many teams.  I have always found that being stressful is a way better lesson to the kids on my teams then trying really hard and failing. Both are valuable lessons, but the goal is inspiration not de-motivation.  Take 2001 a bad game by many people’s standards, and 2006 the best game according to many, mix them together and you get this game, which undoubtedly be somewhere in the middle.

I am also not sure if I will keep up this blog, there is a big hole in the FIRST blogs left by someone who’s name sounds like 12:00pm, but I don’t know that I have the dedication and enough interesting stuff to talk about.  Let me know if you want me to keep this up.

Greg