[MCC] Minimum Competitive Concept 2012

[JesseK]

I have a question for all of you "low goal dump in auto" guys. Which is simpler to build & program for autonomous: a robot that sits in place and launches 2 balls at the basket via a single control loop, or a robot that moves towards the basket (presumably in a straight line ... oh wait) and then dumps?

Now the same question, without knowing about the ball inconsistencies?

Now the same question, with a team who will do what it takes to tweak, hone-in, and otherwise calibrate to mitigate the ball inconsistencies?

[avanboekel]

Originally Posted by JesseK

I have a question for all of you "low goal dump in auto" guys. Which is simpler to build & program for autonomous: a robot that sits in place and launches 2 balls at the basket via a single control loop, or a robot that moves towards the basket (presumably in a straight line ... oh wait) and then dumps?

Now the same question, without knowing about the ball inconsistencies?

Now the same question, with a team who will do what it takes to tweak, hone-in, and otherwise calibrate to mitigate the ball inconsistencies?

I agree with you that it is easier to program a bot to just sit there and shoot than to drive up to the fender and shoot. However, it takes a much more powerful shooter as well as a more precise shot. IMO, it is easier overall to drive up and shoot.

[Chris is me]

In my opinion, the following were this year's essential tasks:

• Floor pickup / reverse
• Cross bridges by self (i.e. can lower bridge and drive on)
• Score in a goal at the fender. (2 point goal?)

1 point or 2 point - In my opinion / observation, it is not that much harder to score in the 2 point goal than it is to score in the 1 point goal. So while I am not sure if it is essential, I would suggest a team go for it as I don't think there is much of any opportunity cost. The autonomous gain of shooting for the higher goal isn't that much (25% more points) but in teleop it's twice as many points per ball which is too big of a margin to ignore unless it is significantly harder to achieve. Which I don't think it is.

Then again, a 20 point contribution to the match alone (low goal in auto + 2 balls on bridge + single balance) is probably significant enough to be competitive at many events this year. Maybe the 2 point goal isn't so important...

In auton, a drive forward and shoot routine is pretty doable. Driving 12 feet straight(ish) is not unfathomable, and the fender itself helps the drive base square up. The 10 points here are somewhat easy to get, if you design for it in particular rather than a more general shooter.

I don't think crossing the bump is mandatory, and I think the other criteria cover most of the other roles the robot could play at higher roles. Having floor pickup and reversal allows for feeding a higher power auton, playing ball starvation defensive strategies, etc. in a match where the robot is the least good scorer. Being able to lower the bridge is important for those easy 10 points and also allows the robot full field mobility.

Scoring 20+ points a match and being able to co-op bridge is probably plenty to seed high at many events. I haven't run the numbers though.

I didn't include anything about orientation, but I think building a robot longer than 28 inches with such simple goals would only limit the robot rather than help it.

In my mind, 4334 is the epitome of the minimum competitive concept. I don't know how reliable their auton is, but they did an awesome job doing the mandatory parts of the game well, and proved themselves as an Einstein worthy asset to an alliance.

[smistthegreat]

I'm not sure how effectively they did it in competition, but at champs i saw 4334 running a low goal auto on the practice field very consistently.

[joelg236]

Originally Posted by smistthegreat

I'm not sure how effectively they did it in competition, but at champs i saw 4334 running a low goal auto on the practice field very consistently.

Funnily enough, we were almost 95% accurate in GTR regional (When we did autonomous), and through some unfortunate mistakes in programming, electrical, placement and of course, chance, we did not do very well in Archimedes. It was luck that brought us in an alliance with 1114 and 2056, two perfectly capable autonomous robots (Who we fed balls to).

First thing's first: a reliable, strong drivetrain and somewhat trained drivers (reliable comes before strong)

Then you'll want good ball pickup capability. Again, with a little driver practice, picking up balls is relatively easy.

Shooting will need to be very accurate. I'd go with a mid shooter that makes the shot 90% of the time instead of a high shooter that makes the shot 50% of the time. In order to really be competitive, low basket scoring won't be seen much. Mainly middle or high, whichever one they're more accurate on.

A bridge lowering-mechanism. The need to get on a bridge to balance is crucial, and the need to cross over to the other side is also helpful, so a wedge-like bridge mechanism will make the robot much more useful.

Other things: A wide robot would increase chances of getting picked. A decent autonomous would also help. A smart strategy also is a nice thing.


Finally, my MCC: A wide bot with a relatively large intake (about 21 inches wide) that can accurately score balls in at least the middle hoop, with a wedge bridge-manipulator that allows them to go to the other side of the field and get on the bridge.

[mikemat]

Originally Posted by SuperNerd256

Finally, my MCC: A wide bot with a relatively large intake (about 21 inches wide) that can accurately score balls in at least the middle hoop, with a wedge bridge-manipulator that allows them to go to the other side of the field and get on the bridge.

I fully agree with the drive train part, but we must remember that the first M in MCC stands for minimum. Something designed with goal 1 being 'get picked'. For this reason, I don't think a shooter should even be considered. MCC, for me at least, is something potentially simpler than 4334 was (they we're simple, but I think MCC could be simpler). IMO, the best thing you could do is design a robot that will never be on your side of the field. It should be easier to sell a good defensive not than mediocre offensive one as a second pick to an alliance captain.

[JakeD]

I'm in love with minimum competitive concepts now and after giving it some thought heres what I came up with. For the record I'm not assuming the team is a rookie but instead has at least some experience and a knowledge of the teams potential/resources and is aware that they're relatively low. Think 3rd year team wanting to play in eliminations for the first time.

Assuming the goal is to play in eliminations the odds of being picked are significantly higher then that of seeding high enough to be a picking robot. But to improve all chances of playing in eliminations I wont write off attempting to seed high still.

Game analysis: Comparing difficulty to reward it shows that balancing on a bridge is relatively easier then scoring balls to obtain a similar number of points. The difficulty to reward ration is increased during eliminations with the 40 point bonus. Thus we'll rely on the bridge as a primary scoring method.

Since we are relying on the bridge to score the majority of our points our robot should be designed to balance 2 robots easily as well as facilitate triple balancing. A wide, 6 wheel, tank drive robot provides the easiest method of accomplishing this strategy. A basic upgrade is to use two super shifters with the 4:1 spread, as the transmissions with 2 cims each. Using reasonable gearing the robot can have an average "high" gear, and an absolutely crawling "low" gear. This low gear provides two advantages. 1. the robot is now very capable of pushing 2 other robots up the bridge relatively easily. A problem a fair number of triple balancing alliances suffered from. 2. The low gear enters the range where internal system friction can be enough to act as a break on an unbalanced bridge. Finally to lower the bridge a simple arm with a wheel on the end (like 61's robot linked earlier in the thread) powered by 2 window motors.

Now for more assumptions. In general robots that shoot well are long. Long robots have more difficulty triple balancing. Not saying that it is impossible but that if a team has the forethought and resources to build a high ball scoring robot that can triple balance easily as well, then the MCC is simply out classed and should just hope to be picked by them. However in general this is a reach and an alliance of good shooting long bots will have difficulty triple balancing. Since shooting requires balls, we will attempt to stop these robots at their source.

Build a diagonal wall across the robot up to the hight limit. It can be netting and PVC to keep it light, sturdy, and cheap. Stuff your starting balls behind the wall to prevent the other team from getting them. After the match starts immediately move into the opposing teams lane and park against the inbounders corner.

Match Situation 1: If your alliance partners can score then this prevents the inbounders from skipping balls across the field to their high scoring robots to keep them replenished. If your inbounders hold the maximum number of balls as well as your team then balls begin to run out quickly. If your teammates can continue to score then inbounders will be forced to inbound balls bouncing them off of your robot and deflecting them toward the key where your scoring teammates can in theory easily pick them up and continue the cycle. Until the last 30 seconds this strategy is effective then the inbounders begin to throw over the wall. Now you drive cross field and hopefully have a partner or two waiting to balance with or else you can leave a bit early and lower the bridge and have someone follow you up instead.
Qualification Score: ~35 with a double balance
Elimination Score: ~70 with a triple balance

Match Situation 2: You begin the match the same. The opposing alliance sends over a robot to deal with you and give you a penalty for being in their lane and/or force you to move. After they cross the goal becomes to keep them on your side. Assuming robots capable of crossing the barrier or bridge quickly are above average and by keeping them away from their side you are preventing them from scoring. The goal is to use your low gear to push the opposing robot into the opposite corner and keep them there. If they stay in the lane at least your denying the opposition of a robot that is playing defense on your team and from scoring. Wait until the last 30 seconds and then go balance.
Qualification Score: ~30 with a double balance
Elimination Score: ~65 with a triple balance

Match situation 3: Your team cannot score baskets. Use the bridge lowering device to cross a bridge and play defense. Push, pin, box in, and possibly use the net wall to block shots if your lucky. Avoid penalties as best as absolutely possible but don't get too down because this is basically the worst case scenario.
Qualification Score: 10 with single balance
Elimination Score: 40 with a triple balance

TL;DR: wide bot, shifters with high torque low gear, diagonal wall to block balls.

Marketable skills:
1. Engine for a triple balance
2. Very low gear for defence
3. Deflector wall

Additional features for improved performance(ranked by difficulty and reward):
1. Wide roller to intake extra balls/spit them out into a shooting robot.
2. Larger (possibly pneumatic) wheels for crossing the bump.
3. Shift weight forward off of the back set of wheels to allow robot to overhang and increase triple balancing capabilities
4. Pneumatic stinger. (2056 style)

[BrendanB]

Team 61 comes to mind this year when it comes to an extremely basic yet effective robot. Pretty much it was a tank drive robot with a low goal dumper and a good bridge mechanism. While I don't have the scouting data for each match we did play with them once at GSR and then again this past weekend at Battlecry. In auton they would drive forward and dump their two into the low goal (8pts). They actually preferred not to score in teleop because they viewed their 1points shots better served doing defense/feeding over the bump then focusing on a double balance or co-op. Overall they were extremely successful and in our match with them at GSR between our two autonomous modes we pretty much had the match won once they hopped up onto the bridge in the first few seconds (51pts when the round ended!). They finished GSR with a record of 7-3!

My minimum competitive concept is very similar. It would essentially be a basic 4wd wide robot with a dumper, basic off the floor pickup, human fed (elevator from the pickup goes straight up to a roller that can also be loaded from a slanted hopper), and a bridge mechanism.

Basic strategy would be to drive to the fender and dump the two balls in auto (8pts) or A-bomb to another robot, knock the balls of the co-op & alliance bridge once teleop begins, cross the bridge, play defense, pickup balls from the floor to return over the bump, load balls from inbounder and return over the bump, and then balance on the co-op or double balance with an alliance member (20pts).

Overall you are only scoring 8pts-20pts a match but you offer so much to an alliance in eliminations between a triple balance, feeding, and autonomous.

EDIT: As to dumping vs shooting in auto they are both challenging. Shooting from the key would require a shooter of some sort which would need to take into account ball in consistency as well as accuracy. Dumping on the other hand entails a smaller mechanical challenge with a programming challenge. Assuming your robot drives relatively straight it wouldn't be too hard to make a program that drives straight to the fender before dumping the two balls. Or you utilize the kinect and let your human player practice lining it up.

[IKE]

This is great discussion, and I really appreciate folks calling out specific examples of teams that executed a solid plan and had strong performance to back it up.

My MCC for 2012 was more simple than most here. In fact it is simple enough I can CAD it right here:
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This little robot is a wide 4WD with large enough wheels and high enough bumpers to plow over the barrier and would likely use about 8" pneumatic tires. The sides are plywood, and the first half of the side profile is flat and att approximately 10" height. The second half is at 45 degrees incline. On the flat section would be a couple of small depressions to set 2 balls during hybrid just to get them off the bridge.

While initially this appears to just be a BOW (box on wheels), it is a very tactical box on wheels. Assuming 0 offensive capability in the alliance, the MCC would cross the barrier and tilt the alliance bridge towards its home side to clear the balls and prep it for the 2 partners to climb the bridge. Once they are on, you back up until just the flat will engage the bridge and have your partners drive forward until it catches them. At 10" you get it very nearly level, close enough for your teammates to make minor tweaks, and the support keeps the robots from Charlie-Browning. 20 pts. 20 pts. was higher than the average score at most events (only a couple of teh 50+ regionals averaged higher than 20 pts./alliance). The average (this includes winning scores as well), thus you would be able to win a majority (though not all) matches this way.
The MCC would then prep the CoOp bridge and hopefully Co-Op almost every match.
How do I know this would work? Not only does the math look good, but at Kettering there was a software issue with the speed control on our shooter which rendered it all but useless for most matches. And we executed this exact strategy. While our robot was far from an MCC, it had the same features built into it, and those were the features we used with a great deal of success in qualifying at that event.

Initially I wasn't thrilled with this concept as I believed it required a partner to do the bridge. Later I learned by watching very similar robots to this concept that you could tilt the bridge and catch it on the rebound if you timed it just right.

This is not a design that would likely win Einstein, but it is one that had a lot of potential to do well at District and regional events. Because it isn't trying to do too much, it would get very good at what it does.

Other roles that it can play when there is good offense on its alliance:
Inbounder alley blocking (between bridges)
Fender Defense
Opponent scavenger blocking (between bridges)
Middle bot for the 40 pt. triple balance in elims.

[JesseK]

Originally Posted by IKE

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Ike, how would this robot seed high? It would be (at best) middle-of-the-pack when it came to autonomous score, thus not be near the top of the rank of robots with identical coopertition/win points. There are several instances where teams had 'lucky' schedules this year, yet when making design decisions in Build Week 1 a team doesn't know that schedule. So I think that this robot would compete and be luckily competitive rather than competitive no matter what.

[IKE]

Originally Posted by JesseK

Ike, how would this robot seed high? ....

I can show you several with this basic strategy that seeded quite high. Focusing effort on a low effort high return scoring element like balancing tended to have higher average scoring capability than running around picking up balls and randomly throwing them at the back board. This gets you above average wins which will/should get you well into the top 20 of a 40 team event. Teams that put extra focus on the Co-Op this year were more successful with the Co-Op plain and simple. Many teams early in the season waited until the last 20 seconds to Co-Op and failed. Many good teams in Michigan gave it a full 60 to 45 seconds, and had a dramatically higher success ratio. This was true of later events elsewhere. By not having the distraction of doing anything with the balls, it this concept will get very good at the things it does well.
Yes, you will have a lower than average HP score which is the second criteria, but you will have above average Wins, and well above average Co-Op points.

The key to this strategy is the assumption that others will not follow Simbots Golden Rule #2. That one says basically it is better to be really good at 3 things than it is to be mediocre or worse at 5 or 6 things.
The other key to this strategy is that allow you will "finish" early, you will use the extra time to develop your drivers. Most teams give their drivers less than an hour or two of drive time before their first competition. Many have never driven the robot as it is still being put together and code being added. If your drivers have an extra week of driving and concentrated practice, they will be better than half the field.

In theory if a high enough percentage of teams listen to this advice, then it would no longer become good advice and teams would need to add features. It has been my experience that many teams will appluad the concept of MCC. Give it as advice to others, and then do the opposite (my own team included on most occasions). Some will do better with a more complicated concept. Most will not.

[Nemo]

Originally Posted by Chris is me

I don't think crossing the bump is mandatory

I won't use the word "mandatory," but crossing the barrier is a low cost / high benefit capability for a robot that is banking on bridge success as the cornerstone of its strategy. I think deleting that capability would reduce the percentage success rate of alliance and co-op bridge balancing below the threshold of "competitive."

[IKE]

Originally Posted by Chris is me

In my mind, 4334 is the epitome of the minimum competitive concept.

Having watched them perform at the IRI, I tend to agree. While their concept is not particular good at seeding high, they picked a very valuable attribute to excel at and thus nearly garuanteed being picked.

[marccenter]

Simplicity & Golden Rules from Simbotics 1114 Presentation
Golden Rule #1: Always build within your team’s limits. Evaluate your abilities and resources honestly and realistically .Limits are defined by manpower, budget, experience . Avoid building unnecessarily complex functions
Golden Rule #2: If a team has 30 units of robot and functions have maximum of 10 units, better to have 3 functions at 10/10 instead of 5 at 6/10
Please list your assumptions, strategy to seed high, estimate of a winning score, and what robot design elements would achieve this score
Background Information for Sophomore FRC Team 3548 - Team consists of 1 sophomore coach, one electrical engineer with Labview programming and robotics experience on teams 47 (2 years) and team 1 (2 years) and 8 students, only 4 of which will be involved in the robot build . High School coach has access to woodshop but no metal cutting tools (lathe or mill) on site. Engineer has new access to water jet at work location 30 miles from office location due to GM sponsorship.
Assumptions: 1) Minimal parental involvement, 2) no time to prototype shooter concepts, 3) Shooter designs will have to access water jet limitations (2 dimensional) and be designed and mostly built by engineer and Andy Mark parts , 4) Robot build will consume all time available, 5) drive team practice before first event less than one hour, 6) Budget limits encourage strong use of KOP components, 7) Additional funds estimated to be $1000 from school, 8) Team resources prevent building of single wheel, hooded ball shooter design.

Midpack robot design goals: 1) Robot drivetrain must never fail – no one wants to pick a sophomore team whose robot fails on the field!, 2) Shoot 2 balls during autonomous and 6 during hybrid period, 3) Must be able to lower bridge in order to score cooperation points, 4) Be able to shoot balls from opponents side into team side to assist in team point scoring, 5) Will not typically go over middle barrier, 6) Part of elimination field of 24 robots in both Michigan District events, 7) Will not attend Michigan State Competition due to budgetary constraints but choose instead to go to third Michigan District event ($500), 8) Take maximum advantage of other FRC team's learnings in first two weeks to help with design direction and order and read FRC book on robot design that featured shooting mechanism's from previous FRC competition (2006?).

Robot Design Elements: 1) 6WD chassis. Read Simbotics presentation on “gold standard”. Will use 6 inch KOP wheels. First time team using 6WD configuration. Will use robot long design configuration for ease of building for students and because of limited number of balls being picked up.
2) Ball collector – used Chief Delphi and Youtube to help design. Team 245, Roch Adams, recommended using ¼ id tubing with barb inserts from McMaster-Carr for belt design. Will use 550 motors with Bane Bot transmissions (new for us). Team 1 recommendation of 64:1 transmission ration accepted. Read instructions for breaking in transmission on Chief Delphi. Stretch factor of 5% on Chief Delphi initially used and found to be too tight. Motors smoked. Reduced friction in rollers. Reduced friction in system. Belt tension reduced to make system operational (thanks Paul C. - Thunderchickens).
3) Bridge Arm – Chief Delphi thread indicated that 20 lbs at given distance required. KOP PG-71 gearmotor sufficient with 3:1 ratio. Chain driven system used with purchased Andy Mark Hubs and sprockets. Only Bridge Arm testing was to lift robot in shop – no measurements made. Bridge arm very successful in Waterford District event.
4) Ball Shooter Design – using information gathered from Chief Delphi, design 4 wheel, dual axle, 6 inch past KOP wheel, direct driven by incorporating Andy Mark SimCIM product on both drive axles. Control backspin by varying motor speed ratio (Chief Delphi). Gravity feed ball between wheels via ramp. Use water jet capability to fashion two end plates that will marry the shooter system.

Michigan District Results. Waterford -There is no measurement scale at school so we arrived and weighed in at 125 lbs (first time over weight due to all robot features) . FRC Waterford Captains Team instrumental in helping us lose 5 lbs in about 2 hours . Missed first match due software issues. Ball collector mechanism design still under development. Very successful in lowering bridge and gaining co-opertition points. Ended event at 8th alliance position. Never dreamed we would be in a position to select other teams . Consulted with Team 1 to arrive at pick list. Team alliance not strong – eliminated quickly from afternoon fun.
Michigan District Results. Troy – This is the toughest Michigan District Event. For some team’s it is their third or fourth event having gone outside of Michigan to compete in the Midwest events. Now our robot could shoot and score consistently (50%) in both hybrid and operator controlled. Robot is fully operational. It’s fun not to have to be building your robot but enjoying the venue. End up being ranked around 24 but not selected for the afternoon. Next year let’s skip Troy and go to Livonia where the competition is reported to be easier!

So, Ike, how did you have us ranked? Were we a Midpack robot or a MCC? BTW, thanks for starting the thread. It gave me a chance to rethink about what happened this season.

Some lessons learned:
1) Need to recruit some varsity athletes for the team (see Simbotics presentation)
2) Need more adult support.
3) Chief Delphi support from FRC teams is invaluable for Mid-pack competitive robotics team.
4) FRC teams are willing to share and help your team build a competitive robot!.
5) Familiarize yourself with the Andy Mark website! Order parts early if possible to beat the rush (FP-0673 motors).